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DEVELOPMENT, IMPLEMENTATION AND FUTURE OF THE NATIONAL SPATIAL REFERENCE SYSTEM HOUSTON DECEMBER 13, 2003 David Doyle Chief Geodetic Surveyor National Geodetic Survey Dave.Doyle@noaa.gov, (301) 713-3178. ACRONYMS US. R. NAD 27. ITRF 00. GRS 80. WGS 84. NSRS. CORS. EGM 96. NAVD 88.
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DEVELOPMENT, IMPLEMENTATION AND FUTURE OF THE NATIONAL SPATIAL REFERENCE SYSTEM HOUSTON DECEMBER 13, 2003 David Doyle Chief Geodetic Surveyor National Geodetic Survey Dave.Doyle@noaa.gov, (301) 713-3178
ACRONYMSUS R NAD 27 ITRF 00 GRS 80 WGS 84 NSRS CORS EGM 96 NAVD 88 HPGN NGVD 29 HARN NAD 83
NATIONAL GEODETIC SURVEY • INFORMATION CENTER • (301) 713-3242 • info_center@ngs.noaa.gov WEB SITE http://www.ngs.noaa.gov
GEODETIC CONTROL • NETWORK OF MONUMENTED POINTS • PRECISELY MEASURED IN ACCORDANCE • WITH STANDARD PROCEDURES • MEET ACCURACY SPECIFICATIONS • ADJUSTED TO TIE TOGETHER • DOCUMENTED FOR MULTIPLE USE
Stainless steel rod driven to refusal Poured in place concrete post
NATIONAL SPATIAL REFERENCE SYSTEM(http://www.ngs.noaa.gov) • The National Spatial Reference System (NSRS) is that component of the National Spatial Data Infrastructure (NSDI) -[http://www.fgdc.gov/nsdi/nsdi.html]which contains all geodetic control contained in the National Geodetic Survey (NGS) Data Base. This includes: A, B, First, Second and Third-Order horizontal and vertical control, Geoid models such as GEOID 99, precise GPS orbits and Continuously Operating Reference Stations (CORS), and the National Shoreline as observed by NGS as well as data submitted by other Federal, State, and local agencies, Academic Institutions and the private sector
NATIONAL SPATIAL REFERENCE SYSTEM • ACCURATE-- cm accuracy on a global scale • MULTIPURPOSE-- Supports Geodesy, Geophysics, Land Surveying, Navigation, Mapping, Charting and GIS activities • ACTIVE-- Accessible through Continuously Operating Reference Stations (CORS) and derived products • INTEGRATED-- Related to International services and standards (e.g. International Earth Rotation and Reference Systems Service, International GPS Service etc.)
METADATA • METADATA IS DATA ABOUT DATA • DATUMS • NAD 27, NAD 83(1986), NAD83 (199X), • NGVD29, NAVD88 • UNITS • Meters, U.S. Survey Feet, International Feet, Vara, Toise, Chains, Rods, Poles, Links, Perchs, Smoots ACCURACY • A, B, 1st, 2nd, 3rd, 3cm, Scaled
METADATA?? Horizontal Datum?? Plane Coordinate Zone ?? Units of Measure ?? How Accurate ??
How Accurate B-Order, 1st-Order, 2cm, 0.01 ft?? Horizontal and Vertical Datums ?? Units of Measure ?? Plane Coordinate Zone ?? METADATA??
THE ELLIPSOIDMATHEMATICAL MODEL OF THE EARTH N b a S a = Semi major axis b = Semi minor axis f = a-b = Flattening a
ELLIPSOID - GEOID RELATIONSHIP H = Orthometric Height(NAVD 88) H=h-N h = Ellipsoidal Height (NAD 83) N = Geoid Height (GEOID 99) TOPOGRAPHIC SURFACE h H N GEOID99 Geoid Ellipsoid GRS80
UNITED STATESELLIPSOID DEFINITIONS BESSEL 1841 a = 6,377,397.155 m 1/f = 299.1528128 CLARKE 1866 a = 6,378,206.4 m 1/f = 294.97869821 GEODETIC REFERENCE SYSTEM 1980 - (GRS 80) a = 6,378,137 m 1/f =298.257222101 WORLD GEODETIC SYSTEM 1984 - (WGS 84) a = 6,378,137 m 1/f =298.257223563
HORIZONTAL DATUMS • BESSEL1841 -------------- LOCAL ASTRO DATUMS (1816-1879) • NEW ENGLAND DATUM (1879-1901) • U.S. STANDARD DATUM (1901-1913) • NORTH AMERICAN DATUM (1913-1927) • NORTH AMERICAN DATUM OF 1927 • OLD HAWAIIAN DATUM • CLARKE 1866PUERTO RICO DATUM • ST. GEORGE ISLAND - ALASKA • ST. LAWRENCE ISLAND - ALASKA • ST. PAUL ISLAND - ALASKA • AMERICAN SAMOA 1962 • GUAM 1963 • GRS80 ----------- NORTH AMERICAN DATUM OF 1983 • (As of June 14, 1989)
COMPARISON OF DATUM ELEMENTS • NAD 27NAD 83 • ELLIPSOID CLARKE 1866 GRS80 • a = 6,378,206.4 m a = 6,378,137. M • 1/f = 294.9786982 1/f = 298.257222101 • DATUM POINT Triangulation Station NONE • MEADES RANCH, KANSAS EARTH MASS CENTER • ADJUSTMENT 25k STATIONS 250k STATIONS • Several Hundred Base Lines Appox. 30k EDMI Base Lines • Several Hundred Astro Azimuths 5k Astro Azimuths • Doppler Point Positions • VLBI Vectors • BEST FITTING North America World-Wide
NAD 83 NETWORK PROBLEMS • NOT “GPSABLE” POOR STATION ACCESSIBILITY IRREGULARLY SPACED POSITIONAL ACCURACY
HIGH ACCURACY REFERENCE NETWORKS • “GPSABLE” • Clear Horizons for Satellite Signal Acquisition • EASY ACCESSIBILITY • Few Special Vehicle or Property Entrance Requirements • REGULARLY SPACED • Always within 20-100 Km • HIGH HORIZONTAL ACCURACY • A-Order (5 mm + 1:10,000,000) • B-Order (8mm + 1:1,000,000)
IMPROVING POSITIONAL ACCURACY • TIME NETWORK LOCAL • NETWORK SPAN ACCURACY ACCURACY • NAD 27 1927-1986 10 Meters First-Order (1 part in 0.1 million) • NAD 83 1986-1990 1 Meter First-Order(1 part in 0.1 million) • HPGN/HARN 1987-1997 0.1 Meter B-Order(1 part in 1 million) • A-Order (1 part in 10 million) • CORS 1994 - 0.02 Meter - Horizontal • 0.04 Meter - Ellipsoid Height
INTERNATIONAL TERRESTRIALREFERENCE SYSTEM DEVELOPED AND MAINTAINED BY THE INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEM SERVICE PARIS, FRANCE (http://http://www.iers.org/) VERY LONG BASELINE INTERFEROMETRY - (VLBI) SATELLITE LASER RANGING - (SLR) GLOBAL POSITIONING SYSTEM - (GPS) DOPPLER ORBITOGRAPHY AND RADIO POSITIONING INTEGRATED BY SATELLITE - (DORIS)
INTERNATIONAL TERRESTRIALREFERENCE SYSTEM • GEOCENTRIC +/- 3 to 4 CM • MODELS FOR PLATE TECTONICS • STATION VELOCITIES • POSITIONAL STANDARD ERRORS • REALIZED AS THE INTERNATIONAL TERRESTERIAL REFERENCE FRAME (ITRF)
WORLD GEODETIC SYSTEM 1984TR8350.2 World Geodetic System 1984 - It’s Definition andRelationships with Local Geodetic Systems(http://www.nima.mil/GandG/pubs.html) DATUM = WGS 84(G730) 5 USAF GPS Tracking Stations 5 DMA Evaluation Stations Datum redefined with respect to the International Terrestrial Reference Frame of 1992 (ITRF92) +/- 20 cm in each component (Proceedings of the ION GPS-94 pgs 285-292) HOW MANY WGS 84s HAVE THERE BEEN???? DATUM = WGS 84(G873) 5 USAF GPS Tracking Stations 7 NIMA Evaluation Stations Datum redefined with respect to the International Terrestrial Reference Frame of 1994 (ITRF94) +/- 10 cm in each component (Proceedings of the ION GPS-97 pgs 841-850) DATUM = WGS 84(G1150) Datum redefined with respect to the International Terrestrial Reference Frame of 2000 (ITRF00) +/- 2 cm in each component (Proceedings of the ION GPS-02) http://164.214.2.59/GandG/sathtml/IONReport8-20-02.pdf DATUM = WGS 84 RELEASED - SEPTEMBER 1987 BASED ON OBSERVATIONS AT MORE THAN 1900 DOPPLER STATIONS
MY SOFTWARE SAYS I’M WORKING IN WGS-84 Unless you doing autonomous positioning (point positioning +/- 6-10 meters) you’re probably NOT in WGS-84 Project tied to WGS-84 control point obtained from the Defense Department -- Good Luck! -- You’re really working in the same reference frame as your control points -- NAD 83?
TRANSFORM BETWEEN WGS 84 & NAD 83 dX = 0.9956 m dY = -1.9013 m dZ = -0.5215 m
THE GEOID AND TWO ELLIPSOIDS CLARKE 1866 GRS80-WGS84 Earth Mass Center Approximately 236 meters GEOID
NAD 83 and ITRF / WGS 84 NAD83 ITRF / WGS 84 Earth Mass Center 2.2 m (3-D) dX,dY,dZ GEOID
VERTICAL DATUMS • MEAN SEA LEVEL DATUM OF 1929 • NATIONAL GEODETIC VERTICAL DATUM OF 1929 • (As of July 2, 1973) • NORTH AMERICAN VERTICAL DATUM OF 1988 • (As of June 24, 1993)
COMPARISON OF VERTICAL DATUM ELEMENTS NGVD 29NAVD 88 • DATUM DEFINITION 26 TIDE GAUGES FATHER’S POINT/RIMOUSKI • IN THE U.S. & CANADA QUEBEC, CANADA • BENCH MARKS 100,000 450,000 • LEVELING (Km) 102,724 1,001,500 • GEOID FITTING Distorted to Fit MSL Gauges Best Continental Model
NOS BENCHMARK LEVELING Distances vary but usually several hundred meters.
GEOID MODELS • U.S. NATIONAL MODEL -- GEOID99(http://www.ngs.noaa.gov/cgi-bin/GEOID_STUFF/geoid99_prompt1.prl) • CANADIAN NATIONAL MODEL -- GSD95 • http://www.geod.nrcan.gc.ca/products/html-public/GSDinfo/English/factsheets/gpsht_fact.html • GLOBAL MODEL -- EGM 96 • (http://www.nima.mil/GandG/wgs-84/egm96.html)
NEW U.S. GEOID MODELRelease by January 2004 • USGG2003 and GEOID03 • USGG = U.S. Gravimetric Geoid • GEOID03 = U.S. Hybrid Geoid • In excess of 11,000 GPS on BMs • (A, B, and 1st- Order GPS on 1st, 2nd and 3rd – Order NAVD 88 BMs) • Possibly overall misfit will be about 2.9 cm.
Standalone Positioning: Since May 1, 2000 • C/A Code on L1 • No Selective Availability 6-11 m
Standalone Positioning: By 2011 • C/A Code on L1 • C/A Code on L2 • New Code on L5 Better resistance to interference 1-3 m
GLOBAL POSITIONING SYSTEM • GPS BLOCK III • Potential Future Developments • 30 - 32 satellites • Second and Third Civil Frequency • (1227.60 MHZ & 1176.45 MHZ) • More Robust Signal Transmissions • Real-Time Unaugmented 1 Meter Accuracy • Initial Launches ~ 2005 • Complete Replacements ~ 2015??
GLOBAL NAVIGATION SATELLITE SYSTEMS(GNSS) • POTENTIAL FUTURE DEVELOPMENTS • (2005 – 2015??) • GPS MODERNIZATION- BLOCK 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
GEODETIC DATA SHEET Geodetic Data Sheets
GEODETIC DATA SHEET National Geodetic Survey, Retrieval Date = NOVEMBER 15, 2003 BN0540 *********************************************************************** BN0540 FBN - This is a Federal Base Network Control Station. BN0540 DESIGNATION - CHERRY BN0540 PID - BN0540 BN0540 STATE/COUNTY- TX/GILLESPIE BN0540 USGS QUAD - CHERRY SPRING (1967) BN0540 BN0540 *CURRENT SURVEY CONTROL BN0540 ___________________________________________________________________ BN0540* NAD 83(1993)- 30 29 48.47740(N) 099 00 39.29203(W) ADJUSTED BN0540* NAVD 88 - 542.733 (meters) 1780.62 (feet) ADJUSTED BN0540 ___________________________________________________________________ BN0540 X - -861,575.021 (meters) COMP BN0540 Y - -5,433,071.971 (meters) COMP BN0540 Z - 3,218,212.963 (meters) COMP BN0540 LAPLACE CORR- -2.38 (seconds) DEFLEC99 BN0540 ELLIP HEIGHT- 520.52 (meters) (05/01/00) GPS OBS BN0540 GEOID HEIGHT- -22.17 (meters) GEOID99 BN0540 DYNAMIC HT - 541.984 (meters) 1778.16 (feet) COMP BN0540 MODELED GRAV- 979,243.1 (mgal) NAVD 88 BN0540 BN0540 HORZ ORDER - B BN0540 VERT ORDER - FIRST CLASS II BN0540 ELLP ORDER - THIRD CLASS I H = h - N 542.73 = 520.52 - (- 22.17) 542.73 542.69 (EGM96 = - 23.09 m)