Ul 'iii Electromagnetic Propagation Effects, APPENDICES AI. Attenuation of RF Waves by Absorption Reference 1 This appendix provides a series of graphs which determine the attenuation of RF waves by the atmosphere through absorption. Blake has integrated the attenuation rate along ray paths through a standard atmosphere to find the total absorptions in decibels, which may be expected as functions of radar range R and angle of arrival E. The calculations cover the frequency region 100-10,000 me. Some of Blake's results are shown in Figs. Al.1(a-d). It is emphasized that this is a theoretical description of the absorption process, and has not been verified by experiment. 5.0 I 4.5 I I 4.0 ----t---t--- 3.5 I I 10,000 me L_----!I-- ...... ;.. 3000 me J----;--- :g 3.0 __ -1 __ I I 1000 me J---t-- Ql '0 c· 2.5 o 2.0 c 1.5 '" > 1.0 N 0.5 o o 600 me --=--i-..=-:=-:=r-= 300 me me 100 me 100 200 300 400 500 Radar-to-target distance, kilometers Al.l(a). Radar atmospheric attenuation-0° ray elevation angle 409
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Ul 'iii
Electromagnetic Propagation Effects,
APPENDICES
AI. Attenuation of RF Waves by Absorption Reference 1
This appendix provides a series of graphs which determine the attenuation of RF waves by the atmosphere through absorption.
Blake has integrated the attenuation rate along ray paths through a standard atmosphere to find the total absorptions in decibels, which may be expected as functions of radar range R and angle of arrival E. The calculations cover the frequency region 100-10,000 me. Some of Blake's results are shown in Figs. Al.1(a-d). It is emphasized that this is a theoretical description of the absorption process, and has not been verified by experiment.
5.0 I 4.5 I I 4.0 ----t---t---3.5 I I
10,000 me L_----!I--......;..
3000 me J----;---
:g 3.0 __ -1 __
I I
1000 me J---t--Ql
'0 c· 2.5 o .~ 2.0 c ~ 1.5 '" > ~ 1.0 N
0.5
o o
600 me --=--i-..=-:=-:=r-=
300 me
+-,,-,,,,,,,-~I=-======t:--=-::-::;:2oo me
100 me
100 200 300 400 500
Radar-to-target distance, kilometers
Al.l(a). Radar atmospheric attenuation-0° ray elevation angle
409
410
3.5
~ 3.0 .0 '0 .g 2.5
§- 2.0 ''::; co ~ 1.5 l!l 10 >- 1.0
~ NO.5
o
Electromagnetic Propagation Effects
I I I I I __ ~ ___ L __ L __ 1 __ ~ __ I I I I 10,000 me
I I I --~-- -~~
I 1000 me ----~-------r--------r---'600mc
,--------+-------t--------t---l200mc 100 me
o 100 200 300 400 500
Radar-to-target distance, kilometers
Fig. Al.l(b) Radar atmospheric attenuation-Jo ray elevation angle
1.0~ I I 0.9~ I I 0.8 ---1---0.7 I
(/)
a; 0.6 .0 '0 ~ 0.5 co 'g ::l C Q)
~ co >-~
0.4
0.3
0.2
NO.1
o o 50 100
~ __ ---+--_----1-_....;1~0,000 me
__ -+------t----r--~3000 me
--1000 me
__ ~-----~----t----6oomc
_~~~~==~--t_--__ ~r_ __ -200mc
100 me
150 200 250 Radar-to-target distance, kilometers
Fig. Al.l(c). Radar atmospheric attenuation-50 ray elevation angle
!J)
Qi ..c '(3 Q)
"0
c· 0 .~
::l c ~ ro >-ro ~ N
A2. Attenuation of RF Waves by Precipitation 411
0.5
10,000 mc L---~----+---~~~
0.4 -+--+--+---1--0.3
I I 3000 mc
I 1000 mc
~ __ ----~--------+-------~ __ ~600mc 0.2
0.1 __ -+-------;--------1---------~--~20.0mc
~ __ ----_1~----_t------_(--------r_--~100mc 0
0 50 100 150 200 250
Radar-to-target distance, kilometers
Fig. Al.l(d). Radar atmospheric attenuation-lO° ray elevation angle
A2. Attenuation of RF Waves by Precipitation References 2, 3
This appendix provides a graph which determines the attenuation of RF waves by the atmosphere through precipitation.
Radar meteorologists have studied the attenuation of microwaves for rainfall. Figure A2.1 compares the attenuation versus wavelengths for various rainfall rates. The results predict intense absorption at the high frequencies. Experimental evidence confirms the theoretical predictions in many cases. Generally speaking, for frequencies between 2-lO GHz, only heavy downpour will provide serious attenuation. However, radar attenuation by rain usually exceeds attenuation caused by absorption.
E "'" CO ~ .;: c: 2 a; " c:
~
412 Electromagnetic Propagation Effects
100
Water at 18°C I
'
---Haddock __ ---1 __ _ ----Ryde
10
~: I X McGill'
:,1 I I ~(30) + ~ -i -- --! -- -- -
25 ''Y", I ~~~.5 I l~~, I
1.0
~k-'-~~--X (4.5) ',I "
I ''Y~ I ... 2.5 I'~'
I I "~" -t T~~-
0.1
0.Q1
o 2 4 5 6 7 8 9 10 Wavelength, A (cm.)
Fig. A2.1. Attenuation versus wavelength for rainfall of various rates
A3. Refraction of RF Waves by the Ionosphere References 2-14
This appendix provides a series of graphs which determine the refraction of RF waves by the ionosphere.
P. Lister and T. J. Kenesha have computed the bending of radar signals by the ionosphere. The results are shown in Figs. A3.1 through A3.1O.
A3. Refraction of RF Waves by the Ionosphere
E "'" ,r '0
" .",
~
450
400 Operating frequency = 200 mc/s Day time model
350
300
250
200
150
100 0.001 0.01 0.1
Angle error, mils
1.0
Fig. A3.1(a). Sighting errors for various beam angles
E "'"
450
400 Operating frequency = 200 mc/s Night time model
350
i 300 a .;::; « 250
200
150
0.001 0.01
Angle error, mils
0.1
Fig. A3.l(b). Sighting errors for various beam angles
413
10
1.0
414
E ~
•• "0 a .~
=<
Electromagnetic Propagation Effects
450
400
350
300
250
200
150
Operating frequency = 200 mcfs Day time model
100L--L~-U~L--L~~~~~-L~~U-~~~~~
0.001 0.1 0.1 10 Distance error J km
Fig. A3.I(c). Sighting errors for various beam angles
450
400 Operating frequency = 200 rocfs Night time model
350
10
~ 300 -8-" 'S 250
=<
200
150
100L-~~~wL~~~~~~~~~~~~~~
0.0001 0.001 0.01 0.1 1.0
Distance error J km
Fig. A3.I(d). Sighting errors for various beam angles
A3. Refraction of RF Waves by the Ionosphere
E "'" -8 a ~
450
400
350
300
250
150
Operating frequency = 400 mcls Day time model
l00~ __ ~~~~~ ____ L-~~~~ ____ L-~~~~
0.001 0.01 0.1
Angle error, mils
Fig. A3.2(a). Sighting errors for various beam angles
450
400
350
] 300 ~ . . ~ ;;: 250
200
150
Operating frequency = 400 mcls Night time model
1.0
100 L-~~~~U-~~~~UL __ ~~~~L-~~~u.u
0.00001 0.0001 0.001 0.01 0.1
Angle error, mils
Fig. A3.2(b). Sighting errors for various beam angles
415
416
E ~
,; "t:I
" .t<
~
E ~
,; "t:I
" ... ~
Electromagnetic Propagation Effects
450
400
350
300
250
200
150
100
Operating frequency = 400 mcls Day time model
~~ __ oo
//J~---5°
~"'-----10°
0.0001 0.001 0,01 0.1
Distance error I km
Fig. A3.2(c). Sighting errors for various beam angles
450
Operating frequency = 400 mcls 400 ~ight time model
350
300
250 400
200
150
100 0,01 0.1 1.0 10
Distance error J meters
Fig. A3.2(d). Sighting errors for various beam angles
1.0
100
A3. Refraction of RF Waves by the Ionosphere
E
"'" ., ."
" .'" ~
E
"'" ., ."
.~ «
450
400
350
300
250
200
150
Operating frequency = 400 mcls Day time model
60°
Distance error, km
Fig. A3.2(e). Sighting errors for various beam angles
450
400 Operating frequency = 400 mcls Night time model
350
300
250
200
150
100 0.01 0.1 1.0 10
Distance error, meters
Fig. A3.2(f). Sighting errors for various beam angles
417
100
418 Electromagnetic Propagation Effects
E
450
400 Operating frequency = 600 mels Day time model
350
""- 300 -8" a ~ 250
200
150
l00L--L~~~~~~~~U-~~~~~~~-U~~
0.0001 0.001 0.01 0.1 1.0
Angle error, mils
Fig. A3.3(a). Sighting errors for various beam angles
450
400 Operating frequency = 600 mcls Night time model
350
E ""- 300 ,," "0 ::I .~
~ 250
200
150
100 0.01 0.1 1.0 10 100
Angle error, XlO-3 mils
Fig. A3.3(b). Sighting errors for various beam angles
A3. Refraction of RF Waves by the Ionosphere
E
'" .; "C a ~
E '" .; "C a .;:; :;;:
450
400
350
300
250
200
150
100
Operating frequency = 600 mcls Day time model
SOO
40°
0.0001 0.001 0.01
Distance error, km
0.1
Fig. A3.3(c). Sighting errors for various beam angles
450
Operating frequency = 600 mcls 400 Night time model
0°
350 40° 5°
300
80° 250
200
150
1.0
l00L-~~~~~--~~~~--~~~~~~~~~
0.01 0.1 1.0 10 100 Distance error, meters
Fig. A3.3(d). Sighting errors for various beam angles
419
420
E .:0<
.; "" 'S <
E "'-.;
"" " .'" ~
Electromagnetic Propagation Effects
450
400
350
300
250
200
150
Operating frequency = 600 mc/s Night time model
0.1 0.01
Angle error, XlO-3 mils
1.0
Fig. A3.3(e). Sighting errors for various beam angles
450
400 Operating frequency = 600 mc/s Day time model
350 0°
300 5°
250
200
40°
150
100 0.0001 0.001 0.01 0.1
Distance error, km
Fig. A3.3(f). Sighting errors for various beam angles
10
1.0
A3. Refraction of RF Waves by the Ionosphere
E "'" .; "0
a . ., «
450
400
350
300
250
200
150
100 0.01
Operating frequency = 600 mc/s Night time model
800 ___ J
0.1 1.0
Distance error J meters
10
Fig. A3.3(g). Sighting errors for various beam angles
450
400 Operating frequency = 600 mc/s Day time model
350
-15- 300
a ~ 250
200
150
0.001 0.01
Angle error J m its
0.1
Fig. A3.3(h). Sighting errors for various beam angles
421
100
1.0
422
E
Electromagnetic Propagation Effects
450
400 Operating frequency = 1000 mc/s Day time model
350
"" 300 " "0
oS « 250
200
150
l00~ __ L-~~~~ __ ~ __ ~~~~ __ ~~~~WU~
0.1 1.0 10 100
Angle error, XlO-3 mils
Fig. A3.4(a). Sighting errors for various beam angles
450
400
350 E
"" ,,' ."
300 a . ., « 250
200
150
100 0,01 0.1 1.0 10 100
Angle error, XlO-3 mils
Fig. A3.4(b). Sighting errors for various beam angles
A3. Refraction of RF Waves by the Ionosphere
450
400
350
E
~. 300 "t:J ,; ~ 250
200
150
Operating frequency = 1000 mc/s Day time model
l00L-__ ~~-W~U-__ L-~LL~~ __ ~~~~~ 0.1 1.0 10
Distance error J meters
Fig. A3.4(c). Sighting errors for various beam angles
E
450
Operating frequency = 1000 mc/s 400 Night time model
Fig. A3.IO(b). Range corrections versus range and elevation angle of arrival (0° - 90°)_ July exponential model atmosphere
References 431
References
1. L. V. Blake, Curves .of Atm.ospheric Abs.orpti.on L.oss f.or Use in Radar Range Calculati.ons, USNRL, Washington, D.C., NRL Report 5601, March 23, 1961.
2. Handb.o.ok.of Ge.ophysics, USAF, Macmillan, 1960. 3. D. Atlas et aI., AF Surveys in Ge.ophysics, No. 23, Geophysics Research
Directorate, Cambridge, Mass., 1952. 4. Von Handel and Hoehndorf, "High Accuracy Tracking of Space
Vehicles", IRE Transacti.ons .on Military Electr.onics, October 1955. 5. Standard Atm.osphere-Tables and Data f.or Altitudes t.o 65,000 Feet,
NACA Report No. 1235. 6. R. A. Minzner and W. S. Ripley, The ARDC M.odel Atm.osphere, Air
Force Cambridge Research Center (AFCRC), TN-56-204, December 1956.
7. K. S. W. Champion and R. A. Minzner, Atm.osphere Densities from Satellite and R.ocket Observati.ons, AFCRC, May 1959.
8. C.ospar Internati.onal Reference Atmosphere, Interscience, 1961. 9. E. A. Guillemin, C.ommunicati.on Netw.orks, Vol. II, Wiley, 1935.
10. C. M. Crain, "Survey of Airborne Microwave Refractometer Measurements", Pr.oceedings .of the IRE, October 1955.
11. Mason, Bauer and E. Wilson, Radi.o Refracti.on in a C.o.ol Exp.onential Atm.osphere, Lincoln Laboratories, M.I.T., Cambridge, Mass., TR-186, August 27, 1958.
12. G. H. Millman, "Atmospheric Effects in UHF and VHF Propagation", Pr.oceedings .of the IRE, August 1958.
13. M. I. Skolnik, Intr.oducti.on t.o Radar Systems, McGraw-Hill, 1962. Particular attention is directed to Chapter 11.
14. G. R. Burrows and S. S. Attwood, Radi.owave Propagati.on, Academic Press, 1949.
From 1950 to 1966 James N. Constant was employed in the U.S. Defense Industry by such firms as Hughes Aircraft, General Dynamics and Aerospace Corporations. During this period he worked on the development of air-to-air fire control, groundto-air point defense, tactical and strategic area defense weapons systems, and the ECM and ECCM systems. Between 1966 and 1968 he was a strategic weapons and countermeasures consultant of the Department of Defense for defining Minuteman and Polaris MIRV and countermeasures systems.
Since 1968 he is an independent consultant whose clients include major U.S. and foreign corporations and several foreign governments.
Mr Constant is the author of Introduction to Defense Radar Systems and Gravitational Action, as well as numerous articles. He holds thirty patents for radar and optical identification and coding, real time synthetic radar, collision avoidance, reconnaissance radiometer, chaff system, digital and optical computers, digital matched filters and correlators, feedforward filters, gravitational mass detector, etc.
6.7,6.8,6.10-6.13 From "Trends in Marine Technology", O.H. Oakley (Naval Skip Engineering Center, NA VSEC). Astronautics and Aeronautics, April 1966. A publication of the American Institute of Aeronautics and Astronautics.
3.8,3.9 From "Empirical Formulas for Ballistic Reentry Trajectories", R. Bate and R. Johnson. ARS Journal, December 1962.
Figure Credit List 443
4.2 From "Air Ionization in the Hypersonic Laminar Wake of Sharp Cones", F.L. Fernandez and E.S. Levinsky. AIAA Journal, October 1964. A publication of the American Institute of Aeronautics and Astronautics.
4.3 From "Hypersonic Wakes and Trails", L. Lees. AIAA Journal, March 1964. A publication of the American Institute of Aeronautics and Astronautics.
1.21 From "The Strategic Survey", International Institute for Strategic Studies, London.
3.4, 3.8 From "Tracking Error Analysis of a Range Ship", K.E. Peress and A. Schwartz. Sperry Engineering Review, Fall 1962. Reprinted by permission of Sperry Rand Corporation.
8.2 From "Threat Simulation for Radar Warning Systems", Countermeasures, August 1975. Reprinted by permission of MILITARY ELECTRONICS/COUNTERMEASURES, 2065 Martin Ave., Suite 104, Santa Clara, CA 95050, USA.
Figure Credit List 445
8.3 From "Command, Control and Technology", L. Paschall, Countermeasures, July 1976. Reprinted by permission of MILITARY ELECTRONICS/COUNTERMEASURES, 2065 Martin Ave., Suite 104, Santa Clara, CA 95050, USA.
Tables 1.1-1.3 From "Strategic Warfare" , Space/Aeronautics Magazine, January 1969, Ziff-Davis N.Y.
7.13 From "Catching a Satellite", J. Fasca, Space/Aeronautics Magazine, September 1965. Ziff-Davis N.Y.