Improved Access to an Accurate Geodetic Reference Frame for the Caribbean

1
Improved Access to an Accurate Geodetic Reference
Frame for the Caribbean
MesoAmerican and Caribbean Sea Hydrographic
Commission Acapulco, Mexico October 3, 2006
Dave Doyle Chief Geodetic Surveyor National
Geodetic Survey
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COMMON REFERENCE SYSTEM PROBLEMS THAT HINDER THE
ACCURATE USE OF GPS

• Non-geocentric coordinate system
• Inconsistent coordinate systems between
  countries
• Ellipsoid best-fitting only locally not globally
• Lack of accurate ellipsoid heights
• Non-GPSable geodetic control points
• Inaccessible geodetic control points
• Inadequate data distribution systems
• Insufficient positional accuracy
• Poor geoid model (/- 2 to 3 m)

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GLOBAL NAVIGATION SATELLITE SYSTEMS(GNSS)

• POTENTIAL FUTURE DEVELOPMENTS
• (2006 2017??)
• GPS MODERNIZATION BLOCK IIR-M III
• GLONASS ENHANCEMENTS
• EUROPEAN UNION - GALILEO
• 70- 90 Satellites
• Second and Third Civil Frequency - GPS
• No Signal Encryption - GLONASS GALILEO
• More Robust Signal Transmissions
• Real-Time Unaugmented 1 Meter (or better!)
  Accuracy

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ELLIPSOID - GEOID RELATIONSHIP
H Orthometric Height (MSL)
h Ellipsoidal Height (ITRF/WGS84)
N Geoid Height (Carib97 or EGM96)

H h - N
h
H
N
Carib97 EGM96
Geoid
Ellipsoid WGS84
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GEODETIC CONTROL

• THE REALIZATION OF ANY DATUM
• NETWORK OF MONUMENTED POINTS
• PRECISELY MEASURED IN ACCORDANCE
• WITH STANDARD PROCEDURES
• MEET ACCURACY SPECIFICATIONS
• ADJUSTED TO TIE TOGETHER
• DOCUMENTED FOR MULTIPLE USE

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PASSIVE SURVEY CONTROL MONUMENTS
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Continuously Operating Reference Stations (CORS)
Parimaribo, Suriname
Toluca, MX
Grand Cayman
Barbados
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New U.S. Coast Guard Site Roosevelt Roads, PR
(2007?) may have a broadcast range of
approximately 200 km Areas of Anguilla, Saba, St.
Barts, St. Maarten/St. Martin, St. Kitts
Nevis could receive 1-2 m real-time correctors
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CONTINUOUSLY OPERATING REFERENCE STATIONS (CORS)

• Dual-Frequency
• Antennas and Receivers
• Allen-Osborne
• Ashtech/Thales
• Leica
• Topcon
• Trimble

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CONTINUOUSLY OPERATING REFERENCE STATIONS (CORS)

• 980 Installed and Operated by various
  Federal-State-local Agencies
• NOAA/National Geodetic Survey
• NOAA/OAR Forecast Systems Lab
• U.S. Coast Guard - DGPS/NDGPS
• Corps of Engineers - DGPS
• FAA - WAAS/LAAS
• State DOTs
• County and City
• Academia
• Private Companies
• Other Countries

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SIGNIFICANT PROBLEMS WITH GPS VERTICAL POOR
REGIONAL GEOID MODEL
National Geodetic Survey, Retrieval Date
SEPTEMBER 28, 2006 AB9262

AB9262 DESIGNATION - VIDAL SPOT AB9262 PID
- AB9262 AB9262 COUNTRY - CAYMAN
ISLANDS AB9262 USGS QUAD - AB9262 AB9262
CURRENT SURVEY CONTROL
AB9262 __________________________________________
_________________________ AB9262 NAD 83(1996)-
19 18 13.18575(N) 081 23 00.57115(W)
ADJUSTED AB9262 LOCAL TIDAL - 0.91
(meters) 3.0 (feet) LEVELING AB9262
__________________________________________________
_________________ AB9262 X -
902,179.696 (meters) COMP
AB9262 Y - -5,953,782.757 (meters)
COMP AB9262 Z -
2,095,098.631 (meters) COMP
AB9262 LAPLACE CORR- -1.47 (seconds)
DCAR97 AB9262 ELLIP HEIGHT-
-12.02 (meters) (12/09/96) GPS
OBS AB9262 GEOID HEIGHT- -15.94
(meters) CARIB97
H h - N 0.91 -12.02 - (-
15.94) 0.91 ? 3.92
H
h
N
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SIGNIFICANT PROBLEMS WITH GPS VERTICAL POOR
REGIONAL GEOID MODEL
National Geodetic Survey, Retrieval Date
SEPTEMBER 30, 2006 AB9309

AB9309 DESIGNATION - H.U.BM 002 AB9309 PID
- AB9309 AB9309 COUNTRY - TRINIDAD
and TOBAGO AB9309 USGS QUAD - AB9309
AB9309 CURRENT SURVEY
CONTROL AB9309 _________________________________
__________________________________ AB9309 NAD
83(1996)- 10 38 56.06799(N) 061 30
51.48661(W) ADJUSTED AB9309 LOCAL TIDAL -
1.38 (meters) 4.5 (feet)
LEVELING AB9309 ______________________________
_____________________________________ AB9309 X
- 2,989,919.531 (meters)
COMP AB9309 Y - -5,510,026.205
(meters) COMP AB9309 Z
- 1,170,854.675 (meters)
COMP AB9309 LAPLACE CORR- -0.11
(seconds) DCAR97 AB9309
ELLIP HEIGHT- -37.95 (meters)
(12/09/96) GPS OBS AB9309 GEOID HEIGHT-
-41.28 (meters) CARIB97
AB9309 AB9309 HORZ ORDER - FIRST AB9309
VERT ORDER - THIRD ? AB9309 ELLP ORDER -
FIRST CLASS I
H h - N 1.38 -37.95 - (-
41.28) 1.38 ? 3.33
N
h
H
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TOLUCA (TOL2), MEXICO Retrieved from NGS
DataBase on 09/07/06 at 151445.
__________________________________________________
___________________________

Antenna Reference Point(ARP)
TOLUCA CORS ARP
---------------------------------------------

PID DH8722



ITRF00 POSITION (EPOCH 1997.0)

Computed in February 2006 using 37 days of data.
X
-1009229.154 m latitude 19 17 35.64465
N Y -5939511.579 m
longitude 099 38 36.49813 W
Z 2094889.315 m ellipsoid height
2651.889 m

ITRF00 VELOCITY

Published in J Geophys Res, Marquez-Azua and
DeMets, 2003. VX
-0.0031 m/yr northward -0.0052 m/yr
VY 0.0063 m/yr
eastward -0.0041 m/yr
VZ -0.0075 m/yr upward
-0.0079 m/yr

L1 Phase Center of the current
GPS antenna TOLUCA CORS L1 PC C
--------------------------------------------------
--------------------------
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CORS DATA QUALITY
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What is OPUS?

• On-Line Positioning User Service
• Processes carrier-phase GPS data
• Global availability (currently masked)
• 3 goals
• Simple
• Consistent
• Reliable

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PURPOSE OF OPUS

• Provide GPS users easier access to an accurate
  global coordinate system
• Direct connections to CORS network

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OPUS OBSERVATION DATA STREAM
GPS data
NGS website OPUS
geodetic magic
DATASHEET
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http//www.ngs.noaa.gov/OPUS
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WHAT DOES OPUS OUTPUT LOOK LIKE?
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OPUS NOT AVAILABEL

• Columbia Panama
• Cuba Saba
• Brazil St. Barts
• Guadeloupe St. Kitts Nevis
• French Guiana St. Martin (French
  side)
• Martinique Turks Caicos
• Montserrat Venezuela

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NGS GEODETIC SURVEYING CAPACITY
BUILDING WORKSHOPS AND SEMINARS
Fundamentals of Geodesy Geodetic and Tidal
Vertical Datums Datum Transformations Using
CORS GPS-Derived Heights
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GOOD COORDINATION BEGINS WITH GOOD COORDINATES
GEOGRAPHY WITHOUT GEODESY IS A FELONY