Class 27: 28 April 2008 Planning and Analysis of a Height Modernization Survey using TM 58/59...

Class 27: 28 April 2008 Planning and Analysis of a Height Modernization Survey using TM 58/59

GISC3325

28 April 2007

NOAA, NOS, National Geodetic Survey

GPS-Derived HeightsPart II

Planning and Evaluating a GPS Vertical Survey

Topics To Be Discussed Review of heights and accuracies

A Guide for Establishing GPS-derived Orthometric Heights

Sample project following NGS’ guidelines

Discussion on base line processing and analysis of repeat base line results

Discussion of adjustment procedures and analysis of results

Height Modernization Initiative

NGS web site and services

Ellipsoid, Geoid, and Orthometric Heights

“Geoid”

PO

P

H (Orthometric Height) = Distance along plumb line (PO to P)

Earth’s

Surface

Ocean

Ellipsoid

“h = H + N”

N

h

Q

N (Geoid Height) = Distance along ellipsoid normal (Q to PO)

h (Ellipsoid Height) = Distance along ellipsoid normal (Q to P)

Plumb Line

Mean SeaLevel

GPS - Derived Ellipsoid Heights

Z Axis

X Axis

Y Axis

(X,Y,Z) = P (,,h)

h

Earth’sSurface

ZeroMeridian

Mean Equatorial Plane

Reference Ellipsoid

P

Simplified Concept of ITRF 00 vs. NAD 83

2.2 meters

NAD 83Origin

ITRF 00Origin

Earth’s

Surface

h83

h00

Identically shaped ellipsoids (GRS-80)a = 6,378,137.000 meters (semi-major axis)1/f = 298.25722210088 (flattening)

Expected Accuracies

• GPS-Derived Ellipsoid Heights 2 centimeters (following NOS NGS-58 Guidelines)

• Geoid Heights (GEOID03) Relative differences typically less than 1 cm in 10 km 2.4 cm RMS about the mean nationally

• Leveling-Derived Heights Less than 1 cm in 10 km for third-order leveling

NOAA Technical Memorandum NOS NGS-58

GUIDELINES FOR ESTABLISHING GPS-DERIVED ELLIPSOID HEIGHTS (STANDARDS: 2 CM AND 5 CM) VERSION 4.3 David B. Zilkoski Joseph D. D'Onofrio Stephen J. Frakes Silver Spring, MD November 1997 U.S. DEPARTMENT OF National Oceanic and National Ocean National Geodetic COMMERCE Atmospheric Administration Service Survey

Recommendations to Guidelines Based on Tests and Sample Projects

• Must repeat base lines Different days Different times of day

» Detect, remove, reduce effects due to multipath and having almost the same satellite geometry

• Must FIX integers

• Base lines must have low RMS values, i.e., < 1.5 cm

N O A A T e c h n ic a l M e m o r a n d u m N O S N G S - 5 8

G U ID E L IN E S F O R E S T A B L IS H IN G G P S - D E R IV E D E L L IP S O ID H E IG H T S( S T A N D A R D S : 2 C M A N D 5 C M )V E R S IO N 4 .3

D a v id B . Z i lk o s k iJ o s e p h D . D 'O n o f r ioS t e p h e n J . F r a k e s

S i lv e r S p r in g , M D

N o v e m b e r 1 9 9 7

U .S . D E P A R T M E N T O F N a t io n a l O c e a n ic a n d N a t io n a l O c e a n N a t io n a l G e o d e t icC O M M E R C E A t m o s p h e r ic A d m in is t r a t io n S e r v ic e S u r v e y

Available “On-Line” at

the NGS Web Site:

www.ngs.noaa.gov

Table 1. -- Summary of Guidelines.

Control 2 and 5 cm

Primary Base 2 cm

Primary Base 5 cm

Secondary Base 2 cm

Secondary Base 5 cm

Local Network 2 cm

Local Network 5 cm

Dual Frequency Required

Yes, if base line is greater than 10 km







Geodetic Quality Antenna with Ground Plane

Yes Yes Yes Yes Yes Yes Yes

Min. Number of Stations

3 3 3 No Minimum

No Minimum

No Minimum

No Minimum

Occupation Time 5 Hours 5 Hours 5 Hours 30 Minutes1 30 Minutes1 30 Minutes1 No Minimum1

Number of Days Station Is Occupied

3 3 3 22 22 22 22

Max. Distance Between Same or Higher-Order Stations

75 km 40 km 50 km 15 km 20 km 10 km 20 km

Average Distance Between Stations No Maximum No Maximum No Maximum No Maximum No Maximum 7 km 10 km

Repeat "Base Line"

YES3 YES3 YES3 YES3 YES3 YES3 YES3

Collect Met Data Yes Yes Yes Yes Yes No No

Fixed Height Pole Yes Yes No Yes No Yes No

Rubbing of Mark Yes Yes Yes Yes Yes Yes Yes

Precise Ephemerides Yes Yes Yes Yes Yes Yes Yes

Fix Integers Yes4 Yes5 Yes5 Yes Yes Yes Yes

Notes for Table of Summary of Guidelines: 1 Analyses have indicated that when following all guidelines in this document, 30 minutes of observations over base lines that are typically less than 10 kilometers will meet the standards. For base lines greater than 10 km, but less than 15 km, 1 hour sessions should meet the standards. For observing sessions greater than 30 minutes, collect data at 15-second epoch interval. For sessions less than 30 minutes, collect data at 5-second epoch interval. Track satellites down to at least 10-degree elevation cut-off. 2 Base lines must be reobserved on different days with significantly different satellite geometry. 3 The observing scheme requires that all adjacent stations have base lines observed at least twice on two different days with significantly different geometry. 4 If base line is greater than 40 kilometers, a partially fixed or float solution is permitted. 5 For all station pairs except those involved with control stations (see note 4

Table 1. -- Summary of Guidelines

Sample Project Showing Connections

CS1

PB2

SB2

LN4LN3LN2

LN5

LN1

LN7LN6

SB1

SB3

SB5SB4 PB4

PB1

PB3

CS2

CS4CS3

A Guide for EstablishingGPS-Derived Orthometric

Heights(Standards: 2 cm and 5 cm)

• Three Basic Rules

• Four Basic Control Requirements

• Five Basic Procedures

3-4-5 System

A Guide for Establishing GPS-Derived Orthometric Heights(Standards: 2 cm and 5 cm)

Three Basic Rules

• Rule 1: Follow NGS’ guidelines for establishing GPS-derived

ellipsoid heights (Standards: 2 cm and 5 cm)

• Rule 2: Use latest National Geoid Model, i.e., GEOID03

• Rule 3: Use latest National Vertical Datum, i.e., NAVD 88

Four Basic Control Requirements

• BCR-1: Occupy stations with known NAVD 88 orthometric heights Stations should be evenly distributed throughout project

• BCR-2: Project areas less than 20 km on a side, surround project with NAVD 88 bench marks i.e., minimum number of stations is four; one in each corner of project

• BCR-3: Project areas greater than 20 km on a side, keep distances between GPS-occupied NAVD 88 bench marks to less than 20 km

• BCR-4: Projects located in mountainous regions, occupy bench marks at base and summit of mountains, even if distance is less than 20 km

NAVD 88 Bench Marks Occupied with GPS NAVD 88 Bench Marks Occupied with GPS

0----------5----------10

Kilometers

0----------5----------10

Kilometers

Geoid 99Geoid 99

Units cmUnits cm

0----------5----------10---------15---------20

Kilometers

0----------5----------10---------15---------20

Kilometers

BCR1: Sketch indicates that

the 20 km rule was met.

BCR2: This requirement is not applicable because the project is greater than 20 km on a side.

BCR4: This requirement is not applicable because project is not in a mountainous region.

BCR Example

BCR3: Circled bench marks are mandatory. Analysis must indicate bench marks have valid

NAVD 88 heights. Other BMs can be substituted but user must adhere to 20 km requirement.

Five Basic Procedures

• BP-1: Perform 3-D minimum-constraint least squares adjustment of GPS survey project Constrain 1 latitude, 1 longitude, 1 orthometric height

• BP-2: Analyze adjustment results from BP-1 Detect and remove all data outliers

FREE ELLIPSOID HEIGHT RESIDUAL BY BASELINE LENGTH

-7

-6

-5

-4

-3

-2

-1

0

1

2

3

4

5

6

7

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0

BASE LINE LENGTH (KM)

RE

SID

UA

L (

CM

)

0113-H83A 3.1

0092-0039 5.1

0114-0913 2.6

0092-0039 3.8

1933--0121 3.1

6666-6669 -4.9

1933-0092 -6.5

6669-0092 -6.5

6666-6669 -4.9

0038-0913 -3.7

0127-6294 --3.5

1933-0092 -3.1

455 BASE LINES - 2.6% ABOVE 3 cm

BP2: After performing minimum constraint adjustment, plot ellipsoid height

residuals (or dU residuals) and investigate all residuals greater than 2 cm.

REPEAT BASELINE DIFFERENCES BY DISTANCE

0

1

2

3

4

5

6

0 5000 10000 15000 20000 25000 30000 35000 40000

BASELINE LENGTH (M)

RE

PE

AT

DIF

FE

RE

NC

ES

(C

M)

0113-H83A3.1

1933-01213.1 0092-1933

3.1

6669-00924.7

6669-6666 4.9

172 BASELINES - 3% Above 3 cm

BP2: Station pairs with large residuals, i.e., greater than 2.5 cm, also have large repeat base line

differences. NGS guidelines for estimating GPS-derived ellipsoid heights require user to

re-observe these base lines. Following NGS guidelines provides enough redundancy for

adjustment process to detect outliers and apply residual on appropriate observation, i.e., the

bad vector.

• BP-3: Compute differences between GPS-derived orthometric heights from minimum-constraint adjustment in BP-2 and published NAVD88 BMs

Five Basic Procedures(continued)

0.8 0.8

1.9 1.9 1.7 1.7 3.5 3.5

3.8 3.8

2.8 2.8 3.6 3.6

2.4 2.4

3.0 3.0 0.6 0.6 2.2 2.2

0.0 0.0 1.9 1.9

-0.1 -0.1

3.2 3.2

1.8 1.8

0.0 0.0

0.8 0.8

0.4 0.4

2.0 2.0

1.2 1.2

0.9 0.9

-1.1 -1.1

-1.1 -1.1 -0.3 -0.3

-0.7 -0.7

GPS-Derived Orthometric Height minus NAVD 88 HeightsGPS-Derived Orthometric Height minus NAVD 88 Heights

0----------5----------10

Kilometers

0----------5----------10

Kilometers

Geoid 99Geoid 99

Units cmUnits cm

BP3: All height differences are under 5 cm and most are less than 2 cm. Almost all relative

height differences between adjacent station pairs are less than 2 cm. However, most of the

height differences appear to be positive relative to the southwest corner of the project.

Five Basic Procedures(continued)

• BP-4: Determine which BMs have valid NAVD88 height values from results from BP-3 Differences need to agree 2 cm for 2 cm survey Differences need to agree 5 cm for 5 cm survey May detect systematic tilt over large areas

» Solve for geoidal slope and scale

• BP-5: Perform constrained adjustment with results from BP-4 Constrain 1 latitude, 1 longitude, all valid orthometric

height values Ensure final heights not distorted in adjustment

BP4: To detect and remove any systematic trend, a tilted plane is best fit to the height

differences (Vincenty 1987, Zilkoski and Hothem 1989). After a trend has been removed, all

the differences are less than +/- 2 cm except for one and almost all relative differences between

adjacent station are less than 2 cm.

-2.4 -2.4

-0.9 -0.9 -1.0 -1.0 0.8 0.8

1.2 1.2

0.5 0.5 1.4 1.4

0.3 0.3

1.0 1.0 -1.1 -1.1 0.4 0.4

-1.4 -1.4 0.5 0.5

-1.3 -1.3

1.6 1.6

0.7 0.7

-0.2 -0.2

-0.5 -0.5

-0.4 -0.4

1.4 1.4

0.5 0.5

0.8 0.8

-0.8 -0.8

-0.7 -0.7 -0.1 -0.1

-0.6 -0.6

GPS-Derived Orthometric Height minus NAVD 88 HeightsGPS-Derived Orthometric Height minus NAVD 88 Heights

0----------5----------10

Kilometers

0----------5----------10

Kilometers

Geoid 99Geoid 99 Units cmUnits cm

Tilted Plane Removed

RMS 1.0

Shift 1.5 cm

e-w -0.01 cm/km

n-s 0.12 cm/km

Tilted Plane Removed

RMS 1.0

Shift 1.5 cm

e-w -0.01 cm/km

n-s 0.12 cm/km

BP5: After rejecting the largest height difference (-2.4 cm), of all the closely spaced station

pairs only 3 are greater than 2 cm, 1 is greater than 2.5 cm and none are greater than 3 cm.

1 National Geodetic Survey, Retrieval Date = JANUARY 4, 1999AW5439***********************************************************************AW5439 DESIGNATION - HGCSD 18AW5439 PID - AW5439AW5439 STATE/COUNTY- TX/HARRISAW5439 USGS QUAD - SATSUMA (1982)AW5439AW5439 *CURRENT SURVEY CONTROLAW5439 ___________________________________________________________________AW5439* NAD 83(1993)- 29 52 45.31262(N) 095 36 41.68709(W) ADJUSTEDAW5439* NAVD 88 - 36.28 (meters) 119.0 (feet) GPS OBSAW5439 ___________________________________________________________________AW5439 X - -541,229.237 (meters) COMPAW5439 Y - -5,508,419.298 (meters) COMPAW5439 Z - 3,158,779.472 (meters) COMPAW5439 LAPLACE CORR- 0.34 (seconds) DEFLEC96AW5439 ELLIP HEIGHT- 8.96 (meters) GPS OBSAW5439 GEOID HEIGHT- -27.43 (meters) GEOID96AW5439AW5439 HORZ ORDER - FIRSTAW5439 ELLP ORDER - THIRD CLASS IAW5439AW5439.The horizontal coordinates were established by GPS observationsAW5439.and adjusted by the National Geodetic Survey in October 1996.AW5439AW5439.The orthometric height was determined by GPS observations and aAW5439.high-resolution geoid model using precise GPS observation andAW5439.processing techniques.AW5439AW5439.The X, Y, and Z were computed from the position and the ellipsoidal ht.AW5439AW5439.The Laplace correction was computed from DEFLEC96 derived deflections.AW5439AW5439.The ellipsoidal height was determined by GPS observationsAW5439.and is referenced to NAD 83.AW5439AW5439.The geoid height was determined by GEOID96.AW5439AW5439; North East Units Scale Converg.AW5439;SPC TXSC - 4,231,486.301 927,255.302 MT 0.99990823 +1 39 36.1AW5439;UTM 15 - 3,308,270.740 247,770.501 MT 1.00038501 -1 18 06.2AW5439AW5439 SUPERSEDED SURVEY CONTROLAW5439AW5439 NAD 83(1986)- 29 52 45.32657(N) 095 36 41.66906(W) AD( ) 1AW5439 NAD 83(1993)- 29 52 45.31197(N) 095 36 41.68755(W) AD( ) 1AW5439 ELLIP HT - 9.33 (m) GP( ) 5AW5439 NGVD 29 - 36.86 (m) 120.9 (f) LEVELING 3AW5439AW5439.Superseded values are not recommended for survey control.

Elevation published

to centimeters.

Orthometric height

determined by GPS.

GPS-Derived

Orthometric Heights

Project

Baltimore County Maryland, NAVD88

GPS-Derived Orthometric Height Project

Baltimore County, Maryland, NAVD88GPS-derived Orthometric Height Project

Project Horizontal and Vertical Control

HYDESHARN

MELSAGEHARN

92

43Baltimore City

KEY

Existing HARNNew Primary Control

1A, 2A, 3A

1A, 2A, 3A

1A, 2A, 3A

1A, 2A, 3A

1A, 2

A, 3A

1A, 2

A, 3

A

Observation Sessions; Primary ControlDay 263 = Project Day 1Day 264 = Project Day 2Day 268 = Project Day 3Session A for all days; 5 hour observations

HYDESHARN

10779

8078

98LINE

81

MELSAGEHARN

829792

94

9184

90

43 SAUTERRESET

Baltimore City

KEY

Observation Sessions; Local ControlDay 269 = Project Day 4Day 270 = Project Day 5Day 271 = Project Day 6Session =A, B, C, D, E; 45 minute observations

6D5B

6D 5B5B6D

5B6D

5A6C

6C, 5A

5A 6C

6C5A

4E 6B

6B4E

4E 6B

4D 6B

6A 4E

4D 6A

4C

5E

4C 4D5E 6A

4D

6A

4C

5E

4A

5C

5C4A

4A5C

4A5C

4B 5D

5D

4B4B

5D

5D 4B

4C

5E

Repeat Baseline Differences

Repeat Baseline Differences(Baselines less than 10 KM)

FROM STATION

TO STATION (Distance, meters)

SESSION NUMBER

OBSERVED MET DATA x1 x2

DIFF cm (x1 - x2)

STANDARD MET DATA y1 y2

DIFF cm (y1-y2)

DIFF cm (x1-y1), (x2-y2)

MELSAGE MELSAGE MELSAGE GIS 92 GIS 43 GIS 92

GIS 92 9,692 GIS 43 13,576 HYDE 25,079 GIS 43 15,768 HYDE 36,954 HYDE 32,400

1A 2A 1A 3A 2A 3A 1A 2A 1A 2A 1A 3A 2A 3A 1A 2A 1A 2A 1A 2A 1A 3A 2A 3A

8.769 8.703

8.769 8.644

8.703 8.644

- 94.766 - 94.724

- 89.525 - 89.457

- 89.525 - 89.473

- 89.457 - 89.473

-103.533 -103.423

5.249 5.256

- 98.297 - 98.167

- 98.297 - 98.117

- 98.167 - 98.117

6.6

12.5

5.9

-4.2

-6.8

-5.2

1.6

-11.0

-0.7

-13.0

-18.0

-5.0

8.664 8.668

8.664 8.669

8.668 8.669

- 94.725 - 94.740

- 89.498 - 89.483

- 89.498 - 89.492

- 89.483 - 89.492

-103.389 -103.406

5.230 5.248

- 98.164 - 98.148

- 98.164 - 98.166

- 98.148 - 98.166

-0.4

-0.5

-0.1

1.5

-1.5

-0.6

0.9

1.7

1.8

-1.6

-0.2

-1.8

10.5 3.5

10.5 -0.5

3.5 -0.5

-4.1 1.6

-2.7 2.6

-2.7 1.9

2.6 1.9

-14.4 -1.7

1.9 0.8

-13.3 -1.9

-13.3 4.9

-1.9 4.9

Height Differences (du) 5 Hour Sessions

Height Differences (du) 45 Minute Sessions FROM STATION

TO STATION (Distance, meters)

SESSION NUMBER

OBSERVED MET DATA x1 (m) x2

DIFF (cm) (x1-x2)

STANDARD MET DATA y1 (m) y2

DIFF cm (y1-y2)

DIFF cm (x1-y1), (x2-y2)

SAUTER RESET GIS 43 GIS 90 GIS 91 GIS 84 GIS 94 GIS 92 GIS 91 SAUTER RESET SAUTER RESET

GIS 43 7,882 GIS 90 6,242 GIS 91 4,062 GIS 84 2,088 GIS 94 3,483 GIS 92 3,288 GIS 91 5,703 SAUTER RESET 13,036 GIS 92 18,029 MELSAGE 11,120

4B 5D 4B 5D 4B 5D 4A 5C 4A 5C 4A 5C 4A 5C 4B 5D1

4C 5E 4C2 5E

- 68.058 - 68.076 63.809 63.879 24.404 24.392 - 42.298 - 42.286 39.767 39.741 17.595 17.574 - 15.079 - 15.067 - 20.205 - 20.167 35.296 35.252 26.646 26.605

1.8 7.0 1.2 - 1.2 2.6 2.1 - 1.2 - 3.8 4.4 4.1

- 68.101 - 68.109 63.897 63.908 24.421 24.407 - 42.331 - 42.325 39.801 39.781 17.614 17.591 - 15.094 - 15.076 - 20.217 - 20.191 35.308 35.298 26.655 26.618

- 0.8 - 1.1 1.4 - 0.6 2.0 2.3 1.8 - 2.6 1.0 3.7

4.3 3.3 - 8.8 - 2.9 - 1.7 - 1.5 3.3 3.9 - 3.4 - 4.0 - 1.9 - 1.7 1.5 0.9 1.2 2.4 - 1.2 - 4.6 - 0.9 - 1.3

1 SAUTER RESET are outside allowable tolerance for base line misclosures and will be reobserved at later date. 2 Large residuals in adjustment, 2.1 cm, and base line lengths are greater than 10 km.

Height Differences (du) 45 Minute Sessions (continued)FROMSTATION

TOSTATION(Distance, meters)

SESSIONNUMBER

OBSERVEDMET DATAx1

x2

DIFF (cm)

(x1-x2)

STANDARDMET DATAy1

y2

DIFF cm

(y1-y2)

DIFF cm(x1-y1),(x2-y2)

GIS 92

GIS 92

MELSAGE

MELSAGE

GIS 97

GIS 82

GIS 81

GIS 97 2,831

MELSAGE 9,692

GIS 97 7,821

GIS 82 6,722

GIS 82 7,958

GIS 81 6,186

LINE 2,462

4C4

5E4

4D 6A

5E 6A

4D4

6A4

4C 5E

4C 5E

4D3

6A 4E 6B

4D3

6A

4E 6B

4E 6B

17.867 17.840 17.869 17.844

17.840 17.844

- 8.687- 8.657- 8.651- 8.649

26.518 26.489

33.542 33.351 33.343 33.403

7.048 6.855

-101.434-101.513

34.841 34.822

2.7

2.5

- 0.4

3.0

0.2

2.9

19.1

- 6.0

19.3

7.9

1.9

17.878 17.849 17.824 17.843

17.849 17.843

- 8.704- 8.664- 8.660- 8.671

26.529 26.524

33.361 33.369 33.389

7.017 6.855

-101.529-101.533

34.846 34.822

2.9

- 1.9

0.6

- 4.0

1.1

0.5

- 2.0

16.2

0.4

2.4

- 1.1- 0.9 4.5 0.1

- 0.9 0.1

1.7 0.7 0.9 2.2

- 1.1- 3.5

- 1.0- 2.6 1.4

3.1 0.0

9.5 2.0

- 0.5 0.0

3 Rejected in adjustment4 Another set of base lines meet allowable misclosure

Height Differences (du) 45 Minute Sessions (continued)

FROMSTATION

TOSTATION(Distance, meters)

SESSIONNUMBER

OBSERVEDMET DATAx1

x2

DIFF (cm)

(x1-x2)

STANDARDMET DATAy1

y2

DIFF cm

(y1-y2)

DIFF cm(x1-y1),(x2-y2)

MELSAGE

LINE

LINE

GIS 98

GIS 78

GIS 80

GIS 79

GIS 107

GIS 80

LINE10,497

GIS 78 6,068

GIS 98 6,135

GIS 78 2,375

GIS 80 366

GIS 79 1,839

GIS 107 2,532

HYDE 4,674

HYDE 8,294

4E5

6B

5A 6C

5A 6C

5A 6C

5A 6C

5B 6D6

341

5B 6D6

341

5B 6D6

341

5B 6D6

341

- 33.261- 33.286

- 56.742- 56.733

- 55.900- 55.886

- 0.847- 0.842

- 0.310- 0.312

- 6.530- 6.545

62.854 62.842

- 55.423- 55.401

0.909 0.907

2.5

- 0.9

- 1.4

- 0.5

0.2

1.5

1.2

2.2

0.2

- 33.271- 33.313

- 56.771- 56.782

- 55.924- 55.937

- 0.845- 0.842

- 0.310- 0.312

- 6.536- 6.545- 6.547

62.894 62.842 62.903

- 55.439- 55.400- 55.449

0.924 0.907 0.914

4.2

1.1

1.3

- 0.3

0.2

0.9 1.1

5.2 - 0.9

- 3.9 1.0

1.7 1.0

1.0 2.7

2.9 4.9

2.4 5.1

- 0.2 0.0

0.0 0.0

0.6 0.0

- 4.0 0.0

1.6 0.1

- 1.5 0.0

5 Large residual, -4.0 cm, in adjustment and base line length greater than 10 km.6 Session reobserved on December 6, 1996 (DOY 341).

Vertical Free Adjustment ResultsGEOID96

StationName

EllipsoidHeightmeters(h)

GeoidHeightmeters

(GEOID96)

GPS-derivedOrthometric

Heightmeters(HGPS96)

NAVD88Orthometric

Heightmeters(H88)

HGPS96 - H88(cm)

HGPS -H88differencesrelative to

MELSAGE(cm)

GIS 43

GIS 91

GIS 92

GIS 107

LINE

MELSAGE

52.664

135.831

155.658

112.555

97.736

129.785

-32.085

-32.062

-32.074

-32.651

-32.399

-32.191

84.749

167.893

187.732

145.206

130.135

161.976

84.777

167.910

187.751

145.228

130.143

161.989

- 2.8

- 1.7

- 1.9

- 2.2

- 0.8

- 1.3

-1.5

-0.4

-0.6

-0.9

0.5

0.0

Vertical Free Adjustment ResultsG96SSS

StationName

EllipsoidHeightmeters(h)

GeoidHeightmeters

(GEOID96)

GPS-derivedOrthometric

Heightmeters(HGPS96)

NAVD88Orthometric

Heightmeters(H88)

HGPS96 - H88(cm)

HGPS -H88differencesrelative toMELSAGE(cm)

GIS 43

GIS 91

GIS 92

GIS 107

LINE

MELSAGE

52.664

135.831

155.658

112.555

97.736

129.785

-32.961

-32.934

-32.944

-33.519

-33.268

-33.062

85.625

168.765

188.602

146.074

131.004

162.847

84.777

167.910

187.751

145.228

130.143

161.989

84.8

85.5

85.1

84.6

86.1

85.8

-1.0

-0.3

-0.7

-1.2

0.3

0.0

Vertical Free Adjustment ResultsGEOID93

Station Name

Ellipsoid Height meters (h)

Geoid Height meters

(GEOID93)

GPS-derived Orthometric

Height meters (HGPS93)

NAVD88 Orthometric

Height meters (H88)

HGPS93 - H88 (cm)

HGPS -H88 differences relative to

MELSAGE (cm)

GIS 43 GIS 91 GIS 92 GIS 107 LINE MELSAGE

52.664

135.831

155.658

112.555

97.736

129.785

-32.421

-32.390

-32.398

-32.962

-32.716

-32.514

85.085

168.221

188.056

145.517

130.452

162.299

84.777

167.910

187.751

145.228

130.143

161.989

30.8

31.1

30.5

28.9

30.9

31.0

-0.2

0.0

-0.5

-2.1

-0.1

0.0

Baltimore County GPS-DerivedOrthometric Height Project

H GPS - H Leveling(88)

(Units = cm)

HYDESHARN

10779

8078

98

LINE

81

MELSAGEHARN

8297

92

94

9184

90

43SAUTERRESET

Baltimore City

KEYGEOID93

GEOID96

G96SSS

-2.1

-0.9

-1.2

-0.1

0.5

0.30.0

0.0

0.0

-0.5

-0.6

-0.7

0.0

-0.4

-0.3

-0.2

-1.5

-1.0

Station Name GPS-derived Orthometric height relative to MELSAGE from

minimally constrained adjustment (m)

GPS-derived Orthometric height from final

constrained adjustment (m)

C=Constrained

Minimally constrained minus final constrained adjustment (cm)

GIS 43 84.762 84.777C -1.5

GIS 78 80.697 80.694 0.3

GIS 79 77.587 77.589 -0.2

GIS 80 81.094 81.094 0.0

GIS 81 97.356 97.357 -0.1

GIS 82 199.366 199.372 -0.6

GIS 84 129.844 129.851 -0.7

GIS 90 146.039 146.046 -0.7

GIS 91 167.906 167.910C -0.4

Final Set of GPS-Derived Orthometric Heights

Station Name GPS-derived Orthometric height relative to MELSAGE from

minimally constrained adjustment (m)

GPS-derived Orthometric height from final

constrained adjustment (m)

C=Constrained

Minimally constrained minus final constrained adjustment (cm)

GIS 92 187.745 187.751C -0.6

GIS 94 168.846 168.851 -0.5

GIS 97 200.692 200.703 -1.1

GIS 98 79.076 79.076 0.0

GIS 107 145.219 145.228C -0.9

HYDE 102.932 102.935 -0.3

LINE 130.148 130.143C 0.5

MELSAGE 161.989 161.989C 0.0SAUTER RESET 140.895 140.918 -2.3

Final Set of GPS-Derived Orthometric Heights (cont.)

Data Processing and Analysis

of Repeat Base Line Results

Vector Processing Controls

• Elevation Mask - 15 degrees

• Ephemeris - Precise

• Tropospheric Correction Model

• Iono Corrections - All baselines longer than 5 km.

• Fix Integers Baselines less than 5 km: L1 fixed solution Baselines greater than 5 km: Iono free (L3) solution

• Looking for RMS - Less than 1.5 cm

Washington Monument

Survey

1999

1934

From To Session DX (m) DY (m) DZ (m) Vector 1st - Next 1st - Next 1st - Next Length (m)

000A WASH 231B 23.3958 -101.5071 142.1077 176.198 230B -0.2463 -0.2060 -0.0313 0.060 229B -0.1140 0.1148 -0.0838 -0.149 229A 0.1718 -0.2620 0.2073 0.341 231A 0.1387 -0.2439 0.2101 0.328

868H WASH 229A 194.0185 -335.8332 -176.4013 426.080 230B -0.0135 0.2206 -0.2093 -0.093 229B -0.1019 0.1925 -0.1924 -0.119 231A -0.0053 0.0117 -0.0331 0.002 230A -0.0354 0.0883 -0.1207 -0.036 231B -0.0983 0.1579 -0.1745 -0.097

JEFF WASH 231B 146.1021 -129.6425 80.2985 211.189 231A 0.1341 -0.2111 0.1901 0.295 230A -0.0595 -0.0776 0.0688 0.033 229B -0.1014 0.1360 -0.1639 -0.216 230B 0.0961 0.0648 -0.0276 0.016

L1, Float Solution, Predicted Weather


000A WASH 229A 23.2992 -101.3609 141.9511 175.974 231A 0.0054 -0.0414 0.0020 0.026 230B -0.0435 0.1553 -0.1650 -0.228 229B -0.0236 0.0825 -0.0953 -0.128 231B -0.1005 0.1497 -0.1596 -0.228

868H WASH 229A 194.0163 -335.8572 -176.3620 426.082 229B -0.0323 0.1054 -0.0964 -0.058 230B -0.0366 0.1522 -0.1457 -0.076 231B -0.1028 0.1360 -0.1370 -0.097 231A -0.0302 0.0540 -0.0590 -0.032 230A -0.0070 0.0198 -0.0440 -0.001

JEFF WASH 230A 146.1764 -129.6260 80.2979 211.230 230B 0.1508 0.0315 -0.0017 0.084 229B -0.0509 0.1939 -0.2241 -0.239 231B 0.0809 0.0107 0.0039 0.051 231A 0.1914 -0.1280 0.1387 0.264

L1, Partial Fixed Solution, Predicted Weather


000A WASH 229B 23.4735 -101.5769 142.1521 176.284 231B 0.0349 -0.0099 -0.0105 0.002 231A 0.1006 -0.0148 0.0467 0.060 229A 0.1578 -0.0754 0.0643 0.116 230B 0.1569 -0.0359 0.0296 0.065

868H WASH 229A 194.1045 -336.0715 -176.2377 426.240 229B -0.0472 -0.0049 -0.0677 0.010 230A 0.0599 -0.0952 0.0204 0.094 231B -0.0604 -0.0141 -0.0716 0.013 230B 0.0733 -0.0290 -0.0379 0.072 231A 0.0061 -0.0184 -0.0120 0.022

JEFF WASH 230A 146.1589 -129.5715 80.2348 211.161 230B 0.1522 0.1006 -0.0685 0.018 231B 0.0187 0.1229 -0.1099 -0.104 229B 0.0319 0.0955 -0.1089 -0.078 231A 0.1027 0.1151 -0.0498 -0.019

L1, Float Solution, Recorded Weather

Analysis of the Data Processing

• Fixed solutions / low RMS

• Repeatability of measurements

• Analysis of loop misclosures

• Be aware that repeatability and loop misclosures do not disclose all problems

From To Session dh Diff Dist RMS Solution Station Station Meters cm Meters Type

BR13 BR14 0780-0780 45.974* 1628 0.016 L1 float double 0770-0770 46.004 -3.0 0.017 L1 fixed double 0761-0762 46.009 -3.5 0.015 L1 fixed double BR13 K251 0780-0780 -12.397 673 0.006 L1 fixed double 0770-0770 -12.400 0.3 0.006 L1 fixed double 0762-0761 -12.408 1.1 0.006 L1 fixed double BR14 GR15 0780-0780 43.680 1133 0.022 L1 fixed double 0770-0770 43.654* 2.6 0.024 L1 fixed double 0762-0765 43.607* 7.3 0.020 L1 fixed double BR19 CL20 0781-0781 54.703* 365 0.047 L1 fixed double 0771-0771 55.031 -32.8 0.022 L1 fixed double 0762-0763 55.007* -30.4 0.019 L1 fixed double BR20 BR30 0782-0782 28.939 9850 0.014 Iono free fixed 0772-0772 28.947 -0.8 0.014 Iono free fixed 0760-0763 28.940 -0.1 0.020 Iono free fixed BR20 VINT HILL 0782-0782 33.045 11967 0.011 Iono free fixed 0772-0772 33.051 -0.6 0.009 Iono free fixed 0760-0763 33.063 -1.8 0.013 Iono free fixed

*NOTE - Reprocess all vectors which have difference greater than 2 cm.

Repeat Vector Analysis

From To Session dh Diff Dist RMS Solution Station Station Meters cm Meters Type

BR13 BR14 0761-0762 46.009 1628 0.015 L1 fixed double 0770-0770 46.004 0.5 0.017 L1 fixed double 0780-0780 46.007 0.2 0.015 L1 fixed double BR13 K251 0770-0770 -12.400 673 0.006 L1 fixed double 0780-0780 -12.397 -0.3 0.006 L1 fixed double 0762-0761 -12.408 0.8 0.006 L1 fixed double BR14 GR15 0780-0780 43.680 1133 0.022 L1 fixed double 0765-0762 43.658 2.2 0.020 L1 fixed double 0770-0770 43.654 2.6 0.024 L1 fixed double BR19 CL20 0771-0771 55.031 365 0.022 L1 fixed double 0781-0781 55.027 0.4 0.023 L1 fixed double 0762-0763 55.019 1.2 0.018 L1 fixed double BR20 BR30 0782-0782 28.939 9850 0.014 Iono free fixed 0772-0772 28.947 -0.8 0.014 Iono free fixed 0760-0763 28.940 -0.1 0.020 Iono free fixed BR20 VINT HILL 0782-0782 33.045 11967 0.011 Iono free fixed 0760-0763 33.063 -1.8 0.013 Iono free fixed 0772-0772 33.051 -0.6 0.009 Iono free fixed

Repeat Vector Analysis After Re-Processing

Adjustment Procedures to Obtain

GPS-Derived NAVD’88

Orthometric Heights

Least Squares Adjustments

• The adjustment minimizes the effects of random errors

• A least squares adjustment computes a single network solution, even with redundant vectors

• Least squares will highlight blunders and large errors

• It will provide estimates on the precision of the coordinates for the stations

Errors• All real observations contain errors

Two types of errors» Random errors which mean to zero» Systematic errors which do not

• Least squares will only give improved results if your errors are predominantly random

Random error

Systematic error

residual theis

nobservatio real theis

model with theconsistant iswhich parameter truetheisˆwhere

ˆ

v

l

l

llv

Least Squares

• Least squares is a mathematical procedure that takes a series of survey measurements which must contain some extra or redundant measurements

• and calculates a single set of coordinates for the stations that will satisfy all of the measurements while minimizing the sum of the squares of the misfit (or residuals)

residuals theare

minimum2

v

v

Least Squares Condition

v1 2 3 41234

Critical value Critical value

Outliers Outliers

SEUW = (estimated errors)2

(residuals)2

Standard Error of Unit Weight

• If the residuals from a least squares adjustment are equal to the errors expected for the order of survey we have performed The standard error of unit weight will have a value of unity

• If the residuals are lower than we would expect given our initial estimates of the errors SEUW will be less than 1

• If they are too high SEUW will be greater than 1

• Often used as a rough indication of whether a survey meets specifications

Minimally Constrained Adjustment

• Hold the minimum number of control points fixed to allow the least squares process to work One fixed point for GPS 2 for triangulation survey

without distance measurements

• The purpose of this adjustment is to Check the internal consistency of

the network Detect blunders or ill-fitting

observations Obtain accurate error estimates

How big do you make the bolt holes?

Constrained Adjustment

• Hold all control points in the network fixed at values from the NGS database Minimum of 2 for GPS surveys 3 for triangulation survey without distance

measurements

• The purpose of this adjustment is to Reference the network to existing control

and develop final coordinates for the new control points that are being established

Verify existing control. If any control points are wrong the standard error of unit weight and the residuals will increase compared to the minimally constrained adjustment

Adjustment of Primary Network Stations

Horizontal Adjustment(Latitude, Longitude, Ellipsoid Heights)

• Minimum Constrained [One fixed station] Fix latitude, longitude and ellipsoid height at one station Resolve all blunders and large residuals Determine which Control and known Primary Base Station

coordinates should be fixed

• Constrained [All suitable stations fixed] Fix latitude, longitude, and ellipsoid heights at Control and

known Primary Base Stations Make sure the constraints did not distort the project

NOTE - Geoid model NOT applied at this time

CORSHARNNAVD’88 BMNew Station

121°40’W122°35’W

37°50’N

38°20’N

LA

TIT

UD

E

LONGITUDE

Primary Base Station

Adjustment of Primary Base Stations

MOLAMART

LAKE

10CCD191

29.6km25.8km

38.7k

m

19.0km

28.7km

25.7km 38.3km

31.6

km•CORS, Control Points (known Primary Control) horizontal

•latitude, longitude, and ellipsoid heights

•No NAVD88 orthometric heights constrained at this time

Adjustment of Local Network Stations

Horizontal Adjustment(Latitude, Longitude, Ellipsoid Heights)

• Minimum Constrained [One fixed station] Fix latitude, longitude and ellipsoid height at one station Resolve all blunders and large residuals Evaluate coordinates at Control and Primary Base Station

» should not be greatly affected by Local Station baselines

• Constrained [All suitable stations fixed] Fix latitude, longitude, and ellipsoid heights at Control and

Primary Base Stations Make sure the constraints did not distort the project

NOTE - Geoid model NOT applied at this time

CORSHARNNAVD’88 BMNew StationSpacing Station

121°40’W122°20’W

37°55’N

38°16’N

LA

TIT

UD

E

LONGITUDE

Primary Base Station

8.2km

Adjustment of Local Network Stations

•Existing and newly derived Primary Control horizontal

• latitude, longitude, and ellipsoid heights


Combined Network Horizontal Adjustment

• Perform combined adjustment

Control and Primary Base network along with local network

Latitude, longitude, and ellipsoid height

• Use GEOID model to obtain geoid heights

• Make sure combined adjustment did not distort the project

Combined Horizontal Adjustment


121°40’W122°35’W

37°50’N

38°20’N

LA

TIT

UD

E

LONGITUDE

Spacing StationPrimary Base Station

8.2km

•CORS, Control Points and existing and new Primary Control horizontal

• latitude, longitude, and ellipsoid heights


3-D Vertical Adjustment(Orthometric Heights)

• Minimum Constrained [One fixed station] Fix latitude, longitude, and orthometric height at one station Resolve all blunders and large residuals Compare orthometric heights from adjustment with published NAVD 88 Determine which NAVD 88 bench marks should be fixed

• Constrained [All suitable orthometric heights fixed] Fix latitude, longitude at one station Fix orthometric heights at all suitable stations Make sure the constraints did not distort the project

Combined Network Vertical Adjustment

Constrained Vertical Adjustment


121°40’W122°35’W

37°50’N

38°20’N

LA

TIT

UD

E

LONGITUDE

Spacing StationPrimary Base Station

8.2km

•1 horizontal latitude and longitude

•All valid NAVD88 orthometric heights

Topography

AB

C

D

E

F

GPS-Derived Heights from GEOID03 Separation

= Published NAVD88 Orthometric Height = New Control

Ellipsoid

hh

hh

hh

GEOID03

N NN N

NN

Hh-N

Hh-NHh-N

Hh-N

Hh-N

Hh-N

Constrained Vertical Adjustment

Topography

AB

C

D

E

F

hadj

hadjhadj

hadj

hadj

hadj

AdjustedEllipsoid

Ellipsoid Height Adjusted to Fit Constrained Orthometric Heights

GPS-Derived Orthometric Heights

= Published NAVD88 Orthometric Height = New Control

H

HH

H

Geoid

GEOID03

N NN N

NN

Ellipsoid

hh

hh

hhHGPS

HGPS

Summary

• Mistakes and systematic errors must be removed before the adjustment

• A least squares adjustment handles random errors and provides a single solution

• The Minimally Constrained adjustment checks the internal consistency of the network

• The Constrained adjustment checks the existing control and references the network to the datum

• The vertical adjustment estimates GPS-derived Orthometric heights

Analysis of aHeight Project

The project consists of 3 different parts as follows:

1. Determine ellipsoid height of the two bridges using three different GPS receivers

on the two bridges, one receiver at the pilot house, and a CORS site.

2. Determine the difference between Geoid96 with NAVD 88 by observing a minimum

of four NAVD 88 bench marks including one primary bench mark at the tidal station.

3. Determine the height from the bottom of the bridges to each of the antenna mounts

on the bridges using classical and trig leveling.

This project plan is for measuring the vertical

clearance for the Cooper River Bridges, known as the Grace Memorial Bridge and Silias Pearman Bridge.

Implementation of real-time, using GPS, sensors that will determine the maximum height of a vessel at the lowest point of a bridge.

This project plan is for measuring the vertical clearance for the Cooper River Bridges.

Vertical clearance is critical for ensuring safe navigation for the Port of Charleston, South Carolina.

MOUNTING THE ANTENNAS

1. Determine ellipsoid height of the two bridges using three different GPS receivers on the two bridges, one receiver at the pilot house, and a CORS site.

GPS OCCUPATION

CLASSICAL LEVELING

2. Determine the difference between Geoid96 with NAVD 88 by observing a minimum of four NAVD 88 bench marks including one primary bench mark at the tidal station.

TRIG-LEVELING

3. Determine the height from the bottom of the bridges to each of the antenna mounts on the bridges using classical and trig leveling.

Height Project

C 69 TBM SILEARP

HOLLINS

10 012

TIDAL 13

CBPA

CHA1CORS

NAVD88 Bench Mark

Temporary (Project) CORS(Mounted to each end of bridge)

(Connection to water surface)

From To Session Length DX (m) DY (m) DZ (m) Vector ppm (Hrs) 1st - Next 1st - Next 1st - Next Length (m)

1001 TIDE 036A 2 -611.0438 -1427.9448 -2098.1300 2610.469 034B 2 -0.0001 0.0092 -0.0018 -0.004 1.36

CBPA CHA1 040A 24 7737.4970 311.1515 -1656.7241 7918.990 037A 24 -0.0029 0.0051 -0.0020 -0.002 0.28 036A 24 -0.0043 0.0088 -0.0042 -0.003 0.38

CHA1 SILE 034A 24 -7178.4232 1466.8512 4311.2394 8501.070 039A 24 0.0007 0.0018 -0.0094 -0.005 0.59 035A 24 -0.0006 0.0030 -0.0076 -0.003 0.33

CPBA TIDE 036A 2 -54.7070 365.4396 546.3072 659.538 034B 2 -0.0001 -0.0016 -0.0011 -0.002 2.71

HOLL SILE 034B 2 2418.6237 255.6238 -149.0401 2436.657 036C 2 0.0028 -0.0270 0.0257 -0.002 0.67

Repeat Vector Analysis

STATION NAME LAT / LON ELLIPSOID SHIFT (cm) SHIFT (cm)

10 012 32.8 *CHARLESTON 1 CORS ARP 0.0 0.0866 5530 TIDAL 13 0.8 1.8 * No Published Ellipsoid Height

Free Adjustment Horizontal PositionsCompared to Published NAD83 Positions

Free Adjustment minus NAD83 Published

0.8cm Horiz1.8cm Ellip. Ht.

FIXED

C 69 TBM SILEARP

HOLLINS

10 012

TIDAL 13

CBPA

CHA1CORS

NAVD88 Bench Mark

Temporary (Project) CORS

32.8cm Horiz

Residuals plotted to help

determine inconsistencies

CJ0085 DESIGNATION - 866 5530 TIDAL 13CJ0085 ______________________________________________________________CJ0085* NAD 83(1992)- 32 46 5233453(N) 079 55 28.70969(W) ADJUSTED CJ0085* NAVD 88 - 2.219 (meters) 7.28 (feet) ADJUSTED CJ0085 ______________________________________________________________CJ0085 ELLIP HEIGHT- -30.96 (meters) GPS OBSCJ0085CJ0085 HORZ ORDER - FIRSTCJ0085 VERT ORDER - FIRST CLASS I

******************************************************************************CJ0578 DESIGNATION - 10 012CJ0578CJ0578 ______________________________________________________________CJ0578* NAD 83(1986)- 32 47 31.79561(N) 079 54 20.99377(W) ADJUSTED CJ0578* NAVD 88 - 5.336 (meters) 17.51 (feet) ADJUSTED CJ0578 ______________________________________________________________CJ0578CJ0578 HORZ ORDER - FIRSTCJ0578 VERT ORDER - FIRST CLASS II

NOTE - Different adjustments for the positions

Sample Data Sheets


C 69 0.4 -1.4HOLLINGS 0.4 -1.3866 5530 TIDAL 13 0.8 -1.810 012 0.4 -1.3TBM SILE ARP 0.3 -0.8CHARLESTON POLIT HOUSE ARP 0.3 -0.9TBM SILW ARP 0.3 -0.6TBM GRAC ARP 0.3 -0.7CHARLESTON 1 CORS ARP 0.2 -0.1TBM SALAIS BOTTOM OF BRIDGE 0.5 -1.7

Adjusted Constrained Horizontal Compared to Free Horizontal Positions

[Station 10 012 Not Fixed]

•Minimum shifts between free and constrained adjustments

•Constraints did not adversely affect adjustment


C 69 5.8 -2.3HOLLINGS 6.0 -2.9866 5530 TIDAL 13 5.3 -1.810 012 32.8 -9.0TBM SILE ARP 6.3 -2.9CHARLESTON POLIT HOUSE ARP 5.2 -1.6TBM SILW ARP 5.9 -2.0TBM GRAC ARP 5.9 -2.1CHARLESTON 1 CORS ARP 0.0 -0.0TBM SALAIS BOTTOM OF BRIDGE 5.2 -1.7

Adjusted Constrained Horizontal Compared to Free Horizontal Positions

[Station 10 012 Fixed]

•A bad constraint in position also affects the ellipsoid heights

STATION NAME LAT / LON ORTHOMETRIC SHIFT (cm) SHIFT (cm)

C 69 0.1 0.6HOLLINGS 0.2 0.1866 5530 TIDAL 13 0.0 0.010 012 0.8 -8.2TBM SILE ARP 0.3 0.9TBM SILW ARP 0.3 0.8

Free Vertical Adjustment Compared to Published NAVD88 Elevations

•GPS-derived orthometric height does not agree with published orthometric height

Free Vertical Adjustment minus NAVD88 Published

C 69 TBM SILEARP HOLLINS

10 012

TIDAL 13

CBPA

CHA1CORS

NAVD88 Bench Mark

Temporary (Project) CORS

-8.2cm

FIXED

0.6cm

0.1cm

0.9cm

Residuals plotted to help

determine trends or

inconsistencies


C 69 0.1 -0.6HOLLINGS 0.0 -0.1866 5530 TIDAL 13 0.0 0.010 012 0.0 -0.4TBM SILE ARP 0.0 -0.7CHARLESTON POLIT HOUSE ARP 0.0 -0.4TBM SILW ARP 0.0 -0.8TBM GRAC ARP 0.0 -0.6CHARLESTON 1 CORS ARP 0.0 -0.6TBM SALAIS BOTTOM OF BRIDGE 0.0 -0.0

Adjusted Constrained Vertical Compared to Free Vertical Elevations

[Station 10 012 Not Fixed]

•Minimum shifts between free and constrained adjustments

•Constraints did not adversely affect adjustment


C 69 0.1 -0.6HOLLINGS 0.0 -0.1866 5530 TIDAL 13 0.0 0.010 012 0.0 -8.2TBM SILE ARP 0.0 -0.7CHARLESTON POLIT HOUSE ARP 0.0 -2.4TBM SILW ARP 0.0 -0.8TBM GRAC ARP 0.0 -0.6CHARLESTON 1 CORS ARP 0.0 -4.2TBM SALAIS BOTTOM OF BRIDGE 0.0 -1.2

Adjusted Constrained Vertical Compared to Free Vertical Elevations

[Station 10 012 Fixed]

•A bad constraint in orthometric height affects all orthometric heights

NGS Data Sheet GEOID03

HT2268 DESIGNATION - S 1320 HT2268 PID - HT2268 HT2268 STATE/COUNTY- CA/SAN FRANCISCO HT2268 USGS QUAD - SAN FRANCISCO NORTH (1975) HT2268 HT2268 *CURRENT SURVEY CONTROL HT2268 ___________________________________________________________________ HT2268* NAD 83(1992)- 37 45 25.30727(N) 122 28 36.34687(W) ADJUSTED HT2268* NAVD 88 - 102.431 (meters) 336.06 (feet) ADJUSTED HT2268 ___________________________________________________________________ HT2268 EPOCH DATE - 1997.30 HT2268 X - -2,711,121.437 (meters) COMP HT2268 Y - -4,259,419.310 (meters) COMP HT2268 Z - 3,884,200.262 (meters) COMP HT2268 LAPLACE CORR- 5.53 (seconds) DEFLEC03 HT2268 ELLIP HEIGHT- 69.78 (meters) GPS OBS HT2268 GEOID HEIGHT- -32.60 (meters) GEOID03 HT2268 DYNAMIC HT - 102.363 (meters) 335.84 (feet) COMP HT2268 MODELED GRAV- 979,964.0 (mgal) NAVD 88 HT2268 HT2268 HORZ ORDER - FIRST HT2268 VERT ORDER - FIRST CLASS I HT2268 ELLP ORDER - FOURTH CLASS I HT2268

H =102.431 =

102.431 102.38

69.78 - (-32.60)- Nh

GEOID96 = 0.17 m

GEOID99 = 0.11 m

GEOID03 = 0.05 m

Station NAVD ’88

–(h - N) cm Ellipsoid

Order/Class Vertical

Order/Class Orthometric Height (m)

L 1241 +3.6 Fourth / I First / I 123.180

U 1320 +3.5 Fourth / I First / I 83.942

S 1320 +4.5 Fourth / I First / I 102.431

941 4819 TIDAL 32 +0.4 Fourth / I First / II 3.569

RV 223 +0.4 Fourth / I First / II 2.335

R 1393 -1.3 Fourth / I First / II 3.198

941 4750 TIDAL 7 -2.4 Fourth / I First / II 2.783

M 554 -0.6 Fourth / I First / I 4.329

M 148 +1.1 Fourth / I First / II 12.335

N 1197 +2.9 Fourth / I First / II 22.731

NAVD ‘88 Relative to (h - N) GEOID03

San Francisco Bay Demonstration Project

San Francisco Bay Demonstration Project

GPS Site

L 1241 (+3.6)

U 1320 (+3.5)

S 1320 (+4.5)

941 4819 TIDAL 32 (+0.4)

RV 223 (+0.4)

R 1393 (-1.3)

N 1197 (+2.9)

M 148 (+1.1)

M 554 (-0.6)

941 4750 TIDAL 7 (-2.4)

0 5 10

KM

H = h - NComparisons with Published

Station Heights (Centimeters)

H = Orthometric Heighth = Ellipsoid HeightN = Geoid Height GEOID03

“Real World”

“Mapping World”

8002 The Opus solution for your submitted RINEX file appears to be

8002 quite close to an NGS published control point. This suggests that

8002 you may have set your GPS receiver up over an NGS control point.

8002 Furthermore, our files indicate that this control point has not

8002 been recovered in the last five years.

8002 If you did indeed recover an NGS control point, we would

8002 appreciate receiving this information through our web based

8002 Mark Recovery Form at

8002 http://www.ngs.noaa.gov/products_services.shtml#MarkRecoveryForm.

8002

First station : SURVEYOR 290 Second station : SURVEYOR 284 Delta height = -.0220 Ellipsoidal distance = .0070 Mark to mark distance = .0231 DX = .0122 DN = .0068 DY = .0163 DE = .0015 DZ = -.0109 DU = -.0220



OPUS ProcessingComparisons

Day 277 2 hr 7 minDay 278 9 hr 23 minDay 284 7 hr 14 minDay 290 2 hr 7 min

= CORS

= Base Receiver

= Rover Receiver

OPUS - Multiple CORS Providing Position to Base Receiver

P

CORS 3

CORS 1

NCORS 2P = Published Point

N = New Point

FINAL POSITION N Process Mean Position + N OPUS Mean Position2 N Process+OPUS Position N Final Position

N OPUS 1 + N OPUS 22 N O 1+2 N OPUS Mean Position

How wellOPUS 1 fitsOPUS 2

P OPUS 1 + P OPUS 22 P O 1+2 P OPUS Mean Position

How wellOPUS 1 fits OPUS 2

P Published Position- P OPUS Mean PositionHow well OPUS fits Published

P-N Process Mean Position- N OPUS Mean PositionHow well Process fits OPUS

P-N Process 1 + P-N Process 22 P-N Process 1+2 P-N Process Mean Position

How wellProcess 1 fitsProcess 2

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Class 27: 28 April 2008 Planning and Analysis of a Height Modernization Survey using TM 58/59...

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