Applications Guide for Propagation and Interference ...

Report No. FAA·RD·77·60

APPLICATIONS GUIDE PROPAGATION AND INTERFERENCE ANALYSIS

COMPUTER PROGRAMS (0.1 to 20 GHz)

M.E. Johnson and G.D. Gierhart

U.S. DEPARTMENT OF COMMERCE OFFICE OF TELECOMMUNICATIONS

INSTITUTE FOR TELECOMMUNICATION SCIENCES BOULDER, COLORADO 80303

March 1978

Document is available to the public through the National Technical Information Service,

Springfield, Virginia 22151

Prepared for

U.S. DEPARTMENT OF TRANSPORTATION FEDERAL AVIATION ADMINISTRATION

Systems Research & Development Service Washington, D.C. 20590

NOTICE

This document is disseminated under the spo1sorship of

the Department of Transportation in the interest of in

formation exchange. The United States Government assumes

no liability for its contents or use thereof.

1. Report No. 2. Government Accession No.

FAA-RD-77-60

4. Title ond Subtitle

Applications Guide for Propagation and Interference Analysis Computer Programs (0.1 to 20 GHz)

Technical Report Documentation Page

3. Recipient's Cotolog No.

: 5. Report Dole

March 1978 6. Perfor1ning Orgoni zafion Code

1--=----,...,,..-------------------------i 8. Perfor1ning Orgonizofion Report No. 7. Author's)

.M. E. Johnson and G. D. Gierhart 9. Performing Orgoni zofion Nome ond Address

U. S. Department of Commerce Office of Telecommunications Institute for Telecommunication Sciences

10. Work Unit No. (TRAIS)

Boulder, Colorado 80303 13. TypeoiReportondPeriodCovered ~~--~--------~-------------------4

12. Sponsoring Agency Nome ond Address

U. S. Department of Transportation Federal Aviation Administration Systems Research and Development Service Washington, D. C. 20591 .

14. Sponsoring Agency Code

ARD-60 15. Supplementary Notes

Performed for the Spectrum Management Staff, ATS Spectrum Engineering Branch.

16. Abatroct

This report covers ten computer programs useful in estimating the service coverage of radio systems operating in the frequency band from 0.1 to 20 GHz. These programs may be used to obtain a wide variety of computer-generated microfilm plots such as transmission loss versus path length and the desired-to-undesired signal ratio at a receiving location versus the distance separating the desired and undesired trans mitting facilities. Emphasis is placed on the types of outputs available and the input parameter requirements. The propagation model used with these programs is applicable to air/ground, air/air, ground/ satellite, and air/satellite paths. It can also be used for ground-toground paths that are line-of-sight or smooth earth. Detailed information on the propagation models and software involved is not provided. The normal use made of these programs involves a Department of Commerce (DOC) response to a Federal Aviation Administration (FAA) ARD-60 request for computer output and reimbursement to the DOC by the FAA for the associated costs.

17. KeyWords Air/air, air/ground, computer program, DME, earth/satellite, EMC, frequency sharing, ILS, interference, navigation aids, propagation model, TACAN, transmission loss. VOR.

18. Oi sfri bution Statement

Document is available to the public through the National Technical Information Service, Springfield, Virginia 22151

19. Security Clouif. (of this report) 20. Security Clossil. (of this poge) 21. No. of P oges 22. Price

Unclassified Unclassified 184

Form DOT F 1700.7 (8-72l Reproductio,.; of completed page authorized i

!

•'

ENGLISH/METRIC CONVERSION FACTORS

LENGTH

,~ Cm m Km in

-5 Cm 1 0,1 1x10 0.3937

ill 100 1 0,001 39.37

l<m 100,000 1000 1 39370

in 2.540 0.0254 -5

2.54x10 1

Itt 30.48 0.3048 3.05x1o" 12

~ mi 160,900 1609 1.609

n mi 185,200 1852 1.852

AREA

~ m

Cm2

,,? Km2

1n2

ft 2

s mt2

n mi 2

VOLUME

~ 1.'1 pm2

iter ~2

3 n

t3

d3

1 oz

1 pt

1 f{t a1

2 2 2 t,;m M K111.

-10 1 0.0001 1x10

10,000 1 b:106

1x1010 1x106 1

6.452 0.0006 -10

6.45x10

929.0 10 0.0929 9.29x108

2.59x1a 2,59x10 2.590

3.43x10° 3.43x18 3.432

3 3 3 Cm Liter m in

1 0.001 1x10° 0.0610

1000 1 0.001 61.02

lx106 1000 1 61,000

0.0163 -5 1 16.39 l.64x10

28,300 28.32 0.02113 1728

765,000 764.5 0.7646 46700 0.2957 -5

29.57 2,96x10 1.805

473.2 0.4732 0.0005 28.88

948.4 0.9463 0.0009 57.75 3785 3.785 0.0038 231.0

MASS

~ g Kg om

g 1 0,001

X& 1000 1

oz 28.35 0.0283

1b 453.6 0.4536

ton 907,000 907.2

TFJfPERATURE 0 1 - 5/9 (oc • 32)

0C • 9/5 (°F) + 32

63360

72930

2 in

0.1550

1550

1.55x109

1

144 9

4.01x10 9

5,31x10

3 ft

3.53x105

0.0353

35.31

0,0006

1

27

0.0010

0.0!67

0.0334 0.133 7

oz

0.0353

35.27

1

16

32,000

ii

ft a mi n mi

0.0328 6.21x106 5.39x106

3.281 0,0006 0.0005

3281 0.6214 0.5395

0,0833 -5

1.58x10 -5

l.37x10

1 l.89x1o" l.64xlo"

5280 1 0.86,88

6076 1,151 1

2 2 2 ft S m1 nmi

0.0011 3.86xlo11 5.llxl011

10.76 3.86x107 5.llx10 7

1.08x107 0.3861 0.2914

0.0069 2.49xl0~0 1.88x1010

1 3.59xl68 2. 7lx1011

2.79x16 1 o. 7548 7

3, 70x10 1.325 1 i

3 iyd fl oz fl pt f1 qt

-6 1.31xl0 0.0338 0.0021 0.0010

0.0013 33.81 2.113 1.057

1,308 33,800 2113 1057 -5

2.14x10 0.5541 0.0346 2113

0.0370 957.5 59.84 0.0173

1 25900 1616 807.9 -5

3.87xl0 1 0.0625 0.0312

0.0006 16 1 1),5000

0.0012 32 2 1 0.0050 128 8 4

lb ton

0,0022 1.10x1o0

2.205 O,OOll

0.0625 3.12xl05

1 0.0005 2000 1

aa1

0.0002

v.2642

264.2

0,0043

7.481

202.0

0.0078

0.1250

0.2500

1

FEDERAL AVIATION ADMINISTRATION SYSTEMS RESEARCH AND DEVELOPMENT SERVICE

SPECTRUM MA:-.JAGE~1ENT STAFF

Statement of Mission

The mission of the Spectrum Management Staff is to assist the De partment of State, Office of lecommunications Policy, and the Federal Communications Commission in assuring the FAA's and the nation's aviation interests with sufficient protected electromagnetic teleconununications resources throughout the world to provide for the s conduct of aeronautical flight by fostering effective and efficient use of a natural resource- the electromagnetic radio frequency spectrum.

This object is achieved through the following services:

Planning and defending the acquisition and retention of sufficient radio frequency spectrum to support the aeronautical interests of the nation, at home and abroad, and spectrum standardization for the world's aviation community.

Providing research, analysis, engineering, and evaluation in the development of spectrum related policy, planning, standards, criteria, measurement equipment, and measurement techniques.

Conducting electromagnetic compatibility analyses to determine intra/inter-system vjability and design parameters, to assure certification of adequate spectrum to support system operational use and projected growth patterns, to defend aeronaut al services spectrum from encroachment by others, and to provide for the e icient use of the aeronautical spectrum.

Developing automated equency selection computer programs/routines to provide frequency planning, frequency assignment, and spectrum analysis capabilities in the spectrum supporting the National Airspace System.

Providing spectrum management consultation, assistance, and guidance to all aviation interests, users, and providers of equipment and services, both national and international.

Ill

TABLE OF CONTENTS

Page Number

LIST OF FIGURES vi

LIST OF TABLES xi

1. INTRODUCTION . 1

2. PROPAGATION MODEL . . . . . . . 2

3. COMPUTER OUTPUTS . . . 5

3.1 GRAPHS 7

3.2 CAPABILITIES 49

3.3 APPLICATIONS . . . 64

4. INPUT PARAMETERS . . . . . . 71

4.1 GENERAL PARAMETERS . . . 72

4.2 SPECIAL PARAMETERS . . . 103

4.3 GRAPH FORMAT PARAMETERS . . 107

5. SUMMARY AND SUBMISSION INFORMATION . . . . 107

APPENDIX A. ADDITIONAL PROBLEM APPLICATIONS . . . 110

APPENDIX B. ABBREVIATIONS, ACRONYMS, and SYMBOLS 161

REFERENCES . . . . . . . . . . . . . . . . . . . 169

-.

v

Figure Number

LIST OF FIGURES

Caption

1-5 Parameter Sheet,

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

ATC

ILS

UHF Satellite

TACAN

VOR

Lobing, ATC . . Reflection coefficient, ATC

Path length difference, ATC

Time lag, ATC

Lobing frequency-D, ATC

Lobing frequency-H, ATC

Reflection point, ATC

Elevation angle, ATC .

Elevation angle difference, ATC

Spectral plot, ATC

Page Number

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

16 Power available, UHF Satellite for sea state 0 25

17-19

17

18

19

20

Power density,

ILS

TACAN

VOR .. Transmission loss, ATC

vi

26

27

28

29

Figure Number

21

22

23

24

25

26

27-29

27

28

29

30

31

32

33

34

35

36-37

36

37

38-39

38

39

40

LIST OF FIGURES (continued)

Power available curves, ATC

Power density curves, ATC

Transmission loss curves, ATC ..

Power available volume, VOR

Power density volume, VOR

Transmission loss volume, VOR

EIRP contours,

ILS

TACAN .

VOR .

Power available contours, TACAN

Power density contours, TACAN ..

Transmission loss contours, TACAN

Signal ratio-S, VOR

Signal ratio-DD, VOR

Orientation, ILS

Service volume,

TACAN .

VOR .

ratio contours,

ILS

VOR .

Geometry for reflection from spherical earth

vii

Page Number

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

50

Figure Number

41


Caption

Geometrical location of constant central angle contours . . . . . . . . . . . .

Page Number

55

42 Sketch illustrating interference configuration 60

43 Orientation geometry for protection points 62

44

45

46

47

48

49

50

51

52

53

Al

A2

A3-A8

A3

Antenna heights and surface elevations . . Normalized antenna gain vs. elevation angle

Normalized antenna gain vs. elevation angle, DME . . . . . . . . . . . . . . . .

Signal-level distributions for ionospheric scintillation index groups . . . . . .

Signal-level distributions currently used with variable scintillation group option

.

.

.

.

Rain zones of the Continental United States .

Rain zones of the world . . .

Surface refractivity for the Continental United States . . . . . ...

Surface refractivity of the world .

Contours of the terrain factor ~h in meters

Problem Al, geometry sketch .

Problems Al and A2, parameter sheet, ATC

Transmission loss, ATC,

vertical polarization, lobing option

81

86

87

92

93

95

96

97

98

102

111

112

113

A4 vertical polarization, variability option 114

AS horizontal polarization, lobing option 115

A6 horizontal polarization, variability option . 116

viii

-·

Figure Number

A7

AS

/\9


circular polarization, lobing option

circular polarization, variability option

Problem /\2, geometry sketch

Page Number

117

118

119

AlO-All Transmission loss, 1\TC, vertical polarization,

AlO rolling plains .

All mountains . . . . . .•

Al2 Problem A3, geometry sketch

Al3 Problem A3, parameter sheet, TACAN .

Al4-Al6 Power density, TACAN

Al4

AlS

Al6

Al7

Al8

main lobe at normal elevation

main lobe at 0° elevation

main lobe tracking aircraft

Problems A4 and AS, geometry sketch

Problems A4 and AS, parameter sheet, VHF satellite ..... .

Al9-A21 Power available, VHF satellite,

120

121

122

123

12S

126

127

128

129

scintillation index group 0, sea state 0 Al9 130

scintillation index group s ' sea state 0 A20 131

A21

A22

A23

variable scintillation index group, sea state 0 . . . . . . . . . . . . . .

Problem AS, parameter sheet, UHF satellite

Power available, VHF satellite, scintillation index group 0, sea state 6 .....

A24-A25 Power available, UHF satellite,

A24 scintillation index group 0, sea state 0 ..

ix

132

134

13S

136

Figure Number

A25

A26


Caption

scintillation index group 0, sea state 6

Problem A6, geometry

Page Number

137

138

A27 Problems A6 through A9, parameter sheets, ILS 139

A28 Geometry for S . m1n

A29-A43 Signal ratio-S, ILS,

A29

A30

A31

A32

A33

A34

A35

A36

A37

A38

A39

A40

A41

A42

A43

higher undesired facility elevation .

equal site elevations ..

lower undesired facility elevation

poor ground . .

average ground

good ground

sea water ..

fresh water .

smooth plains .

rolling plains

hills ..

mountains .

extremely rugged mountains

path parameters from topographic maps

path parameters from ECAC terrain file

X

141

142

143

144

146

147

148

149

150

152

153

154

155

156

159

160

LIST OF TABLES

Table Page Number Ca]2tion Number

1 Plotting Capability Guide . . . . . . . . 8

2-4 Parameter S]2ecification

2 General . . . . 73

3 Special 76

4 Graph Formats 78

5 Surface Types and Constants . 89

6 Estimates of oh for Sea States . 100

7 Estimates of ~h . . . . . 101

8 Climate Types and Characteristics 104

9 Time Block Ranges . . . . . . . 105

Al Additional Problem Applications . . . . 110

xi

xii

APPLICATIONS GUIDE FOR

PROPAGATION AND INTERFERENCE ANALYSIS COMPUTER PROGRAMS (0.1 to 20 GHz)

M. E. Johnson and G. D. Gierhart 1

Assignments for aeronautical radio in the radio frequency spectrum must be made so as to provide reliable services for an increasing air traffic density [30]2. Potential interference be

tween facilities operating on the same or on adjacent channels

must be considered in expanding present services to meet future demands. Service quality depends on many factors, including the

desired-to-undesired signal ratio at the receiver. This ratio varies with receiver location and time even when other parameters, such as antenna gain and radiated powers, are fixed.

The computer programs cover.ed in this report were developed

by the Department of Commerce (DOC) with the sponsorship of the Federal Aviation Administration (FAA). Although these programs

were intended for use in predicting the service coverage associ

ated with ground- or satellite-based VHF/UHF/SHF air navigation aids, they cari be used for other services in this frequency range.

The propagation model used with these programs is applicable to air/ground, air/air, ground/satellite, and air/satellite paths over smooth or irregular terrain. It can also be used for ground/

ground paths that are line-of-sight, smooth earth, or have a common horizon. These computer programs are useful in estimating

2

The authors are with the Institute for Telecommunication Sciences, Office qf Telecommunications, U. S. Department of Commerce, Boulder, Colorado 80303.

References are listed alphabetically by author at the end of the report so that reference numbers do not appear sequentially in the text~

1

the service coverage of radio systems operating in the frequency

band from about 0.1 to 20 GHz. They may be used to ohtain a wide

variety of computer-generated microfilm plots such as transmis

sion loss [43, 44] versus path length, and the desired-to

undesired signal ratio at a receiving location versus the dis

tance separating the desired and undesired transmitting facili

ties.

This type of information is very similar to that previously developed by DOC during the last decade [19, 20, 21, 22, 23, 24,

26, 27, 32, 38, 39, 49, 55]. The use of such information in spec

trum engineering has been discussed by Hawthorne and Daugherty

[28] and Frisbie et al. [18]; other information on spectrum engineering for air navigation, and communications systems is avail

able [13, 14, 15, 16, 29, 33].

The potential user should

1) read the brief description of the propagation model

provided in section 2 to see it the model could be

applicable to his problem,

2) select the program(s) whose output(s) is most appro

priate from the information provided in section 3,

3) determine values for the input parameters discussed

in section 4, and

4) utilize the information provided in section 5 to re

quest program runs.

Many examples of the graphical output produced by these pro

grams are provided in section 3.1, and additional examples are included in Appendix A (see list of figures). Most abbreviations, acronyms, and symbols used in this report are identified in Ap

pendix B.

2. PROPAGATION MODEL

The DOC has been active in radio wave propagation research and prediction for several decades, and has provided the FAA with

many propagation predictions relevant to the coverage of air

2

navigation and communications systems [20, 21, 22].

During 1960-1973, an air/ground propagation model applicable

to irregular terrain was developed by the Institute for Telecom

munication Sciences (ITS) for the FAA and was documented in de

tail [24]. This IF-73 (ITS FAA-1973) propagation model has e

volved into the If 77 model which is applicable to air/ground,

air/air, ground/satellite, and air/satellite paths. It can also

be used for ground/ground paths that are line-of-sight, smooth

earth, or have a common horizon. Model applications are restric

ted to telecommunication links operating at radio frequencies

from about 0.1 to 20 GHz with antenna heights greater than 1.5 ft

(0.5 m). In addition, the elevation of the radio horizon must be

less than the elevation of the higher antenna. The radio horizon

for the higher antenna is taken either as a common horizon with

the lower antenna or as a smooth earth horizon with the same ele

vation as the lower antenna effective reflecting plane [24, sec.

A.4.1.]. Ranges for other parameters associated with IF-77 will

be given later (table 2).

At 0.1 to 20 GHz, propagation of radio energy is affected by

the lower nonionized atmosphere (troposphere), specifically by

variations in the refractive index of the atmosphere [1, 2, 3, 4,

5, 6, 31, 35, 40, 47, 49, SO, 51, 52]. Atmospheric absorption

and attenuation or scattering due to rain become important at SHF

[24, sec. A.4.5.; 35, sec. 8; 49, ch. 3; 51; 54]. The terrain,

along and in the vicinity of the great-circle path between trans

mitter and receiver, also plays an important part. In this fre

quency range, time and space variations of received signal and

interference ratios lend themselves readily to statistical de

scription (39; 45; 49, sec. 10].

Conceptually, the model is very similar to the Langley-Rice

[37] propagation model for propagation over irregular terrain,

particuarly in that attenuation versus distance curves calculated

for the (a) line-of-sight [24, sec. A.4.2], (b) diffraction [24,

sec. A.4.3], and (c) scatter [24, sec. A.4.4] regions are blend

ed together to obtain values in transition regions. In addition,

3

the Langley-Rice relationships involving the terrain parameter 6h

are used to estimate radio horizon parameters when such informa

tion is not available from facility siting data [24, sec. A.4.1].

The model includes allowance for . '~~'-..

. ; 1

' a)'\\average ray bending [4, ch. 3; 6; 24, p. 44; 49,

sec. 4; 56],

b) horizon effects [24, sec. A.4.1],

c) long term fading [24, sec. A.5; 49, sec 10],

d) facility antenna patterns (figs. 45, 46),

e) surface reflection multipath [7; 8; 23, sec. 2.3;

24, sec. A.6; 27, sec. CI-D.7],

f) tropospheric multipath [2; 11, sec. 3.1; 24, sec.

A. 7; 31; 36, pp. 60, 119, B-2],

g) atmospheric absorption [21, sec. A.3; 24, sec. A.4.5;

49, sec. 3],

-...J h) ionospheric scintillations [23, sec. 2.5; 27, sec. CVII; 46; 58], and

i) rain attenuation [10, 51, 52, 54].

'· The model is an extended version of the IF-73 model previ

ously described in detail by Gierhart and Johnson [24, sec. A].

These extensions include provisions for

a) sea state (table 6),

b) a divergence factor [25, sec. 3.2],

c) a ray length factor for situations where the free

space loss associated with a surface reflected ray

may be significantly greater than that associated

with the direct ray [25, sec. 3.3], d) an antenna pattern at each terminal (sec. 4.1), e) circular polarization [25, sec. 3.5],

f) frequency and temperature variations of the complex dielectric constant of water [25, sec. 3.5],

g) long-term power fading as a function of radio cli

matic region (table 8) or time block (table 9), h) rain attenuation [25, sec. 4.4],

4

i) ionospheric scintillation ( g. 47),

j) an improved method for calculating the transmission

loss associated with tropospheric scatter [25, sec.

5 J ' k) ray elevation angle adjustment factors to allow for

ray tracing [25, sec. 10.2],

1) antenna tracking options (sec. 4.1), m) an improved estimate of the distance where horizon

effects can be neglected [25, sec. 7],

n) a free-space loss formulation that is applicable to

very high antennas [25, sec. 8], and o) a formulation for facility horizon determinations

that includes ray tracing [25, sec. 9.2]. Detailed documentation covering these extensions is provided in another report [25].

3. COMPUTER OUTPUTS The propagation model described in section 2 has been incor

porated into ten computer programs. These programs are written in FORTRAN for a digital computer (CDC 6600) at the Department of Commerce Laboratories, Boulder, Colorado. Since they utilize

the cathode-ray tube microfilm plotting capability at the Boulder

facility, substantial modification would have to be made for oper

ation at any other facility. Average running time for the pro

grams ranges from a few second, for each graph produced, to a minute or so. These programs are extensions of programs previ

ously developed and described [24; 27, sec. CII]. The extensions

involve a more comprehensive propagation model (sec. 2) and a

larger variety of computer generated microfilm outputs. A guide to the plotting capabilities of these programs is

provided in table3 1. Potential users should use it to select

the program(s) whose outputs are most appropriate for their problems. Figure numbers given in table 1 refer to graphs of section

3 Tables and figures for sections 3 and 3.1 are grouped together following the section 3.1 text.

5

3.1. Short discussions for each capability are given 1n section

3.2. Simple problem applications involving the graphs of section

3.1 are provided in section 3.3. Some additional graphs and prob

lems are given in Appendix A. Input parameters needed to operate

the various programs and plotting options such as a choice of

English or metric units (table 4) are discussed in section 4.

Each program causes the computer to produce (a) listings of

parameters associated with particular runs and (b) microfilm

plots. These outputs are provided for each parameter set used as

input to the computer and are tied to each other by a run code

consisting of the date and time at which calculations for a par

ticular parameter set started.

Parameter sheets for all programs have a similar format and

provide similar information. In programs associated with inter

renee analysis, a parameter sheet is produced for both the de

sired and undesired facility when the input parameters associated

with them are not identical [24, figs. 8, 9].

Computer produced parameter sheets do not have dual English/

metric units and are either English or metric depending on the

unit option selected (sec. 4.3). Sample parameter sheets similar,

except for dual units, to those produced by the programs are

shown in figures3 1 through 5. These parameters were used in de

veloping the curves provided in section 3.1 to illustrate the

plotting capabilities of the programs. Systems considered are

Air Tra c Control communications (ATC, fig. 1), Instrument

Landing System (ILS, fig. 2), UHF Satellite (fig. 3), Tactical

Air Navigation (TACAN, fig. 4), and VHF Omni directional Range

(VOR, fig, 5). Parameters are given in about the same order as

they are discussed in section 4.1. The effective area, AI, re

quired to convert power density, SR, to power available at the

output of an ideal (loss less) isotropic receiving antenna, PI,

is given at the bottom of the parameter sheets for power density

predictions (figs. 1, 2, 4, 5); i.e.,

6

3.1 GRAPHS

Figures 6 through 39 are sample graphs associated with the

various capabilities summarized in table 1. These graphs are

meant to illustrate general capability and care should be taken

in using them for particular problems where the parameters re

quired may differ from those used to develop the graphs. They

should be used, rather, as examples to help select the graph

types that are most appropriate for the particular applications.

Graphs produced by the computer are very similar to these, but

do not include all the labeling. In particular, the supplemen

tary scale is not computer generated and only provides an approx

imate correspondence with primary units. More accurate readings

can be obtained by using the primary scale, and then converting to

the desired units by using an appropriate conversion factor (p.ii).

This method was used to obtain dual values for readings given in

the text.

Options available (sec. 4.3) for units result in the plotting

of the primary grid and heading data in English (nautical or sta

tute) miles, or metric units. Except for figures 6 through 15

where the metric option was used, all figures in this section were

generated with the nautical mile option. An option to plot a

gainst central angle (fig. 41) instead of distance was used to

produce figure 16.

4 The notation used for the units of these quantities is intended to imply that they are decibel-type quantities obtained by taking 10 log of a quantity with the units indicated after dB-; e.g., A [dB-sq m] = 10 log {A 2 [sq m]/4n)} (where A [m] is wavelen~th). Equations used in this report are dimensionally consistent. Where difficulties with units could occur, brackets are used to indicate proper units.

7

Table 1. Plot!ing~ C~pabili ty Guide

Capability

Lobing**

Reflection coefficient**

rath length difference**

Time lag**

Lobing frcquency-D**

Lobing frequency-Hww

Reflection point**

Elevation angleR*

Flevation angle difference**

Spectral plotw*

Power available

!'ower density

Transmission loss

Power available curves

Power density curves

Transmission loss curves

Power available volume

Power density volume

Transmission loss volume

r:r RP contours

Power available contours

Power density contours

Transmission loss contours

Signal ratio-S

Figure(s)* Program

6 LOBING

7

8

9

10

11

12

13

14

lS

16

17-19

20

21

22

23

24

25

26

30

31

32

33

LOBING

LOBING

LOBING

LOBING

LOBING

LOBING

LOBING

LOBING

LOBING

ATOA

ATOA

ATOA

ATLAS

ATLAS

ATLAS

III POD

JIIPOD

HI POD

APODS

;\PODS

APODS

APODS

A TAll./

8

Remarks

Transmission loss versus path distance.

Effective specular reflection coefficient versus path distance.

Difference in reflected and direct ray lengths versus path distance.

Same as above with path length difference expressed as time delay.

Normalized distance lobing frequency versus path distance.

Normalized height lobing frequency versus path distance.

Distance to reflection point versus path distance,

Direct ray elevation angle versus path distance.

Angle by which the direct ray exceeds the reflected ray versus path distance.

~litude versus frequency response curves for various path distances.

Power available at receiving antenna versus path distance or central angle for time availabilities ·s, SO, and 9S percent.

Similar to above, but with power density ordinate.

Similar to above, but with transmission loss ordinate.

Power available curves versus distance are provided for several aircraft altitudes with a selected time availability, and a fixed lower antenna height.

Similar to above, but with power density as ordinate.

Similar to above, but with transmission loss as ordinate.

Fixed power available contours in the altitude versus distance plane for time availabilities of S, SO, and 9S percent.

Similar to above, but with fixed power density contours.

Similar to above, but with fixed transmission loss contours.

Contours for several EIRP levels needed to meet a particular power density requirement are shown in the altitude versus distance plane for a single time availability.

Similar to above, but with power available contours fOr a single EIRP.

Similar to above, but with power density contours.

Similar to above, but with transmission loss contours.

Desired-to-undesired, D/U, signal ratio versus station separation for a fixed desired facility-to-receiver distance, and time availabilities of S, SO, and 95 percent.

Capability

Signal ratio-DO

Orientation

Service volume

Signal ratio contours

_j~Jot t_irlg C<1:_pab il i ty Guide L<:_<.'_!l:!_-_1

Figure(s)* Program

34 OODD

35 TWIRL

36-37 SRVWM

38-39 DURATA

Similar to above, but abscissa is desired facility·to· receiver distance and the station separation is fixed.

Undesired station antenna orientation with respect to the desired to undesired station line versus required facility separation curves are plotted for several desired station antenna orientations. These curves show the maxinun separation required to obtain a specified D/U signal ratio value at several aircnft locations (i.e., protection points).

Fixed D/U contours are shown in the altitude venus distance plane for a fixed station separation and time availabilities of S, SO, and 95 percent.

Contours for several D/U values are shown in the altitude versus distance plane for a fixed station separation and time availability.

Additional discussion, by capability, is provided in the text. *~ Applicable only to the line·of·sight region for spherical earth geanetry. Variability with time and

horizon effects are neglected and the counterpoise option is not available. The phase change associated with surface reflection in the lobing region is taken as 0 or 180° to avoid missing lobe nulls.

9

PARAMETERS FOR ITS PROPAGATION ,MODEL IF-77 77/07/18. 17.33.01 RUN

POWER DENSITY FOR ATC

~~~~!~!~~!!9~-~9~!~~

AIRCRAFT (OR HIGHER) ANTENNA ALTITUDE: FACILITY (OR LOWER) ANTENNA HEIGHT: FREQUENCY: 125. MHZ

SPECIFICATION OPTIONAL

AIRCRAFT ANTENNA TYPE: ISOTROPIC POLARIZATION: HORIZONTAL

45000. FT (13716.M) ABOVE MSL 50.0 FT (15.2M) ABOVE FSS

EFFECTIVE REFLECTION SURFACE ELEVATION ABOVE MSL: 0. FT (O.M) EQUIVALENT ISOTROPICALLY RADIATED POWER: 14.0 DBW FACILITY ANTENNA TYPE: ISOTROPIC

POLARIZATION: HORIZONTAL HORIZON OBSTACLE DISTANCE: 8.69 N MI (16.09KM) FROM FACILITY*

ELEVATION ANGLE: -0/ 6/30 DEG/MIN/SEC ABOVE HORIZONTAL* HEIGHT: 0. FT (O.M) ABOVE MSL

REFRACTIVITY: EFFECTIVE EARTH RADIUS: 4586. N MI (8493.KM)* MINIMUM MONTHLY MEAN: 301. N-UNITS AT SEA LEVEL

SURFACE REFLECTION LOBING: CONTRIBUTES TO VARIABILITY SURFACE TYPE: AVERAGE GROUND TERRAIN ELEVATION AT SITE: 0. FT (O.M) ABOVE MSL TERRAIN PARAMETER: 0. FT (O.M) TIME AVAILABILITY: FOR INSTANTANEOUS LEVELS EXCEEDED

POWER DENSITY (DB-W/SQ M) VALUES MAY BE CONVERTED TO POWER AVAILABLE AT THE TERMINALS OF A PROPERLY POLARIZED ISOTROPIC ANTENNA (DBW) BY ADDING -3.4 DB-SQ M.

* COMPUTED VALUE

Notes: 1) Aircraft antenna information is not actually used in power density calculations.

2) Parameter values (or options) not indicated are taken as the assumed values (or options) provided on the general parameter specification sheet (table 2).

3) To simulate computer output, only upper case letters are used. Dual units are not provided on actual computer output.

Figure 1. Parameter sheet~ ATC (Air Traffic Control).

10

PARAMETERS FOR ITS PROPAGATION MODEL IF-77 77/07/19. 11.39.28. RUN

POWER DENSITY FOR ILS

~~~~!~!~~!!2~-~9~!~~ AIRCRAFT (OR HIGHER) ANTENNA ALTITUDE: FACILITY (OR LOWER) ANTENNA HEIGHT: FREQUENCY: 110. MHZ




EFFECTIVE REFLECTION SURFACE ELEVATION ABOVE MSL: 0. FT (O.M) EQUIVALENT ISOTROPICALLY RADIATED POWER: 24.0 DBW FACILITY ANTENNA TYPE: 8-LOOP ARRAY (COSINE VERTICAL PATTERN)

POLARIZATION: HORIZONTAL HORIZON OBSTACLE DISTANCE; 2.88 N MI (5.33KM) FROM FACILITY*

ELEVATION ANGLE: · -0/ 2/09 DEG/MIN/SEC ABOVE HORIZONTAL* HEIGHT: 0. FT ABOVE MSL




* COMPUTED VALUE


2) Parameter values (or options) not indicated are taken as the assumed values (or options) provided in the general parameter specification sheet (table 2).


Figure 2. Parameter sheet~ ILS (Instrument Landing System)

11

Notes:


POWER AVAILABLE FOR UHF SATELLITE SEA STATE 0

~~~~~~~~~!~2~-~9~!~~ AIRCRAFT (OR HIGHER) ANTENNA ALTITUDE: 19351. N MI (35838.KM) ABOVE MSL FACILITY (OR LOWER) ANTENNA HEIGHT: 30000.0 FT (9144.M) ABOVE FSS FREQUENCY: 1550. MHZ


AIRCRAFT ANTENNA TYPE: JTAC BEAMWIDTH, HALF-POWER: 10.00 DEGREES POLARIZATION: CIRCULAR TILT IS -90.0 DEGREES ABOVE HORIZONTAL

EFFECTIVE REFLECTION SURFACE ELEVATION ABOVE MSL: 0. FT (O.M) EIRP PLUS RECEIVING ANTENNA MAIN BEAM GAIN: 41.0 DBW FACILITY ANTENNA TYPE: JTAC

BEAMWIDTH, HALF-POWER: 20.00 DEGREES POLARIZATION: CIRCULAR ANTENNA IS TRACKING

HORIZON OBSTACLE DISTANCE: 208.85 N MI (385.79KM) FROM FACILITY* ELEVATION ANGLE: -2/49/36 DEG/MIN/SEC ABOVE HORIZONTAL* HEIGHT: 0. FT (O.M) ABOVE MSL

IONOSPHERIC SCINTILLATION INDEX GROUP: 0 REFRACTIVITY:

EFFECTIVE EARTH RADIUS: 4586. N MI (8493.KM)* MINIMUM MONTHLY MEAN: 301. N-UNITS AT SEA LEVEL

SURFACE REFLECTION LOBING: CONTRIBUTES TO VARIABILITY SURFACE TYPE: SEA WATER

STATE: 0 CALM (GLASSY)

0.00 FT (O.OOM) RMS WAVE HEIGHT TEMPERATURE: 10. DEG CELSIUS

3.6 PERCENT SALINITY TERRAIN ELEVATION AT SITE: 0. FT (O.M) ABOVE MSL TERRAIN PARAMETER: 0. FT (O.M) TIME AVAILABILITY: FOR INSTANTANEOUS LEVELS EXCEEDED

* COMPUTED VALUE

Parameter values (or options) not indicated are taken as the assumed values (or options) provided in the general parameter specification sheet (table 2) .


Figure 3. Parameter sheet~ UHF Satellite. 12


POWER DENSITY FOR TACAN SPECIFICATION

AIRCRAFT (OR ANTENNA ALTITUDE: 40000. FT (12192.M) ABOVE MSL FACILITY (OR LOWER) ANTENNA HEIGHT: 30.0 FT (9.14M) ABOVE FSS FREQUENCY: 1150. MHZ


AIRCRAFT ANTENNA TYPE: ISOTROPIC POLARIZATION: VERTICAL

EFFECTIVE REFLECTION SURFACE ELEVATION ABOVE ~$L: EQUIVALENT ISOTROPICALLY RADIATED POWER: 39.0 DBW FACILITY ANTENNA TYPE: TACAN (RTA-2)

POLARIZATION: VERTICAL

0. FT (O.M)

HORIZON OBSTACLE DISTANCE 6.73 N MI (12.46KM) FROM FACILITY* ELEVATION ANGLE: -0/ 5/ 2 DEG/MIN/SEC ABOVE HORIZONTAL* HEIGHT: 0. FT (O.M) ABOVE MSL


SURFACE REFLECTION ~OBING: CONTRIBUTES TO VARIABILITY SURFACE TYPE: AVERAGE GROUND TERRAIN ELEVATION AT SITE: 0. FT (O.M) ABOVE MSL TERRAIN PARAMETER: 0. FT TIME AVAILABILITY: FOR INSTANTANEOUS LEVELS EXCEEDED


* COMPUTED VALUE




Figu:tae 4. Pa1.1ameteP sheet~ TACAN (Tactical AiP Navigation}.

13


POWER DENSITY FOR VOR

~~~~~~~~~~~Q~-~Q~~~Q AIRCRAFT (OR HIGHER) ANTENNA ALTITUDE: FACILITY (OR LOWER) ANTENNA HEIGHT:

30000. (9144.M) ABOVE MSL 16.0 FT (4.88M) ABOVE FSS

FREQUENCY: 113. MHZ



EFFECTIVE REFLECTION SURFACE ELEVATION ABOVE MSL: EQUIVALENT ISOTROPICALLY RADIATED POWER: 22.2 DBW

0. FT (0. !-1)

FACILITY ANTENNA TYPE: 4-LOOP ARRAY (COSINE VERTICAL PATTERN) POLARIZATION: HORIZONTAL COUNTERPOISE DIAMETER: 52. FT (15.8M)

HEIGHT: 12. FT (3.66M) ABOVE SITE SURFACE SURFACE: METALLIC

HORIZON OBSTACLE DISTANCE: 4.91 N MI (9.09KM) FROM FACILITY* ELEVATION ANGLE: -0/ 3/41 DEG/MIN/SEC ABOVE HORIZONTAL* HEIGHT: 0. FT ABOVE MSL

REFRACT'IVITY: EFFECTIVE EARTH RADIUS: 4586. N MI (8493.KM)* MINIMUM MONTHLY MEAN: 301. N-UNITS AT SEA LEVEL

SURFACE REFLECTION LOBING: DETERMINES MEDIAN SURFACE TYPE: AVERAGE GROUND TERRAIN ELEVATION AT SITE: 0. FT (O.M) ABOVE MSL TERRAIN PARAMETER: 0. FT (O.M) TIME AVAILABILITY: FOR INSTANTANEOUS LEVELS EXCEEDED


* COMPUTED VALUE




Figure 5. Parameter sheet~ VOR (VHF Omni-Directional Range.)

14

~ .... V1

R~JII Ctdt 71/0711'. 17 . .tB. 57.

,-----rRANSMISSION LOSS ·-HI tS. • (SO.Oft)rnsl Smooth earth H2 t371&. • (45000. f.t)rnsl Polarization Horizontal rrtjjuUCy 12S. f1Hz

Distance in n rni

91) 0 40 60 80 120 110 140 160 180 220 220 240 ---· ------· I ' I I I -L---

90

m "U

I 0 0 c -.... 110 .... 0 -c 120 0 -.... .... no -li .... c::

I .CO 0 ._ 1-

~~ Lobe 4 --·~~ -

... Lobe 3 (\ •- . Lobe 2 . ··- ·-~oo,_

---~ ·-~ .. (. ·~ ····· ... ········ Lobe l In phase ··•·· ... ········ .. I I 1 lf 1 ---~

(low loss) I 0 I ........ .......... .

~ II I I I I • I I·!· I I t -.....

... ········ I-- --·-·. -. Free sp • • • • • ,,, 1'----

~ • I I

~ j ace loss ... • . '- ..

\ I "r-f-- •. -·--r-·-

·l·-. .\ . ..

ISO

1~0

t7

... 1--- .. -

· .. ·· -... .. Out of phase _.-· · · · ... ...... (high loss) J...-·

r-- -- ···--.. ... _tee ----············· ~~-

0 2S so 75 I 00 125 ISO l15 200 225 2SO 275 300 325 350 3'J5 400 425 450 H~ Oistal\ce il\ kll\

Figur>e 6. Lobing, ATC. Tr>ansm1:ssion loss for> the fir>st ten lobes inside the r>adi._; hor>izon, limi values associated ZJith in and out of phase conditions and fr>ee-space Z.oss vs. oath distance ar>e shOZJn. These cur>ves 1Jer'e computed for> the pcwconetePs of fiJUY'e 1.

0::: ... u ·---... 0 u

0: 0

r-a 0\ u ... --... ....

... > --u ... --w

R ... ~ Code 77107/ll. 17.,8. 37

REFLECTION COEFFICIENT HI 15. 111 (50. Oft)msl · Smooth earth H2 1371 G. 111 (45000. ft)msl Polarization Horizontal frequHcy 125. MHt

Distance in n mi

1. 210 40 60 80 1po 1(0 1~0 160 1~0 2QO 220 240 I

I 1.6

~ ~ ...

,/ v

'; .B

6

.4

.z

0' o, zs so 75 too 125 1so 175 200 225 25a 275 no 325 350 375 4oo 425 450 .ns

Oistal'\ce il'\ k"'

Figure 7. Reflection coefficient, ATC. Effective reflection coefficient vs. path distance is shOI.Jn for the parcuneters of figure 1.

A1111 'odt 71/07/IA. t1. 48. 31.

PATH LENGTH DIFFERENCE --HI 15. • (50.0ft)msl Smooth earth H2 1371G. • (45000. ft)msl Polarization Horizontal r •• ~ .. tllcy 125. HHt

Distance in n mi

35 ~0 40 60 80 100 120 140 1~0 180 200 220 240 • I • •

1- 110

1·-f- -

1\ r--

i-

100

90

30

25 t- 80

f-' e 20 ---.)

c. ·-~

15 0

~

\ 70 .jJ

4-4

60 c •rl

p:; 50

C!l ... .jJ

-.. 0 .. 1\ 1-

\ ··~ --

r-i

40 ~

30

"" 1'-

["-.... r--r- '" r--t--

20

10

5

L.._ __ -00 25 50 71) 10~ 125 ISO 11S 200 225 2St 275 500 325 351 315 AOO 425 tSO HS

Dis tone• i 1'\ k111

Figure B. Path 'length difference, ATC. Path length difference or the extent by uJhich the length of the reflected ray that of the direct ray vs. path distance is shown for para-meters of figure 1.

...... co

u ... .... .:0:

0:::

0'\ a

... 6 -t-

lh11 Cotle 71/07114. 17. 48. n TIME LAG HI 15. • (SO.Oft)msl Smooth earth H2 1371G. • (45000. ft)msl Polarization Horizontal Fre.,.ency 125. t114t

Distance in n mi

100

30

2p 40 6? 80 100 120 140 160 180 200 220 240 ' .

~~· ao

10

!;O

50

\

\ 41

30 1\ \

20 t- i\.

" I 0

~ 1"--.... ....._

t---I--0o 25 so 75 1 oo 125 J5o 175 2oo 225 250 275 300 325 3So ns •oo •2s •so ns

Distol\ct il\ k111

FiguPe 9. Time tag, ATC. Time lag of tPansmission via the suPface peflection path Pelative to the direct path vs. path distance is shown for the parameters of figuPe 1.

~ .. 11 Codt 11/071\4. 11. 48. 31.

NORMALIZED DISTANCE LOSING FREQUENCY I-ll 15. • (SO.Oft)msl Smooth Earth H2 1371&. • (45000.ft)msl Polarization Horizontal f r tllwtll cy 125. 11Hz

Distance in n mi

IL..

20 40 60 80 1po 120 140 lpO 180 200 2f0 ~40 I 1.0 .c 1.8 ......... e

""' I .~

(j) -......... - I .a .8 1. 6 .t!

' -.... X - N

1.4 :r: 8

......... .... :r: -

' .1 ' N :r:

1.2 ,;: ' .6 c

·.-l .......

~

\D

c: ·-.Q 0 -

;

4

.5

4

l.O tl' c ·.-l .a 0

0.8 r-1

<lJ u ..,

u c: 0 -.... ·-0

5 l\

1\ ?

\

c 0.6 m

.1-l (j)

·.-l Cl

0.4

I

" I'-r--. I 0

o. ·o 2s so 75 100 125 cso 175 200 225 250 21s 3oo 325 350 375 .eu 425 .eso .t1S

0.2

Oista~ce ift ka ·

10. ATC. vs. pa

N 0

R-.11 ~ode 71107114. 11. 48. H.

NORMALIZED HEIGHT LOSING FREQUENCY HI 15. • (50. Oft)ms1 Smooth·earth H2 1511G. • (45000. ft)ms1 Polarization Horizontal ~ •t~1.1fH!; 125. 11H%

Distance in n mi

. Ot 20 40 60 80 100 1~0 1~0 160 180 200 220 240

0 L -~ .018 -e.

....... s ~

c •.-t

. DS

F. ~

....... ......

~ . " "

.016 1':

' +J '~--<

. DS

-·~ I 1-....... .....

:r;: ~

~ ·-

" " 1\ D

\ )

\

.014 ' ..-N :r:

. 012 E-t

' N :r:

.010 c

.04

.04

03

en ~

·-A 0

D

1\ 5 \

•.-t

0"

.008 -~ ..a 0

r-l

03

. 02

-..If: 0

' . 01 4J

:X: .01

0

"' ) " ' ~ 0 b-.

.006 ~ o·

·.-t ())

. 004 :r:

. Ol

...__ --r--- 1-s .002 QO

0.00 00 2S 50 . 75 I 00 125 ISO 175 2ot 225 250 2 5 !00 325 350 H5 400 425 A 50 A75 Distance in k•

Figure 11. Lobing frequency-H, ATC. Normalized height lobing frequency, NHLF, vs. path distance is shown for the parameters of figure 1.

. .

t'<,)

f--1

'\.

e ~

.:: --.:: -0 Q..

c 0 -.. u

"' --"' .... 0 -"' u c a -"" ·-

0

Ru~ Code 17/07/14. 17. 48. H.

REFLECTION POINT DISTANCE HI 15. • (50. Oft)msl Smooth earth H2 IHIG. • (45000.ft)msl Polarization Horizontal f't1Uf11Cy 125. ttH:

Distance in n mi 20 40 60 80 100 120 140 160 180 200 220 240

I . 1/ I

2.0

I. 8

~,, I ~ '

I ' ' v l . "

I I. 2

I 1.0 / B .8 I

/

.b b v v v "

/ v

,....,.-' .,..-

i---~ i------_,..,..-.-

'\ -I- ..__ __

o. ·o 25 so 75 100 125 ISO 175 200 2Z5 250 215 nt 325 550 375 .tot .t25 .t5o .n5 Oistor.ce ir. k111

~

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

FiguPe 12. Reflection point, ATC. Distance fPom facility to tion point vs. ;Jath distance shown foP the paPametePs o.f figuPe 1.

.,

·r1 s s;::

s;:: ·r1

.jJ s;::

•r1 0 0.. s;:: 0

·r1 .jJ u Q)

.--l 4-1

<J)

k

0 .jJ

Q) u s;:: 11.1 .jJ (f)

·r1 0

N N

I lO

I 9 0"\ u

"0 8 l 0:: -

1 7 u -17'\ t: 0 ' c 0 5 5 ·-... 0 ::0. I. I. u -

L.a.J 1

I

I

RIJ~ Codt 17101111.. 17. 48. 37.

ELEVATION ANGLE HI 15. • (SO.Oft)rnsl Smooth earth H2 l37lG. • (45000. ft)rnsl Polarization Horizontal rrt4!Yfllq 125. 11Ht

Distance in n rni 20 40 60 80 100 120 140 160 180 200 220 240

. I

1\

1\ \ 1\

\ [\

\ ~

'\

1""-

""' ""' """ "' f'-..,. r---.. r---r-. r-- i--. 0 25 50 75 lDO 125 151 175 201 225 Z5Q 215 500 325 350 375 400 125 450 175

Oistaftce ift ka

Pigur>P 13. ElPVation angle, ATC. Elevation angle of the dir>ect my at the facility above the hor>izontal vs. path distance is shouJn for> the par>ameter>s of figur>e 1.

N VI

Rwt. Codt 17/011J4. 17. 48. 37.

ELEVATION ANGLE DIFFERENCE HI 15. • (SO.Oft)msl Smooth earth

0"\ ., "'C

H2 1371&. • (45000.ftlmsl Polarization Horizontal F'tt~uucy 125. ,.,..,

c Distance in n mi -., ~0 40 60 80 1po 120 140 l?O 180 200 220 240

I l 20 ::1"\ 0 ...

"'C ., -u ., --., ....

"'0 c 0

I 1\

\ \

--U I

r\ ' :I \ i l

1 B

1&

14

12

-u ., ... ·-"'0

I l\ I

\ I

I

""' I

'\

11

8

c: ., ., • -., "' .J ' ~ II

"' I ...Q

., -Ch c <

----.......

""" ~ ' t-.. r--r--r-- ~

I

0 25 SO 75 100 125 ISO 175 ZOO 22S 250 275 !OO !25 350 375 410 425 450 475 ·Oistal'lct il'l k"'

Figure 14. Elevation angle differenceJ ATC. The amount by which elevation angle of the direct ray at the facility exceeds that of the reflected ray vs. path distance is shmJn for the parameters of figure 1.

N +:..

T

SPECTRAL PLOT

8o11dw idth 100 kHz Lob• 1 t~ •

43 dB

Distance

1 v V 1kLobe 4 .. Frequency f-f f

f f f+fff

Figure 15. Spectral plot, ATC. Fading acrvss flat spectra with 100 kHz bandwidth for the lobing struc-ture in figure 6 and parameters of figure 1. ,.,..:.:- ........ ,_.... . ,-,~

"'~--~:

N t.n

=m "Q

·140

·ISO I

c: -lbO J

.... .n a ·17

a ::..

a ·18 ..... .... • 0

Q.. -19

-2 0

II

I

I

I

R~o~~ Collt 77/09/01. 17.43.34.

VHf SATELLITE SEA STATE C ... ·········· F' ttt SPOU F'rt~~o~tuy 1550. MHr EIRP' 41. 0 dBW ! ul''t rl s~ Hl 30000. ft{9l44.m} fss Saeotl\ tortl\ laictllltl so~ H2 1"51. ~ ai(35838.km)mslPtlaritotio~ Ci rc~o~lar !I o•trl 95~

·~--

--- ......

~ ~ ---·

"' ··- -

··-

' "

21 ·o 10 20 30 40 50 GO 70 80 90 Central angle in deg

Figure 16. Power available~ UHF satellite for sea state Power available values computed w~th par'a-meters from figure 3 for time availability of 5, 50~ and 95 per!:!ent. Cent·ml ang (fig. 41) is related to distance by (7) and (8).

N Q'\

F'1~; 1Ul'(' 1 ,, ( .

R~a Ctdt 77/07/t!. lt. S!.21 .

lLS LOCALIZER ............... Frtt .,.,, Frt4jYtllCY 110. rt+a ElltP z•.o 4&w c-.,.,, 51. HI 5.5 ft(l.6Bm)fss Sattt" urt" la144ltl 501. H2 •zso. ft (190S.·.n}ms1 Pel.,iutita Her i Ita ttl lltwtrl t$1.

Distance in km

20 40 6,0 a,o 1~0 120 140 160 180 I L ·SO

a r:r IIIII

....... Jill

,t\ ,~'\

-u

·70 1

m -a ......

······ ·80 -= ,-~ ........ ~ ..........

-:n -·- '

··~ ................. ...................... I . . ................ ~. .. .............

~ -~~ ..... ,. ...... ~

-!0

IIIII

-= • 'U

~

• • 0 Q...

·11

J

~ ~ t--..... ~ ~ r---. r--:----..

' """' -...

~ ~ I --

·lGD

·110

·120

·t• I

' . - -. -- --·IS .. AI ID 20 lO •• ,, 101 •• so ,. 70 Ohtoftce 1ft ft aJ

Power density, ILS. Parameters used in the aaZculations are summarized in figure 2. This 9raph pr>ed1:cts power density on the ILS ZocaHzer front course. In other dir>ecHons, the pre<Hetions shouZd be adJusted according to the ZocaUzer> 's hori-zontaZ antenna patter>n.

..

Rva Code 77/07/19. II. 39.31.

TACAN 39.D 4Bw

···········-·· r ru ,,.u F'rt1utacy 1150. tttz ElRP lupperl 51. HI 30. It (9.lm}fss Sauth urth lalddltl 501. H2 •oooo. It (12192. m} msl Ptltriutlta Vert iul ···- llntrl !51.

Distance in km 50 100 l~O 2~0 2~0 3QO 3~0 400 450 sqo 550 I .,0

ll

&r

"' ....... ::.

I (X)

"'0

c -N

:n ~~ -

"' c

~ 1 oo

I!\ ,---- ._ 1,_ ..... -II- -

~ ~ ...... -....... ~ r--... ----~ ~ ~-- ........... -~-) .....

~ --.........

"' ~ ~ -1\\ ~ \

-70

·80

·90

-110 • "'0

.... • a 0

a..

\ ~" 0 ""' ~\ "" 0 -

·12

·13

\~ 0 ~

\ w--- . ------

·I•

·15

"" 10 25 so 75 I 00 125 I I D I '5 200 225 ~D 2 s so ·I' 0

Olttol\ce '" " al

1 R. TACAN. Parametn•s used the ca are 4.

R~a Ctdt 77/07119. 11.39.3&.

VOR ··············· r,., .... ,. r,,~~uc, 11!. I'Jofr ElRP 22.2 d8W ~~ .... .,, 51. Hl 1,. ft (4. 9m) fss S..ttll tertii l•lddhl 501. H2 30000. ft (9144.m)msl Ptltrizetlta Htr i ua tel lhwtrl !51.

Distance in km 50 100 150 200 2?0 3po 3~0 400 450 500 55f

I ·&0

&

rr II'\

......... :a

I co "0

.: -N

:n ():) -·-II'\

.: ., "0

... ., a 0

a.. • 15

lA

f'\ I f• ~ .. ... ~ ........

....... ~

. ..... -~ .......... I

... -·····-··· -~·- .. ~ .... ~ ~

···-· ~·~··· .•..•.. ••••••n•-••

~ • ·-••••••~u••

)

~ -............

) t'-. ~

"' ~\ ' '\' ~'\ 'r\'\ --.....

I

\' r-- -I "'

·70

·80

·90

·l 0 0

• t t 0

·120

·l!O

·140

·I&

) ~ ..... _ ·17

·It )0 25 so 7S )00 t2S 11 D ITS 200 225 2' D 2~ lD 0 0 J I tOI\Ct II\ ft ai

19. PoweP density~ VOR. PaPametePs in the calculations aPP swnma1•izPd in j'iguPe 5.

N 0

R~a Code 77107115. 22. 15.49.

TRANSMISSION LOSS. ATC ............... f:'rtt IPOCI

r:'rt1~tllcy !25. 11Hz Goi11 C.O dBi ~~'''rl 57.

Hl 50. It (15.2m) fss Sauth torth --- !aiddltl 5D7. H2 45000. It (l3716.m)msl. Polorizotita · Horiztlltol ---!leur! 957.

Distance in km 100 200 300 1]()0 500 690 700 I 90

00 "U

,;: -M M 0 -,;: 0 -M

~ --

~ \' '

~ )r\ ............

._ r--0"

......._,..., "- r--- ~

............ - -0 ............ ~ ~ r::::·· ~ ... ··--·· ······ .. - ..... ...... ... r, "·"'= !:-~ ...... " ~ ~ " I

'\ ['\\ 0

1 0 0

II 0

120

130

140

ISO M -&

"' ,;: 0 .... .....

18

\\ \ 0 --1--·----\ l\

--"" 0 ~

\' I'- "" 0 ~ ~ ' ""- ~

:

1&0

110

19 r-- .___ r......._ i 20

21 I. 25 SC 75 100 125 150 175 200 225 250 275 500 525 350 375 4DD

Distance in n ml

Figure 20. Transmission loss, ATC. Transmissior1 loss valuPs computed 1Jith paramet;ers in figure 1 for t;hrJP avaaab1:Uty of 5, so) and 95 pereent.

:.. en -110 'U

c:: -120 -.., -

..0

VI 0 ~

0 ·-0 > 0

.... ·170 .., • -180 0 I H n..

·19

POWER AVAILABLE, ATC Fre~~~•~c~ 125. MHz H) 50. It (15.2m)fss EIRP 14.0 dBW

100 200 300

in

R1111 Coc!t 71/Dl/18. 17. 55. 29.

S•u 1 1'1 to rtl'l Polorizotioll Horizo11tol

Distance in km

400 500 600 700

Frtt SPOCt

951.

800 900

eet (meters)

(15, (13,716) (12,192 (10, 668

(9,144) (7L620 (6,096)

5,000 (4, 572) 0,000 (3,048

I I

Oistol\ce ;,., 1\ 111i

Figu~e 21. Powe~ available cu~es~ ATC. Powe~ available c~es we~p ~ompu with pa~amete~s r~om figu~e 1.

I'!

cr If\

......... Jill

I

en v

::T\ vi .... 1-'

If\ ,;:: 4,)

v

..... 4,)

• 0

0...

- II 0

-12C

P.~o~ft Codt 77107119. 17.H.OI.

PO~ER DENSITY. ATC F'rt~ut~cy 125. MHz HI 50. ft (15.2m)fss EIRP 14.0 dBW

S•ootll tort)l Polo•izotio~ Horizofttol

Distance in krn

(1, 524' ~

.. · · F'ru ''oct 951.

(15,240 -t--+~----1 (13, 716) .. (12,192) (10,668)

(9,144)

(7,620)--+-+

(914) ~~~~ (610)-f-- ...... ~

~~~ (457) ...... §

( 305 )-(152'

-230 I ~ I I I I I I _..J_..-J 0 ?1\ c:;n ,~ I At\ 1')C:: •Cf' f '1r: .,1'1;1'1 'l""l'r' "1r'A , ...... ':IrA A """ .... ,.. ........................... alP• ........ ..

n rni

Figur•p 22. Pm.Jer> rh:msity cuPVes, ATC. Power density curoes '"'erP eompute::d with para.me::ter•s [rom f'tgure 1.

~

en "0

c:

.....

..... 0

VI c: N 0 -.....

..... -I!. ..... c: 0 ~

......

TRANSMISSION LOSS, ATC Frt1wt~cy 125. MHz HI 50. It (15.2m)fss li•i~ 0.0 dBi

I 2 0

I 30

140

150

IGO

170

180

190

Wu in feet (meters) 21 0 2 5 '000

22~ 3,000 2,000

Ru~ Code 7710&127. 1&.43.0&.

Suotll urtll Polarizatio~ Horizo~tal

Distance in km

Fru IPICt

957.

(15,240 (13,716)

.....

0,000 (12,192) 35,000 (10,668

(9,144) (7,620) (6,096) (4' 572) (3,048)

250l I ,--I : ... _,,, I I I l I I I I I I I I I I I 0 ?C: c~ .,c .,., .. ,11\,. ................. --- --- --- --- --- _ _ _ _

ift f\ l'lli

FigurP 23. Transmission loss curves, ATC. Transmission loss cunJPB were computed with parameters from figure 1.

.,

~ ...... ...... 0

"' "U iC 0

"' ::J 0

.c:. ~

t.N iC V-l

... "U

::J ~ ·-... -0

~

...... 0 ~

u ~

-<

FigurA 24.

.<

R~,~11 Code 77/0.C/1 '· 12. 27. 0 1. Facilit' Pouer ovoi !obit

VOR POtii[R AVAILA8LE VOL~.~€ .............. ·Free apou EIRP 22.2 d8W F' """' .. (' 113. I"Hz I I I I I I I I 5.001. HI 16.0 ft(4.9m}fss P•lorizati•" Horizutal 50.001. Power ovolloblt -114. d8W S..•ttl earth ----- 95. 001.

Distance in km

100 50 100 150 200 250 300 350 400 450 500 550

' •

90

80

I v I I

I

/ I I

/

30

25 I / •' I I

I

70 I J ,•' El

~

&0

50

.co

30

20

10

/ v ... I II

I I • I

'/ ... •

/ .I

' , , llr

// ~I II , v ••

// II • I I

, v ,lr , I

~,~ ••• •

~ "' . •• •• I I ,, •

~ ~ ••••• - Ia t I I tl I

0 2S so 75 100 125 I 0 1'5 200 225 250 275 Olstal\ce if\ 1\ Mi

Pou.JPY' availablf': volume, V()R. Power availabl.P vol-ume for '1 sing for• .S, 50, and 9.') per•cent time ava·Z: l-ability ur;ing the parameters

20 -~ Q) ro ;:1 .j..l ·rl -- 15 .:: tO

.j..l lH llj l--1

10 u l--1 ·rl A:

5

30 0

{XJI"Wr avai tab f·igure 5.

VI .r.:.

Rua Cedt 71/0.C/19. 12.27.27. F'ocilit!f Power dtuity

V~ PO'IIER DENSITY VOLI,t( ............... r,., .,.u EIRP 22.2 d9W Frtf!u .. cy t t'5. !'tit t II It til 5, 001. Hl 16.0 ft{4.9m)fss Peloritetiea Htriuatol 50.001. Power deasity ·111.0 dB·W/sfl • S..eth terth ----- 95. 001.

Distance in km 50 100 150 200 2:0 300 350 400 450 500 55? I I • 1 00 ... - / v I

30 - 90 J 0

.,.. "U

I I I I

I I 80 25 ~ a .,.. :J 0

.c. ... ~ ·-.,

"U :J .... ·-... -a .... -a '-.., '-·--<

5

I IT ,~

J I • . •' / I I

I, v 1 .. I •' I ••• ,

I

'/ •• , •' ,

I , •• , ,r // •• ~· •'' I , v • I"

~'/ I I

I I

D I

,' v I lp

,/ • •• 0 •• I

~ I I •• , •• •••

0 ~' I I

~ ~ ... I tl •

- •• lo 25 so 75 IOC 125 ,. 0 t 'S 2DO 225 2!0 215 lO

70

GO

.. l

2

~ 20 .~

Q) '0 ::1 +l ......

15 ~ l1l

+l 4-l l1l

10 ~ ~ . .....

I<(

5

0 Olstaftct 1ft ft •i

Figu~e 25. Power density volume, VOR. Powe~ density volume fo~ a single power density value availability using the pa~amete~s in figure 5 . for 50, ar0 95 pe~cent

. .

VI tf1

100 --- '0 0

M '0 80 c:: a M :J 70 0

.c. - '0 c:: -41 so '0 :J -·- .co --a so --a ... 20 u ... -< 10

0 g

R~ Ct4t 77/0.C/1,, 12.27.5'5 Feel! It~ Tr•nlultl l•n

V~ TRANSI'IIS ICtJ LOSS VCX..IA'( ............... F'ttt •P•c• ,.,. 0.0 dBi F , ....... ~, 11'5. l'tiz I I I I I I I I 5, 007. H1 16.0 ft(4.9m)fss Pel•rlzetlll Htriaeat•l 50.007. Ttaa,.latlta less 1'S.c. d8 S..ttll ••rUt ----- 95. 007.

Distance in km 50 100 1~0 200 250 300 350 4~0 450 500 ssp

/ L .~' I v

I

J I I I

I ~·· / I I 1 ..

I II

II I

..1 ·-..,l_j_ lr II

I I

' II

,' v II ,,.. II _..· ·-v ... ~ •• ...

~' _.. ··-,'/ ·-•• •• II

,;/ II •• •• I I

I I

-:P:. I I•

~ I I

... ~ ,

• • . I I I

~ ~ .. I •••• .......,

25 so ~~ 100 125 11 0 1 '5 200 225 2!0 215 '!0( Otstat~ce It~ " •i

30

25

.Q c

20 ·ri

(!)

'0 :;j -I.! ·ri

15 .:: Ill

-I.! 4-l ~m

~ 1--1

10 ~

5

·ri ~

26. Transmission loss volu'!le, VOR. Transmission loss volume for a single transmission loss vaLue for 5, 50, and 95 percent time availability wn:ng the parameters in FZ:gure 5.

.... --0

"" -,;, ll:! 0

"" :::J 0

.c. (..;~ ..... 0\

ll:! -., -,;,

:::J .... ·-... -0

.... -0 t-u t-

·--c:

R~n Codt 17/01/15. 22.57. 55. Facility 95. 007.

llS ElRP CONTOURS ............... Po .. r dnsity -lf I. 0 dB-W/s~ • Frt~~<ncy I U. MHz ........ HI 5.5 ft(l.68m)fss Polarizotiu Horizontal

S•ooth tar th Distance in km

20 40 60 80 100 )r---

I I v I

I I

1 0

I I

1 I I

: I I : I

I • I l I . I I I •

I . I I

I I I I I

I I

I I I I I • I I

i . I I

: I 1/ I I I I I I

• I I . ..L ' i .I I

1/ I I • . I I I ; I I II

I I

; l' .. ··I . i I I

• I

! • ~

I II lw I I . I I • i I • I I • II

' I I • . \ ·. I'

I ~ ) ) .• • ) , . I I •'L

, I • ~

, I !' I .. . ·7 , .. . . , , , .

I ./ . ,

9

8

7

G

5

4

!

2

0. --I C 20 !0 40 Distance

50 &D in n mi

-----120 140 _, ~·

I

I I

--70 -. 80

ElRP ·54 n4 0 ·20 a11d ' ·10 nd I 0 ·& alld 20

160 180 __ L ___ __L ..

I"

r

i

'0 IOC

3.0

2.5

1;1 c:

2.0 ·..-!

(l)

'd :;1 .j.J ·.-I .j.J

1.5 .-I n1

.j.J 4-l

111 1-l u

l.O 1-l ·.-I ~

0.5

27. EIRP contouPsJ ILS. EIRP contouPs aPe shown in the a tude vs. distance plane foP a 95% time availability and the paPametePs of figuPe 2 .

..

(,A

'-1

.... ....... .......

0

..., "'0 c a ..., ::I 0

..c. .... c

II)

"'0 ::I .... ·-.... -a ....

....... a ..... u ..... ·-.-.::.

Ru11 Ctdt 77/04/08. 14. 35. 55. Foci 1 it¥ 95. 007. EIRP

TACAN ElRP CON OURS . ·············• 24 n4 l9 Po11tr dt11sity ·8b.0 d8·W/s1 • Fre1ut11cy 1 tSO. ttlz I I I I I I I I 23 ad .42 HI 30 ft{9.1rn)fss Po 1 or i u t i 011 Vertical '50 nd 45

S.ooth earth ------ 'SG nd 48 Distance in krn

50 100 150 200 2~0 300 350 400 450 500 550 • 100

2

I : • I I I I

~~· : I I

I

V/ ··-: I Lt

I II J I

I ~I i ·---I lw

/"' I i I I , • / I l • I t--

I I. ~ I ~ ! • i I

/ I

I

• I r•., I I .· •• I /L' •• .· • I I I .. I : I I I I I / J' . I ~

I i / .~'/ I • j • I I • I / ... . • I I • I .. _

....... ·~ ...... : l I I ... / " I I ./ ~··· /

I

' ; I

I ' ' ,

I

: r I I ,.l •• v,., : . I I fl ! '

I I I

I ' •'I ./ ~' . . I •

r I ,i

,

~ I ·' • ,. .. ""' • • J

, ~· •''../ ! J. ..A" ,

90

eo

70

': sc

40

30

-I v/. 1/ / ~ ..,. ...

~~ ... ,_ ........ ·~ 25 50 75 100 125 11 0 175 200 225 ~0 215 ]Q •

Dls\al\ct '" " 1111

a

30

25

12 c

20 ·rl <J)

'0 ::J +' ·.-I +'

15 ..-i ((j

+' ~ ((j H

10 ~

5

•.-I ,<:(

Figure 28. F:.TRP contour•s, TACAN. ETRP contours are shown ,·.n the altitude vs. distance plane for a 95% time avaUabili b; and the parameter>s of figure 4.

lN C:>

Ru~ Codt 77107/12. 20. !2.00. F" CIC i I i t !I 95. 0 07. E~RP VOR EIRP CONTOVRS ....... """ ~ Q nd 2: Power dusit!l • I I I. 0 dB- 'II s 'I " f:" rf'!llt~C!j ll'S. MHz t I t I I t I I 5 nd 25 HI IIi. 0 It (4.9rn)fss Polodutio~ Horizo11tol 10 llld !C

S•oo t h eo r t h ----- 15 CillO 55 Distance in kro

..... --0

.... -o ~

0 .... ::J 0

s;;. • A

~

u -o

::J ... -..... -0 .. -0 ... u ... ·-<

50 100 150 200 250 300 350 400 450 500 550 : I I .. ..... ' ' I ' I ' ' I ' ' . .

: : I I .... ,r

V~ .

1 .. ·· ' . .

' / . ' ' .• v I ..... . / ,' . I .

~ . I . . .... . ~ .

j I . ~

: . • I ··· ...

I J ,, .... . v ~

·-. J . . ./ I'··· .. . If ~ .

/ . ~ )·-- . . ~

I ~ ... v ·" ~ . , . J .· ~ . Dr--- . J ~·.' •' L 1~

•• L' ..... .. ' v~ " . I ~

' I • . .~' '

' . .· : .· v _; " !_...... '

~ ,..

• ' ~ ... . , ,. _ ...... •• . . . "'

. l'/ " ~ .............. ~

,' ' " ,..

•• / . ,' .. ··· ,• ~ ;---· • ~v ,/ L··· . ...- ,• • V, .. ... ' . ~ . ... .. ,, ... . ,

1---

~ v ,·" .. · ~

... ... ~

. • ... . ... ~ .

1 c c

90

80

70

GO

so

,, 3/1

" 111

30

25

~ 1: . ...

20 Q)

"0 ::l .j.J ·.-I .j.J

15 rl Ill

.j.J 4-1 Ill ~ 0

10 ~ .... ,.;(

5

0 25 50 75 100 125 150 175 200 ---225 --250 . 275 300

Oistol\ce il\ 1\ Nd

Figu~P 29. EI~P contou~sJ V0R. EIRP contou~s a~e shown in the altitude vs. distance pZanP for a .9,~'h t£me availability and the parameters of figure 5 .

..

..... --0

"' "0 .: 0

"' ;:J

0 .s::. -

u~ .: <..:l .,

"0 ;:J ... ·----0 --0 ... u ... ·-...:

FiguT>e 30.

R~~ Ctdt 77/07112. 20. 5A.A8. F'ocility ~5.007. Power Available in dBW

T~C~N POWER ~VAILABLE CONTOURS ............... ·100 nd ·Ill EIRP 5!. 0 d9W FPt1~t11Cy 1150. I"'H: . II..... ·I 0' 1111 d • liS HI 30.0 ft(9.lm)fss Ptlorizatiu Vertical -10& llld ·118

Sauth taPti\ ----- •JQ!) Olld ·121 Distance in km

50 100 150 200 2~0 ;300 350 400 450 spa 550 I .. I I . I ,' . I .

: • . . . I ' I . • ---

~ I ...... / I . I .

/ I . ) r----~ . I ---- .. I ,'r v I I . I . I . . I

/ • . I ~ . I .

-~ ~

1/ I // ~' .

I _: . ~ . . / . I . ~ 01--- .. - .

' .. - .'' v , :

J I . ~~ .

I . . I . . _f . I . lr---~ .· I I . '/ ~ . .

~;' ........ ' ~ • 't I " . 0---,___ --- : .

' ;

-... // r ....... . . ,•'/ ~,

i ' / . ' ' ~

Or- ; . I /

.... / ;I .... . .. v /_. .~·/ I

0 I

' , ... / •·.. v _,~ __ .... . •' .. u;, .,"

... ·:/-<· •• v : L ~ ...

.... · .. v .. ~:··~ ~ .... •• <II! .: . .t ..................

100

~0

80

70

GO

50

AO

50

20

30

25

12 >::

20 •.-l

Q)

'0 ::I .jJ •l"i

15 ~ <\1

.jJ 4-1

<\1 ~

10 ~ •ri ~

5

I -- -0 25 so 75 I 00 125 ISO 175 200 225 250 275 300 Oistar.ct ir. 1'\ Mi

PoueT> available contours, TACAN. PoueT> available contouT>s aT>e shoun in the altitude vs. distance plane for a 95% time availability and the paT>ameteT>s of figure 4.

'""" 0

.... --0

VI -g c: CJ VI ::;, 0

..c. -c:

"" -g ::;, .... -CJ --CJ L.

u ._

<C

Ru~ Cod• 77/QA/t!. tO. 10.2' Facility

TACAN POWER DENSITY CONTOURS EIRP 39.0 d8W Ftt~utftcy ltSO. HHz

Polarizotioft Vtrticol S•ooth torth

95.001. p, •• , OtAII\~ ............... -77 ..... ·8, ... 1 .... -eo ... ., ·!2

Hl 30 ft (9. 1m) fss ·83 ncl -ss ----- ·8G llllcl .,.

Distance in km 150 200 250 300 350 400 450 500 55~

1001 I I I ; ! I / /" v .r t-30 I I I I ' ' ' I 90 I I I I : • l ! • ) I I I

I I I I : : I I : ,.··; 1/ • I • • I I I I .

1 I / • I 25 eo · • •

50 100

1 I / 11 I ]

I I l I : r I / / .. r v v I 0

I : 1} I 701 I I : • : •

I I I I : I !/ ,' ./ II I / . 20 -~ I 1 1

GD'---' I I: .: o1

I ~ I I I 1.: • I / / .'' / ::l

5

I • I / I +J I I .•· II , ·rl

I I I : / / I / +l

so I I I ! : I I / I. v . I 15 ';ri : I I . • I ~ • . •• . +l

I l I : •' 1 ./ ,• ., Lj..j 40 I I I / •• v I ...... •''/" .,' ~ ! I I ... .• . / u ' I l I i •' I I / I I 1 0 -~

301 J 1 : _rr/ .. · 1• 1 <( I . I ~ •• I

i l/ ,.. 'I J 20 1 1 1 1 .~ ,· ./ ' 1

/ _, I I I l I I ·1 I I/ .~ ' ··· ~· )_ ,'

• •/ I •' I ' . / / ... ...,, I o 1 /

11 11 •• •••• • • /. ...,., 1 I l I I I I 'I /' .•'V , : ... ~~· I

··~···.:: ~~ k:.U............., 1 I I I I J

25 50 75. 100 125 · tSO 175 200 225 250 275 300 0 i s tal\ c e i 1\ 1\ rwd

co

Figu~e 31. Powe~ density conto~s, TACAN. Power density aontou~s a~e shown in the aLtitude vs. distance pLane for a 95% time avai lity and the parameters of fig~e 4 .

....

.p. 1-'

Ru11 Code 77/0'11'5. 10.17.:2.

r ac i 1 it~ 95.007. Trou•initfl !tu TACA.N TRA.NSMIS ON LOSS CONTOlJ'R ............... 125 Ofld lotS Goi11 0.0 d8i Fre~tuti\C!t ! 150. 11-iz I I I I I I I I 130 01\d ISO HI 30 ft(9.1m}fss Polarizotio11 Vtrti col 135 01\d 1&0

S.ooth torth ----- !.tO ol\d 170 Distance in km

100 --50 100 150 200 250 300 350 400 450 500 550 .

.' I I 30

- 90 0

11"1 ""0 eo

..::: Cl 11"1 :::J 70

/ : / L I I I I I

I

I I" v I I I

: I

I I I

25

s ..1(

0 ..c:. - bO

..:::

4U 50 ""0

:::J - 40 ---Cl

30 --Cl ..... 20 u ..... -~ 10

0

I .I I I

... 1 I I I

I --~ : .· ... ' I

I , I

I I • ... I I ... I

I [l"

/ ,' I l • ,

I I It Ia I I I ... II ... ...

I If : I v ... : •• 1

, • l , I • I : I , • .,'

f I i ,. "' .. l • " I •

/ .,. ...

·' ··· ... I .· I , .. ~r J / ,•' , .. v .. ~ ••

~ ., ...

! / ' ' •• ,. .. I I .•

! ' ~// .··•· .. ... v-·"' ~ -~,~ /... ,, ·~.J,<r~ . -

) 25 50 75 100 125 11 0 1 5 200 225 250 275 30

20 .s (]) "fj ::l .jJ •.-!

15 ;:: ((!

.jJ Il-l

t"O H

10 u H

•.-! ,:(

5

Distance in n Mi

FiguPe 32. TPansmission loss contouPsJ TACAN. TPansmission contouPs aPe shown in the altitude vs. distance plane fa~ a 95% t·Lme availabilityJ and the pa~ametePs of fig~e 4.

Du ired dis ta11ce 100. n mi (185. km) R~~ Code 17/0(/19. 12.22.(3. Otsirtd facility

VOR SI~ RATIO-S Vlldesired facility ............... Fru space

HI lG.C ft (4.9m)fss Soae as desired facility I~,.,. tr I 57. H2 30000. ft (9144 .m)msl l•iddlel 507. Fre41J~e11cy ::5. I'Ht llowerl ~7.

Station separation in km

) 100 290 300 400 500 600 700 50

I 40 )(/~ m "'0 lh r; ) 30 .: -0

·-+:.. -N

a '-

-a .::.

~ /I I

~ ~ y

I / / ~

........... ... ~ .....

~ •······· ·····-· ········ )

20

10

0 0'\ -..,

::> ........ 0

··;; iii' ,..· I ,. I ,..

/I ~ I

·1 0

·20

·3 0 v •

·.C 00 25 so 7S 100 t25 ISO t75 200 225 250 275 300 325 !! o r~ .cc a Station separation in n mi

Figure 33. Signal Patio-S~ VOR. DesiPed-to-undesiPed~ D/U, signat Patio vePsus station sepaPation cuPVes aPe shown foP a desiPed facitity-to-PeceiveP distance and time availabilities

5, 50~ and 95 Bot~ the desiPed and undesiPed stations have the paPametePs vf figuPe 5.

.j:::..

(.A

m "0

c: -0 ·-.... a ... -a c: lin -....

::;, ....... 0

Stotio11 uporotioll 250. n mi(463.km) Ru11 Codt 17/07/U. 00.31.01.

On i rtd foci I it~ Vlldtsirtd focilit~ 1 VOR SI,NAL RATIO·OO ............... f: Pit I !IOU

HI 1&.0 ft (4.9m}fss So•• os duirtd focilit~--- lu1111trl 51. 1 H2 30000. It (9144.mlmsl l•ldd!tl 501.

f:rt .. uiiiC~ 113. MHz n ... ,, !151. Desired distance in km

50 1qo l~Q 2(\0 250 300 3(0 400 450 I • __.___

- \ .\"' ~~ ~

(''' .......

"''\ ~ l ,,

'• ·•·· ..... "" ~ ···· .... ' ··•·· ........

~ .. .... ~ ........... ['....

"' ~ K"··· ... ··•·····

50

AO

30

20

I 0

0

·I 0

" ~ .... .

·· ...• ['.. ····, .. ·20

·3 '\ ~~

.. '• .. ..

!"'- '

·.& I -~"' ~"'\ I ·5.0 25 so 75 1 0 0 125 15 0 I 75

Desired distaftce ift ft Mi

I"'\ 1\ --200 - --225 250

Figu~e 34. Signal ~atio-DD. VOR. Desi~ed-to-undesi~ed. DIU. signal ~atio ve~sus desi~ed lity-to-reoeiver distance ou~ves a~e shown for a fixed station separation and time availabilities of so. and 95 percent. Both desired and undesi~ed faciUties have the parametel'S of figure 5.

..,. ..,.

D/U 23 dB for 95% R11ft Ctdt 71/01122. 13. 4\. 4.&.

Ouirtd lo,iJity Vnduirtd h(i)ity ............... 0 _d•l:l•t2 0. S-LOOP ARRAY Hl 5.5 It (l.68m)fss Soat as dtsirtd lo,ility ----- ~c. ud ISO. H2 4500. ft (1372.m)msl &0. Gild uo.

• ' • '. ' l • so . Facility separation in km

.., ., .,

.... 17'\ .,

"'0

.c -., -17'\

.c a ., .c ·--., .., .... :::J 0 y

"'0 ., .... -.... .,

"'0 .c :>

12

20 40 60 80 100 120 1<10 160 180 200 220 240 I _L I • I . .l I • i/ I ) 1.' ,, . . ;

I ~-

/I ,' .' . ~~-~ [,/ • I . . • --

/,' :·· • • I l ~-

. I

I " )- 1---- I I . ( F

~\ i ' I \ \

I I '· ..

'\ . ,. ·· .. . 1\ ' ...

) 'II ,· .. ~ · ..... .

I \ \·: . =

,, I \ ·. • I : ;; . . ,. .

0 I

/~ ,' / I

/i / • . 0 . .

V/ I. v / L· I .

I I I / I

i I ;

[\\ .. . \ ·.

I . \ ·.

. '\_I·. I 1\ '\ t··~ 'II I i\ ··· .... I • \ \\ ~\ ....

I

\ '· 0 I I ~: -- -. -. ..

3GO

330

300

270

240

210

l8C

150

!

b

3

0 I 0 20 ~0 50 40 GO 70 80 90 100 110 120 130 140 Facilityseporotion inn Mi

Figure 35. OPientation, ILS. Facility sepaPation needed to obtain a D/U of 23 dB foP a time availability of 95 pePcent is provided as a function of undesired (ordinate) and desired (line code) course line angles (fig. 43). PaPametePs for both the desired and undesired facilities are as given except that the aiPcraft altitude is 4500 ft (13?2 m) msl. See page 61 fop discussion of critical protection points.

.... --0

.., 'V c:: 0 M :I 0

.c. .... +>-V1

c:: ·-... 'V :I .... .... -0

.... -0 .... ..., .... ·-...::

Station separation 400.n mi(74l.km) R .. 11 Code 77/07113. oa . .c5.S5.

Ouhed foci I i ty Vlldtsired facility II d8 TACAN VOLUME , .............• F'ret ,tee EIRP "· 0 d8W 1150. MHz So•• as desired facility ----- 5.007. HI 30 ft(9.lm)fss 50.001. Polorizotiu Vertical t I I I I I I I 95.001.

Desired path distance in km

I 0 0 50 100 150 200 250 3?0 350 400 450 500 550 • . .. _,___....__j_

I~ I \ . \ . ' I

90 1\ • ' 1---- -~

eo

70

&0

50

•o

so

20

1 a

00 25

F1.:gur>e 36.

\ ' I

' I

' • . \

•• \ • • ' • . \ . \ \

I . \ . \ • . : \ ..

\ I ~. I : ·. • \ \ ---•• l\ \

• . II

I \

.. 1.~ ·-\ .i II

~ \ .. I •

··:1 I ., I . \ I ' v ' I' ' ; •• \ I I ..

\

~ .... . . •• 1 I i •

j i 50 15 I 0 Q f25 IS 0 175 200 225 250 275 soo

Desired poth disto~ce in n ad

Service volwne~ TACAN. Par>ameter>s pr>ovided in figur>e 5 ar>e applicable to both desir>ed and undesir>ed facilities.

30

25

20

~ s:::

•.-I

(!)

'd ;::l .j.J •.-I .j.J

15 ';ri .j.J 4-l l1j ~

10 ~

5

·.-I r<:C

... --0

... ~ c: 0 ... ::J 0

.c. ... -!>-0'1

c:

.. ~ ::J ... ·---0

--0 L.

u L.

·-oe:

Statio!\ separatiol\ 400. n mi(74l.km) Rllll Code 77/071!3. 08.48.25.

Oulrtd faciiit' Ulldttirtd facilit' 23 d8 VOR VOLUME ••a.•·········· F'ru tPICI EIRP 22.2 d8W 113. MHr Sa•• at desired facilit' ----- 5.001. HI 16.0 ft(4.9m)fss 50.001. Polariratln HtriUIItal I t I f I f I • 95. 001.


) 50 lQO liO 2QO 2~0 3QO 350 400 450 500 550

I \ \ • . \ I \ I I ··, \\ I I I

I I I

• \ 1\ I I

\ • I \ I

• \\\ . . I

• I . • '\ \'· •

1', • • . I • -..

'• \ \ I \ I

I I I I\ \ I

I·~~\ \

""

100

90

80

70

GO

so

.40

JO

30

25

~ t:

·.-!

20 Q)

't1 :;1 .;.J ·.-! .;.J .-l

15 <l1

.;.J 'l-1

<l1 1-4 u

10 1-4 ·.-!

2

...

\'\ I • •' ... .:c

I ·v k-"" / II \ I \ I

5

~ I ~~

. : •• I I 'ol. I tl

0 25 so 7S I 00 125 ISO 175 200 225 Desired 'ath dfstaftee ift ft •I

250 275 SOD

Figui'e 3?. Service volume, VOR. Pai'ametei's pPovided in figui'e 5 ai'e applicable to both desiPed and undesired facilities.

..

1 0 ! ----- I 9 0

"' -o 8 c:: a

"' ::I 7 0

..c. .j::. ..... '-1 b

c:: -.., 5 -o

::I ..... ·- 4 ..... --a

3 ..... --a '- 2 u '--

•:C

oc

Statio!'\ !Separatiol'\ 95. n mi(l76.km) Ruft Code 11/04/ll. 15. l2. IG. Desired facility Undesired facilit~ 95.001. 0:/U ill d9 9 ·LOOP ARRAY ··············· ·34 Olld 8 EIRP 24.0 dBW 110. MHz Sa.e as desired facilit~ ----- ·20 Olld 12 H1 5.5 ft(1.68m)fss _, 01\d 2J Polarization HorilOIItal

I I I I I I I I 0 01\d 23 Desired path distance in km 20 40 60 80 100 1~0 1~0 160 180 I

I I I I

I I I I

I I : I

I : ~ i • f • • I I I I I I

1--I I : : I I I I • • I : I

I • I

if i : I I I I I ,.. I • l • I ; I I I ~ ~ : j I I

I I I I I • I I I I

I I i : .. I I • I • : I I • • I

I ; : I • ~ I

I I • • ~ \ I I I 1-I

~\\ i i I .· • . . • .. · \ I J I .... · \ I

II~ \

! I I ... ~

\ ... I .. ""

. \ , ! I j I

I I :r I I 1/ I I :

II II , ~-' l i

.. 10 20 30 40 50 GO 70 80 90 100

Desired path distal'\ce il'\ "Mi

F1:gur>e ,7,8. Signal r>atio contour>s> ILS. Par>ameter>s used in the ca leu lati.ons ar>e swnmar>ized in figW'e 2.

3.0

2.5

s .:.:: 2. 0 s::

•.-I

Q.)

'0 ::I +J ·.-I

1.5!:: Ill

+J 4-l Ill

1.0 ~ u ~

·.-I ,:t;

0.5

---0

M "U c: a M :J 0

.c. ~ -co c: -..

"U :J -,_ .... -a .... -a .... u .... ·--<

Stat ion separation 400. n ml(74l.km) Ru11 Code 77/07115. 2Z.K5t.

Du i rtd foci I it 'J II OR EIRP 22.2 dBW 113. 11tiz Hl 16.0 ft(4.9m)fss Polorizotioll Horizo11tof

Vlldtsirtd facilit'J

Saae as du<rtd foci)it'J


100

' ' ' '

150 200 250

95.C01:

-----l f t 1 t I I I

OIV ;, cl9 5 ud 8 Ud

II ncl II •11c1

17 20 23 2'

f--'30

25

.Q 20 c

·..-I

(!) "0

B L_ ____ _j ______ ~------~------+------1r-----~~~~lr~~~t:~--~r------r15 ~ ttl

.jJ 4--1

10 ~ 0 ).I

•..-I

"' 1- 5

·1. l I I .. l .. J~·· I 00 20 40 GO 80 \00 120 140 1&0 180 20~

Otsirtd path distance inn ai

Pigur>e 39. Signal r>atio contour>s, VOR. Par>ameter>s used in the calculations ar>e summar>ized in figur>e 5.

. .

3.2 CAPABILITIES

A brief discussion of each capability summarized in table 1

is given in this section. Each discussion title contains the

capability name and indicates (in parentheses) the gure and a

sample problem that are associated with the capability. Applica

tion examples in the form of sample problems, with solutions, are

provided in section 3.3.

LOBING ( g. 6, p. 15; prob. 1, p. 64) Transmission loss is plot

ted against path distance for (a) lobing (solid curve) caused by

the phase difference in direct and reflected rays for the first

10 lobes inside the radio horizon, (b) limiting values associated

with in phase (low loss, upper curve with small dots) and out of

phase (high loss, lower curve with small dots) conditions, and

(c) free space (curve with large dots) [27, sec. CII-C.l]. As

indicated in a table 1 footnote, this graph and others generated

via program LOBING are applicable only to the line-of-sight re

gion for spherical earth geometry, and time variability and hori

zon effects are neglected. Figure 40 illustrates this geometry,

shows the two rays involved (r0

and r12

= r1

+ r2), and defines

variables that will be used in the discussion of plots produced r

with LOBING.

Antenna gains are included in transmission loss since it is

the difference (dB) between power radiated (dBW) , and the power

available (dBW) at the output of an ideal receiving antenna (no

internal losses), but in the sample run presented here, transmis

sion loss is the same as basic transmission loss because isotro

pic antennas were assumed. Spacing between the limiting curves

decreases as the reflection coefficient decreases. A test is

built into the program to prevent unrealistic null depths [8,

p. 393]. It limits the maximum transmission loss to its free

space value plus 40 dB.

REFLECTION COEFFICIENT (fig. 7, p. 16; prob. 2, p. 64) The ef

fective reflection coefficient is plotted against path distance

49

Horizontal terminal 1----~~

Antenna height for terminal 1 or 2 = H

1,2

Difference in ray elevation angles = ed

Direct ray elevation angle = e hi

Direct ray length= r 0

Effective earth radius= a a

Grazing angle = w Great-circle path length= d = d +d

1 2 Reflected ray length= r

12 = r

1 +.r

2

Figure 40. Geometry for ref!eetion from sph~ricaZ earth.

50

(d of fig. 40). Relative antenna gains, surface parameters (di

electric constant, conductivity and roughness), frequency, and grazing angle (w of fig. 40) are included in the calculation of

effective reflection coefficient [27, sees. CI-D, CII-C.2]. The

drop in reflection coefficient at short distances is associated with the ray length reduction factor [27, sec. CI-D.S]. The drop

in reflection coefficient at the far distances is caused by the divergence factor [27, sec. CI D.l].

PATH LENGTH DIFFERENCE (fig. 8, p. 17; prob. 3, p. 65) The ex

tent c~r) by which the length of the reflected ray (rl2 of fig. 40) exceeds that of the direct ray (r of fig. 40) is plotted

0 against path distance [27, sec. CII-C.3]; i.e.,

t:.r = r 12 - r . . 0

(2)

This equation is not actually used to calculate t:.r since it in

volves the difference of two, large, nearly equal terms. The formulatiori used [24, fig. 16] avoids this precision problem.

TIME LAG (fig. 9, p. 18; prob. 3, p. 65) The time lag of trans

mission via the surface reflection path relative to the direct path is plotted against path distance [27, sec. CII-C.4]. This

is the (free space) time (T) required for a radio wave to travel

the path length difference (t:.r) of figure 8; i.e.,

T [nsec] = 3. 34 [nsec/m] ~r[m]. (3)

LOBING FREQUENCY-D (fig. 10, p. 19; prob. 4, p. 66) Lobing frequency with distance (fd) for an aircraft traveling directly toward (or away from) the facility may be determined from values of

normalized distance lobing frequency (NDLF) read from this graph, radio frequency (f), and the magnitude of its velocity (Vd); i.e.,

fd[Hz] = NDLF[(Hz/THz)/kts]f[THz]Vd[kts], ( 4a)

fd[Hz] NDLF[(Hz/THz)/s mi/hr)]f[THz]Vd[s mi/hr], (4b)

or fd[Hz] NDLF[(Hz/THz)/(km/hr)]f[THz]Vd[km/hr]. (4c)

Note that f is in terahertz (THz) where one terahertz is 10 12 Hz

51

6 or 10 MHz, but that fd is in hertz.

Received signal level will vary with aircraft location as it

moves through the lobing structure (fig. 6) associated with the

phase difference between direct and surface reflected rays. The

frequency at which this variation occurs is called the lobing

frequency, lobe modulation frequency, or Doppler beat modulation

[11, sec. 4; 27, sees. CI-C.4, CII C.S]. Reed and Russell [47,

ch. 10] developed formulas using both lobe modulation and Doppler

beat modulation concepts to show that" ... no fundamental differ

ence exists between the lobe modulation and the Doppler-beat

modulation concepts. They differ only in the treatment of the

independent variable".

The lobing frequency (f~) encountered by an aircraft can be

estimated from fd and fh (see eqn. 6); i.e.,

f9_ 2. fd + fh. (5)

Here < is needed since it is possible for an aircraft to follow a

flight pattern such that the lobing with distance is compensated

for by lobing with height so that f2

~ 0 even though fd + fh > 0;

e.g., an aircraft flying the glide slope of a conventional ILS in

which the lobing structure is used to determine the desired

flight path.

LOBING FREQUENCY-H (fig. 11, p. 20; p~ob. 4, p. 66) Lobing fre

quency [27, sees. CI-C.4, CII-C.6] with height (fh) for an air

craft in vertical ascent (or descent) may be determined from

values of normalized lobing frequency (NHLF), radio frequency (f),

and the magnitude of the ascent rate (Vh); i.e.,

fh[Hz] = NHLF[(Hz/THz)/(ft/min)]f[THz]Vh[ft/min], (6a)

or

fh[Hz] = NHLF[(Hz/THz)/(m/min)]f[THz]Vh[m/min]. (6b)

Values of fh can be used in (5) to estimate lobing frequency.

52

:

REFLECTION POINT (fig. 12, p. 21; prob. 2, n. 64) Distance (dl

of g. 40) from the facility to reflection point is plotted a

gainst path distance [27, sees. CI C.2.3, CII C.7].

ELEVATION ANGLE (fig. 13, p. 22; prob. 2, p. 64) The elevation

angle (ehl of fig. 40) of the direct ray at the facility in de

grees above horizontal is plotted aga st path stance [27, sees.

CI-C.2.3, CII-C.8].

ELEVATION ANGLE DIFFERENCE (fig. 14, p. 23; prob. 2, p. 64) The

amount (ed of f . 40) by which the elevation angle of the direct

ray at the facility exceeds that of the reflected ray (elevation

angle difference) is plotted against path distance [27, sees. CI

C.2.3, CII-C.9].

SPECTRAL PLOT (fig. 15, p. 24; prob. 5, p. 66) Figure 15 shows

one spectrum corresponding to each path distance point calculated

for the lobing graph (fig. 6). Each spectrum is of bandwidth

2fff, where ff is a fraction of the carrier frequency f; i.e.,

bandwidth= (2)(0.0004)(125) = 0.1 MHz =100kHz. The scale

along the diagonal axis is proportional to the distance shown for

that point on the lobing graph, and the amplitude scale is linear

in decibels with a maximum range of 43 dB [27, sec. CII-C.lO].

POWER AVAILABLE (fig. 16, p. 25; prob. 6, p. 67) Power available

(see eqn. 1) at the output of an ideal antenna (no internal los

ses) is plotted against central angle for a particular satellite

(or higher antenna such as an aircraft) altitude. Available power expected to be exceeded for 5, 50, and 95 percent of the

time (i.e., 5, 50, and 95 percent time availabilities) is plotted

along with the available power that would be present under freespace propagation conditions. The term "EIRPG" used in the para

meter summary at top of the graph is an abbreviation for equiva

lent isotropically radiated power IRP) plus receiving antenna

main beam gain (see eqn. 12). Options exist to express the

abscissa (path length) in kilometers, statute miles, nautical miles, or degrees of central angle.

Central angle is the angle subtended by the great-circle

53

path (e0

of fig. 41 inset); it is useful when coverage estimates

for a geostationary satellite are desired since the central angle

corresponds to latitude along the subsatellite meridian, and lon

gitude along the equator from the subsatellite point. Loci of constant central angle are circles on earth projections normally

used to show earth coverage [23, 46]. Figure 41 illustrates such

loci for a geostationary satellite located at 100° W. Great-circle

path distance (d of fig. 41 inset) is related to central angle by

or

d [n mi]

d[s mi]

d[km] e [ deg]

0 8 [ deg]

0

= 60.0 [n mi/deg] 8 [deg], 0

= 69.l[s mi/deg]e0

[deg],

= 111.2[km/deg]e [deg], 0

0.0167(deg/n mi]d[n mi],

= 0.0145[deg/s mi]d(s mi],

(7a)

(7b)

(7c)

(Sa)

(8b)

80

[deg] = 0.00899[deg/km]d(km]. (8c)

POWER DENSITY (figs. 17-19, pp. 26-28; prob. 7, p. 67) Sample

"POWER DENSITY" graphs are provided for ILS (fig. 17), TACAN (fig. lS), and VOR (fig. 19). Power density (see eqn. 1) at the

receiving antenna location (aircraft in this case) is plotted a

gainst path distance for a particular aircraft (or higher antenna)

altitude. The curves show the power density expected to be ex

ceeded for 5, 50, and 95 percent of the time along with the power

density that would be present under free space propagation condi

tions. Options exist to express the abscissa in kilometers, statute miles, nautical miles, or degrees of central angle. Central

angle is useful when coverage estimates for a geostationary satel

lite are desired (see POWER AVAILABLE, fig. 16, discussion).

TRANSMISSION LOSS (fig. 20, p. 29; prob. 1, p. 64) Transmission loss (see LOBING, fig. 6, discussion) is plotted against path

distance for a particular aircraft altitude. The curves show

transmission loss values that are unexceeded for at least 5, 50, and 95 percent of the time along with the transmission loss that

would be present under free-space propagation conditions. The

54

:

, --- .. Central angle

f 4 ; so ··4o -- 3v 1 ~ ~

Earth radius= a 0

Ce n t r a I a n g J e = e 0

Great-circle path length=d

Figure 41. Geographic location of constant central angle contours The subsatellite point is at 100°W [23~ figs. B~ 9].

55

term "GAIN" used in the parameter summary at the top of the graph

is an abbreviation for the sum of the transmitting and receiving

antennas' main beam gains. Since GAIN = 0 in this case. trans

mission loss is really basic transmission loss. Options exist

to express the abscissa in kilometers, statute miles, nautical

miles, or degrees of central angle. Central angle is useful when

coverage estimates for a geostationary satellite are desired (see

POWER AVAILABLE, fig. 16, discussion). Values obtained from figure 20 may differ somewhat from those

obtained from figure 6 since the calculations for figure 20 in

eluded lobing as part of the time variability along with horizon

effects, while those for figure 6 did not.

The increase in variability for distances somewhat less than

150 n mi (278 km) occurs because of the specular surface reflection multipath contribution to variability that occurs somewhat

inside the horizon. Lower short-term variability near the hori

zon has been observed in propagation data [1].

POWER AVAILABLE CURVES (fig. 21, p. 30; prob. 8, p. 67) Curves

of power available (see eqn. 1) at the output of the receiving

antenna are plotted against distance for several aircraft alti

tudes, a single facility antenna height, and a time availability

of 95 percent. Options exist to exnress the abscissa in kilo

meters, statute miles, or nautical miles, and to use other time

availabilities.

POWER DENSITY CURVES (fig. 22, p. 31; prob. 9, p. 68) Curves of

power density (see eqn. 1) at the receiving antenna location

(aircraft in this case) are plotted against distance for several

aircraft altitudes, a single facility antenna height, and a time

availability of 95 percent. Options exist to express the ab

scissa in kilometers, statute miles, or nautical miles, and to

use other time availabilities.

TRANSMISSION LOSS CURVES (fig. 23, p. 32; prob. 1, p. 64) Curves

of transmission loss (see LOBING, fig. 6, discussion) are plotted

56

:

against distance for several aircraft altitudes, a single facility

antenna height, and a time availability of 95 percent. Options

exist to express the abscissa in kilometers, statute miles, or

nautical miles, and to use other time availabilities.

POWER AVAILABLE VOLUME (fig. 24, p. 33; prob. 10, p. 68) Contours

for a single available power (see eqn. 1) are plotted in the alti

tude versus distance plane for time availabilities of 5, SO, and

95 percent. When symmetry about the ordinate axis can be assumed

(e.g., omnidirectional antenna), the volume formed by rotating

a contour about the ordinate axis defines the air space in which

the time availability will almost always equal or exceed that

associated with the contour used to form it. This volume might

include some air space with inadequate time availability, since

it may not describe conditions directly above the desired facility

perfectly. Noise and interference levels are not considered in

this display. Options exist to express the abscissa in kilome

ters, statute miles, or nautical miles, and to express the ordi

nate in.feet or meters.

POWER DENSITY VOLUME (fig. 25, p. 34; prob. 11, p. 68) Contours

for a single power density value are plotted in the altitude

versus distance plane for time availabilities of 5, 50, and 95

percent. When symmetry about the ordinate axis can be assumed






it may not describe conditions directly above the desired facility

per ctly. Noise and interference levels are not considered in

this display. Options exist to express the abscissa in kilo

meters, statute miles or nautical miles, and to express the or

dinate in feet or meters.

TRANSMISSION LOSS VOLUME (fig. 26, p. 35; prob. 12, p. 69) Con

tours for a single transmission loss (see LOBING, fig. 6,

57

discussion) value are plotted in the altitude versus distance

plane for time availabilities of 5, 50, and 95 percent. When

symmetry about the ordinate axis can be assumed (e.g., omnidirec

tional antenna), the volume formed by rotating a contour about

the ordinate axis defines the air space in which the time avail

ability will almost always equal or exceed that associated with

the contour used to form it. This volume might include some air

space with inadequate time availability, since it may not de

scribe conditions directly above the desired facility perfectly.

Noise and interference levels are not considered in this display.

Options exist to express the abscissa in kilometers, statute

miles, or nautical miles, and the ordinate in feet or meters.

EIRP CONTOURS (figs. 27-29, pp. 36-38; prob. 13, p. 69) Sample

"EIRP CONTOURS" graphs are provided for ILS (fig. 27), TACAN

(fig. 28), and VOR (fig. 29). Several (up to eight) contours

of EIRP (see eqn. 11) levels needed to meet a single power den

sity requirement are plotted in the altitude versus distance

plane. The contours pass through points where the power density

requirement can be met by using the EIRP associated with the con

tour. A single time availability is applicable to all contours.


miles, or nautical miles, and the ordinate in feet or meters.

POWER AVAILABLE CONTOURS (fig. 30, p. 39; prob. 14, p. 69) Sev

eral (up to eight) contours of available power (dBW, see eqn. 1)

are plotted in the altitude versus distance plane. Identical

values (one each) of time availability and EIRP (see eqn. 11) are

used for all contours. Options exist to express the abscissa in

kilometers, statute miles, or nautical miles, and the ordinate

in feet or meters.

POWER DENSITY CONTOURS (fig. 31, p. 40; prob. 15, p. 70) Several

(up to eight) contours of power density (dB-W/sq m, see eqn. 1)

are plotted in the altitude versus distance plane. Identical

values (one each) of time availability and EIRP (see eqn. 11) are

58

used for all contours. Options exist to express the abscissa in

kilometers, statute miles, or nautical miles, and to express the

ordinate in feet or meters.

TRANSMISSION LOSS CONTOURS (fig. 32, p. 41; prob. 16, p. 70)

Several (up to eight) contours of transmission loss (see fig. 6

discussion) are plotted in the altitude versus distance plane for

a single time availability value. Options exist to express the

abscissa in kilometers, statute miles, or nautical miles, and the


SIGNAL RATIO-S ( g. 33, p. 42; prob. 17, p. 70) Desired-to

undesired (D/U [dB]) signal ratio available at the output of the

receiving antenna (aircraft in this case) is plotted against sta

tion separation. The curves show D/U ratios for time availabil

ities of 5, SO, and 95 percent along with the D/U values that

would be obtained under free space propagation conditions. Figure

42 shows the inter renee configuration. Aircraft-to-desired

facility great-circle distance (dD) and aircraft-to-undesired

great-circle facility distance (du) are used to determine station

separation (S) from

s

where dD and du do not have to be part of the great-circle con

necting the facilities. Aircraft location relative to the de

sired facility (altitude and dD) is xed for each graph. An

option exists to express the abscissa in kilometers, statute

miles, or nautical miles.

(9)

IGNAL RATIO-DD (fig. 34, p. 43; prob. 18, p. 70) The D/U [dB]

signal ratio available at the output of the receiving antenna

(aircraft in this case) is plotted against the desired facility

to aircra distance (DD or dD of fig. 42). The curves show D/U

ratios for time availabilities of 5, SO, and 95 percent along with D/U values that would be obtained under free-space propagation conditions. Aircraft altitude and station separation (see

SIG~AL RATIO-S, fig. 33, discussion) are fixed for each graph.

59

0 Vl

'"C VI It .....

U1 U1

60

An option exists to express the abscissa in kilometers, statute

miles, or nautical miles. ..

ORIENTATION (fig. 35, p. 44; prob. 19, p. 71) Curves showing the

relative azimuthal orientation of the undesired facility course

line C~u) with respect to the great circle-path connecting the

desired and undesired facilities are plotted versus the facility

separation required to achieve a specified D/U ratio or better at

each of five specified protection points. Each curve represents

a different relative azimuthal orientation of the desired facility

course line (¢D) with respect to the path connecting facilities.

Orientation geometry for the protection points is illustrated in

figure 43. These protection points are located relative to the

desired facility by a distance from the desired (D ) A,B,C,D,E facility and relative azimuth angle from the desired facility

course line (aA BCD E). In the calculations for figure 35, (a) ' ' ' ' the protection points were at

Distance Angle

DA = 10 n mi (18. 5 km) a A = 32 5°

DB 18 n mi (33.3 km) aB 350°

DC = 18 n mi (33.3 km) ac = oo DD = 18 n mi (33.3 km) aD = 10°

DE = 10 n mi (18. 5 km) aE = 35°

(b) ~D was varied in 30° increments from 0 to 180° (see line code

in upper right of fig. 35), (c) ~U was varied in 10° increments

from 0 to 360°, and (d) azimuth (horizontal) patterns for the

8-loop localizer were used for both facilities.

Protection point C on figure 43 is used to illustrate the

difference between facility separation (Sf) calculated via pro

gram TWIRL and station separation (S) used elsewhere (see SIGNAL

RATIQ-~, fig. 33, discussion). In particular, Sf~ S since S

need not be measured along the great-circle path connecting the

facilities. Note that (a) the du to point C changes as.~D changes, even if Sf remains fixed, and (b) the angle from the

61

Q'\ N

Desired facility

Facility connecting Undesired

ir==::::: ~ I I I s f .

All angles are positive clockwise.

du

\For Undesired facility

course line

aircraft at point C where d

0 =DC

Desired facility course line

Angles to course lines, *o,u• are measured from facility connecting line.

Angles to protection points, a E, are measured from the desired station course line. A,B,C,D,

Point C is along the course line so that aC = 0, but this is not a required condition.

Facility separation, Sf' is in general less than station separation, S, ~henS is calculated

from S = d0 + dU where d0 U are facility to aircraft distances. This is illustrated •

for protection point C.

Figure 43. Orientation geometry for protection points.

undesired facility to point C chan s with both ¢0 and ¢u even if

Sf remains fixed, so that the applicable gain for the undesired

facility varies in accordance with its horizontal pattern.

The geometrical consequences of these complications are

handled as part of the calculations performed by program TWIRL.

These calculations would be very tedious to perform by hand even

if appropriate signal ratio graphs (fig. 33) were available. A

graph similar to figure 35 is constructed for each protection

point and the maximum Sf for each combination of ¢0 and ¢u is

selected for the final graph. These intermediate graphs have a

format identical to figure 35 and are available as computer out-·

put even though no samples are provided here.


miles, or nautical miles.

§ERVICE VOLUME (figs. 36-37, p. 45-46; prob. 20, p, 71) Sample "SERVICE VOLUME" graphs are provided for TACAN (fig. 36) and

VOR (fig. 37). Fixed D/U contours are plotted in the altitude

versus distance plane for free space conditions and for time

availabilities of 5, SO, and 95 percent. A fixed station separa

tion (see SIGNAL RATIO-S, fig. 33, discussion) is used for each

graph. When symmetry about the ordinate axis can be assumed






it may not describe conditions directly above the desired facil

ity perfectly. Service limitations associated with noise level

are not considered in this display. Options exist to express the


ordinate in et or meters.

SIGNAL RATIO CONTOURS (figs. 38-39, pp. 47-48; prob. 21, p. 71)

Sample "SIGNAL RATIO CONTOURS" graphs are provided for ILS (fig.

38) and VOR (fig. 39). Several (up to eight) D/U signal ratio

63

contours are plotted in the altitude versus distance plane (cf.,

figs. 36, 37). Single values of time availability and station separation are used for each graph. Options exist to express the



3.3 APPLICATIONS Graphs like those provided in section 3.1 and discussed in

section 3.2 can be used to solve a wide variety of problems where

system reliability is dependent upon radio-wave propagation. The

application of each plotting capability is illustrated by a prob

lem and solution in the remainder of this section. These prob

lems are ordered by the capability applied in accordance with the

table 1 listing.

LOBING GRAPH (fig. 1, p. 10; fig. 6, p. lS; fig. 20, p. 29; fig.

23, p. 32).

Problem 1: Estimate the extent of smooth earth coverage for a

system with the parameters of figure 1 and an allowable transmis

sion loss of 13S dB.

Solution: Figure 6 indicates potential coverage gaps from

7S to 87 n mi (139 to 161 km) and no coverage beyond 232 n mi

(430 km). Figure 20 indicates coverage to 2S9, 233, and 220 n mi

(480, 432, and 407 km) for time availabilities of S, SO, and 9S

percent. Figure 20 has the effects of surface reflection multi

path included statistically in the signal level variability so

that nulls, while not ~hown, are accounted for in the time availability estimate. Figure 20 also provides a better estimate of

transmission loss near the horizon. Figure 23 could have been

used instead of figure 20 to obtain coverage for a 9S percent time availability.

REFLECTION COEFFICIENT (fig. 6, p. is; fig. 7, p. 16; fig. 12, p.

21; fig. 13, p. 22; fig. 14, p. 23). Problem 2: Determine the reflection coefficient, reflection

64

.-

point location, elevation angle, and elevation angle fference

associated with the null ide the horizon for the conditions of

problem 1. These parameters are useful in evaluating potential

methods of reducing the null depth by effective reflection coef

ficient reduction. For example, terrain near the reflecting point

could be altered to reduce surface reflectivity or an antenna pat

tern could be used that has low gain tow~rd the reflecting sur

face.

Solution: The required parameters are obtained from graphs

produced by program LOBING; i.e.,

and

distance to null (fig~ 6) is 79 n mi (147 km),

effective reflection coe cient (fig. 7) for 79 n mi

(147 km) is 0.96,

distance to reflection point (fig. 12) for 79 n mi

(147 km) is 0.15 n mi (0.28 km),

elevation angle (fig. 13) for 79 n mi (147 km) is 4.5°,

difference in direct and reflected ray elevation angle

(fig. 14) for 79 n mi (147 km) is 9°.

PATH LENGTH DIFFERENCE (fig. 8, p. 17; fig. 9, p. 18)

Problem 3: For the conditions of problem 1, find the maximum

time by which a pulse traveling the reflected ray route will lag

the pulse traveling the direct ray route. Pulse distortion asso

ciated with smooth earth multipath can be avoided if the pulse

duration is much lar r than the time lag.

Solution: The maximum path length difference (fig. 8) oc

curs at 0 n mi (0 km) and is 30.4 m. This path difference, ar,

is converted to time lag via (3); i.e.,

-r = 3.34 [nsec/m] t.r [m] = (3.34)(30.4) = 102 nsec.

Note that values for -r can be obtained directly from gure 9

where the time lag is given as slightly larger than 100 nsec.

TIME LAG This capability was used in the solution to problem 3.

LOBING -D (fig. 1, p. 10; fig. 10, p. 19; g. 11, p. 20).

Problem 4: For the conditions of problem 1, determine the lobing

65

frequency via (5) for an aircraft at 4.8 n mi (8.9 km) with a radial velocity of 250 kts (463 km/hr) and an ascent rate of 10 3

ft/min (305 m/min). Solution: First, required parameters are obtained from

put of program LOBING; i . e. ,

and

Then,

f (fig. 1) is 125 MHz = 1. 25 X 10- 4 THz,

NDLF (fig. 10) is 1. 52 (Hz/THz)/kts or 0.819 (Hz/THz)/ (km/hr) at 4.8 n mi (8.9 km),

NHLF (fig. 11) is 10-2 (Hz/THz)/(ft/min) or 0.035

(Hz/THz)/(m/min) at 4.8 n mi (8.9 km).

fd[Hz] = NDLF[(Hz/THz)/kts]f[THz]Vd[kts] from (4a), fd = (1.52)(1.25xlo-4)(250) = 4.75xlo-2Hz,

out-

fh[Hz] = NHLF[(Hz/THz)/(ft/min)]f[THz]Vh[ft/min] from (6a), fh (lo- 2) (1.25xlQ-4) (103) = 0.125xlo- 2 Hz,

f1

< fd + fh from (5), and

f1

< (4.75 + 0.125)10- 2 Hz = 4.9 x lo-z Hz.

Therefore the maximum value of f1

at 4.8 n mi (&.9 km) is 4.9 x lo- 2 Hz.

L~~ING FREQUENCY-H This capability was used in the solution to problem 4.

REFLECTION POINT problem 2.

This capability was used in the solution to

ELEVATION ANGLE

problem 2. This capability was used in the solution to

ELEVATION ANGLE DIFFERENCE

tion to problem 2. This capability was used in the solu-

SPECTRAL PLOT (fig. 6, p. 15; fig. 15,,p. 24).

Problem 5: For the conditions of problem 1, would spectra associated with lobing within + 50 kHz of 125 MHz be flat for distances

66

from 27 n mi (50 m) to the radio horizon? Frequency selective

fading (i.e., when all frequencies within a receiver bandpass do•

not fade together) can distort a modulated signal so that intel

ligibility is lowered. It does not occur when spectra are flat.

Solution: Figure 6 indicates that the top of the lobe 4 oc

curs at a distance somewhat less than 27 n mi (50 km). Therefore,

the spectra shown in figure 15 are applicable to this problem,

and these spectra are flat, so the answer is yes.

POWER AVAILABLE, UHF SATELLI (fig. 3, p. 12; fig. 16, p. 25).

Problem 6: Determine how far north coverage from a geostationary

UHF satellite extends when the parameters of figure 3 are appli

cable, and a time availability of 95 percent and a power available

of -160 dBW are required.

Solution: Figure 16 is applicable to this problem, and it

indicates that coverage out to an angular distance of 80° can be

obtained for the required time availability. Therefore, coverage

to 80°N is possible along the subsatellite meridian. The great

circle distance for this arc can be obtained using (7c); i.e.,

d[km] = 111.2 [km/deg]e0

[deg],

(111.2)(80) ~ 8,900 km (4,800 n mi).

POWER DENSITY (fig. 5, p. 14; fig. 19, p. 28)

Problem 7: For the VOR parameters of figure 5, determine the in

terference range of a VOR at 30,000 ft (9,144 m) when a time a

vailability of 5 percent and a power density of -134 dB-W/sq m

or more are used to define the interference range.


indicates an interference range of 236 n mi (437 km).

TRANSMISSION LOSS

problem 1.

This capability was used in the solution to

POWER AVAILABLE CURVES (fig. 1, p. 10; fig. 21, p. 30)

Problem 8: For the ATC parameters of figure 1 where the aircraft

is at 45,000 ft (13,716 m), determine the service range when a

67

time availability of 95 percent and a power available of -130 dBW

are used to define service range. Solution: Figure 21 is applicable to this problem, and it

indicates a service range of 239 n mi (443 km).

POWER DENSITY CURVES (fig. 1, p. 10; fig. 21, p. 30; fig. 22, p.

31). Problem 9: Solve problem 8 using the power density graph of

figure 22. Solution: First, convert the power available requirements

of problem 8 to power density using (1) and the conversion factor

provided in figure 1; i.e.,

and

P1 (dBW] = SR[dB-W/sq m] + AI[dB sq m],

SR = PI - AI = PI - (-3.4),

SR = -130-(-3.4) = -126.6 dB-W/sq m.

Then, using this power density, read the 95 percent time avail

ability curve of figure 22. This gives 241 n mi (446 km), which

is less than 1 percent larger than the answer obtained previously for problem 8 using figure 21.

TRANSMISSION LOSS CURVES

tion to problem 1. This capability was used in the solu-

POWER AVAILABLE VOLUME (fig. 24, p. 33) Problem 10: For the VOR parameters of figure 5, a time availa

bility of 95 percent, and an available newer of -114 dBW, deter

mine the minimum altitude at which the service range extends to 150 n mi (278 km).


indicates a minimum altitude of 30,000 ft (9,144 m) for the 150

n mi (278 km) service range.

POWER DENSITY VOLUME (fig. 5, p. 14; fig. 25, p. 34)

Problem 11: For the VOR parameters of figure 5, a time availabil

ity of 95 percent, a power density of -111 dB-W/sq m, and

68

altitudes up to 100,000 ft (30,480 m), determine aircra

for which service is not available at 150 n mi (278 km).

altitudes


indicates that service is not available at 150 n mi (278 km) for

altitudes below 31,000 (9,449 m).

TRANSMISSION LOSS VOLU!v1E (fig. 5, p. 14; fig. 26, p. 35)

Problem 12: For the VOR parameters of figure 5, a time availa

bility of 50 percent, and altitudes up to 100,000 ft (30,480 m),

determine the altitudes for which a basic transmission loss of

134 dB is exceeded at a distance of 175 n mi (324 km).

Solution: Figure 26 is applicable, and it indicates that

the 134 dB transmission loss level is exceeded 50 percent of the

time at a distance of 175 n mi (324 km) for altitudes below

40,000 ft (12,192 m).

EIRP CONTOURS (fig. 4, p. 13; fig. 28, p. 37)

Problem 13: For the TACAN parameters of figure 4, determine the

minimum EIRP of transmitted pulses necessary to maintain a pulse

power density greater than -86 dB-W/sq m for 95 percent of the

time at an altitude of 30,000 ft (9,144 m) and a distance of

125 n mi (232 km).


indicates that an EIRP of 42 dBW would be sufficient.

POWER AVAILABLE (fig. 4, p. 13; fig. 30, p. 39)

Problem 14: For the TACAN parameters of figure 4, a service range

defined by a time availability of 95 percent, and a power density

of -86 dB-W.sq m, determine the service range available at 30,000

ft (9,144 m) by using figure 30.

Solution: First convert the power density requirement to

power available using (1) and the conversion factor provided in

figure 4 ; i . e . ,

and

PI[dBW] = Sa[dB-W/sq m] + AI[dB-sq m],

PI = -86+( 22.7) = -108.7 dBW.

Then, using this power available, read the 95 percent time

69

availability curve of figure 30. This gives 111 n mi (206 km).

POWER DENSITY CONTOURS (fig. 4, p. 13; fig. 30, p. 39; fig. 31,

p. 40).

Problem 15: Solve problem 14 using figure 31.

Solution: Figure 31 indicates that the service range at

30,000 ft (9,144 m) is 111 n mi (206 km), which is the same an

swer obtained previously for problem 14 usine figure 30.

TRANSMISSION LOSS CONTOURS (fig. 4, p. 13; fig. 32, p. 41)

Problem 16: For the TACAN parameters of figure 4 and a time a

vailability of 95 percent, determine the minimum altitude for

which a basic transmission loss of 150 dB is not exceeded at a

distance of 100 n mi (185 km).

Solution: Figure 32 is applicable since it was developed

with antenna gains set to zero so that basic transmission loss

is obtained. It indicates that 150 dB of basic transmission loss

is not exceeded for 95 percent of the time at 100 n mi (185 km)

for altitudes above 18,000 ft (5,486 m).

SIGNAL RATIO-S (fig. 5, p. 14; fig. 33, p. 42; fig. 42, P• 60) Problem 17: For the VOR parameters of figure 5, a time availa

bility of 95 percent, and a desired facility to aircraft distance,

dD' of 100 n mi (185 km), determine the station separation (fig. 42) necessary to obtain a desired-to-undesired signal ratio, D/U,

of 23 dB at an altitude of 30,000 ft (9,144 m).

Solution: Figure 33 is applicable to this problem, and it indicates that a station separation of 320 n mi (593 km) is ade

quate to obtain D/U (95%) = 23 dB with dD = 100 n mi (185 km).

However, this signal ratio is not available beyond 100 n mi

(185 km) for altitudes less than 30,000 ft (9,144 m).

SIGNAL RATIO-DD (fig. 5, p. 14; fig. 34, p. 43)


bility of 95 percent, and a D/U of 23 dB or more, determine the maximum dD available for a station separation of 250 n mi (463

km).

70

Solution: Figure 34 is applicable to this problem and it

indicates that a maximum dD of 59 n mi (109 km) is available.

!ENTATION ( g. 2, p. 11; fig. 35, p. 44; fig. 43, p. 62)

Problem 19: For the ILS localizer parameters of figure 2, but

with altitude of 4500 ft (1,372 m), the protection point loca

tions associated with figure 43 (see ORIENTATION, fig. 35, dis

cussion in sec. 3.2), a time availability of 95 nercent, and a

D/U of 23 dB determine the facility separation required when the

undesired course line angle (¢u in fig. 43) is 150° and the de

sired course line angle (¢D of fig. 43) is 60°.


indicates that a facility separation of 88 n mi (163 km) is suf

cient.

SERVICE VOLUME (fig. 5, p. 14; fig. 37, p. 46)


bility of 95 percent, and a station separation of 400 n mi (741

km), determine the maximum dD for which D/U = 23 dB is available

at an altitude of 40,000 ft (12,192 m).


indicates that a dD of 144 n mi (267 km) is available at 40,000

ft ( 12, 19 2 m) .

SIGNAL RATIO CONTOURS (fig. 2, p. 11; fig. 38, p. 47)

Problem 21: For the ILS localizer parameters of figure 2, a time

availability of 95 percent, and a station separation of 95 n mi

(176 km), determine the maximum dD available at 1,000 ft (305m)

for which D/U ~ 23 dB.


indicates that a dD of 30 n mi (56 km) is available at 1,000 ft

(305 m) .

4. INPUT PARM1ITERS

Parameters that may be specified as input to the programs

are summarized in tables 2, 3, and 4. Blank spaces are provided

71

in these tables so that copies of them can be used to specify in

put requirements for program runs. These tables cover input para

meters for 10 programs which have 28 plotting capabilities (table 1) so that only information for a small f~action of the parameters

listed need be provided for any one capability.

Table 2 covers general parameters that are usually a~plicable to many programs, and multiple entries or two copies of this table

may be used if the desired and undesired facilities have different

parameter values. Note that, although about 40 items can he spe

cified, specification of only 3 is required. These "primary pa

rameters" consist of antenna heights and frequency. Values for

"secondary parameters" will be computed or assumed if not speci

fied. A more detailed discussion of table 2 is provided in sec

tion 4.1.

Table 3 covers special parameters required for particular

capabilities. Some of these parameters are required by more than

one capability, and 13 (i.e., first 13 of table 1) of the capa

bilities do not require parameters from table 3. Additional dis

cussion of table 3 is provided in section 4.2.

Table 4 covers parameters associated with graph formats. In

many cases, an adequate selection of these·parameters can be made

by the program operator so that complete speci cation via table

4 is not often required. Options associated with ordinate (feet

or meters) and/or abscissa (kilometers, statute miles, or nau

tical miles) units are available. These options are selected via

table 4. A more detailed discussion of table 4 is provided in

section 4.3.

4.1 GENERAL PARAMETERS (Table 2, p. 73)

General parameters that are usually applicable to many pro

grams may be specified by using copies of table 2. Multiple en

tries or two copies of this table may be used·if the desired and

undesired facilities have different parameter values associated with them. In the absence of such information, it will be as

sumed that the two facilities have identical parameters. All

72

'-J vt

Table 2. Parameter Specification, General

--------------------------------------------~P~R~IMA~R~Y~P~A~RAMETERS, SPECIFICATION REQUIRED

Parameter

Aircraft (or higher) antenna height above mean sea level (msl)

Facility (or lower) antenna height above facility site surface (fss)

Frequency

Range

~ Facility horizon height

> 1.5 ft (0.5 m) above fss

0.1 to 20 GHz

SECONDARY PARAMETERS, SPECIFICATION OPTION Specified, Computed, or Assumed

Aircraft antenna type options

Beam width, half-power

Polarization options

Tilt, main beam above horizontal

Tracking options

Effective reflection surface elevation above msl

Equivalent isotropically radiated power

Facility antenna type options

Beam width, half-power

Counterpoise diameter

Height above fss

Surface options

Polarization options

Tilt, ~in beam above horizontal

Tracking

Isotropic*, or as specified

0.1 to 45°

None, identical with facility

-9o• t 9 go•

Directional* or tracking

At fss• or specified value above msl

0.0 dBW* or specified

Isotropic• or as specified

0.1 to 45•

o• to 500 ft (152 ml

o• to 500 ft (152 ml Below facility antenna by at least 3 ft (1 m) but no more than 2000 ft (610 a)

Poor, average, or good ground, or fresh or sea water, concrete, or metal*

Horizontal,* vertical, or circular

-90" to 90•

Directional* C•r trackinq

Value

ft, m, k.nt, n mi, s tni,

ft, m

MHZ

deg

d0!9

ft, Ill

_____ dllll

-·-- deg

f't, •

ft, •

deg

-...]

.f;>.

Table 2.

Frequency fraction (half-bandwidth)

Gain, receiving antenna (main beam}

Transmitting antenna (main beaJII)

Transmitting antenna location

Horizon obstacle distance from facility

Parameter Specification, General (cont.)

Ran9e

0 to 0.2 {0.1)*

o• to 60 dBi

o• to 60 dBi

Aircraft or facility*

From 0.1 to l times smooth earth horizon distance (calculated)*

Elevation angle above horizontal at facility <12 deg (calculated)*

Height above msl

Ionospheric scintillation options

Frequency scaling factor

Index group

Rain attenuation options

Attenuation/km

Storm si:te

ZOne

Refractivity

Effective earth's radius

or ainimum monthly mean, N0

Surface reflection lobing options

0* to 15,000 ft-msl(4572 m-msl) and ~ aircraft altitude

No scintillation* or specified

Not used* or (136/frequency in Mllz)n with l<n< 2

0* to 5, 6 for variable

NOne* or c0111puted with dB/km or zone

0 dB/km and up

5, 10,* 20 laa

l t:o 6

4010 to 6070 n mi (74l7 to 11,242 kal

200 to 400 N-units (301 N-units)*

Contributes to variability* or determines ...,dian level

~

___ ___;dBi

____ dlli

ra.un ai, ----__ __:de9

ft, •

___ ...::dB/ka

lr-ii II ai. -----'

~-J

U1

Table 2. Parameter Specifi~ation, General (cont.)

Surface type options

Sea state

or rms wave height, crh

Temperature

Terrain elevation above msl at fa~ility

Parameter, ~h

Type options

Time availability options

Climates

or time blocks ---------

Range

Poor, average• or good ground, fresh or sea water 1 concrete, metal

Value

O~glassy,* 1-rippled, 2-smooth, 3-slight, 4-moderate, 5-rough, 6-very rough, 7-high, a-very high, 9-pt,enomenal

0 to 50 m (164 ft)

0, 10,. or 2:0°C

o• to 15,000 ft-msl (4572 m-m$1)

o• or greater

Smooth* or irregular

For instantaneous levels exceeded* or for hourly median levels exceeded

o•-continental all year, 1-Equatorial, 2-Q:>ntinental subtropical, 3-Marlt ime subtropical, 4-Desert,-6-continental Temperate, ?a-Maritime Temperate Overland, 7b-Maritime Temperate Overseas

1, through 8, summer, winter

_____ ft, m

_____ ft, 1D

ft, m

(a) Copies of this table may be used to provide data for computer runs by utilizing the blanks provided in the value column and circling desired options. These parameters are common to most programs, However, additional information is needed for various programs and it may be supplied via tables J and 4. If desired and undesired facility parameters are not identical, two table 2 parameter specifications, or appropriate notes on a single copy are required.

(b) Parameters are listed in about the same order as on parameter sheets produced by the various programs (figs. 1 through 5). Parameter sheets produced by the various programs are similar, but not identical since only those parameters relevant to a particular proqra. and run will be listed. For example, if the counterpoise diameter is input as zero, the counterpoise will not be considered and none nf the parameters associated with it will be listed on the parameter sheet (c.f., fig. l with fig. 5).

Values or options that will be asaumed when specific designations are not made are flagged by asterisks.

!.' ~

'-l 0

Table 3.

Capability Program



Transmission loss curves

Power available volume

Power density volume

Transmission loss volume

EIR.P contours



Transmission loss contours

Service volume

Signal ratio contours



Transmlssi~n loss curves

EIR.P contours



Transmission loss contour$

Or!ent.1tion

Si~\al ratio contours

} J l }

J

ATLAS l

HI POD

APODS

SRVWM

OURATA

ATLAS

APOOS

TWIRL

DURATA

Parameter Specification, Special

Parameter and Value(s)•

Aircraft altitudes, up to 25, may be sp&cified to cover airspace required:

ft-mal,

--------------------------------------------------------------------~or m-sal.

Time availability: percent. Acceptable values ran~• from 0.01 to 99.99 percent. A value of 95 percent will be used if a value ls not specified.

"-1 "-1

Table 3. Parameter Specification, Special (cont.)

Caj2abilit~ Pr~ram

Power available volume HI POD

Power density volume HI POD J EIRP contours APODS

Transmission loss vol~ HI POD

I!IR:P contours APOOS

Power available contours APOOS

Power density contours APOOS

Tra~ission loss contours J\1'005

Signal ratio-DO 0000

Service 110lume SRVUIM

Signal ratio contours DURATA

Signal ratio-S ATJ\DU

Orientation TWIRL }

Service volume SRV'LUM

Orientation TWIRL

NOTE: Azimuth is relative to desired station course line with positive values taken as clockwise, and distance is the desired facility-to-aircraft great circle distance

*Par~r valuea required for particular capabilities that are not specified in table 2 may be specified by using the blanks provided here. Circle desired unite Where aultiple units are given.

Parameter and Value(s)•

Power available: dBW.

Power density:~ __ _dB-W/sq m

Transmission loss: dB.

EIRP'S, up to 8: dBW.

Powers available, up to 8: dBW.

Power densities, up to 8: dB-W/sq m

Transmission loss, up to 8: dB

Station separation: km, n mi, or s mi.

Desired facility-to-aircraft distance: km, n mi, or s mi.

Desired-to-undesired signal ratio: dB.

Protection point location, up to 6:

Azimuth Distance

deg ____ k.m# n mif or s mi

'"--! c::>

Table 4. Parameter Specification, Graph Formats

Capability(a) __ ~~og~am Lower

Lobinq LOSING

Reflection coefficient LOSING

Path length difference LOSING

Time delay LOSING

Lobing frequency -D LOSING

Lobing frequency -H LOB!NG

Reflection point LOSING

Elevation angle t..OBING

Elevation angle difference LOSING

Spectral plot LOSING Plot lobe

Power available ATOA

Power density ATOA

Transmission loss ATOA

Power available curves ATLAS

Power density curves ATLAS

Transmission loss curves ATI.AS

Powr available curves HI POD

Power density volume Ill POD

Transmia•ion losa volume lliPOD

EIRP contours APODS

Power available contours APODS

Ordinate

Upper Il'lcremenL Unit:_.;_ (b) Left Side Right

dB

m

nsec

(llz/THz)/(lon/hr) (Hz/THz) /kts

--~~ll~z=/Tllz) I (s mi!h_r_> __ _

(Hz/THzl/lm/min) _____ l_Hz_/THz)/!ft/mi_n_l ____ __

Jan, n mi, or s mi

deg

deg

--------~hru , counting from the Horizon(c)

dBW

dB-W/Sq m

dB

dBif

dB-W/11q Ill

dB

ft or •

ft or •

ft or 111

ft or •

ft or •

Absci.csa

~zld" mi, or

l?'n.t n mi, or

~thin mi, or

~dlin mi, or

l?'dlt n mi, or

l?'.tun mi, or

ll"'z~.t" mi, or

ll:'-~ot" mi, or

l?'.t.in ai, or

~gil lf• n ai,

~g~~ ft• n ai,

~·.n.fl,

~, 8n.fi,

~~.n.Ji,

~·en.fl,

~·.".fl·

~·.".fl· ~·.n.J:i,

~~.n~.

~·.n.f1•

"' \.0

Table 4. Parameter Specification, Graph Formats (cont.)

Ordinate Abscissa

Capahility(al Program Lower Upper Increment Units(b) Left Side Right Side Incre~nt Units(b)

Power density contours A PODS

Transmission loss contours A PODS

Signal ratio -s ATTADU

Signal ratio -DD DUDD -~

Orientation TWIRL

Service volume SERVLUM

Signal ratio contours OORJ\TA

ft or m

ft or m

dB

dB

deg -----ft or m -------ft or m

---~--

~,snrn'fi,

~'snmfl' km, n 111i, or a ou

~'s0mrt'

deq

~, 8n.'fi,

~·snm'fi,

(a) In many cases appropriate graph limit can be adequately selected by the program operator so that values need not alwey~ be provided here. However, in such cases the capabilities desired should be indicated (circled), and where required (a,b) units st~uld be specified. l\ plotting capability guide is provided in table 1.

(b) Circle desired units when multiple units are given. Selections for a particular capability must be conaistant1 i.e., all Enqlish or all metric units.

(c) Any 5 consecutive lobes within 10 lobes of the radio horizon may be specified.

capabilities that involve the use of desired to undesired (D/U)

signal ratios involve two facilities. This includes the last 5

capabilities listed in table 1.

Although about 40 items can be specified with table 2, re

quired specification involves only 3. These "primary parameters"

consist of antenna heights and frequency. Values for "secondary

parameters" will he computed or assumed if not snecified. Para

meter values (or options) that will he assumed in lieu of speci

fication are indicated in the table along with the acceptable

value range (or options available).

The nomenclature used to distinguish between the two anten

nas of a particular path may be misleading to the uninitiated but

is used for convenience. The lower of the two ant~nnas is called

the "facility" even though it may be an aircraft. The other an

tenna must be equal to or higher in altitude than the "facility

or lower" antenna and is designated as the "aircraft" even though

it may be a ground-based antenna or a satellite.

For convenience, the parameters in table 2 are listed alpha

betically within categories. A short discussion of each parameter

is provided in the remainder of this section, and these discus

sions are ordered in accordance with the order of appearance of

the parameter in table 2.

AIRCRAFT OR HIGHER ANTENNA HEIGHT As shown in figure 44, this

altitude is measured above mean sea level (msl). The propagation

model is not valid for antennas located below the surface, and

radio horizons may not be treated correctly if the aircraft alti

tude is less than the facility antenna horizon elevation above

msl. Use of such aircraft altitudes will result in an aborted

run after an appropriate note has been printed on the comnuter

generated parameter sheet (e.g., fig. 1). Notes are printed,

but the run is not aborted if the altitude is (a) less than 1.5

ft (0.5 m) where surface wave contributions that are not included

in the model could become important, or (b) less than the effec

tive reflecting surface elevation plus 500 ft (152 m) where the

80

model may fail to give proper consideration to the aircraft radio

horizon.

FACILITY ANTENNA HEIGHT As shown in figure 44, this

height is measured above the facility site surface ( s). The

propagation model is not valid for antennas below the surface,

and such a facility antenna height will result in an aborted run,

after an appropriate note has been printed on the computer-gener

ated parameter sheet (e.g., fig. 1). A note is printed, but the

run is not aborted if the height is less than 1.5 ft (0.5 m),

for which surface wave contributions not included in the model

could become important.

AIRCRAFT ALTITUDE ABOVE msl --------------------------------------.-

FACILITY ANTENNA HEIGHT ABOVE fss

FACILITY SITE SURFACE (fss) ELEVATION ABOVE msl -------------r-

EFFECTIVE REFLECTION SURFACE ELEVATION ABOVE msl----~-

MEAN SEA LEVEL (msi)----------------------------L-----~------~-

Figure 44. Antenna heights and surface elevations. Note that the aircraft altitude is e~evation above ms~ whi~e the faci~ity antenna height is measured with respect to fss.

81

FREQUENCY Notes are printed if the frequency is (a) less than

100 MHz, when neglected ionospheric effects may become important;

(b) greater than 5 GHz, when neglected scattering from hydromete

ors (rain, etc.) may become important; and (c) greater than

17 GHz, when the estimates made for atmospheric absorption may be

inaccurate. For frequencies less than 20 MHz or greater than

100 GHz, the run is aborted.

AIRCRAFT ANTENNA TYPE OPTIONS These options involve the antenna

gain pattern of the aircraft antenna in the vertical plane. Op

tions currently built into the program include isotropic, cosine

(voltage), and JTAC (see eqn. 10) patterns (fig. 45). Program

modifications can easily be made to accommondate other patterns

that are specified in terms of gain versus elevation angle. Hori

zontal (or azimuth) patterns for the aircraft antenna are not

used in any program.

Antenna pattern data are used to provide information on gain

relative to the main beam only. The extent to which the main beam

antenna gain exceeds that of an isotropic antenna is listed in

table 2 as a separate item (i.e., under GAIN) and is included in

the specification of EIRPG (see eqn. 12).

AIRCRAFT ANTENNA BEAM WIDTH This parameter is currently used

only in connection with the JTAC [33, p. 51] antenna pattern

where relative (voltage) gain (g) is a function of the half-power

beam width (eHP), beam tilt above horizontal (et), and the ray

elevation angle (ee) for which g is desired [24, (67)]; i.e.,

g[V/V] = [1 + (2iee-etl/eHP)2.5J -o.s (10)

where ee' et' and eHP must all be expressed in the same units of

angular measure, such as degrees or radians.

AIRCRAFT ANTENNA POLARIZATION IONS Polarization of the air-

craft is not optional. It is always taken as being identical

with that of the facility antenna, which may be specified as cir

cular, horizontal, or vertical. Therefore, losses associated

82

with polarization sense mismatch are not included in the programs.

However, provisions do exist to allow antenna gain patterns for

horizontally and vertically polarization components to be individ

ually specified for calculations involving circular polarization.

AIRCRAFT ANTENNA TILT The aircraft antenna main beam tilt above

horizontal is currently used only with the JTAC antenna pattern

formulation of (10).

AIRCRAFT ANTENNA TRACKING OPTION If this tracking option is

used, the main beam of the aircraft antenna will always point at

the desired facility antenna.

EFFECTIVE REFLECTION SURFACE ELEVATION As shown in figure 44,

this elevation is measured above msl. If not specified, it will

be taken as the terrain elevation above msl of the facility site

surface (fss). This factor is used when the terrain from which

reflection is expected is not at the same elevation as the fa

cility site; e.g., a facility located on a hilltop or cliff edge.

When the elevation of the ility antenna or horizon obstacle

is below the effective reflection surface level, a note will be

printed and the run aborted. This elevation is also used as the

elevation of average terrain for terrain other than the facility

site and horizon obstacle.

The following guidelines are useful in estimating effective

reflecting surface elevations:

1) Do not specify a value for this elevation (then a value equal

to the facility site elevation will be assumed) if (a) terrain in

formation is too di cult to obtain, or (b) the path profile

[49, sec. 6.2] is such that a reasonable estimate is difficult.

For example, do not specify a value when the facility-to-horizon

reflection would be expected to occur from a tilted plane and the

facility horizon obstacle elevation is greater than the facility

site elevation.

2) Take this elevation as the facility horizon obstacle eleva

tion if the path pro le is such that the facility-to horizon re-

flection would be expected to occur from a tilted plane and the

83

horizon obstacle elevation is less than the facility site eleva

tion; e.g., when the terrain slopes downward from the facility

site to its horizon so that none or very little of the terrain be

tween the two has an elevation less than that of the horizon

obstacle.

3) This elevation should, in most cases, be taken as an estimate

of average terrain elevation in the vicinity of the surface along

the great-circle path that is expected to support reflection be

tween the facility antenna and the facility horizon obstacle. In

a plane tangent to the reflecting point, the angle of incidence

should equal the angle of reflection; i.e., grazing angles (w of

fig. 40) are equal at the reflecting point [8, sec. ll.A; 27, sec.

CI-C.2].

The effort required to determine appropriate terrain input

parameters for IF-77 when the first two guidelines are not appli

cable can be very difficult for inexperienced personnel without

adeq~ate tools. Experienced personnel and computer programs use

ful in processing terrain data are available at DOC and should be

utilized for difficult problems.

EQUIVALENT ISOTROPICALLY RADIATED POWER Equivalent isotropically

radiated power (EIRP) is the power radiated from the transmitting

antenna increased by the antenna's main lobe gain; i.e.,

EIRP[dBW] = PTR[dBW] + GT[dBi] (11)

where PTR is the total power radiated from the transmitting an

tenna and GT is the main beam gain of the transmitting antenna.

The term EIRPG is sometimes used (e.g., fig. 16) to indicate EIRP

increased by the receiving antenna main beam gain (GR); i.e.,

EIRPG(dBW] = EIRP[dBW] + GR[dBi]. (12)

In the calculation of transmission loss (e.g., fig. 23) only the

sum of the antenna gains is involved, and the term GAIN is used where

GAIN(dBi] = GT[dBi] + GR[dBi]. (13)

84

For exam~le, a radiated power of 10 dBW, a transmitting antenna

gain of 10 dBi, and a receiving antenna gain of 6 dBi would result

in 20 dBW EIRP, a 26 DBW EIRPG, and a 16 dBi GAIN. Effective ra

diated power (ERP) is similar to EIRP but is calculated with an

antenna gain specified relative to a half-wave dipole; therefore~

an EIRP value is 2.15 dB higher than an equivalent ERP value when

the same radiated power is involved.

FACILITY ANTENNA TYPE OPTIONS Tl1ese options involve the antenna

gain pattern of the facility antenna. Some of the vertical plane

patterns currently available include those illustrated in figures

45 and 46 where antenna gain, normalized to the maximum gain, is

plotted against elevation angle (measured above the horizontal).

Figure 45 shows vertical patterns for the cosine, isotropic,

TACAN RTA-2 [12], and Tull. The "cosine" (voltage) pattern [24,

(67)] is used for a vertically polarized electric dipole or a

horizontally polarized magne~ic dipole such as the antenna associ

ated with VOR. Heasured gain data on the RTA-2 and modified RTA-

2 antennas, supplied to DOC by FAA, were used in obtaining the

patterns for these TACAN antenna types. The Tull pattern is the

vertical radiation pattern associated with the localizer nortion

of the Tull Microwave Instrument Landing System and is a piece- .

wise linear fit to data provided via the FAA.

Figure 46 shows vertical patterns for different Distance Mea

suring Equipment (DME) antennas. These patterns are all piece

wise linear fits to information provided by the FAA. Dashed lines

are used where the curves are extended beyond the data provided.

The pattern labeled "DME-Specification" was developed from a FAA

specification [17, sec. 3.5.7] by using minimum acceptable gain

values.

One pattern is currently available that allows beam width

and tilt to determine the pattern. This pattern is the JTAC pat

tern previously discussed under "Aircraft antenna beam width"

where (10) defines the relative gain in terms of beam width and

tilt. Program modifications can easily be made to accommodate

85

. ' I

r--1,3, I

j:Q

ol I 1 1,5,2,4,3 "'(j

. I I I 1 1 ... I t.:: ·~~

t.:: t.::·~ ·~ o:l

r . 2 o:lbO I bO

E o:l ;:j. t.::E t.::·~ (I) X .f..Jo:l t.::E o:l

0 >...f..J

...... ..... (I)

rl> ·~ ·~ -, I'- I 3

co U.f..J

-30, I 3 I 7 1 I 0\ cdcd 4-1~

(I) '4 1. Isotropic "'(j,... 5 2. Cosine (voltage) (I)

Nt.:: 3. Tull Localizer ·~·~

ricd 4. TACAN RTA- 2 cdbO -40 5 . Modified TACAN RTA-2 S"-' ,...

I I . 0 z

-80 L 1 1 I I 1 I · -so, , • .1.._ 20

40 60 80 -60 -40 -20 0

Elevation angle above the horizontal in deg

Figwe 45. No:r>malized antenna gain vs. elevation angle .

·. . .

t::Q 'U

~ 0 ·rl

,-... ~ ~

•rl •rl ro ro t.()t.()

1 1

~ zJ; 2

ro s -10 1. Isotronic 4 \ ~;;:l ~ s (]).,...; +.JX ~ro ro s ~0

-20 +J+J •rl ,......((])

00 ·rl ? -..] U·rl

ro+.J 4-1ro -30

,......(

2. fviontak DHE

4\ r\:r 3. Cardon mm 3 4. DME Specification E\ I

l '1:)(]) (])f..< N

·rl ~ ,......( •rl ro ro -40 sc.o f..<'-' 0 z

-so -80 -60 40 -20 0 20 40 60 no

Elevation angle above the horizontal in deg

Figure 46. Normalized antenna gain vs. elevation angle~ DME

other patterns that are specified in terms of gain versus eleva

tion angle.

Program TWIRL is the only program which involves the use of

horizontal plane (azimuth) antenna patterns (see ORIENTATION, fig.

35, discussion in sec. 3.2). An example of such a pattern is the

localizer portion of an ILS 8 loop array antenna (22, fig. 1].

This pattern and preliminary patterns for other ILS localizer

antennas are currently available, but program modifications can

easily be made to accommondate other patterns that ar~ snecified

in terms of gain versus azimuth angle. Antenna pattern data are used to provide information on gain

relative to main beam only'. The extent to which the main beam

antenna gain exceeds that of an isotropic antenna is listed in

table 2 as a separate item (i.e., under GAIN) and is used in the

specification of EIRP as per (11) when the antenna is transmitting.

FACILITY ANTENNA BEAM WIDTH This parameter is currently used

only in connection with the JTAC antenna pattern given by (10).

FACILITY ANTENNA COUNTERPOI ER The counterpoise was in-

corporated into the model for the VOR. It will not be included

in the calculations if its diameter is specified as zero, and the

parameters associated with it will not be printed. A diameter

greater than 500 ft (152 m) will cause a warning note to be

printed, but will not abort the run.

FACILITY ANTENNA COUNTERPOISE HEIGHT If the counterpoise height

above the facility site surface ( s) is less than zero, it will

be set equal to zero. An appropriate note will be printed and

the run aborted if the height is (a) greater than 500 ft (152 m),

or (b) greater than the facility antenna height. The facility

antenna should be above the counterpoise by at least one-third

of a wavelength, which is 3 ft (1 m) at 100 MHz, and by not more

than 2,000 ft (610 m).

88

FACILITY ANTENNA COUNTERPOISE SURFACE OPTIONS Counterpoise sur-

face options fix the conductivity and dielectric constant associ

ated with the counterpoise surface. Values associated with each option are given in table 5.

FACILITY ANTENNA ZATION OPTIONS These options include circular , horizontal, and vertical polarization [47, ch. 8].

Polarization for the aircraft antenna is always taken as being

identical with that of the fa~ility antenna. Therefore, losses

associated with polarization sense mismatch are not included in

the programs. However, provisions do exist to allow antenna gain

patterns for horizontally and vertically polarized components to

be individually specified for calculations involving circular polarization.

FACILITY ANTENNA TILT The facility antenna main beam tilt above·

horizontal is currently used only with the JTAC antenna pattern

formulation of (10). However, it can also be used to adjust the" tilt of other patterns.

FACILITY ANTENNA TRACKING OPTION If this tracking option is

used, the main beam of the facility antenna will al~ays point at the aircraft.

Table 5. Surface Types and Constants

[25, table 6]

Type

Poor ground

Average ground

Good ground

Sea water

Fresh water

Concrete Metal

Conductivity (mhos/m)

0.001

0.005

0.02

5*

0.01*

0.01

10 7

Dielectric Constant

4

15

25 81*

31*

5

10

*More appropriate values are calculated if surface sea tempera

ture is specified.

89

FREQUENCY FRACTION This is the fraction of the carrier frequency

that corresponds to half the bandwidth used for the spectral plot

capability (fig. 15). For example, a carrier frequency of 125 MHz

and a fraction of 0.0004 would result in a bandwidth of

( 2) ( 0 . 0 0 0 4 ) (12 5) = 0 . 1 MH z = 1 0 0 kH z .

GAIN, RECEIVING ANTENNA This item is the main beam gain [dBi]

of the receiving antenna. A 0 dBi value will be assumed if no gain is specified.

GAIN, TRANSMITTING ANTENNA This item is the main beam gain

[dBi] of. the transmitting antenna. A 0 dBi value will be assumed

if no gain is specified.

TRANSMITTING ANTENNA LOCATION This item is included to provide

a more complete specification of problem parameters and to allow

the program operator to check for potential incorrect power den

sity or D/U estimates. Other predictions have transmitter/receiver reciprocity. Power density and D/U calculations assume

that the transmitting antenna is located at the facility.

HORIZON OBSTACLE DISTANCE FROM FACILITY If not specified, this

distance will be calculated from horizon parameters that are spec

ified and/or by using the terrain uarameter Ah. When the dis

tance is not within 0.1 to 3 times the smooth earth horizon dis

tance, a warning note will be printed, but the run will not be aborted.

HORIZON OBSTACLE ELEVATION ANGLE ABOVE HORIZONTAL AT FACILITY

If not specified, the horizon obstacle elevation angle at the

facility will be calculated from horizon parameters that are spec

ified and/or by using the terrain parameter Ah. When the angle

exceeds 12°, a warning note will be printed, but the run will not be aborted.

HORIZON OBSTACLE HEIGHT If not specified, this height will be calculated from horizon parameters that are specified and/or by using the terrain parameter Ah. When the height is not within

90

the 0 to 15,000 ft-msl (4572 m) range, a warning note will be

printed, but the run will not be aborted.

IONOSPHERIC SCINTILLATION FREQUENCY SCALING FACTOR The use of

this simnle scaling factor is optional. It should only be used

when estimates of the variability associated with ionospheric

scintillation at a particular frequency (f in ~fll:) must he based

on data collected at 136 MHz [55, sec. 3.4]. Use of this factor

results in scaling by (136/f)n where n varies from 1 to 2 as a

.function of facility latitude [55, (27)].

IONOSPHERIC SCINTILLATION INDEX GROUP Variability associated

with ionospheric scintillation for paths that pass through the

ionosphere (e.g., earth station/satellite path) is considered via

the distributions shown in figure 47. Input requirements involve

the speci cation of the particular scintillation index groun (fig. 47) of interest. Scintillation index is the ratio of peak

excursion om mean power to mean power [46, (2); 58]. Provi

sions exist (table 2, index group= 6) to allow the signal level

variability associated with ionospheric scintillation to change

with earth facility latitude. Figure 48 shows the distributions

currently used when this option is selected. These distributions

were developed by mixing distributions for particular scintilla

tion index groups in accordance with the estimated time for which

they would be present at a frequency of 136 MHz [55, sec. 3.4] so

that the frequency scaling factor discussed above should be used

with these distributions. However, only minor program modifica

tions would be necessary to incorporate other distributions that

might be of interest.

RAIN ATTENUATION OPTIONS An allowance for rain attenuation may

be made by using a fixed attenuation rate (dB/km) or by using

rain attenuation statistics for a particular rain zone and storm

size. Rain attenuation via the rain zone model is present for less than 2 percent of the time so that only time availabilities greater than 98 percent will be affected.

91

l.C

8

~ 4 "C

...... <lJ > il.l 0 ......

..... Cll ~ at ..... "'

SCINTILLATION SCINTILLATION INDEX ( %} INDEX GROUP

:;:: -4 <11 .....

"C (!)

E 0 0 - 19 20 - 39 1 ..... -8 ::s 40 - 59 2

60 - 79 3

80 - 89 4

> 90 5

'-0 0 N .D

ro >-..... a -12

.D <11 ..... l-t <1l

> -16

-20

0.01 0.1 0.5 2 5 10 20 50 80 90 95 98 99 99.5 99.9 99.99 Percent of time signal amplitude exceeds ordinate

Figure 47. Sign.al-level distributions for ionospheY'ic scintillation index gY'oups.

(.Q

tN

.-i <lJ 2 > <lJ

.-i

.-i ttl 0 1:: 0.';

•rl (/)

6

~ ~ ~ ~ ~ ~ ~--- .... 1-- --- r---~

!"-~""'·· ~ ~

~ ~ ~ ~ - R ~ ~

~ -..;;;: r'--... ~"'-....... r-..... ~ -+- ......... r-..... i""--- .....

4

1::

.~ -2 "d

<lJ E

.... ~ -4

..0 ttl

>-. .... •rl -6 .-i •rl .c ttl

•rl f.< (\j -8 >

-10

-~ ~ ~- I ......;:

~ ~~ ~ r\ 1"--,

'\~ !'\~ .. ~ ·~ -t-- ---!----

\ ' -~-

' ' ' I\' -+-

~ ~ ~-North latitude

OQ --- -· \ i\\

5 Q _,_,_,_,_, ___ - - --- f--

I 1o· \ \~ I

14° -~--- ~ i\ ~ i -I 17-52° --- ~ --f-~ -~

~ ~ \ 57 (I ---------

60 ° ..........................

- 1":_

0.01 0.1 0.5 l 2 5 10 20 50 80 90 95 98 99 99.5 99.9 99.99

Percentage of time signal amplitude exceeds onlinatc

Figure 48. Signal-level distributions currently used with variable scintillation group option selected. These distributions were developed from data co~l?~teg at 136 MHz [55~ sec. J.4] so that the frequency scaling factor should be used with them.

""

RAIN ATTENUATION/KM With this option, rain attenuation is cal culated as the product of the attenuation rate and the length of

the most direct ray path between the terminals that is within the

storm.

RAIN STORM SIZE This is the length (or diameter) of the storm

over the great-circle path connecting the terminals. It is as

sumed that this length is made up by a single storm that extends

to an altitude above average terrain that is equal to the storm

size and contains as much of the most direct ray nath as possible.

For the models used here the greatest length of path subjected to

rain attenuation is limited to the rain storm length and the smal

lest is zero since the direct ray could be entirely above the

storm for an air-to-air propagation path.

RAIN ZONE If the option involving

is desired, a rain zone number from

tinental United States or figure 50

is selected [51, 52, 53,- 54, 57].

statistical attenuation rates

either figure 49 for the con

for other parts of the world

Rain attenuation

tion is present for less than 2 percent of the time

time availabilities greater than 98 percent will be

via this op

so that only

affected.

REFRACTIVITY Values for the minimum monthly mean surface refrac

tivity referred to mean sea level (N ) may be estimated from ei-o

ther figure 51 for the continental United States or figure 52 for

other parts of the world. Other information [3, 4, 5, SO, 51, 52]

which may be more appropriate for the particular conditions (e.g.,

time of year and location) involved can be used to estimate N0

or a minimum monthly mean value for effective earth radius. Spec

ification of N outside the 200-to-400 N-unit range will result 0

in N being set to 301. If 0

the surface refractivitv (N ) calcu-' s

lated [49, (4.3)] from N 0

is less than 200 N-units, N will be s

set to 200 N-units and an appropriate note printed. An N of 301 s N-units corresponds to a~ effective earth radius factor of 4/3

[49, fig. 4.2], If desired, a value for effective earth radius

can be specified directly.

94

1.0 Ul

..s ( I

') ' i& /~ I

'\ ) . I . 1\~7- o.

~ Q

I I -.?

q

. h. a \ £:::, <:)

~

Figure 49. Rain zones of the continental United States [54, fig. 10]. Areas where the 5-min rainfall rate in inches/hour is expected to occur once in 2 years on the average are shown; e.g., area 5 ranges from 4 1/2 to 5 1/2 in/hr (110 to 140 mm/hr). Rain Y'ates of 1, 3, 4, 5, and 6 in/hr are equivalent to rates of 25, 51, ?6, 100, 130 and 150 mm/hr, respectively. ., ' '

·-:::;~

~ ".

~ w ~ • ~ ~ ~ ~~~6-00'r- -r--,-T-iT ---,-

JO•

. ----'--t l >' ~ I 5o-

40'

w g --I'"' \1 I'L h.~v h I . I i I I . . V«'C~p:.:&;-r--,----,--- I I I I I I ~,-l:T-tl 20' i 1-

!;r - I _J &j. ~{) !. I ,., 1 I I I I I r~-r"":-61\'~ l-l~+.::l I _ ~~r-ii

o•

10' L I ;j 6' ·[ I d.~ ' " \•_, i I I I I I I ~~~0 '\5'i I 'l_Gl ~l -~~

20'

lO'

40'

50"

00' • • ~ ~ eoo~~• ~ ~ w • 4~ fll'fll'

Figu~e 50. Rain zones of the wo~td (Samson, DOC, informal communication). This map is based on much tess data than the figu~e 49 and should be used onty to p~ovide a ~ough indication of the ~eas in which ~ain attenuation may be a significant facto~. Zone numbe~s used he~e have the same significance as those used in figu~e 56.

\0 '-)

·-·----~---.-·-·-('1·-· ... -' ... ~I \ .r ! '0 I I ·-,

...r'"~

~'~ Figur>e 51. Sur>face Pefr>activity for> the continental United States [48, fig.

34]. Minimum monthly mean sur>face r>efr>activity values shown aPe r>efeY'Ped to mearz sea level, N in N-unlts.

0

.,

I

120 100 eo 60 40 20 w o E 20 40 ro eo 100 120 140 1so E 100 .--.~--r-,--,--,-,--,--,-,

N

~ ~

ro ro

60 60

50 50

40 40

w ~

20 20

10 10 H N

<.0 I o o co s s

tit

10 10

20 20

~ ~

40 40

50 50

60 --,~~ 60 . '-..., _.-1305

':j""""":j::::,=F==::t::::::>,_, ....e-t::::::- -...-- I

70 ---~~== 70

eo ·---~~= eo s ' I S

Figure 52. Surface refractivity for the world [49> fig. 4.1]. Minimum monthly mean surface refractivity values are referred to mean sea level~ N in N-units.

0

..

SURFACE REFLECTION LOBING

phase difference between

Lobing a~sociated with the

reflected rays in the line-of-

sight region contributes to the short-term variability (within the

hour fading) or is used to define the median level in the line-

. of-sight region. These options can result in predictions that

are very different. The variability option provides a more reli

able estimate of propagation statistics in most cases. l!owever,

the lobing pattern option is useful when selecting antenna heights

to avoid low signal levels (nulls) in particular portions of air

space. With the variability option, lobing is treated as part of

the short-term (within-the hour) variability when the reflected

ray path length exceeds the direct ray path length by more than

half a wavelength (inside horizon lobe) so that the lobing pat

tern is not plotted. The other option allows t median level to

be determined by such lob for the first ten lobes inside the

radio horizon so that the lobing pattern will be plotted. Regard

less of the option selected, lobing caused by reflection from the

counterpoise (if present) is used in median level determination

and does not contribute to the short-term fading; i.e., if pre

sent, counternoise lobing is plotted with either .option.

SURFACE TYPE OPTIONS These options fix the conductivity and di

electric constants associated with the effective reflecting sur

face. Values associated with each option are given in table 5.

If the surface is water, the constants of table 5 may be used or

surface constants may be calculated using surface sea temperature.

SURFACE SEA STATE If fresh or sea water is chosen, an allowance

may be made for water roughness by specifying sea state or the

root mean-square deviation of surface excursions within the lim

its of the first Fresnel zone in the dominant reflecting plane

(ah). Table 6 shows the relationship used to relate sea state to

ah. Values for a oh provided in table 6 were estimated using

significant wave height (IT 113 ) est.imates from Sheets and Boat-

wright [53, table 1] with a formulation given hy Moskowitz

99

Table 6. Estimates of ah for Sea States [27r p. CI-81].

(a) Sea State Code

0

1

2

3

4

5

6

7

8

9

. t' (a) Descr1p 1ve Terms

Calm (glassy)

Calm (rippled)

Smooth (wavelets)

Slight

Moderate

Rough

Very rough

High

Very high

Phenomenal

Average Wave Height Range Meters (feet)

0 (0)

0 - 0.1 (0 - 0.33)

0.1 - 0.5 (0.33 - 1.6)

0.5 - 1.25 (1.6 - 4.0)

l. 25 - 2. 5 (4 - 8)

2.5 - 4 (8 - 13)

4 - 6 (13 - 20)

6 - 9 (20 - 30)

9 - 14 (30 - 46)

>14 (>46)

H 113

(b)

Meters

0 (0)

0.09 (0. 3)

0.43 (1.4)

1 ( 3. 3)

1.9 (6 .1)

3 (10)

4.6 (15)

7.9 (26)

12 (40)

>14 (>45)

(feet)

(a) Based on international meteorological code [42, code 3700].

Meters (feet)

0 ( 0)

0.00 (0.08)

0.11 (0.35)

0.25 (0.82)

0.46 (1. 5)

0.76 (2. 5)

1.2 ( 3. 8)

2 ( 6. 5)

3 (10)

>3.5 (>11)

(b) Estimates significant wave heights, average of highest one-third, HI [53, table 1].

1 3

(c) Estimated using a formulation provided by Moskowitz [41, (1)] with H I estimates.

1 3

100

[41, (1)]. However, oh may also be specified directly.

SURFACE SEA TEMPERATURE The dielectric constants and the conduc

tivity of water vary with frequency, salinity, and temperature

[27, sec. CI-D.8]. The programs allow water surface constants to

be calculated for either fresh water or average sea water (3.6%

salt) and three water temperatures (0°, 10°, or 20°C).

TERRAIN ELEVATION This is the elevation of the facility site

above msl (fig. 44). Values less than zero are set to zero, and

a note will be printed if the 15,000 ft-msl (4572 m msl) limit is

exceeded, but the run will not abort.

TERRAIN PARAMETER The terrain parameter (tih) is used to charac

terize irregular terrain. Values for it may be calculated from

path profile data [37, annex 2] or estimated using table 7. ~~en

the aircraft is much higher > 10 times) than the facility, the

terrain us to determine tih should be that terrain between the

facility and its radio horizon. Estimates can also be made using

gure 53 when profile data or terrain type information is not

conv~niently available.

Table 7. timates of tih [37, table 1]

Type of Terrain tih tih

Water or very smooth plains 0 - 20 0 - 5

Smooth plains 20 - 70 5 - 20

Slightly rolling plains 70 -130 20 40

Rolling plains 130 260 40 - 80

Hills 260 -490 80 150

Mountains 490 -980 150 -300

Rugged Mountains 980 -2000 300 -700

101

...... (:n (I)

'1j ....... (I)

'1j ;:i

-{.:!

'..:> -{.:!

1-' tj

N 0 N ~

~ ~ ;g

'iUI \ fl I I"' I ~, ,, v .. ~ " I I V .>OI'>Il~ 4 I L fi-t:-' TTl 7 I

30.

25 --

- - . -, --~·······-· . ._ . . .

120 110 100 90 70 West longitude (deg)

FiguPe 53. Contours of the tePPain factoP ~h in metePs (infoPmal communication, G. A. HuffoPd, DOC). The computations assumed Pandam paths and homogeneous tePPain in 50 km (30 n mi) blacks. Allowances should be made foP otheP situations. TePPain paPameteP values of 3, 10, 30, 100, 300 and 1,000 m ape equivalent to 9.8, 33, 98, 328, 984, and 3,281 ft.

. '

~40

"30

25 65

TERRAIN TYPE OPTIONS If the smooth earth option is select

all calculations will be based on smooth earth parameters even

though parameters specified elsewhere imply irregular terrain.

For example, smooth earth specification would cause specified hor

izon parameters to be neglected and smooth earth values us in

their place.

TIME AVAILABILITY OPTIONS If the first option is selected,

short-term (within the-hour) fading will contribute to the vari

ability, and time availability is applicable to instantaneous lev

els that are available for specific percentages of the time. With

the second option, only long-term (hourly median) variations are

included in the variability, and time availability is applicable

to the hourly median levels that are available for a specific nercentage of hours.

TI~fE AVAILABILITY CLIMATES OR TIME BLOCKS If no option is sele~

ted under climates, the programs will use the long term (hourly

median) variability as described in Gierhart and Johnson [24,

sec. A.S]; i.e., continental all year climate. Climates similar

to those defined by the CCIR [9] and described in table 8 are

available. Variability functions for these climates were devel

oped at the DOC (informal communication, A. G. Longley and G. A.

Hufford). The factor used in the propagation model to avoid ex

cessive variability for paths with a very high antenna (satellite)

was developed for the continental all year climate [23, fig. 2],

and the use of other climates for satellite paths may result in

excessive variability. Time blocks for the continental temperate

climate also are options. The time block periods are defined in

table 9.

4.2 SPECIAL PARAMETERS (Table 3, p. 76)

Special parameters required for particular capabilities are

covered in table 3. Some of these parameters are required for

more than one capability, and the 13 capabilities associated with

programs LOBING and ATOA (table 1) do not require parameters from

103

t-o ~

Table 8. Climate Types and Characteristics

Approxi- Seasonal Radio- mate Tempera- Annual Seasonal

CCIR Climate Latitude ture (°F) \'ariation in

~lean \ . s

Climate IX>sigwtor Range Variation Precipitation ----- --------

\'lind Near sea -1e,·e 1 --- _____ "-:_u=ni.:..t::_s ___ _

-\nnua 1 Range of

\fonthh· ~lean \.

s Remarks

6

Equatorial l00N-100S Small High all 40-100 ~axima near seasons (1 0 2 2 54) no xes (Mar.

Sept. 23) ; no complete! y dry season.

Continental 10°-20° '4:ld.,rate Winter: 10-100 Dry winter, Monsoonal shift in direction.

suh- tropical mderatc to(ZS 254) rainy summer. high; Slllll!lef: high

Maritime 10°-20° M:Jderate High 10-100 (25-254)

winter, sumner.

Monsoonal shift in direction. sub-tropical

Desert

Mediterranean

Continental temperate

20°- 30° Very large Very low <10 <(25)

30°-40°

30°60°

Moderate (mild winters and hot SUI11l1e rs J

~kxlerate to high

IS- 35 (38- 89)

Very large Varies 15- 45 greatly with(38 114) air mass

high-

Dry all seasons, large year-to-year variations.

Very dry summer; most rain in winter.

Variable

Spring & summer Variable thtmder-showers, "'inter snow. Pre-vai 1 ing winds off· shore (land to sea); shielded by mountains from on- shore moist winds.

360

320

370

280

320

32(J

7a ~larit ime temperate, Overland

30°-60° ~bderate Moderate to 25-100 high (varies(64 254) with wind

flriest season tends to be spring or :;ummer; high rain-fall coastal mountains.

Prevailing winds 320

'b Maritime temperate, OVersea

s Polar

direction & air mass changes)

30°-60° ~kxlerate High

60°·90° Very large LCJN

2S- 60 (M-15~1

5- IS (13- 381

h'inter snow very dry; most precipitation in sunrner sho\~ers.

off sea & unobstructed by mountains; flow off land mass brings lowest htm1idity. May be significant land- sea breeze effects.

32n

3fln

0- 30 Shower type rain nates; any anomalous propJgation occurs in stable periods between showers.

60-100 \\'here land is dry, ducts may form at t irocs most of rear.

30 60 Usually lowlands near sea.

20- 80 Scatter propagation poor, especially in summer.

10- 30

211- 40

20- 30

These reg ions close to the sea, many are subject to eleo vated ducting in dry season.

Affected by roving ston!Ls, fronts, and pressure Sheltered from sea or lake influences, ~s in

plateau areas may be 250-280.

areas are west coost continents or large islan:J

in latitudes of westerlies (United Kingdom, west Europe west coast~- America), Japon more nearly climate 6.

20- 30 Applies to coastal & oversea areas where hoth hon · zons of path are on sea. Ducts mar occur frequent I r.

10- 40

Table 9 • Time Block Ranges [47, E· III-45]

No. Months Hours

1 November - April 0600 1300

2 November April 1300 - 1800

3 November - April 1800 2400

4 May - October 0600 - 1300

5 May - October 1300 - 1800

6 May October 1800 - 2400

7 May - October 0000 0600

8 November April 0000 - 0600

Summer May - October all-hours

Winter November - April all-hours --·-··-

table 3. Short discussion for each of the parameters given in

table 3 are provided in this section. These discussions are or

dered by order of appearance in table 3. Information as to how

these parameters are related to particular capabilities can be

obtained from the capability discussions nrovided in section 3.2

and table 1.

AIRCRAFT ALTITUDES These represent the altitudes (a) for which

specific curves of power available (fig. 21), power density, (fig.

22) or transmission loss (fig. 23) curves will be developed, or

(b) that are used to cover the altitude versus distance airspace

for which volume (e.g., power available volume, fig. 24) or con

tour (e.g., EIRP contours, fig. 27) type graphs are desired. Es

timates of the altitudes required for the latter can be made by

the program operator from the graph format specifications of

table 4 so that the specification altitudes in table 3 are not

always required. Altitude is measured with respect to mean sea

level (msl) and provision for the ~se of units of feet (ft-msl)

or meters (m-msl) are made in table 3. The appropriate units

should be circled or explicitly stated, if different from the

choices provided.

105

TIME AVAILABILITY The specification of time availability (see sec. 4.1, TIME AVAILABILITY ... discussions) is required for those

capabilities where a single time availability is used. It may range from 0.01 to 99.99 percent. Statistical rain attenuation effects will only be present for time availabilities greater than

98 percent (see sec. 4.1, RAIN ZONE discussion). A time availability of 95 percent will be used when another value is not specified.

POWER AVAILABLE, POWER DENSITY, TRANSMISSION LOSS AND/OR EIRP Single and/or multiple values of power available, power density,

transmission loss, and/or EIRP are needed for several capabili

ties.

STATION SEPARATION The specification of station separation (fig.

42) is required for those capabilities where a single station

separation is used. The appropriate units should be circled or explicitly stated, if different from the choices provided.

DESIRED FACILITY-TO-AIRCRAFT DISTANCE This distance is re-

quired for the Signal Ratio-S (fig. 33) capability where the

location of the aircraft is fixed (altitude and distance) rela

tive to the desired facility. The appropriate units should be

circled or explicitly stated, if different from the choices provided.

DESIRED-TO-UNDESIRED SIGNAL RATIO Specification of desired-

to-undesired signal ratio (D/U) is required for those capabilities where a single D/U ratio is u~ed.

PROTECTION POINT LOCATIONS Protection point locations must be specified for the orientation capability. Th~se points are

located relative to the desired facility as illustrated in figure 43 with angles relative to the desired facility course

line, and desired facility to protection point distance. Pro

tection point locations will be taken as those associated with figure 43 when they are required, but not specified. The appropriate units should be circled or explicitly stated, if

different from the choices provided. 106

4.3 GRAPH FORMAT PARA~1ETERS (Table 4, p. 78)

Parameters associated with graph formats are covered ln ta

ble 4. In many, if not most, cases, an adequate selection of

these parameters can be made by the program onerator so that

complete specification via table 4 is not often required.

Some graphs have options associated with the ordinate (feet

or meters) and/or abscissa (degrees, kilometers, nautical miles,

or statute miles) units. These options are selected via table 4

by circling the choice desired. The degrees option involves the

use of central angle instead of path distance (fig. 41). This

option is useful when coverage estimates for a geostationary

satellite are required.

Except for the spectral plot capability, the parameters re

quired for table 4 are associated with the ordinate (lower-to

upper) and abscissa (left-to-right) scales. End points, incre

ment between grid lines, and units are specified. The interval

between end points should correspond to an integer number of increments. Except when transmission loss is plotted, the unner

value should exceed the lower value. In all cases, the right

value should exceed the le value and values less than zero

should not be used.

Spectrum plots may be made with the spectral nlot capability

for any 5 consecutive lobes within 10 lobes of the radio-horizon where the first lobe is taken as the first lobe inside the radio

horizon (see SPECTRAL PLOT, fig. 15, discussion ln sec. 3.2).

For example, speci cation to "plot lobe 3 through 7" would re

sult in plots for lobes 3, 4, 5, 6, and 7.

5. SUMMARY AND SUBMISSION INFORMATION

The ten computer programs covered by this report are useful

in estimating the service coverage of radio systems operating in

the frequency band from 0.1 to 20 GHz. These programs and the propagation models (sec. 2) used in them are extensions of work

previously reported [24; 25, sec. CII]. They may be used to

107

obtain a wide variety of computer generated microfilm plots.

Plotting capabilities are summarized in table 1 and discussed in

section 3.2. Sample graphs are provided in section 3.1 and sam

ple problem applications are given in section 3.3. Concise in

formation on input parameter requirements is provided in tables 2

through 4 (sec. 4)

A potential user should

1) read the brief description of the propagation model

provided in section 2 to see if the model is anpli

cable to his problem,

2) select the program(s) whose output(s) are most apnro

priate from the information given in section 3 (ta

ble 1),

3) determine values for the input parameters discussed

in section 4 (table 2 through 4),

4) request a cost estimate for appropriate computer

runs, and

5) submit the formal request and/or purchase order that

may be required.

FAA requests should be addressed to:

Federal Aviation Administration Spectrum Management Staff, ARD-60 Systems Research and Development Service 2100 Second Street, S.W. Washington, D. C. 20591

Attention: Navigation Specialist

Telephone contact is strongly encouraged, and Mr. Robert Smith,

Navigation Specialist, can be reached at 426-3600 if the Federal

Telecommunications System (FTS) is used, or (202)426-3600 if com

mercial telephone is used.

Other requests should be addressed to:

Department of Commerce Spectrum Utilization Division, OT/ITS 1 325 Broadway Boulder, CO 80303

Attention: Mary Ellen Johnson

108

Telephone contact is strongly encouraged and Mrs. Mary Ellen John

son can be reached at 323-3587 if FTS is used or (303)499-1000

x 3587 if commercial telephone is used. If extension 3587 can't

be reached, try extension 4162, which is the Spectrum Utilization

Division office.

6. ACKNOWLEDGEMENTS

The authors wish to acknowledge the assistance and advice of

several people at DOC; in particular, Dr. George A. Hufford for

his general advice and help with the scatter model; Mrs. Anita

Longley for her assistance with the long-term variability in re

gard to climates; Mr. Joe H. Pope for his assistance with the

ionospheric scintillation model; Mr. C. A. Samson for his assis

tance with the rain attenuation; Mrs. Rita Reasoner for program

ming assistance; and, Mrs. Beverly Miranda and Mrs. Beverly Gould

for manuscript preparation.

109

APPENDIX A. ADDITIONAL PROBLEM APPLICATIONS

This appendix provides additional problem applications simi

lar to those of section 3.3. These problems were included toil

lustrate the effects of varying particular parameters on system

performance. The subject of each problem is summarized in table

Al, and these subjects have been used ns headings in the text as an aid to the reader.

Problem

Al

A2

A3

A4

1\5

A6

A7

A8

A9

Table Al Additional Problem Applications

System

ATC

ATC

TACAN

Satellite

Satellite

ILS

ILS

ILS

ILS

Predicted Parameter

Range

Range

Range

Range

Margin

Separation

Separation

Separation

Separatjon

ATC, Range, Polarization

Variable Parameter

Polarization

Terrain Parameter

Beam Tilt

Scintillation Index

Sea State

Site Elevation

Surface Constants

Terrain Parameter

Terrain Profile

Problem Al: timate the gapless service range for the geometry

illustrated in figure Al and the ATC system with parameters of

figure A2 for vertical, horizontal, and circular polarization by

using both the lobing and variability options of the transmission

loss capability. Use a time availability of 95 percent, and ba

sic transmission loss, Lb (95%), value of 125 dB to determine ser

vice range. Here, gapless implies that satisfactory service,

Lb(95%) ~ 125 dB, is available at all distances within the service range; i.e., no gaps.

110

Solution: Key parameters associated with this problem are

illustrated in figure Al. Figures A3 through A8 were developed

in response to this problem and the values of maximum gapless

range tabulated below were taken from them.

Polarization Figures Gapless Service Range [n mi (km)]

Lobing Option Variability Option

Vertical A3,

Horizontal AS, Circular A7,

A4 A6 A8

179 (332)

28 (52)

75 (139)

82 (15 2)

56 (104)

67 (124)

Note that (a) the use of vertical polarization results in the

greatest range in all cases since it has the lowest reflection co

efficient associated with it, (b) the variability option results

in the lower range in two cases since it is usually more pessi

mistic when low (< about 0.5) reflection coefficients are in

volved, and (c) the lobing option results in the lowest range for

horizontal polarization since it tends to be more pessimistic for

high (> about 0.5) reflection coefficients. --- -- -- ----Horizontal polarizatiOr' is perpendicular to both..........._::--.......

thE' '.ac!lity-to~airc,.aft ray (FAR) and tht! ~~Aircraft altitudee: 9redt-c:rcle path plane (GCPP) ' 4'" 000 f (I 7 6

Veftica! po',aritat:on :c, p~rpend

and in t",e GCPP,

Circular polarizatior' has ooth horizm,~al and'

vert i cd: polar i zat i OP C~JI"HI)Onen~s.

Faci I i tv antenna height"' 50 f t (15. 2 m)

UU"' De,irec facility-to-aircraft q<cco{-clrcle distunc~.:.

'- ). t 3. I m)

'- ......

Figure Al. Problem Al~ geometry sketch (not drawn to scale).

111


BASIC TRANSMISSION LOSS FOR ATC

§~~~!~!~~!!2~-~g~f~~ AIRCRAFT (OR HIGHER) ANTENNA ALTITUDE: FACILITY (OR LOWER ANTENNA HEIGHT:

45000. FT (l3716.M} ABOVE MSL 50.0 FT (l5.2M) ABOVE FSS

FREQUENCY: 125. MHZ



EFFECTIVE REFLECTION SURFACE ELEVATION ABOVE MSL: GAIN SUM OF MAIN BEAMS: 0.0 OBI FACILITY ANTENNA TYPE: ISOTROPIC

POLARIZATION: HORIZONTAL

0. FT (O.M)

HORIZON OBSTACLE DISTANCE: 8.69 N MI (16.09KM) FROM FACILITY* ELEVATION ANGLE: -0/ 6/30 DEG/MIN/SEC ABOVE HORIZONTAL* HEIGHT: 0. FT (O.M} ABOVE MSL


SURFACE REFLECTION LOBING: CONTRIBUTES TO VARIABILITY SURFACE TYPE: AVERAGE GROUND TERRAIN ELEVATION AT SITE: 0. FT (O.N) ABOVE MSL TERRAIN PARAMETER: 0. FT (O.M) TIME AVAILABILITY: FOR INSTANTANEOUS LEVELS EXCEEDED

* COMPUTED VALUE

Notes: 1) Polarization, surface reflection lobing option and terrain parameter used for figures A3 through A8 and AlO and All vary as indicated in the figure captions.

2) Parameter values (or options} not indicated are taken as the assumed values (or options) provided on the general parameter specification sheet (table 2).


Figure A2. ~oblems A1 and A2~ parameter sheet~ ATC.

112

p 1-' (.rl

R~a Ctdt 77/07/19. II. 3,.42

VERTICAL WITH LOBIN' ··············• F"ru IPUt F"rt~t~o~tU~ 125. ""' '•ia 0. 0 d9i r~,~,,,, 51. HI SO. It (15.2m)fss S•etth t•rth [•lddltl S01. H2 4SOOO. It (13716 .m)ms1 Pet•riutlea V•rt iul !IIWtrl 951.

Distance in km

90 I 100 200 300 4QO 5QO 600 720 I

CD -g

.::: -41" 41"

:~ I

..... ~ l t-.......

l I .....

~ l ~ .......... ·~ ' ~-· ~ .. ·-.... ...... .

100

110

120

150 0 -.::: 0 ·-41"

"" ·~·· ..•. . ...... t

~ !'\

" l'\\ 140

ISO ... -• \\ '"'

,,0 M c 0 &..

1-

\~ " ~ \" 1'--- ~

[--.... I

170

180

' --~ i'... ' I 190 1--......_

~ I 200

0 25 50 75 100 125 150 175 200 225 250 275 no 525 5! 0 3 5 .tO 210

OJstaftce ift ft Mi

Figure A3. T1•ansmission loss~ ATC~ vertical polarization~ tobing option. Transmission toss values were computed with parameters in figure A2 except for polarization and tobing option.

~

~ .j::o.

R11r. Ctdt 77107/19. 11.59.47.

VERTICAL WITH YARlABlLJT¥ ··············· Frtt spoct F"rt111UCy 125. l'tHz leoir. D. 0 dB; l~&,trl 51. HI 50. It (15.2m}fss S•ttth urth l•lddltl 501. H2 45000. It Cl3716.m)msl Ptlorizetitt Vtttictl ,, .. .,, 951.

Distance in km 100 200 300 400 sco 600 700 ,,___ 90

cO "0

iC -"" "" 0 -iC 0 ·-"" "" -• "" iC a ....

1--

I~ ,~ ...

~~--h-I !'I. to--..

'-........... ...... ~ ....... ~·· ~-· ............. ........

~ ... ···~ .........

~ ~ '\ l'\\ ~ l~ \~ ............

"" I

\~ i'-r-..... '"""" I

!DO

II 0

120

130

lAO

ISO

••o 170

180

19 ' --.. ~ ~ I

r---~ ' ~ ' 2C

21 'o 25 sc 75 100 125 150 115 2DD 225 250 275 soo 525 550 '~ 40 0 Oistaftct 1ft ft •i

Figure A4. TPansmission loss~ ATC~ vertical polarization~ VaPiability option. Transmission loss values were computed with parameters in figure A2 except for polarization.

......

...... U1

R~• Ctdt 7710711!. 11.3!.51. --

HORIZONTAL WITH LOBIN' ............... Fru JPIIct FrtiJI4tU~ 125. P'IHt ,.i. 0.0 cl8i r~pperl 51. HI 50. ft (15. 2m) fss Sattth urth lalddltl 501. H2 .tSOOO. ft {137l6.m)ms1 Ptltr i tot ita Heriteatel lltwtrl !51.

Distance in km

' I 100 2QO 3_QO 400 SQO 600 700

I 0 I

(X) II "'CJ

.: 12

II\

15 II\

I 1... ~

~\ ) ·• .. J

1 I ..... •···•··· .. :::::;

~ ...........

) ~· ~ .. ··--~. ·•·•· . 0 -l.t .:

0 ·- 15 II\ II\ -• IG

" .•...•.

···~··· •1

~ i'\ 0

'\ l\\ 0

~ ~ 0 "' .: 0 17 ~

....... 18

\~ ........... ~ 0

\' 1'- """' 0 !'-..... I

' --~~ ~ I " r---1--~ I 20

• 'o 25 so 75 100 125 lSD 175 2Ga 225 250 275 !OD 325 550 1 r5 .tO 0 21

Oistol\ce II\ 1\ Mi

Figure AS. TPansmission loss, ATC, hoPizontal polarization, lobing option. TPansmission loss values wePe computed with paPameters in figure A2 except for the lobing option.

j--1 j--1

cr.

m 'V

a=

.. .. 0

a= 0 -.. .. -• .. a= a L-

t-

Rwft Ctdt 77/07/1,, 11.1,.4,.

HORIZONTAL WITH VARIABILITY ............... ,, ... ,.u Frt<twtacy 125. 11Hz Goia 0.0 d8i fll,ff J 51. Hl 50. ft (15.2m)fss Sauth ttrth la144ltl 501. H2 45000. ft (l37l6.m)msl Pel•ritttita Her i ua to I llt•trl !51.

Distance in km

I 90 lQO 200 3QO ~0 5QO 6QO 7QO

l.t

15

I~ 0 ~ I~ '""" -- ........_

~ r--r--.. ~

'""" -.... ~ -~ ~ .. r-- ~··· ··--·· ·•······ -- ......

~ ~ ..•...•. ...........

1'\ I

"\ L\\ I

1 0 0

11 0

120

1 50

1& I \\ \.. 17

\ ~· --.... ['.... 0

18 \' i'-.. ..............

!--...... 0

19 ' -~ "" 0

r-- r--. ~ ) 20

L - - 75 300 325 350 ' 5

40 21

50 5 1 DO 125 ISO 175 200 225 250 2 0 Distance inn mi

FiguPe A6. TPansmission loss~ ATC~ hoPizontal polaPization~ vaPiability option. TPanamiasion loss values wePe computed with parametePs in figuPe A2.

..,

Rwa Ctdt 77/07/19. 11.19.5•.

CIRCULAR VITH LOBIN' ··············· F'ree tll•ct F're•weuy 125. P'liz ,.;, 0. 0 d8i lwll!ltrl 51. HI 50. ft (15. 2m)fss Sattth .. rth lalddltl 501. H2 •sooo. ft ll37l6.m)msl Pe!triutlea Ci rcwltr I ltwtrl S$1.

Distance in krn

90 100 200 3QO 4QO 5QO 600 700,

:~ ~· :-.......... I v ....... .... -.. ·~ ~ ' I ~· ~·· ··- ........

~ ~~ ~ ·~·~···~ ····•·••j

I

'\ l'\\ I

\\ "' I

'~ .......... ~

\~ j'-...... 1"-- "

IOD

liD

120

150

1'0

150

I'D

170

180

·' -~ l'.. 190 r--. r--~ 200

21 10 25 so 75 100 125 HO lr! 200 225 2 0 vs 300 325 5! 0 1 rs •o 0 Olstaftce 1ft "al

Figure A?. Transmission loss~ ATC~ lo~ polarization~ Zobing option. Transmission loss values were oompu with parameters in figure A2 except for polarization and lobing option.

1-' 1-' 00

R,." Ctdt 77107/". II. 39.5,,

C!RCVLAR W)TH VAR!AB!LITY ............... F'ru .,.CI F'rt116111C!f 125. MHr bllill o. o dB i r,.,.,l St H1 50. ft(l5.2m)fss S•••th unh !•iddltl Sot H2 45000. It (13716.m)msl Ptleriutitll Ci rc,.Jer llturl 95t

Distance in km 100 290 300 4~0 500 600 700 I 90

co '0

..:: -"" "" 0 -..:: 0 ·-""

I!IJ...

I~ ~ " ~ r' r--

to--. r-- ....._ '

~ ~ -~ .. r-... ~ .... ··-..... ·····•· --

"' 1'\ •···•· .. ~ ..•... ~ '\ :'\\

100

11 0

120

150

t•o

150 "" -• \\ ~ I 1£0 "" ..:: 0 .... ..__

'[\ ""' ~ I

\~ ~ r--. ............

I

170

180

19 ' -~ I'. I

r--r--. t"'---... I 20

'o 25 so 15 100 125 l! 0 t'S 200 225 21 0 215 5DO m " o r'5 •• 21

0 Clttaftce II\ " •I

Figure AB. T~ansmiss1~n loss~ ATC~ ci~cular pola~ization~ va~iability option. T~ansmission loss values ZJe~e computed with pa~amete~s in figure A2 except fo~ pola~ization.

ATC, Range, Terrain Parameter

Problem A2: Estimate the maximum gapless service range for an

ATC system with the geometry illustrated by figure A9 and the

parameters of figure A2 with vertical polarization for smooth

earth, rolling hills, and mountains by using the transmission

loss capability with the variability option. Use a time availa

bility of 95 percent and basic transmission losses of 130 and

150 dB.

Solution: Pigures A4, AlO and All are applicable to this

problem and the values of gapless range tabulated below were ta

ken .from them. The increase in service range with terrain irreg

ularity for Lb(95%) = 130 dB is caused by a decrease in the specu

lar reflection coefficient as sur ce roughness increases, while

the decrease for Lb(95%) = 150 dB is caused by a decrease in radio

horizon distance. Except for the last case (mountains, 150 dB)

increasing irregularity tends to increase the service range be

cause of a corresponding decrease in reflection coe cient. In

the last case the decrease of service range occurs because of a

decrease in radio horizon distance. --------

Facility antenna 50 f t ( 1 5. 2 m)

--- ---....-.....-.... -

--------

Surface roughness computed from ~h is used in the calculation of reflection coefficients.

dD= Desired fac iIi ty- to-aircraft great-circle distance.

...... (

Aircraft altitude= 45.000 ft 113,716 m)

...... -........ .........

.........

' ..........

' ' ' ' ' -- ___ ......._ 0 ' ----- " ,/" I ......_

,/ I ' I

/ I / I

\ ' I '. ..... ,/ I

I

Facility horizon parameters are computed using the terrain parameter,~h. Beyond this horizon the earth is considered smooth.

Figure A9. Problem A2~ geomd-l'U ._,7<.etah (not draum to saale). 119

1-' N <:::)

Ru~ Codt 77/0./12. 15.52. ~8.

ROLL!tJG PLAINS-ATC ............... F'rtt lfiCICI F requertc~ 125. MHz Gai11 0. 0 dBi (upptrl 51. Hl 50. ft (l5.2m) fss Ah 195. ft l•iddltl 507. H2 45000. ft (l37l6.m)msl Polarization Vertical tlo11trl 957.

Distance in km

9 100 200 300 100 500 600 700 )-··

~

10

en 11 -o

1\.

~" I!.. ........... ~ c:

12 V\

13 V\ 0 --

14 c: 0

·- 15 V\

I -r-::: -r--.. !'-- -~ r=.:.::··· ~· '- ............ ·····-·· I ..__ ..........

-··~ ...... r---... ~ [\ I

'\ [\\ I

V\

-e. 16 I \\ 1\_ V\ c: 0 ..._

1--

IS

\ l\ ~ ~ I

1\-1'-r--... ~ I

" ......... ~ ~ I 19

r--r-- r-.... I 20

J \ 21 ·c 25 50 75 I 00 125 ISO 175 200 225 250 275 '500 325 '550 '575 •oo

Distance in n mi

Figure AlO. Transmission loss, ATC~ vertical polarization~ rolling plains. Transmission loss values were computed with parameters from figure A2 except for polarization and irregular terrain with 6h for rolling plains (195ft, 59 rn). Horizon parameters were calculated from 6h.

1-' N 1-'

Ru~ Codt 1110•112. 1&.••.22.

MOUNTAINS-ATC ............... F rtt ,,OCt F',. ql.ltll c ~ 125. l'tiz Gai11 0. 0 dBi 1~.~,.,: 57. HI 50. ft (15. 2m) fss lh 740. ft l•iddlt) 507. H2 45000. ft (l3716.m)msl Polarizatioll Vertical llo .. r: 957.

Distance in km 100 200 300 400 500 6QO 700 r·-•--90

ro -o

c:

)~

~ i

...........

) ~ -......

I 00

II 0

120 ..., ..., 0

c: 0 -..., ..., -e. ..., c: Cl ....

I--

!40

-~ ~ ~ ~-· '\···· ~ ........ J -·····--.............. L\\ ····- ........... ~ J

~ l\ I 0 I

\~\ c r-...

\\ ~ ~ 0

\ '-.....,

"" 1---0 ~

130

ISO

1&0

170

19

I~ --. ~ o~--\9

-....... ..___ 1--r--... : 2~

I

'-21 25 so 75 too 125 tso 175 200 225 2so 275 3oo 325 3So 375 •oo

D i s tal'\ c e in. n M i . Fi(JI--tre A11. Transmission loss~ A1'C~ vertical polarization~ mountains. 1'rl1nsm-ission loss values 1.Jere

computed with pcn•ameters from figure A2 except for polarization and irregular terrain 7Jith M for mountains (740 ft~ 226 m). Horizon parameters wePe calculated fNJm t:.h.

Terrain Fi e Gar less Service Ran~e [n mi (km)]

130 dB 150 dB Smooth earth A4 118 (219) 254 (470)

Rolling plains AlO 165 (306) 254 l470) :.1ountains All 175 (324) 244 ( 4 52)

TACAN Beam Tilt

Problem A3: Estimate the maximum service range for the geometry

illustrated in figure Al2 and the TACAN parameters given in fi~

ure Al3 for three antenna main beam tilts, (a) normal, (b) 0°,

and (c) adjusted to track the aircraft. Use -86 dB-W/sq m of

power density and a time availability of 95 percent to define

maximum service range.

----- rAircraft altitude= --- 40,000 ft (12,192 m) ---

do= Desired faci 1 ity-to-aircr~ft great-circle distance.

........... ....................

.......... ..........

'-.... (a) Tracking, mainbeam always

points at aircraft

(b) Normal, mainbeam elevation

anqle fixed at 7°. (c) Mainbeam elevation angle

fixed at ou.

FiguPe A12. Problem A3~ geometPy sketch (not dPa~ to scale).

122


POWER DENSITY FOR TACAN

§~~~!~!~~~!~~-~Q~!~~ AIRCRAFT (OR HIGHER) ANTENNA ALTITUDE: FACILITY (OR LOWER) ANTENNA HEIGHT:


FREQUENCY: 1150. MHZ


AIRCRAFT ANTENNA TYPE: ISOTROPIC POLARIZATION: VERTICAL

EFFECTIVE REFLECTION SURFACE ELEVATION ABOVE MSL: 0. FT (O.M) EQUIVALENT ISOTROPICALLY RADIATED POWER: 39.0 DBW FACILITY ANTENNA TYPE: TACAN (RTA-2)

POLARIZATION: VERTICAL HORIZON OBSTACLE DISTANCE: 6.73 N MI (12.46KM) FROM FACILITY*





* COMPUTED VALUE


2) Parameter values (or options) not indicated are taken as the as-sumed values (or options) provided in the parameter speci-fication sheet (table 2).


Figure A13. A 3.. parameter TACAN.

123

Solution: Figures Al4 through Al6 were developed for this

problem and the values tabulated below were taken from them. The

larger range for the normal tilt angle is caused by better surface

reflection discrimination associated with the antenna pattern

tilt.

Beam Tilt Figure Gap less Service Range [n ml (km)]

Normal Al4 125 (232) oo Al5 100 (185)

Tracking Al6 108 (200)

Satellite, Range, Scintillation Index

Problem A4: Estimate the maximum north latitude for which satis-

factory service is available r a VHF geostationary satellite

with the geometry illustrated in figure Al7 and the parameters of

figure Al8. Let the ionospheric scintillation index group be

fixed at 0 or 5. Also, use the variable scintillation option

(table 2, scintillation index group code of 6) with the frequency

scaling factor option (table 2). Use a power available at the

receiving antenna terminal of -140 dBW and a time availability of

95 percent to define satisfactory service.

Solution: Figures Al9 through 21 are applicable to this

problem, and the values tabulated below were taken from them.

The maximum north latitude occurs along the subsatellite meridian.

0

5

Variable

Al9

A20

A21

Maximum North Latitude

During worst case conditions (group 5), the power available 95

percent of the time never exceeds -137 dBW so that a 3 dB increase

of the received power requirements would result in unsatisfactory

service for all angles. However, the same increase in received power requirement would not decrease coverage to a maximum north

latitude significantly for the other two conditions examined.

........ N U"1

P.ur. Code 11/0.C/12. "· .CB . .CO.

HAIN LOBE AT NORMAL ELEVATION .............. , F'ru IJIGCI F'requer.c~ 1150. MHz . EIRP 39. 0 d81t luJIJI tr I 57. HI 30. ft (9.lm)fss S111ooth earth l•iddltl 507. H2 40000. ft (12192.m)msl Polar i zat ior. Vertical llowtrl ~?.

Distance in km

-bO 5Q lClO 1~0 2DO 2?0 300 350 400 4_{0 5QO 550 I

E. -70

cr II'\

......... 3 -80

I

a:l "\::)

-90 ~

-::r-. -I 00 -II'\

c -110

lL\. - - l lL'\7' ........... IY" ~

~ I I

~ ~ I I --~ """--.. ~ ---.

~-........._ ~ .. ····-····-·· ······· I

~ r--- ---~ \ -D\ 1\ ... ""0

,_ -120 \ \~ 4.1 :a 0

-130 Q... 1\\ ~

-140 \" ~! -150 \

~ i -- --I bOO

25 so 75 I 00 \25 \SO 175 200 225 250 275 300 0 i stance in 1'1 rni

Figure A14. Power densit;t, TACAN, main lobe at normal elevation angle. POtJer density values I,,epe eomputed with the parameters from figure A 13.

f-A N 0\

£

o· VI

........ Jll

I en -u

c

-GO

-70

-80 I

-90 J

~ -too ) -VI

) c -110 .., -u

.... • \20 .., ll 0

a... -1'50

- t4 I

-15 I

1'1 ·1 '·o

R1111 Code 7?/04/20. I G. 1'5. '53.

MAIN LOBE AT 0 ELEVAT!O:; ····· ········· F'ru space Frt~lltiiC!f 1150. l'tiz E:RP '59.0 dSW t~&pptr) 57. HI '50. h (9.1m)fss S.ooth urth l•iddltl 507. H2 40000. ft (l2192.m)msl Po:arizotioll 'itrtical !lower) 957.

Distance in km 50 100 150 200 2~0 300 350 400 4'30 500 5SG

/},. rr ~ --t--- r-- --!'--... 1'---. r---......_ -... ~ ·~· ~

............. ,,

1---......... _.

1--- t-- ·•·····•····· .............. ....... 1-- ~\' r---

\' l\ \\" ~ l\_~ \ ~

'\ ~

' 25 so 75 100 125 150 t75 200 --225 -250 ---21'5 '500

Distance in n mi

Fif1Ur>e l'.l ,s. Po1.JeY' dens i. t.'l, TAr'AN, f11ain lobe at oo elevation. Power• density vo lues ?;Je:re comvuted h'lth 1Y<I'Ofl1eteY's f'Y'om [1:guY'e A1.1 f'o:r elevation angle.

~"II :odt 17101/U. ll. 03. H.

TAC~N TRACK JN; ··········F'•u HOCI r., 1 .. tt~cy 115 D. 11Ht [JRP 39.0 d8W I"H"I 52 HI 3D. f\(9.lm)fss S•oo th tot\~. l•iddltJ 501. H2 40000. fl (12192.m}msl Polori:otioll Vtrtical lion•' 957.

Distance in km

e

50 100 150 200 250 3QO _3~() 400 4/0 soo sse I ---..1 I ..L ··- - __.1_

' "-... 1·-

_,0

·70 cr ....

........ :a • en

-c:;,

,;::

·-1-' 7'\

~ r---. - r---r---1----·-

""" -~ ··-\· 1'--- ~ "··-......... ............. .............. ....._ t---.. It-- ·-·--1--- r--- ~~' r---,..... 1-- ------- ----

·80

·90

·UO N --..,_]

"' ,;:: I \\ l\ 1--- -· -·-· -110 ...

"0

._ \ l\" "' ---120 ...

Jl 0

tL \"" ----- ···-·-·130

-14

I \ ~ l 1--··-- 1-

l '\ ~ I -------- ~-·15 ..........,

I

l . -·I &.0 25 50 75 100 125 ISO 175 200 225 275 250 300

Oistal\ce il\ 1\ mi

?ipure A16. ?m,,~'i' fens1~t71j TACMJj lobe tr•acking aircraft. Po7,Jer 1Jo.lues /,,ere eon~':<. . !.'1: th .figure A13 except .for trac'V.inp opHo-r:.

/Geostationary satellite altitude=. 19,351 n mi (35,838 km)

----...._ --- Aircraft altitude= 30,000 ft (9, 144m)

sur face

Central angle,80 , is latitude along the subsatel lite meridian.

128


POWER AVAILABLE FOR VHF SATELLITE SEA STATE 0

§~~~!~!~~!!2~-~Q~!~~ AIRCRAFT (OR HIGHER) ANTENNA ALTITUDE: 19351. N MI {35838.KM) ABOVE MSL FACILITY (OR LOWER) ANTENNA HEIGHT: 30000.0 FT (9144.M) ABOVE FSS FREQUENCY: 125. MHZ





HORIZON OBSTACLE DISTANCE: 208.85 N MI (385.79KM) FROM FACILITY* ELEVATION ANGLE: -2/49/36 DEG/MIN/SEC ABOVE HORIZONTAL* HEIGHT: 0. FT (O.KM) ABOVE MSL



SURFACE REFLECTION LOBING: CONTRIBUTES TO VARIABILITY . SURFACE TYPE: SEA WATER

STATE: 0 CALM {GLASSY) 0.00 FT (O.OOM) RMS WAVE HEIGHT

TEMPERATURE: 10. DEG CELSIUS 3.6 PERCENT SALINITY

TERRAIN AT ELEVATION SITE: 0. FT {O.M) ABOVE MSL TERRAIN PARAMETERS: 0. FT (O.M) TIME AVAILABILITY: FOR INSTANTANEOUS LEVELS EXCEEDED

* COMPUTED VALUE

Notes: 1) Parameter values (or options) not included are taken as the assumed values (or options) provided in the general parameter specification sheet (table 2) .


Figure AlB. Problems A4 and AS~ parameter t~ VHF satellite.

129

R~,~,. Code ll/09/01. 11 . .&2 . .&1.

VHF SATELLITE SEA ST~lE 0 ...... ··· i=ru HOCt F'rt11.1t!\Clf 125. ~: ElRPG 35.0d8W hillllttJ 57. HI 30000. f t ( 9144 .rn) fss Saooth eorth l•iddlel SO?. H2 19351. ~ llli{35838.km)rns1Poloritotior. Circul~r !lower I 957.

-120 -

-130

::. en -140 "e

·········~ ...... ~

~ - -150 t'-.

~ -i-' ..Q VI 0 ·I bO 0 -...

0 > 0 ·170 ... ~

ll . t 80 0

Q...

-130

-20~

l\ I \ J l

I : 1 I i

J l -2t00 30 lO 50 'O 10 20 80 10 9'

Central angle in deg

h'i({UY'e A 19. PmueY' available, VHF satell1: scintillation index gY'oup 0, sea state 0. available values /,JeY'e calculated for' the paY'ameteY's of figuY'e AlB.

PouJeY'

I-' tM I-'

Run Codt 77/09/01. 17.42. 50.

SCINT!LL~TICN GROvP S ....... "··Fret spact F rt~uncy 125. MH: EIRPC. 35. 0 dB'i :uppt ri 51. HI 30000. lt{9144.m)fss S•oo 111 earth '•iddltl 507. H2 19351. n 111i(35838.km)mslPolarization (irc~o~lar tlowtr! 951.

-·20 I

I ·130

]II CIC ~

\ ............ .... ) -140

c:: ' -"'

I !\ ..... ·150

-..0 0 -I 60 I

0 > 0 -170 I t...

"' :. ·18 0 k\ I

Q..

-I~ I t----· -

-20 I \ ' I i \ -21.0 I 0 20 30 40 50 60 70 80 90

Cerdral ar~gle ir~ deg

Figure A20. Power available~ VHF satellite~ scintillation index group 5~ sea state 0. Power available values were calculated for the parameters of figure A18 except for scintillation index group 5~ and the use of the frequency scaling factor.

,__. c..N N

Rul\ Codt 71/09/0l. 17. 42. 53.

SCINllLLATION ~ROVP V'RIABLE ..... · ...... F'ret s,oct r a ""'uc ~ 125. MHz EIRP\0 35. 0 dBii :~.~,ul 57. HI 3COOC. f t (9144 .m) fss Saoo t 1'1 tor! II faiddltl 501. H2 19351. f\ llli(35838.km)mslPo!orizatio~ Circwlar flourl 951.

·12 0 I

I -- t:5 0

:ill co "0 ·14 --- .......... ; ......

~I\ I

c:: -·15 ~ I ., -Jl

0 - • I G 0 ·-0 > 0 -17 I

.... ., ll -19 0

a...

-19 ' \ '

-20 I \' , 30 .co so '~ 70

I 1 . - . -·21.0 10 20 80 90

Central angle in deg

Figu~e A21. Powe~ availableJ VHF satellite, va~iable scintillation index g~oup, sea state 0. Powe~ available values we~e calculated fo~ the pa~amete~s of fig~e AlB except fo~ a va~iable scinti?lation index g~oup, and the use of the f~equency scaling facto~.

Satellite, Margin, Sea State

Problem AS: Estimate the fade margin required for the VHF and

UHF satellite systems with the para~eters of figures Al8 and A22

at a central angle (fig. Al7) of 70° when the sea state is 0 or 6

and ionosphere scintillation is neglected. Take the required

fade margin as the difference between power available curves for

a time availability of 50 and 95 percent.

Solution: Figures Al9, A23, A24, and A25 are applicable, and

the values tabulated below were obtained from them.

Satellite Sea State Fade Margin (dB]

VHF 0 Al9 1

VHF 6 A23 0.5

UHF 0 A24 1

UHF 6 A25 <0.5 ·~-----·

-·----·---·-~

Fade margins required for smooth sea (sea state O) are greater

than those required for very rough sea (sea state 6, table 6) be

cause the roughness of the reflecting surface lowers the magni

tude of the specular reflection coefficient so that the short

term variability associated with surface reflection multipath is

reduced for higher sea states. The factor used to reduce the

specular reflection coefficient [24, (66)] provides more reduc

tion at higher frequencies (i.e., roughness expressed in wave

length increases with frequency), but is unity for a smooth sur

face regardless of frequency.

133


POWER AVAILABLE FOR UHF SATELLITE SEA STATE 0

~~~~!~!~~!!~~-~g~!~~ AIRCRAFT (OR HIGHER} ANTENNA ALTITUDE: 19351. N MI (35838.KM) ABOVE MSL FACILITY (OR LOWER) ANTENNA HEIGHT: 30000.0 FT (9144.M) ABOVE FSS FREQUENCY: 1550. MHZ





HORIZON OBSTACLE DISTANCE: 208.85 N MI (385.79KM) FROM FACILITY* ELEVATION ANGLE: -2/49/36 DEG/MIN/SEC ABOVE HORIZONTAL* HEIGHT: 0. FT (O.M) ABOVE MSL



SURFACE REFLECTION LOBING: CONTRIBUTES TO VARIABILITY SURFACE TYPE: SEA WATER

STATE: 0 CALM (GLASSY)

0.00 FT (O.OOM) RMS WAVE HEIGHT TEMPERATURE: 10. DEG CELSIUS

3.6 PERCENT SALINITY TERRAIN ELEVATION AT SITE: 0. FT (O.M) ABOVE MSL TERRAIN PARAMETER: 0. FT (O.M) TIME AVAILABILITY: FOR INSTANTANEOUS LEVELS EXCEEDED

* COMPUTED VALUE

tlotes: 1) Parameter values (or options) not indicated are taken as the assumed values (or options) provided in the general parameter specification sheet (table 2).


PiguPe A22. FPobZem AS~ paPameter sheet~ UHF Satellite

134

, ...... lM V1

Figure A23.

-120

-1!0

:a 00 ·I AO "'Q

.,:; -

-150 ... -..0 0 -1&0 -·-0 > 0 -110 ,_ ... ! -18C

a..

·19C

-200

·210 0

Rw~ Codt 771:9/~1. 17.A3.3t.

VH~ SATELLITE SEA STAT£ & ~,~~~~~cy 125. M~r £IRP' 35.0 d8W HI !OOOC. lt(9144.m)fss Saootll tortll H2 19!51. ~ ai(35838.km)ms1Polorizotioll Circ~lor

............ ~ , .. ,,.,. :~,.,; 57. !aiddltl 507. n ... ,l '5'-

~···~·1'-·····

~

1 90 10 20 30 'C 50 GO 70 8Q

Cer\tral ol'\,le il"' de' Power> avaitab VHF satel values weJ'e calculated fo~

teJ scintillation index g~oup OJ sea state par•ameter>s of figur>e A18 except for sea

e. P01Jer• available state.

1-' (A (]\

:ill CD v

·l•o If--

·ISO

c: • '&0

"' .n 0 -{7 I

0 ::. 0 -1 e I ._

"' :II 0

0- ·19 I

·2 0 I

I ·21.0

R-.t. Ctdt 77109/Cl. 11. -'3. "5-'.

UHf SATELLITE SEA STATE C ............ r,., .,ou ~ 'flll-.tiiC\j :550. I'!Ht ElRPii ":.o d9w : .. ,.,, 57. 1-11 3000C. lt(9144.m)fss Sautil urtil [aiddltl 501. H2 19351. " ai(35838.km)ms1Pelt,izotiu Circ-.for 'l•••, l ~7.

" ~ ~

"" '

1 0 2D !0 U 50 GO 70 -. to 90 Ctr\tral Or\9lt ir\ dt9

Figure A24. Power available~ UHF satellite~ scintiUaticm index group o. sea state 0. Power avaiZaMe values were calculated zJith the r>a:t'ameters of figure A22.

~

lN '-1

Ruft Codt 77/09/01. 11.43.37.

VHf SATEL~JTE SEA STAlE & ............... F'ru spoct F' rt1YtiiC~ 1550. MHz EIRPCi 41. 0 dBW { YPPI rl 57. HI 30000. It (9144. m} fss Saootll urtl\ {aiddltl 507 H2 1335). 11 ai(35838.km)ms1Poloritoti011 C i rculor f1 owtrl 951.

I -140

.) r--'--:;. l

·ISO

co "0 ~ ole -... -- ~

·1&0

..0 a -110 -·-a > a r---180 ... ... :II 0

Q... lr---190

-200 0

I 1 --·21.0 30 4~ SO GO 70 80 90 I 0 20

Cer\tral Or\,le ir\ de'

Figu.rt: .. ; ·~s. PoweY' available, UHF satel Ute, scintillation index gY'oup 0, sea state 6. PoweP available values were calculated with paramete.ros from figure A22 except foY' sea state.

ILS, Separation, Site Elevation

Problem A6: For the geometry illustrated in gure A26 and the

desired ILS localizer facility parameters of figure A27, determine

the station separation required to obtain a 23 dB desired-to

undesired localizer signal ratio at the aircraft \vith a time a

vailability of 95 percent when the parameters for the undesired

locali:er are identical to those of the desired localizer except

that its site elevation is (a) 1,000 rt (305 rn) higher, (h) 0 ft

higher, and (c) 1,000 ft (305m) lower.

2,000 ft (610 m)- msl~ , ... ~

I ,000 ft (305 m)- m~~~.--"

/

/ /

/

/ /

/

/ /

/ /

/

Desired facility (elevation fixed)

/ /

/

.,.------ 7,250 ft (2,210 m) - msl

-----+--:---------------- ....... -

138

Undesired facility (elevation variable)


DESIRED STATION IS LOCALIZER

§~~~!~!~~!!~~-~g~!~~ AIRCRAFT (OR HIGHER) ANTENNA ALTITUDE: FACILITY (OR LOWER) ANTENNA HEIGHT: FREQUENCY: 110. MHZ




EFFECTIVE REFLECTION SURFACE ELEVATION ABOVE MSL: 1000. FT (305.M) EQUIVALENT ISOTROPICALLY RADIATED POWER: 24.0 DBW FACILITY ANTENNA TYPE: 8-LOOP ARRAY (COSINE VERTICAL PATTERN)

POLARIZATION: HORIZONTAL HORIZON OBSTACLE DISTANCE: 2.88 N MI (5.33 KM) FROM FACILITY*



SURFACE REFLECTION LOBING: CONTRIBUTES TO VARIABILITY SURFACE TYPE: AVERAGE GROUND TERRAIN ELEVATION AT SITE: 1000. FT (305.M) ABOVE MSL TERRAIN PARAMETER: 0. FT (O.M) TIME AVAILABILITY: FOR INSTANTANEOUS LEVELS EXCEEDED

* COMPUTED VALUE

Notes: 1) The aircraft is 25 n mi (46.3 km) from desired facility, on the desired facility course line, and on an extension of the undesired facility course line, i.e., the course lines are directed toward each other.

2) These parameters, except as specifically modified in problem statements, also apply to the undesired facility.

3) Although the configuration assumed here may be taken as worst case in that a station separation sufficient to provide protection at the critical point considered (i.e., point C of fig. 43 with ~ =0 and ~ =180°) would probably provide sufficient protection at o~her crit~cal points, difference in terrain and/or facility antenna gains associated with these points could make a more extensive analysis necessary (see sec. 3.2 ORIENTATION discussion, fig. 35).



Figure A27. Problems A6 through A9~ parameter sheet~ ILS. 139

Solution: Examination of figure A26 shows that the aircraft

is at a constant elevation with respect to both mean-sea level

(msl) and the desired ILS site sur ce for all three parts of the

problem, but that aircraft elevation with respect to the undesired

ILS site surface changes for each part of the problem. Lower air

craft altitude with resnect to the undesired facility means that

the undesired signal level at the aircraft is expected to he

lower for a particular undesired facility-to-~ircraft distance

which will translate in the context of this 11rohlem to a decrease

in the station separation requirement. Conversely, a higher air

cr t altitude with respect to the undesired facility would be

expected to result in a larger station separation requirement.

Site surface elevations for various parts of the problem are

drawn as dashed lines in figure A26 and are extended from facility

to- ility to show that use of different site elevations is not

compatable with the use of a smooth earth for all of the terrain

between the facilities since different elevations result in dif-

rent earth radii. Desired and undesired signal levels are

computed independently for the parameters applicable to each

ility so that this difficulty is not recognized by the pro

grams, but must be considered in using the computer output. One

way to do this is to assume that each site elevation is valid at

least to the smooth earth horizon distance for its facility an

tenna and that the computed results are invalid when terrain at

the higher site elevation is visible to the other antenna. These

conditions are illustrated in figure A28 and result in a minimum

station separation (S . ) for which predictions are valid. Values - m1n for S . can be estimated from m1n

where s . == .V 2aHD +V2aH, +~ 2aHu mln ue

a= effective earth radius,

HD U =height of desired or undesired ' facility antenna above its site

surface elevation

140

(Al)

and ll 1n site el va tiOTlS*

Each term of (Al) is a smooth earth horizon type distance as il

lustrated in figure A28.

Figures A29 through ,:'\31 were deve1oped. fo1 thb problem and

the ration sPparation requirements resulting 1rom them 3re t

l:itcd l~elow alon~: with

Site Elevation Above msl

(ft CmL Desired Undesired

nnn

F

1,000(305)

1,000(305)

1,000(305)

2,000(610) A29

1,000(305) A30

0 A31

a

va1lJe:;:.:

e

141

btained fr m U):

uired Sttition ratio:1.

[nmi (km)J

100 (185)

l 7 (l 8

113 (209)

I l

[nmi (km)]

45 (83)

Not Apfllicablc

45 ( 8

\. /2nHU

S . = ~D ., 12aH + ~~ m 1 n t\e u

j-J

.j::>.

N

De,ired dis!o~~e 25. n mi(46.3km} Ru~ (odt 11101113. 22. 16.05.

--- ol;-i7ed (oc il i '~ Uri de ' i r r d I o ~ il i r~ ~-----

LOCALIZER I LOCALJZ£P. 2 .. '"•tt UOCt HI 1005.5 r 1 (306.5m)ms1 HI 20115.5 H(6ll. 3m)ms1 ___ ( ... -.. d 57. H2 7250. fl (2210.m)ms1 H2 1251. lt(2210.m)ms1 (•iddlt) 507. f rt1ut~C~ lfD. HH1 Oo•trJ 957.

Station separation in km 25 50 75 100 125 150 175 200 2i25 I • 50

I 40 / ~ CX) "0

,:; -

/~ t::/ v I

~ ...... v

~ v--I ---

30

21 0 --

•

~ r:---~ . .............. I .... 10 0 ....

-0 ,:; (T\ -...

"=> ......... C)

• 3

~ v . -~'' .•...•...... ...

h

"AI ,

,, I

/'Z I

~ ,

I

~ I

0

·I 0

·20

·4

I -s-o 10 zo !O 40 59 U 70 80 90 100 110 121 1!0 Station separation in n mi

Figure A29. Signal ratio-S~ ILS~ higher undesired ;acility elevation. Parameters are as given figure A2? except that the undesired facility site elevation is 2~000 ft (610 m).

Ouired di,ta11ce 25. n mi(46.3km) Ru11. Code 77101/13. 22. I G. 08. Ouired locility V11desired locilit~

............. I=' rtt S'OCt LCCALIZER I LOCALIZER 2 HI 1005.5 f: (306.5m}ms1 HI 1005.5 lt(306. 5m)ms1 luHtd 57. H2 7250. 1: (2210.m)msl li2 1250. f t(2210 .m)ms1 l~aiddltJ 507. l='recp .. ucy 110. ttHz llo-trl 957.

Station separation in km 25 50 75 100 125 150 175 200 225

I 1 5D

AD I /

CXl ~

-= -

/ ~ v I """

~ ~ l--- l.--7

I .....r: ~

30

20

0

·-1-' ... -!::> 0 tN L-

-0

-= ~

-"'

':) ........ 0

-1

~ ~ ~

~ ~

I • ......... ,A• .............

# ~ .... ······•···

....... · ...

I

,.,.· ~ I .' 1,

/"/ J

If' , I h

t'l

1 0

0

·2

·3

·l I

l -5.0 \D 20 30 lO 50 GO 70 80 90 100 110 1(0 130

Statior. separatior. ir. n ft'li

A.30. Signal ILS> equal site elevatz:ons. Parameters are as given in A27.

1-' +:» +:»

QQ "0

-=

0 --0 ....

-0 c 0"\

... ':) ........ 0.

'

50

40

30

20

10

0

·I 0

·20

·30

Ou i ud dis tallc t 25. n mi {46. 3km) R~11 Codt 17101115. 22. ''·II.

Ouirtd lacilit'l LOCALIZER 1 HI 1005.5 ft 1306.5m)ms1 H2 725G. lt (2210.m)msl f"rt~ufHij ]IQ. 11Hl

Vt~dtsirtd lacilil~ LOCAL llER 2 HI 5.5 it(l.68m}ms1

· .... l='ru s~act

(~Hf rJ 51. (aiddltl 507. Ch•••l ~57.

li2 7250. 1:{2210.m)ms1---

Station separation in km 50 25 225 75. 100 125 150 175

• ...1. 200

~ ~ ~ ,_. ...................... .

~ .............. ·····

-

v;r r7 ... c

-so 0 I 0 20 30 40 50 u 70 80 ~0 100 110 120 131

Statiol'l stparatiol'l in 1'1 1rd

FigUPe AJl. Signal ratio-S~ ILSJ lower undesired facility elevation. Parameters are as given in figu:r•e A27 exaept that the undesired lity site elevation is 0 ft (0 m).

ILS, Separations, Surface Constants

Problem A7: For the geometry illustrated by the equal site ele

vation portion of figure A26 and the ILS localizer parameters of

figure A27, determine the station separation required to ohtain

a 23 dB desired-to undesired localizer signal ratio at the air

craft with a time availability of 95 percent when the surf~ce con

stants (table S) are taken as those associated with (a) poor

ground, (b) average ground, (c) good ground, (d) fresh water, or

(e) sea water

Solution: Figures A32 through A36 were developed for this

problem, and the station separation requirements listed below

were taken from them.

Surface Type

Poor ground

Average ground

Good ground

Sea water

Fresh water

Hence, for this problem,

Figure

A32

A33

A34

A35

A36

surface type is

Station Separation [n mi (km2]

107 ( 19 8)

107 (198)

107 (198)

107 (198)

107 (198) .

not an important para-

meter. Other situations where vertical or circular polarization

and large (> 1°) grazing angles ($of fig. 40) are involved would

be expected to show greater dependence on surface type [49, figs.

III.l through III.8]. Even then the dependence may be masked by

surface roughness (probs. AS and AS), which makes the specular

reflection coefficients smaller as roughness increases.

145

Ouiu4 distcl\ct ZS. n mi(46.3km) Ru11 (odt 77/0l/13. 22. I G. 14.

l)u ired foe d i1y POOR 'ROIJNO

'Jl-.c~esiud locili\y ..... ;:-,,. , .. ,.

~· U05.5 lt(306.5m)ms1 Sou os dnirtd focility luHtrl 57. H2 7Z51. t t (2210 .m) ms1 laiddlt~ 507. ;:-,,~ .... 1\c;y 110. t1Hz n ... ,, 351.

Station in km

5 25 50 75 100 125 150 175 200 2t5 ~ I I

.co I /

en / ~ v L 3G

v

cr;:: - ~ r;: v-v '

......--::: 20 0 ·-

1-' -"""

0

Q'\ .._

-~ ~

~

h ······ ....... .............

I

~ .•

# .

..... . ····•··

I

I 0

0 cr;:: Ch -...

::> ........ C)

/~ 71 I ,"'

• I f.. ,. ,

A t r;

. \

·2

-3

-.c I

It -5~6 lO 20 30 '6 50 GO 70 80 '0 100 120 130 Ito

Station stporotion i~ n Mi

A3'2. r>atio-S,.ILS, gr>ound. Par>ameter>s ar>e in f1:aur>e A27

f-J .f::>. '-1

co -,;,

,;::

0

·-.... 0 ,_

0 ,;:: D"''

-.,.. ':)

' Q

Desired disto11ce 25. n mi{46.3km) R~o~11 Code 11101113. 22. l&. IG.

Ouirtd focili\~ -.vERAGE {.ROIM> HI IDDS.S lt(306.5m)ms1

V11 d u i red fa c i l i t ~

Saae as desired facility H2 72SO. ft (2210.m)ms1 ---

~ru HGtt

l~o~PHr) 51 <•iddltl 507. (Jo .. r) 957. ~ re quuq llO. HHz

Station separation in km 100 125 150 . 25

so 50 75 175 200 225

401------- /

H ~-20

10

0

~ ........... .~ ............ .. ~ .... L .. '··"·

-10

-20

-501-------

l7 -•o

-so 10 20 0 50 • • so u 70 80 90 '00 150 II 0 120

Statior. separatior. ir. r. ll'li

FiguY'e A.3.3. Signal raHo-8, average ground. Parameters aY'e as given in figur•e A2?.

50 I

40 I

Q) 30 I "'0

0::: - I 20 0

·-1-' ..... I 0 I .p. a co ...

- I 0 a 0::: cr. - -I 0 I ...

:::» ........ -20 I C)

-5 I

-l I

, -5.0

Duirtd ditlo!Ht 25. n mi(46.3km) R~~ Code 11101113. 22. K 18.

Ouirtd fc~eili\~ U11 du i r t d fa c i I i \ ~ ···· · ········ F'rtt tpact C.OOO 'ROVNO

HI 1005.5 ft(306.5m)ms1 Sou os dnirtd hcili\~ l~;p,ul 51. H2 1251. ft (22l0.m)ms1 lai ddltl 50'7. I=' rt ~~;ti\C~ 110. 11H: tlutrl 957.

Station separation in km 25 50 75 100 125 150 175 200 225 I.

/

/ ~ v ..,

~ ~ ~ v

........:: k---

~ V"":: ......-

~ v--

.......... , .... .............

~ ~ .... ·•······ ....... ....... ···'

......... ··

• I -K ~ ,

I

t'l I

-. 10 20 50 lO 50 '0 70 80 90 100 II 0 120 130 Stotiof'l seporotiof\ ir. r. 111i

Figure A34. Signal ratio-S, ILS, good gr•ound. ParameLers are as given in figure A27 except for surface

~

Dn i • e d d •' 1 o ~ c e 2 5. n rn i ( 4 6. 3 krn) R .. ~ Code 11/01/13. 22. tb. 59.

Du i • e d f o c ;t i t ~ V11clui~ed focilil':l ............ ' F"ru UCICt SEA 1111. TER

HI 1005.5 It (306.5rn)rnsl Saae os desired locilil~ ,,.,trl 57. H2 7250. It ( 2 210. rn) rns 1 laiddltl 501. F ''""'nc':l II 0. t1Hz llowtrl 957.

Station separation in krn 25 50 75 100 125 150 175 200 225

) .J.. _l t ' SD

I 40 /

CXl ~ v / "" 30

"0

,;: - ~ ~ ~ 1.-/

......-:::: l---20

0

·-1-' a ~ ,_ <-:::>

-a ,;: 17'\ -M

:::> ........ 0

It ~ ~ .....--

b .......... .... ,, ...........

# ~ .... •···· .. .. ····· ..

I •' ··•·· ...

I

-~ ! ,,""',...

• '/ i..

~ ,

1--- r;

0

- l D

·2

·50

·l I

I ·5~0 10 20 30 .co so GO 10 eo 9o 1 oo II 0 120 130 Stotior. separatiol'\ ir. 1\ ~ni

Y1:guPe A35. D1:gnaL Y'otio-S, ILS, sea water'. PaY'ametePs aPe m: g1:vr-!n in f1:guPe A27 except for' suPface

Dtsiltd dista~ct 25. n rni(46.3km) Ruft (odt 77/07/1,. 22. ll.Ol.

Ouirtd lacilit':l Vt~dtsirtd facility · ........ · · J:'ru nact ~P.ESH 'IIA.TER

HI 1005.5 ft{306.5m)msl Sou as dtsi rtd foe iIi 1':1 ["" t rl 51. H2 7250. It (2210.m)msl '•; ddl ., scr. Frt'lutnc':l II 0. 11Ht llutrl 951.

Station separation in km 25 50 75 100 125 150 175 200 225 I so

40 I /

(X) / ~ v 1 ""' H

"'0

c: - ~ ~ v-v I ...........:: 21

0

·-1-' .... tn 0 0 ....

-0 c: 0"\

-""

:::> ........ 0

~ ~ ,...--

) ~ ····· ...... ..............

~ ...... ··''

~ .. . ' •.... ' .

.. .... I

~ I ,)1.,.,.,.. ..

-,r/

I

a i.

" ,

l 0

- I Q

-20

·3 1-- ~ r;

·.t I

I -· ·5.0 I 0 20 '0 AO SD 'o 10 eo 90 101 llO 120 no Station separation inn nd

Figure 1136. Signal Pat?:o-8, ILS, fpesh water. Parameters are as given in ;'iguN< A27 except for surface .

ILS, Separation, Terrain Parameter

Problem A8: For the geometry illustrated by the equal site ele

vation portion of gure A26 and the ILS localizer parameters of

figure A27, determine the station separation required to obtain

a 23 dB sired to-undesired localizer signal ratio at the air

craft with a time availability of 95 percent when the terrain

parameter is selected as (a) smooth, (b) smooth plains, (c) rol

ling plains, (d) hills, (e) mountains, and (f) extremely rugged

mountains.

Solution: Figures A33 and A37 through A41 are applicable to

this problem, and the station separation requirements taken from

them are listed below along with the terrain parameter (~h) value

used for each terrain type (see table 7):

Terrain Parameter Station Separation Terrain T_n~e Figure [ft (m)] [n mi (km)]

Smooth A33 0 (0) 107 (198)

Smooth plains A37 40 (12) 108 (200)

Rolling plains A38 195 (59) 106 (196)

Hills A39 375 (114) 93 (172)

Mountains A40 740 (226) 70 (130)

Extremely rugged A41 2625 (800) >125 (>232). mountains

The following comments concerning these results are appropriate:

(a) the station separation increase for the smooth to

smooth plains case is caused by a decrease in the reflection co

efficient associated with the undesired facility which increases

the undesired signal level,

(b) the station separation decrease that occurs from smooth

plains through mountains is caused by a decrease in the line-of

sight range associated with the undesired facility which decreases

the undesired signal level,

(c) the large station separation increase for the moun

tains to extremely rugged mountains case is caused by a decrease

in the line-of-sight range associated with the desired facility

151

Ouiud distuce 25. n mi(46.3km) R"~ Code 11/07/ll. 22. 17. 03.

Duirtd facility v~ctsirtd iocili ly .... r:rtt HGct SMOQTJ.I PU..JJ.JS

HI 1~05.5 ft(306.5m)ms1 Saat as des•red facility luJPtrl 57. H2 7250. ft (2210.m)ms1 laiddltl 507. f •tqljt!\(~ 110. Ml-lz C:owt•) 957.

Station separation in km I

25 50 75 100 125 150 175 200 225 50

I .40 / cx::l

t;::: l/ / / 30 "0

.c::: - ~ v l.---v L ~ 20

0

·-f-.' -tn 0

N ....

-0 .c::: en -""

:::> ........ 0

-3

~ ~ ~

I ~ ~ ... ..... .........

~ ~ < .. ...... '

/ :::.G ~ j .

~ ~ ,/"

. _i ~ I

~ v I

[/

10

0

·10

·20

·I. I

40 50 '0 70 80 90 JOO I ·STO

10 20 30 no 120 130 Station separation inn mi

F1:gure A37. 8ignal ratio-8" IL8" smooth plains. Calculations were made for the parconeters of f1:gure A27 except th a Ah for smooth plains (40ft" 12m). Horizon pa:t'ameters were calculated _rY.om !',h.

~

f-1 U1 VI

co ""0

-= 0

·--0 L-

0

-= en

"' '::> ........... a

so

40

50

20

I 0

0

-I 0

-20

-50

Desired dis!a~ce 25. n mi(46.3km) ~~~ Code 77/07/15. 22. 17.05.

Oesirtd facilit!:! v~desirec facilit!:i ROLLINCi PL.t.INS ···· ·········· f."rtt HOC I

HI 1005.5 ft(306.5m)ms1 Sou as desired facilit~ I~Htrl 5% H2 7250. It (2210.m)ms1 laiddlt) 507. f."req ... t~c!:l 110. 11Hz , . . . llo111trl 957.

Station separation ~n km

25 so 75 100 125 1so 175 200 225

)jV ~/j

/~/v v-vv

......... ~ -- / ................. . VI,_....,.... I/ .... . / ~~·:J;;?~ ....... .

hV:V~ ~~~ ~v v

-40 ~---+----~----~---+----~----~--~----~--~~---L----~---- -----

-500 10 20 50 AO 50 c;o 70 80 90 lOt 110 120 150 Station separation in n rni

FiguPe AJB. Signal Patio-S~ ILS~ Polling plains. Calculations wePe made foP the paPametePs of figuPe A27 except with a 6h foP Polling plains (195 ft~ 59 m). HoPizon paPametePs uJel1 e calculated fPom 6h.

Ouired disto~ct 25. n rni(46.3km} Run Code 71/01/13. 22.17.07.

Ollired r iIi ty Vndtsited focillty ............. F'rtt ''ott HILLS

HI 1005. 5 It ( 306. 5rn) rns1 So•e os desired locility (""' r) 57. H2 nso. rt (2210.rn}rns1 (•iddlt) 501. F're~ ... e~cy 110. tlHt CluerJ 951.

Station separation in km

25 50 75 100 125 150 175 200 225

' I _1_ so

I .40 V£ / lXI "'0

,::: -

I ~ v I .L '/ ~

'50

20 0

·-....... -tn 0 .p. ._

-0 ,::: 0'\ -"'

::;, ........ 0

·3

I ~ / ~ . ····· ....... ············· / ~ ;;/ , .. ·•"' .. ...........

/ ~ I ...-

h v ~ I /

' !J ~ ~ I

IIJ

0

-IG

·20

-I. )

I ·5 •• 10 20 30 .CO 50 U lO 80 90 I 00 II 0 120 130 Statio!\ stparatiol\ il\ n mi

Figure A39. Signal ratio-S, hills. Ca lations were for the parameters of figure A27 except with a 6h for lls (375 114m). Horizon parameters were calculated from 6h.

"

50 I

40

Q'J 30 "0

r;:: - I 20

0

·-~ .... ' 10 Vl a Vl t-

- 0 I a r;:: 17"\

- • 10 I If\

::>

' I -20 0

·30 I

·40 ~

~ -5~0

;140. except

Du,rtd di'U"'" 25. n mi(46.3km) R.,.. Codt 77107/)3. 22. 17. 10.

Oui~td locili.~y ll11duired facility ............... f:" 'tt 'POet rt OliNH I tiS

f.jJ 1005.5 ft (306.5m)ms1 So•t "' dt'i'td laci:ity ~. .. ,,.,, 57. H2 7250. ft (2210.m}ms1 l•iddltl 507. F,t~utl\cy IU. I1H1 II nt, I 951.

Station separation in km .

25 50 75 100 125 150 175 200 225

L v v v /

j ~ v I! :;

1/1 . ............. ........

v, fj ··"' ····•·· .......... ./ ~

... -·····

~ ~ v ~ J v ~ I

!

I

10 20 30 .CO 50 £0 10 80 ,. IOD )It 120 131

for>

Station separation inn nd

Ca (?40

A2?

(

.... tn 0.

Figure A 41.

Onirtd distollct 25. n mi{46.3km) R~11 Codt 17101113. 22. 17. 12.

Du i rtd foe iIi t~ EXTREMEL~ RUGGED MlS

u~dtsirtd foci[ity ............. f:'rtt HOCI

HI 1005.5 ft(306.5m)msl Sou os dtsirtd focilit~ f~o~Htrl 5% H2 1250. ft (22lO.m)msl l•idclltl 507. F' rt~~o~UC~ II 0. 11Hz llntrl 957

Station separation in km 25 50 75 100 1~5 150 175 200 225 so

AD ---v

en "D

1:! -0

·--a ....

-a 1:! cr. -....

::;:)

' c

. \

v-~ I I --v v ~ I ~ ~ ~

/ v v ~ .----- ....-

I I / ~ ... ,, ........ / ~··· , .............

.~" .... ' ..... ~ ! / / v--I . ,........

/ / /"' v

.---/ ./ I

/ / v

i .. I ,.-

/ I

I

30

20

lD

0

·20

·3

·A I

D j_

--·5.0 10 20 30 •o so u 10 eo 90 uo Ill 121 130 Stotiofl stporotior~ ifl "11d

Sigr~l ratio-S~ ILSJ extremely rugged mountains. Calculations were made for of figure A2? except with a 6h for extremely rugged mountains (2J625 ft; BOO pa1'ameter<s wer•e calculated from D.h.

the parameters Horizon

which decreases the desired signal level, and

(d) the exclusive use of nh to describe terrain could easily

result in station separations that are not appropriate for speci

fic paths. Actual horizon information should be used whenever it

is available.

ILS, Separation, Terrain Profile

Problem A9: For geometry similar to the equal site elevation por

tion of figure A26 and the equipment parameters of figure A27,

determine the station separation required to obtain a 23 dB de

sired-to-undesired localizer signal ratio at the aircraft with a

time availability of 95 percent when terrain parameters are de

termined using (a) topographic mars and (b) the Electromagnetic

Compa~ibility Analysis Center (ECAC) terrain file. Sites should

be selected to have equal elevations as shown by topographic maps,

and the terrain between them should be "severe".

Solution: Locations at Seattle (47°15'00"N, 122°22'47"W)

and Portland (45°33'22"N, 122°30'25"\11) were selected for the de

sired and undesired ilities, respectively. These locations

were selected based on the problem requirements for equal site

elevations and severe terrain from paths for which topographic

profile data are available on £omputer cards [39, fig. 2.22]. It

is unlikely that these particular locations would ever actually

be selected as localizer sites.

In calculating the desired signal level at the aircraft, only

terrain characteristics associated with the desired facility are

used, and beyond the facility horizon obstacle the terrain is ta

ken as smooth with an elevation equal to the effective reflecting

surface elevation for the desired facility. Similar considera

tions are involved in the calculations of the undesired signal

level. Hence, actual terrain between the facility horizon ob

stacles is not involved in station separation calculations since

only terrain between each facility and its horizon obstacle is

utilized to determine key terrain characteristics.

157

Figures A42 and A43 were developed for this problem, and the

required station separations obtained from them are given below

along with site and horizon parameters for the two sets of terrain

data used: Terrain Data From

Parameters*

Required station separation [n mi (km)]

Figure

Topographic Maps

72 (133)

A42

Desired Facility (Seattle)

Effective reflection

surface elevation [ft (m)] 19.7 (6) Horizon distance [n mi (km)] 2.6 (4.9) Horizon height [ft (m)J 325 (99) Site elevation [ft (m)] 19.7 (6) Terrain parameter [ft (m)] 394 (120)

Undesired Facility (Portland)

Effective reflection

surface elevation [ft (m)] 19.7 (6) Horizon distance [n mi (km)] 34.6 (64.0) Horizon height [ft (m)] 4,268 (1,301) Site elevation [ft (m)] 19.7 (6) Terrain parameter [ft (m)] 1,654 (504)

*A surface refract1viti- r-eferred to niean sea

ECAC Terrain File

75 (139)

A43

98.4 (30)

31.56 (58.44)

3,199 (9 7 5) 98.4 (30)

692 (211)

200 (61) 34.67 (64.21)

3,930 (1,198)

200 (61) 1,470 (448)

-

level value of

279 N units was used (see fig. 51). Equipment related parameters

are as given in figur~ A27~ The larger required station separation for the ECAC terrain

case is caused by the greater site elevation and lower horizon

height associated with the undesired facility which increases the

undesired signal level. Both required separations are at least 25~ lc~~ than the actual great c:irc1c site separation of 101.7 :ri mi

(188. 4 km) . 1S8

..

Q) "'Q

,;: -0

·-........ .... (Jl a t.D ...

-a ,;: cr. -"' ~ ........ 0

,..,. rtpure A42.

I so

40 I

I 30

20

10

0

-10

-20 I

·30 )

·lO )

~ ·Sw0

Desired disto11ce 25. n mi(46.3km) R ... 11 Code 71/01113. 22.11. 13.

Ouired locilit~ SEATTLE

Vlldttired locilit~ PORTLAND ............ F'ru HUe

HI 25. 2 It (7. 7m) ms1 ~I 25.2 ft(7. 7m)ms1 ,.,.,.,, 51. H2 G2711. f t ( 1911. m) ms1 H2 (aiddhl 501. G21D. it(191l.m)ms1 F're111otiiC~ I It. 11Hz II ower) 951.

25

I 0 20

Station separation in km· 50 75 100. 125 150 175 200 225

-~

~ --- ~ f.-..-" ..----~ ~

. ········ .... .......

v-- ... ······ ~ .......... ........

...-k<: ~ ~

........ ~

~ ~ ,.,.,.....

~ io""'

/; ·.

~ l

-----

3G .CO 50 GO 10 80 90 100 110 121 13D Statio~ separatio~ i~ ~ mi

Signal rat?:o-5, TDS, th fr>om topo(:rr'aph?;c maps (see t;c:;xt). Equipment parame ter>s ar>e as g<:ven in fig.UY'e A2?. The sharp incN'!I1Se "J/U YJ.ear> ?0 n

30 km) response to a sharp decr>ease in the undesir>ed sipnal level occur>s as of sight cond1: tions ar>e lost overo the li ty to path fips. 113? throur.rh .441).

en "U

.::: -0

·-f-1 0\ 0 0 ....

-0 c a-.. -....

:::> ........ 0

Figur>e !J·J3.

Duired dis\ol\ct 25. n mi(46.3km) Rw~ Codt 77107/l~. 22. 17.52 .

. Oui•td focility Vl\dts i rtd foe il i ty · ..... ····· · J:'ru sPace SEA TllE PORTLAND

HI 103. 9 It ( 31. 7m) ms1 HI 205.5 ft(62.6m)ms1 IIIHtd 57. 1-12 '348. It (1935 .m)ms1 H2 G348. 1!(1935.m)ms1 l•iddh) 507. F •• 4!YII\C y II 0. l'tHt Ll .. t•l '51.

Station separation in km 25 50 75 100 125 150 175 200 225 I 50

v---~ ~ f.--,.,.... ~ I ,.......-.40 ,...... ~

I 30

20

'

.,

............ ............. .... ·-~ .............. ·····' ....

~ ~ ~ ......

/ .-'

~ ~ .....--- !-'"""

v lJ v

I r

I 0

0

·I 0

·3 I

-.c 1~-

I ·S.t 10 20 30 .co 50 U lt 81 'I IU 110 120 130

Stotiol\ stporotiol\ il\ 1\ l'fti l r'atio-S~ JL:.;~ hor·i;:;on pm•ame to•s j'r>om ECAC ter>rain ."'i (see text). Equ-ip

ment parameters ar>e as given in figuPe A27. The sharp increase in D/U near• 74 n mi (13? km) is in r>esponse to a sharp decrease in the undesired signal level that occur>s as line-of-sight conditions ar>e Z.ost over the undesired facility to aircraft path (see figs. AJ? throuph A41).

LT OF S s

This list in 1 r of th

symbol.s used in th s rencrt. \ian~o a~·c :' miLlr :o those JHC'\'iously

d · th t r-"' ,..,,., -_, use ::tn o _,("r repor s r-.-+. ~.- 1, .) .• 4 J • T un1ts given

bols in this list are those required hy or resu~ting from equa

tions as given in this report. Exc t where otl erwise indi ated,

equations are dimensionally consistant so that :.ppropriate units

can be selected ser.

In the following l st, the lish alp et prece s the

Greek alphabet, letters precede numbers, lo~er case letters

precede upper-case letters. '\!iscellaneous symbc,ls and notations

are given after the alphabetical items.

a

a a

APODS

ARD

ATADU

ATC

ATLAS

ATOA

ern

CCIR

CDC 6600

Ef ctive earth radius used in (A1).

An adjusted e figure 40 [24,

ctive eJ.rtl ( 44) ] .

Earth radius ( . 41).

A program name (t le 1).

radius shown in

Aviation ReseJrch and Development.

A program name table 1).

Air Traffic Control.

A program name (tahle 1).

A program name (t le 1).

Effective receiving area [dB-sq m] of an isotropic antenna used in (1).

Centimeters 10-~ m).

International Radio Consultative Committee.

Control nata orporation's 6600 digital uter.

161

CRPL

d

dB

dBi

dBW

dB-sq m

dB-W/sq m

deg

dD

du

dl

d2

DD

Delta R

DME

DOC

DOT

DUDD

DURATA

Central ~adio Propagation Laboratory.

Great circle distance between facility and aircraft. For line-of-sight paths, it is calculated as indicated in figure 40. It is related to central angle by (7) and (8).

Decibels, 10 log (dimensionless ratio of powers).

Antenna gain in decibels greater than isotropic.

Power in decibels greater than 1 watt.

Effective area in decibels.

Power density in decibels greater than 1 watt per square meter.

Degrees.

Desired facility-to-aircraft distance shown in figure 42.

Undesired facility-to-aircraft distance shown in figure 42.

Facility to reflection point distance shown in figur~ 40 and plotted in figure 15.

Reflection point to aircraft distance shown in figure 40.

Used for dD (table 1).

Path length difference (6r) or extent by which the length of the reflected ray exceeds that of the direct ray (fig. 40) and calculated using (2).

Qistance ~easuring E_quipment.

United States Qepartment of Commerce.

United States Qepartment of Iransportation.

A program name (table 1) .


162

D A,B,C,D,E

D/U

eqn.

ECAC

EIRP

EIRPG

ERP

ESSA

f

fss

ft

FAR

FORTRi\N

FTS

g

GAIN

Desired facilitv to-aircraft distances shown in figure 43. '

Desired-to-undesired signal ratio [dB] avail able at the output of an ideal (loss less) receiving antenna.

Equation.

Electromagnetic ~ompatibility ~nalysis Center.

Equivalent isotropically radiated power TdBW] as defined by (11) .- -

EIRP (dBW] increased by the main beam gain TdBIJ of the receiving antenna as in (12).

Effective radiated power [dBW] as defined in the section 4.1 discussion on EIRP.

Environmental Science Services Administration.

Frequency.

Facility site surface (table 2).

Feet.

Lobing frequency [Hz] with distance from (4).

Frequency fraction for half-bandwidth (fig. 15) .

Lobing frequency [Hz] with height from (6).

Lobing frequency [Hz] from (5).

Federal Aviation Administration.

facility-to-~ircraft ray.

FORmula T~~Nslating system, a family of programming languages.

federal Telephone §ystem.

Normalized voltage antenna gain from (10).

Sum [dBi] of transmitting and receiving antenna main beam gains.

163

GCPP

GHz

GOES

GPO

hr

HI POD

Hz

Hl

HZ

in

IEEE

IF-73

IF-77

ILS

ITS

IRE

JTAC

~reat-£ircle £ath ~lane.

Gigahertz (109 Hz).

Geostationary Operational Environmental Satellite. -

Government ~rinting Office.

Gain [dBi} of the receiving antenna main b e am for (12 ) or (13) .

Gain [dBi] of the transmitting antenna main beam for (11) or (13).

IIour.

A program name (table 1).

Hertz.

Facility antenna height above fss or msl.

Aircraft altitude above msl.

Height of desired or undesired facility antenna above its site surface. Used in (Al).

Antenna elevations above the reflecting surface shown in figure 40.

Significant wave height.of table 6.

Magnitude of the difference in site eleva tions. Used in (Al).

Inches.

Institute of Electrical and Electronic Engineers.

ITS-FAA-1973 propagation model.

ITS-FAA-1977 propagation model.

Instrument Landing ~ystem.

Institute for Telecommunication Sciences.

Institute of ~adio Engineers.

Joint Technical Advisory Committee.

164

kHz

km

kts

log

LOBING

m

mhos

min

mm

msl

MHz

n

n mi

nsec

NBS

NDLF

NHLF

NOAA

NTIS

N 0

Kilohertz (103Hz).

Kilometer (103m).

Knots [n mi/hr].

Common (base 10) logarithm.

A computer program (table 1).

Basic transmission loss [dB] level not exceeded for 95% of the time.

Meters.

Unit of conductance or siemens.

Minutes.

Millimeters (lo-3 m).

Mean sea level.

Megahertz (105 Hz).

A power used in the ionospheric scintillation frequency scaling factor discussion of section 4.1.

Nautical miles.

Nanoseconds (lo- 9 sec).

National Bureau of Standards.

Normalized distance lobing frequency used in ( 4) .

Normalized height lobing frequency used in ( 6) •

National Qceanic and ~tmospheric ~dministration.

National Technical Information Service.

Minimum monthly mean surface refractivity (N-units) referred to mean sea level from figure 51 or 52.

165

N s

N-units

Prob.

PTR

rad

rms

r 0

RTA-2

sec

sq m

s mi

s

SHF

SRVLUM

s . m1n

t1inimum monthly surface refractivity [N-units] (sec. 4.1, refractivity discussion).

Units of refractivity [4, sec. 1.3] corresponding to (refractive index -1) x 10 6 .

Problem.

Power available [dBW] at the output of an ideal (loss less) isotropic receiving antenna from (1).

Total radiated power [dBW] used in (11).

Radians.

Root mean square.

Direct ray length shown in figure 40.

Segments of reflected ray path shown in figure 40 and components of r 12 .

. Reflected ray path length as shown in figure 40.

A TACAN facility antenna type.

Seconds.

Square meters.

Statute miles.

Station separation shown in gures 42 and 43, and calculated from (9).

~uper-High ~requency (3 to 30 GHz).


Facility separation shown in figures 42 and 4 3.

Minimum valid station separation calculated from (Al).

Power density at receiving antenna [dB-W/sq m] used in (1).

166

TACAN

THz

TWIRL

UHF

VHF

VOR

aA,B,D,D,E

t:.h

t:.r

0 e

8 t

8 0

TACtical Air Navigation, an air navigation aid used to provide aircraft with distance and bearing information.

Terahertz (1012Hz or 106 MHz).

A program name (table 1).

Ultra-~igh Frequency (300 to 3000 ~fifz).

~ery !i_igh Frequency (30 to 300 Milz).

VHF Omni Directional Range, an air navigation aid used to provide aircraft with bearing information.

Volts per volt.

Magnitude of aircraft radial velocity for ( 4) .

Magnitude of aircraft vertical ascent rate for (6).

Angles identified in figure 43.

Terrain parameter used to charcterize terrain, from table 7 or figure 53.

Path length difference for rays shown in fig ure 40 and calculated using (2).

Angle between direct ray and reflected ray at the facility as shown 1n figure 40.

Ray elevation angle used in (10).

Direct ray elevation angle shown in figure 4 0.

Half power beam-width of facility with JTAC antenna pattern, used in (10).

Beam tilt above horizontal of facility antenna, used in (10).

Central angle shown in figure 41 and used in (7) and (8).

Root-mean-square deviation of surface excursions within the limits of the first Fresnel zone in the dominant reflecting plane from table 6.

167

T

Wavelength.

Time lag [nsec] of reflected ray with re spect to the direct ray, om (3).

Angles defined in figure 43.

Grazing angle shown in figure 40.

Degrees, e.g. 12°.

Degrees celsius.

168

[ 1]

[ 2]

[3]

[ 4]

[5]

[6]

[ 7 J

[ 8 J

[9]

[10]

[11]

[12]

REFERE:-JCES

Ames, L.A., P. Newman, and T. F. Rogers (1955), VHF tropospheric overwater measurements for beyond the radio h or i z on , Pro c . IRE , ±i, No . 1 0 , 13 6 9 - 13 7 3 .

Barnett, W. T. (1972), 1v1ultipath propagation at 4, 6, and 11 GHz, Bell Sys. Tech. J. 51, No. 2, 321-361.

Bean, B. R., B. A. Cahoon, C. A. Samson, and G. D. Thayer (1966), A World Atlas of Atmospheric Radio Re fractivity, ESSA Mono. 1 (GP0) 1 •

Bean, B. R., and E. J. Dutton (1968), Radio Meteorology (Dover Publications, Inc., New York, N.Y.).

l

Bean, B. R., J. D. Horn, and A.M. Ozanich, Jr. (1960), Climatic Charts and Data of the Radio Refractive Index for the United States and the World, NBS Mono. 22 (GP0) 1 •

Bean, B. R., and G. D. Thayer (1959), CRPL Exponential Reference Atmosphere, NBS Mono. 4 (GPO) 1 •

Beard, C. I. (1961), Coherent and incoherent scattering of microwaves from the ocean, IRE Trans. Ant. Prop. AP-9, No. 5, 470-483.

Beckmann, P., and A. Spizzichino (1963), The Scattering of Electromagnetic Waves from Rough Surfaces, Internat1. Series of Monographs on Electromagnetic Waves ~(Pergamon Press, New York, N.Y.).

CCIR (1975), Propagation data required for trans-horizon radio-relay systems, Rept. 238-2, XIIIth Plenary Assembly, Geneva (Int1. Telecomm. Union, Geneva).

Crane, R. K. (1971), Propagation phenomena affecting satellite communication systems operating in the centimeter and millimeter wavelength bands, Proc. IEEE 22_, No. 2, 173-188.

Dougherty, H. T. (1967), Microwave fading with airborne terminals, ESSA Tech. Rept. IER 58-ITSA 55 (NTIS, N-70-73581) 2 •

FAA (1963), TACAN ground station equipment, FAA specification3, FAA-E 2006.

169

[ 13]

[14]

[15]

[16]

[17]

[18]

[19]

[20]

[21]

[ 2 2]

[ 2 3]

FAA (1_965), VHF/UHF Air/Ground Communications Frequency Engineering Handbook, FAA Handbook 3 , 6050.4A.

FAA (1965), Radio Frequency Hanagement Principles and Practices; General, Organization and Functions, FAA Handbook3, 6050.8.

FAA (1969), Frequency Management Engineering Princinles; Geographical Separation Criteria for VOR, DME, TACAN, ILS, anJ VOT Prcquency Assignments, FAA Ilnndhook 3 ,

6050.5A.

FAA (1969), Frequency Management Principles Spectrum Engineering Measurements, FAA Ilandbook 3 , 6050.23.

FAA (1975), DME ground station equipment terminal area, FAA specification 3 , FAA-E-2444-A.

Frisbie, F~ L., D. J. Hamilton, C. D. Innes, F. S. Kadi, and G. M. Karren (1969), A comparative analysis of selected technical characteristics for several frequency bands available to aeronautical satellite services, Unpublished 4 FAA Report 3 .

Gierhart, G. D., A. P. Barsis, M. E. Johnson, E. M. Gray, and F. M. Capps (1971), Analysis of air ground radio wave propagation measurements at 800 MHz, OT Telecomm. Res. and Engrg. Rept. OT/TRER 21 (NTIS, COM-75-10830/AS) . 2

Gierhart, G. D., and M. E. Johnson (1967), Inter renee predictions for VHF/UHF air navigation aids, ESSA Tech. Rept. IER 26 ITSA 26 (NTIS, AD 654 924) 2 •

Gierhart, G. D., and M. E. Johnson (1969), Transmission loss atlas for select aeronautical service bands from 0.125 to 15.5 GHz, ESSA Tech. Rept. ERL 111 ITS 79 (GPO) 1 •

Gierhart, G. D., and M. E. Johnson (1971), Interference predictions for VHF/UHF air navigation aids (supplement to IER 26 ITSA 26 and ERL 138-ITS 95), OT Telecomm. Tech. Memo. OT/ITSTM 19 (NTIS, AD 718 465) 2 .

Gierhart, G. D., and M. E. Johnson (1972), UHF transmis sion loss estimates for GOES, OT Telecomm. Tech. Memo. OT TM-109 (NTIS, COM-73-10339) 2 •

[24] Gierhart, G. D., and M. E. Johnson (1973), Computer nrc-grams for air/ground propagation and interference analysis, 0.1 to 20 GHz, DOT Rent. FAA-RD-73-103 (NTIS, AD 770 335)2. -

170

[25] Gierhart, G. D., and M. E. Johnson (1973), Pronagation model (0.1 to 20 Gllz) extensions for 1977 computer programs, DOT Rept. FAA RD 77-129.

[26] Gierhart, G. D., R. W. Hubbard, and D. V. Glen (1970), Electrospace planning and engineering for the air traffic environment, DOT Rept. FAA RD 70-71 (NTIS, AD 718 4 4 7) 2 •

[27] Hartman, W. J., Editor (1974), Multipath in air traffic control frequency bands, DOT Rept. FAA-RD-74-75, I & ll (NTIS; AD/A-006, 267 and 268) 2 .

[28] Hawthorne, W. B., and L. C. Daugherty (1965), VOR/DME/ TACAN frequency technology, IEEE Trans. Aerospace Nav. Electron. ANE-1~, No. 1, 11-15.

[29] ICAO (1968), International Standards and Recommended Practices Aeronautical Telecommunications, Annex 10 I (Internatl. Civil Aviation Organization; Montreal 3, Quebec, Canada).

[30] IEEE (1970), Special issue on air traffic control, Proc. IEEE ~. No. 3.

[31] Janes, H. B. (1955), An analysis of within-the-hour fad ing in the 100- to 1000-Mc transmission, J. Res. NBS ~ No. 4, 231-250.

[32] Johnson, M. E. (1967), Computer programs for tropospheric transmission loss calculations, ESSA Tech. Rent. IER 45-ITSA 45 (GPO)l.

[33] JTAC (1968), Spectrum Engineering- The Key to Progress, Joint Tech. Advisory Committee (IEEE, New York, N.Y.).

[34] JTAC (1970), Radio Spectrum Utilization in Space, Joint Tech. Advisory Committee (I E, New York, N.Y.).

[35] Kerr, D. E. (1964), Propagation of Short Radio Waves, MIT Radiation Lab. Series 13 (Boston Tech Publishers, Inc., Lexington, Mass.).

[36] Lenkurt (1970), Engineering considerations for Microwave Communication Systems (GTE Lenkurt, Dept. Cl34, San Carlos, CA, $10.00).

[37] Longley, A. G., and P. L. Rice (1968), Prediction of tropospheric radio transmission loss over irregular terrain, a computer method-1968, ESSA Tech. Rent. ERL 79 ITS 67 (NTIS, AD 676 874) 2 •

171

[38] Longley, A. G., and R. K. Reasoner (1970), Comnarison of

[39]

propagation measurements with predicted values in the 20 to 10,000 MHz ran~e, ESSA Tech. Rept. ERl 148 ITS 97 (NTIS,AD 703 579) ..

Longley, A. G., R. K. Reasoner, and V. L. Fuller (1971), Measured and predicted long-term distributions of tropospheric transmission loss, OT Telecomm, Res. and Engrg. Rept. OT/TRDR 16 (NTIS, COM 75 11205) 2 .

[40] McCormick, K. S., and L. /\. Maynard (1971), Low angle tropospheric fading in rc13tion to satellite communi cations and broadcasting, IEEE ICC Record z, No. 12, 18-23.

[41] Moskowitz, L. (1964), Estimates of the power spectrums for fully developed seas for w d speeds of 20 to 40 knots, J. Geophys. Res. ~. No. 24, 5161-5179.

[42] Naval Weather Service Command (1972), International Meteorological Codes (Newsfd, Asheville, N.C.).

[43] Norton, K. A.· (1953), Transmission loss in radio propa-gation, Proc. IRE il• No. 1, 146 152.

[44] Norton, K. A. (1959), System loss in radio-wave propaga-tion, Proc. IRE 47 No. 9, 1661.

[45] Norton, K. A., L. E. Vogler, W. V. Mansfield, and P. J. Short (1955), The probability distribution of the amplitude of a constant vector plus a Rayleigh-distributed vector, Proc._ IRE 43, No. 10, 1354-1361.

[46] Pope, J. H. (1973), Ionospheric scintillation predictions for GOES, NOAA Tech. Rept. ERL 257-SEL 24 (NTIS, COM-73 50381)2.

[47] Reed, H. R., and C. M. Russell (1964), Ultra High Fre-quency Propagation (Boston Tech. Publishers, Lexington, MA.).

[48] Rice, P. L., A. G. Longley, and K. A. Norton (1959), Pre-diction of the cumulative distribution with time of ground wave and tropospheric wave transmission loss, Part 1 - the prediction formula, NBS Tech. Note 15 (NTIS, PB151374)2.

[49] Rice, P. L., A. G. Longley, K. A. Norton, and A. P. Bar sis (1967), Transmission loss predictions for trope spheric communication circuits, NBS Tech. Note 101, I and II revised (NTIS; AD 687, 820 and 821) 2 •

172

[50] Samson, C. A. (1975), fractivity gradients in the northern hemisphere, OT Rept. 75-59 (NTIS, Cm1-75-10776/AS)2.

[51] Samson, C. A. (1975), /\tmosrheric consideration 1n radio system eng ering at 10 to 30 Cll:, ClT Rept. 75-6b (NTIS, COM 75-11095/AS) 2 •

[52] Samson, C. A. (1976), Refractivity and rainfall data for radio system engineering, OT Rept. 76-105 (NTIS, PB-260-723/AS)2.

[53] Sheets, H. E., and V. T. Boatwright, Jr. (1970), Hydro-nautics (Academic Press, New York, NY).

[54] Skerjanec, R. E., and C. A. Samson (1970), Rain attenua-tion study for 15 GHz relay design, DOT Rept. FAA RD-70-21 (NTIS, AD 709 348) 2 .

[55] Tary, J. J., R. R. Bergman, and G. D. Gierhart (1971), GOES telecommunication study - 1971, OT Telecomm. Tech. Memo. OT TM-64 (NTIS, COM-72-10431) 2 .

[56] Thayer, G. D. (1967), A rapid and accurate rav tracing algorithm for a horizontally strati ed atmosphere, Radio Sci. l (New Series), No. 2, 249 252.

[57] U.S. Weather Bureau Hydrologic Services Div. (1955), Rainfall intensity duration frequency curves, Tech. Report. No. 25 (GPO)l.

[58] Whitney, H. E., J. Aarons, and D. R. Seemann (1971), Estimation of the cumulative amplitude probability distribution function of ionospheric scintillations, AF Cambridge Res. Labs. Rept. AFCRL-71-0525, Cambridge, MA.

-·-··-----1

2

3

Copies of these reports were sold by the Superintendent of Docu-ments, U.S. Government Printing Office, Washington, D. C. 20402, and may still be available.

Copies of these reports are sold by the National Technical Infor-mation Services, Operations Division, Springfield, Vi inia 22151. Order by indicated accession number.

Requests for copies of these documents should be addressed to the FAA as shown in section 5.

4This document is in the public domain since it was issu as of

cial government writing. However, it is co~sid~red_unp~blished since it was not printed for wide publ1c d1str1bUt1on.

173

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