Top Banner
NAVD 88 Helmert Orthometric Heights from NAD 83 GPS heights and the GEOID99 high resolution geoid height model Dru A. Smith, Ph.D. Daniel R. Roman, Ph.D. National Geodetic Survey Presented at the 2000 Meeting of the American Congress on Surveying and Mapping Little Rock, Arkansas March 21, 2000
21

NAVD 88 Helmert Orthometric Heights from NAD 83 … · NAVD 88 Helmert Orthometric Heights from NAD 83 GPS heights and the GEOID99 high resolution geoid height model Dru A. Smith,

Aug 26, 2018

Download

Documents

vutu
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Page 1: NAVD 88 Helmert Orthometric Heights from NAD 83 … · NAVD 88 Helmert Orthometric Heights from NAD 83 GPS heights and the GEOID99 high resolution geoid height model Dru A. Smith,

NAVD 88 Helmert Orthometric Heights from NAD 83 GPS heights and the GEOID99 high resolution

geoid height model

Dru A. Smith, Ph.D. Daniel R. Roman, Ph.D.

National Geodetic Survey

Presented at the 2000 Meeting of the American Congress on Surveying and Mapping

Little Rock, Arkansas March 21, 2000

Page 2: NAVD 88 Helmert Orthometric Heights from NAD 83 … · NAVD 88 Helmert Orthometric Heights from NAD 83 GPS heights and the GEOID99 high resolution geoid height model Dru A. Smith,

- Review of Height Systems

- Status of HARNS

- Creation of GEOID99 model

- Comparison with GEOID96

-Accuracy analysis of .. GPS leveling ..

Page 3: NAVD 88 Helmert Orthometric Heights from NAD 83 … · NAVD 88 Helmert Orthometric Heights from NAD 83 GPS heights and the GEOID99 high resolution geoid height model Dru A. Smith,

h H

N

h=H+N

.. Ideal .. situation

Earth's Surface

GEOID

In the USA: N < 0

Page 4: NAVD 88 Helmert Orthometric Heights from NAD 83 … · NAVD 88 Helmert Orthometric Heights from NAD 83 GPS heights and the GEOID99 high resolution geoid height model Dru A. Smith,

Real Situation

Earth's Surtace

-------------- - -------------------- ------------ N ~~~~~~~ --- -----

99 ----. ----~~~------ ......

, ----------_, __ _

,,- ', , ',

,, -------, ---_, --- -, __ , '

, ----

NAVDaa H::::o

Page 5: NAVD 88 Helmert Orthometric Heights from NAD 83 … · NAVD 88 Helmert Orthometric Heights from NAD 83 GPS heights and the GEOID99 high resolution geoid height model Dru A. Smith,

STATUS of the HARNs

- 1998 : Last of original 48 CONUS HARNs

NGS begins FBNVC (FBN Vertical Component)

- 1999 : Wisconsin FBNVC observed, processed, loaded into NGSIDB

Washington and Oregon FBNVC observed and preliminarily processed. Not loaded into NGSIDB.

GEOID99 released, reflecting 45 original HARNs and 3 FBNVC states (WI, WA, OR)

Page 6: NAVD 88 Helmert Orthometric Heights from NAD 83 … · NAVD 88 Helmert Orthometric Heights from NAD 83 GPS heights and the GEOID99 high resolution geoid height model Dru A. Smith,

GPS/BMs for GEOID99 (6169 points)

-126.0 -96.0 -66.0 so.o~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~so.o

+

Q)

"C :::s ... 37.0 37.0 ..... "' ...J

24.o~~~TTTIII~rr~TTII~rr~TT~,.~~~~,.~rriiTTII~rrll~~~~24.0

-126.0 -96.0 -66.0

Longitude

Page 7: NAVD 88 Helmert Orthometric Heights from NAD 83 … · NAVD 88 Helmert Orthometric Heights from NAD 83 GPS heights and the GEOID99 high resolution geoid height model Dru A. Smith,

Differences 50 N

40 N

30 N

230 E 240 E 250 E 260 E 270 E Long itude

-·.. : • ..;1 - • ~-

.. . - -. : "'7 .. ~

- 0 .10 - 0.05 0 .00 meters

280 E 290 E 300 E

0 .05 0 .10

Page 8: NAVD 88 Helmert Orthometric Heights from NAD 83 … · NAVD 88 Helmert Orthometric Heights from NAD 83 GPS heights and the GEOID99 high resolution geoid height model Dru A. Smith,

GEOID99 basic information

!nPY! data - 2.0 Million gravity observations (1.6 from

the NIMA evaluated gravity database) - 0.6 Million altimetric gravity anomalies - EGM96 (NASAINIMA) - 1 km OEM supplemented by

30m OEM in Northwest USA - 6169 GPS heights on leveled benchmarks

Theory - Faye anomalies ,..., Helmert anomalies - Remove/Compute/Restore using EGM96

and 1-0 FFT - Collocation to model h-H-N long

wavelength systematic differences

OutpY! Grids - 1 arc-minute grids - CONUS: up to 58 degrees North - Alaska, Hawaii, Puerto RicoNirgin Islands

Page 9: NAVD 88 Helmert Orthometric Heights from NAD 83 … · NAVD 88 Helmert Orthometric Heights from NAD 83 GPS heights and the GEOID99 high resolution geoid height model Dru A. Smith,

30 meter OEM in Northwest USA

-USGS makes 30 meter DEMs available in 7.5 minute quadrangular areas on UTM grid

- NGS acquired, cleaned, and regridded the data onto 1 arcsecond grid in the region 39/49 North and 231/256 East (NGSDEM99)

- Decimated 3 arcsecond OEM used for terrain corrections

- Geoid impact of new OEM in Northwest USA: -14 em (1 cr) locally (max +1- 40 em) -7 ppm tilts (1 cr) {max +1- 200 ppm)

Page 10: NAVD 88 Helmert Orthometric Heights from NAD 83 … · NAVD 88 Helmert Orthometric Heights from NAD 83 GPS heights and the GEOID99 high resolution geoid height model Dru A. Smith,
Page 11: NAVD 88 Helmert Orthometric Heights from NAD 83 … · NAVD 88 Helmert Orthometric Heights from NAD 83 GPS heights and the GEOID99 high resolution geoid height model Dru A. Smith,

(j)

u ::J

-I-'

50 N

c; 40 N _j

30 N

230 E

-50

240 E 250 E

- 40

GEOID99

260 E 270 E Long itude

- 30 meters

280 E 290 E 300 E

- 20 -1 0

Page 12: NAVD 88 Helmert Orthometric Heights from NAD 83 … · NAVD 88 Helmert Orthometric Heights from NAD 83 GPS heights and the GEOID99 high resolution geoid height model Dru A. Smith,

50 N

~ 40 N :J

..........

.......... 0 -'

30 N

230 E

- 0.20

240 E

Dif ferences bet ween GEOID99 and GEOID96

250 E

- 0 .10

260 E Long itude

0.00 meters

270 E 280 E

0 .10

290 E

0.20

Page 13: NAVD 88 Helmert Orthometric Heights from NAD 83 … · NAVD 88 Helmert Orthometric Heights from NAD 83 GPS heights and the GEOID99 high resolution geoid height model Dru A. Smith,

GEOID96 vs GEOID99

GEOID96 GEOID99 Grid 2'x2' 1 'x1' North edge 54 58 OEM TOP030 (3011

) corrected TOP030 and 111 NGSDEM99

TCs 3011 3 11 and 30 11

GPS/BMs 2951 6169 NAVD 88 bias -31 em -52 em

RMS wrt GPS/BMs 5.5 em 4.6 em

Page 14: NAVD 88 Helmert Orthometric Heights from NAD 83 … · NAVD 88 Helmert Orthometric Heights from NAD 83 GPS heights and the GEOID99 high resolution geoid height model Dru A. Smith,

c 0

-+-' 0

·::; Q)

a "0 '-0 "0 c 0

-+-' (/)

+ I

I I

tt+

Em irical Standard Deviation for ee_ 1 km

+ + + +

+++ + -t+ + +

+ + +

+ +

-1--- ----- -- - ---- -- ------- - -- --- -~------------------1

+

+

0 20 40 Distance (km)

+

60 80

+ + +

100

Page 15: NAVD 88 Helmert Orthometric Heights from NAD 83 … · NAVD 88 Helmert Orthometric Heights from NAD 83 GPS heights and the GEOID99 high resolution geoid height model Dru A. Smith,

9

8

7

L

2 5 L w "D 4 L

0 "D

§ 3 ....... (J)

2

1

+ +

Standard Deviation of differential (h-N)

X

Xx X X X X XXXX X XX X X X X XXX X X X XxXX X X xxXXX X xX~ XX X X X XX X xX X

Xx X X X X X X

X

X

A

8

+ + + + +

+ + + + + + + + c

+ +

D

E

20 40 60 80 100

Point spacing (km )

Page 16: NAVD 88 Helmert Orthometric Heights from NAD 83 … · NAVD 88 Helmert Orthometric Heights from NAD 83 GPS heights and the GEOID99 high resolution geoid height model Dru A. Smith,

DIFFERENTIAL {SINGLE TIE} GPS-DERIVED ORTHOMETRIC HEIGHT ACCURACY

LINE Description 5 km lines --()(ppm)

A GEOID96 6.7 em (13 ppm)

8 GEOID99 5.2 em (1 0 ppm)

c GEOID99* (WA,OR,WI) 4.7 em (9.4 ppm)

D GEOID Error only? 0.8 em (1.6 ppm)

E 2nd order, class II 0.3 em (0.6 ppm)

1Q km lines cr (ppm)

6.9 em (6.9 ppm)

5.5 em (5.5 ppm)

4.1 em (4.1 ppm)

1.6 em (1.6 ppm)

0.4 em (0.4 ppm)

* = Experimental solution taylored to the 1 em (1 cr) GPS in these states

Page 17: NAVD 88 Helmert Orthometric Heights from NAD 83 … · NAVD 88 Helmert Orthometric Heights from NAD 83 GPS heights and the GEOID99 high resolution geoid height model Dru A. Smith,

DIFFERENTIAL GPS-DERIVED ORTHOMETRIC HEIGHT ACCURACY

cr can be reduced through;_

- Multiple ties (4 ties = half the cr of a single tie)

- Better knowledge of the geoid (i.e. Baltimore county)

Local ( <5 km) cr .!§ hard !Q know due !Q lack .Qf §pecial studies

Page 18: NAVD 88 Helmert Orthometric Heights from NAD 83 … · NAVD 88 Helmert Orthometric Heights from NAD 83 GPS heights and the GEOID99 high resolution geoid height model Dru A. Smith,

pairs.0.0-0.5km.latlon

-130.0 -98.0 -66.0 so . o ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~so.o

+

++ +

+ +

+ + +

Q)

'0 + :::J + ..... 37. 0 37.0 ..... as ...J

+

+ ++

+ + +

24 . 0 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~24.0

-130.0 -98.0 -66.0

Longitude

Page 19: NAVD 88 Helmert Orthometric Heights from NAD 83 … · NAVD 88 Helmert Orthometric Heights from NAD 83 GPS heights and the GEOID99 high resolution geoid height model Dru A. Smith,

\....

0 \.... \.... w \J \....

0 \J c 0 ..._,

(/)

Standard Deviation of d.ff . I erentlal (h-N)

A

B

+ + + + + + +

+ + + + + + + c

+ + + +

D II' .

~~~'~~ - F

1

(!) (!) tl. 4i. (!)

Ali. Ali.

All. A ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• E At:.

A o ooooooooo o 0 oO

0~0 ----~--~----~--~-----v 20 40 60 80 100

Point spacing (km)

Page 20: NAVD 88 Helmert Orthometric Heights from NAD 83 … · NAVD 88 Helmert Orthometric Heights from NAD 83 GPS heights and the GEOID99 high resolution geoid height model Dru A. Smith,

CONCLUSIONS

- GEOID99 has 4.6 em RMS absolute agreement with GPS/BM (GEOID96 was 5.5 em)

-Short lines(< 5 km) are hard to evaluate due to lack of data

-Medium lines (5-40 km) are 4-10 ppm with single-ties

-Longer lines (40+ km) may be influenced by leveling error

- Establishing NAVD 88 heights from GEOID99 and GPS can be improved if multiple ties are used and the geoid is better known

Page 21: NAVD 88 Helmert Orthometric Heights from NAD 83 … · NAVD 88 Helmert Orthometric Heights from NAD 83 GPS heights and the GEOID99 high resolution geoid height model Dru A. Smith,

GEOID99 Availability

WWW (Sept. 30): http://www.ngs.noaa.gov/GEOID/geoid99.html

CD-ROM (Mid-October): Information Services Branch NOAA/National Geodetic Survey, N/NGS12 1315 East-West Highway, Station 9202 Silver Spring, MD 20910-3282 voice: 301-713-3242 fax: 301-713-4172