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MODERNIZATION OF THENATIONAL SPATIAL REFERENCE SYSTEMS
Surveyors Association of West JerseyMount Laurel
September 9, 2010ftp://ftp.ngs.noaa.gov/dist/DaveD/NJ
Dave DoyleNGS Chief Geodetic Surveyor
Mission and Vision of NGS
To define, maintain and provide access to theNational Spatial Reference System to meet ournation’s economic, social, and environmentalneeds
“Maintain the NSRS” means “NGS must track allof the temporal changes to the defining points ofthe NSRS in such a way as to always maintainthe accuracy in the NSRS definition.”
Vision - Modernize the Geopotential (“Vertical”)and Geometric (“Horizontal”) datums
Problems with NAD 83 and NAVD 88NAD 83 is not as geocentric as it could be (approx 1-2 m).
Surveyors don’t see this – Yet
NAD 83 is not well defined with positional velocities.
Most surveyors still think of NAD 83 as 2-dimensional (lat/long, N/E)
NAVD 88 is realized by passive control (bench marks) most of which have notbeen releveled in 40 years.
NAVD 88 does not account for local vertical velocities (subsidence and uplift)Southern NJ appears to be subsiding at 2-3 mm p/yr (CORS multi-yearsolution should confirm movements – late 2010)Post glacial isostatic readjustmentSubsurface fluid withdrawalSediment loadingSea level rise – Trenton is beach front in approx. 13,300 years
.
The National Geodetic Survey 10 year planMission, Vision and Strategy
2008 – 2018http://www.ngs.noaa.gov/INFO/NGS10yearplan.pdf
Official NGS policy as of Jan 9, 2008Modernized agencyAttention to accuracyAttention to time-changesImproved products and servicesIntegration with other fed missions
2018 Targets:NAD 83 and NAVD 88 re-definedCm-accuracy access to all coordinatesCustomer-focused agencyGlobal scientific leadership
1807President Thomas Jefferson signs legislation
establishing the Survey of the Coast
Global Satellite Triangulation Network1964-1973
ECHO/PAGEOS Balloon Satellitetype of satellite photographed by BC-4
BC-4 camera photographstars in circular pattern
satellite is a series of dots in straight line.
US Navy Transit Satellite1964 (Military), 1967 (Civilian)
DOPPLER and VLBI
GLOBAL POSITIONING SYSTEM
• 1978 1st NAVSTAR Satellite Launched(October 22, 1978)
• 1995 Fully Operational
• 2000 Selective Availability turned off(May 1, 2000)
• 2005 Additional Band L2C
• 2010 Additional Frequency L5 added(May 28, 2010)
• 2020? 10-50 cm real-time accuracy?
The Global Navigation SatelliteSystems (GNSS) Constellations
• Three positioning and navigation systems– Navstar/GPS – US (Currently 31)
– GLONASS – Russia (Currently 19)
– Galilleo – EU (Currently 2)
– Beidou (Big Dipper/Compass) – China(?)
• All satellites available for positioning purposes.
Russia - GLONASS
US - GPS
EU - Galilleo
National Spatial Reference System(NSRS)
Consistent National Coordinate System
LatitudeLongitude
HeightScale
GravityOrientation
and how these values change with time
• National Shoreline- Consistent, accurate, and up-to-date
• National CORS Network- A network of GPS Continuously Operating ReferenceStations
• Networks of geodetic control points- Permanently marked passive survey monuments
• Tools-Models of geophysical effects on spatial measurements-e.g., NADCON, INVERSE, SPCS83, UTMS, FORWARD
NSRS COMPONENTS
• Tools-Models of geophysical effects on spatial measurements-e.g., NADCON, INVERSE, SPCS83, UTMS, FORWARD
The NSRS has evolved
1 MillionMonuments
(Separate Horizontaland Vertical Systems)
PassiveMarks(Limited
Knowledge ofStability)
GPS CORS GNSS CORS
70,000Passive Marks
(3-Dimensional)
1,400 GPSCORS
(Time DependentSystem Possible;4-Dimensional)
GEODETIC DATUMS
HORIZONTAL2 D (Latitude and Longitude) (e.g. NAD 27, NAD 83 (1986))
VERTICAL1 D (Orthometric Height) (e.g. NGVD 29, NAVD 88, Local Tidal)
GEOMETRIC3 D (Latitude, Longitude and Ellipsoid Height)
Fixed and Stable - Coordinates seldom change(e.g. NAD 83 (1996), NAD 83 (2007))
also
4 D (Latitude, Longitude, Ellipsoid Height, Velocities) Coordinates changewith time
(e.g. ITRF00, ITRF08)
National Geodetic Survey, Retrieval Date = AUGUST 23, 2010KV6044 ***********************************************************************KV6044 DESIGNATION - DOT SOUTHKV6044 PID - KV6044KV6044 STATE/COUNTY- NJ/MERCERKV6044 USGS QUAD - PENNINGTON (1995)KV6044KV6044 *CURRENT SURVEY CONTROLKV6044 ___________________________________________________________________KV6044* NAD 83(2007)- 40 15 25.50408(N) 074 47 55.33944(W) ADJUSTEDKV6044* NAVD 88 - 37.452 (meters) 122.87 (feet) ADJUSTEDKV6044 ___________________________________________________________________KV6044 EPOCH DATE - 2002.00KV6044 X - 1,278,098.343 (meters) COMPKV6044 Y - -4,703,763.341 (meters) COMPKV6044 Z - 4,099,814.418 (meters) COMPKV6044 LAPLACE CORR- 4.40 (seconds) DEFLEC09KV6044 ELLIP HEIGHT- 4.094 (meters) (02/10/07) ADJUSTEDKV6044 GEOID HEIGHT- -33.36 (meters) GEOID09KV6044 DYNAMIC HT - 37.434 (meters) 122.81 (feet) COMPKV6044KV6044 ------- Accuracy Estimates (at 95% Confidence Level in cm) --------KV6044 Type PID Designation North East EllipKV6044 -------------------------------------------------------------------KV6044 NETWORK KV6044 DOT SOUTH 0.31 0.29 0.51KV6044 -------------------------------------------------------------------KV6044 MODELED GRAV- 980,166.0 (mgal) NAVD 88KV6044KV6044 VERT ORDER - FIRST CLASS IKV6044KV6044.The horizontal coordinates were established by GPS observationsKV6044.and adjusted by the National Geodetic Survey in February 2007.KV6044KV6044.The datum tag of NAD 83(2007) is equivalent to NAD 83(NSRS2007).KV6044.See National Readjustment for more information.KV6044.The horizontal coordinates are valid at the epoch date displayed above.KV6044.The epoch date for horizontal control is a decimal equivalenceKV6044.of Year/Month/Day.
KV6044KV6044; North East Units Scale Factor Converg.KV6044;SPC NJ - 158,100.270 124,590.832 MT 0.99990794 -0 11 34.9KV6044;SPC NJ - 518,700.64 408,761.75 sFT 0.99990794 -0 11 34.9KV6044;SPC PA S - 106,763.168 851,019.280 MT 0.99996518 +1 54 53.2KV6044;SPC PA S - 350,272.16 2,792,052.42 sFT 0.99996518 +1 54 53.2KV6044;UTM 18 - 4,456,311.147 517,117.842 MT 0.99960361 +0 07 48.3KV6044KV6044! - Elev Factor x Scale Factor = Combined FactorKV6044!SPC NJ - 0.99999936 x 0.99990794 = 0.99990730KV6044!SPC PA S - 0.99999936 x 0.99996518 = 0.99996454KV6044!UTM 18 - 0.99999936 x 0.99960361 = 0.99960297KV6044KV6044 SUPERSEDED SURVEY CONTROLKV6044KV6044 NAD 83(1996)- 40 15 25.50397(N) 074 47 55.33935(W) AD( ) BKV6044 ELLIP H (06/06/05) 4.119 (m) GP( ) 3 1KV6044 ELLIP H (10/23/02) 4.118 (m) GP( ) 4 1KV6044 NAD 83(1996)- 40 15 25.50462(N) 074 47 55.33977(W) AD( ) 1KV6044 ELLIP H (05/14/99) 4.144 (m) GP( ) 4 1KV6044 NAD 83(1986)- 40 15 25.50351(N) 074 47 55.34209(W) AD( ) 1KV6044 NAVD 88 (06/06/05) 37.45 (m) 122.9 (f) LEVELING 3KV6044 NGVD 29 (01/10/92) 37.757 (m) 123.87 (f) ADJUSTED 1 1KV6044KV6044.Superseded values are not recommended for survey control.KV6044.NGS no longer adjusts projects to the NAD 27 or NGVD 29 datums.KV6044.See file dsdata.txt to determine how the superseded data were derived.
ELLIPSOID - GEOID RELATIONSHIP
H = Orthometric Height (NAVD 88)
H = h – Nh = Ellipsoidal Height [NAD 83 (1996) or (2007)]N = Geoid Height (GEOID 09)
H h
EllipsoidGRS80
N
GeoidGEOID09
Tectonic Motions
HORIZONTAL VELOCITIES
VERTICAL VELOCITIES
International Earth Rotation andReference System Service
(IERS)(http://www.iers.org)
The International Terrestrial Reference System (ITRS) constitutes a set of prescriptionsand conventions together with the modeling required to define origin, scale, orientationand time evolution
ITRS is realized by the International Terrestrial Reference Frame (ITRF) based uponestimated coordinates and velocities of a set of stations observed by Very Long BaselineInterferometry (VLBI), Satellite Laser Ranging ( SLR), Global Positioning System andGLONASS (GNSS), and Doppler Orbitography and Radio- positioning Integrated bySatellite ( DORIS).
ITRF89, ITRF90, ITRF91, ITRF92, ITRF93, ITRF94, ITRF95, ITRF96, ITRF97,ITRF2000, ITRF2005
International Global Navigation Satellite Systems Service (IGS)
International Laser Ranging Service (ILRS)
International Very Long Baseline Service (IVS)
International DORIS Service (IDS)
International Terrestrial Reference Frame4 Global Independent Positioning Technologies
Simplified Concept of NAD 83 vs. ITRF00
NAD 83Origin
ITRF 00Origin
Earth’sSurface
h83h00
Identically shaped ellipsoids (GRS-80)a = 6,378,137.000 meters (semi-major axis)1/f = 298.25722210088 (flattening)
Problems using traditional leveling(to define a National Vertical Datum)
• Leveling the country can not be done again– Too costly in time and money (Estimate ~ 1B$)
• Leveling yields cross-country error build-up;problems in the mountains
• Leveling requires leaving behind passivemarks– Bulldozers and crustal motion do their worst
How accurate is aGPS-derived Orthometric Height?
• Relative (local) accuracy in ellipsoid heightsbetween adjacent points will be better than 2cm, at 95% confidence level
• Network accuracy (relative to NSRS) inellipsoid and orthometric heights will be betterthan 5 cm, at 95% confidence level
• Accuracy of orthometric height is dependenton accuracy of the geoid model – CurrentlyNGS is improving the geoid model with moredata, i.e. Gravity and GPS observations onleveled bench marks from Height Mod projects
1. Using GNSS is cheaper, easierthan leveling
2. To use GNSS we need a goodgeoid model
Height ModernizationBottom line
Types and Uses of Geoid Height Models
Gravimetric (or Gravity) Geoid Height ModelsDefined by gravity data crossing the geoidRefined by terrain models (DEM’s)Scientific and engineering applications
Composite (or Hybrid) Geoid Height ModelsGravimetric geoid defines most regionsWarped to fit available GPSBM control dataDefined by legislated ellipsoid (NAD 83) andlocal vertical datum (NAVD 88, PRVD02, etc.)May be statutory for some surveying &mapping applications
GGPSBM2003: 14,185 total 579 Canada STDEV 4.8 cm (2 )
GGPSBM1999: 6,169 total 0 Canada STDEV 9.2 cm (2 )
• Official NGS policy as ofNov 14, 2007– $38.5M over 10 years
• Airborne Gravity Snapshot
• Absolute Gravity Tracking
• Re-define the VerticalDatum of the USA by2018
Transition to the Future – GRAV-DGravity for the Redefinition
of the American VerticalDatum
Gravity Survey Plan
• National Scale Part 1
– Predominantly through airborne gravity
– With Absolute Gravity for ties and checks
– Relative Gravity for expanding localregions where airborne shows significantmismatch with existing terrestrial
Gravity Survey Plan – Part 2
– Epochal (annual?) absolute gravity re-measurements at key areas
– GOCE for more global signatures (Gravity fieldand steady-state Ocean Circulation Explorer)
– Monitor changes in gravity over time andmodel geoid changes
– Use GNSS to monitor changes in ellipsoidheights
GOCEGravity field and steady-state Ocean Circulation Explorer
March, 2009 ~ October, 2011
GRAV-D: Campaign I Testing
• Test varieties of flightheights / speeds / spacingsfor optimal benefit
• Test area for proof ofconcept to definevertical datum fromGPS + gravimetricgeoid
CONTINUOUSLY OPERATING REFERENCE STATIONS(CORS)
1460+ Installed and Operated byvarious Federal-State-local Agencies
NOAA/National Geodetic SurveyNOAA/OAR Global Systems DivisionU.S. Coast Guard - DGPS/NDGPSCorps of Engineers - DGPSFAA - WAAS/LAASState DOTsCounty and CityAcademiaPrivate Companies
REGIONAL CORS NETWORK
= NAD 83(NSRS 2007)
TRENTON (NJTR), NEW JERSEY_____________________________________________________________________________
| || Antenna Reference Point(ARP): TRENTON CORS ARP || ---------------------------------------------- || PID = DG7014 || || || ITRF00 POSITION (EPOCH 1997.0) || Computed in September 2004 using 25 days of data. || X = 1278260.726 m latitude = 40 15 27.49204 N || Y = -4703706.569 m longitude = 074 47 48.07837 W || Z = 4099884.432 m ellipsoid height = 40.025 m || || ITRF00 VELOCITY || Predicted with HTDP_2.7 September 2004. || VX = -0.0167 m/yr northward = 0.0044 m/yr || VY = -0.0018 m/yr eastward = -0.0166 m/yr || VZ = 0.0035 m/yr upward = 0.0002 m/yr || || || NAD_83 (CORS96) POSITION (EPOCH 2002.0) || Transformed from ITRF00 (epoch 1997.0) position in Sep. 2004. || X = 1278261.271 m latitude = 40 15 27.46275 N || Y = -4703708.030 m longitude = 074 47 48.07235 W || Z = 4099884.563 m ellipsoid height = 41.295 m || || NAD_83 (CORS96) VELOCITY || Transformed from ITRF00 velocity in Sep. 2004. || VX = -0.0000 m/yr northward = 0.0000 m/yr || VY = -0.0000 m/yr eastward = 0.0000 m/yr || VZ = 0.0000 m/yr upward = 0.0000 m/yr ||_____________________________________________________________________________|
ITRF00 – NAD 83(CORS96)Horiz = 0.915mEHt = 1.270m
GPS data Mark Information Local Referencesphoto(s)
NGS website:
OPUS-DB
DATASHEET
OPUS-DB OBSERVATION DATA STREAM
NGS magic
OPUS – DB
SimpleShared Data
NGS Archived
OPUSTool Box
OPUS-Projects$$ Receivers
2-4 Hours of dataMultiple ReceiversNetwork Solution
Results shared or not
OPUS-RS$$ Receivers
15 Minutes of dataResults not shared
OPUS-DB$$ Receivers
4 Hours of dataResults shared
OPUS-S$$ Receivers
2 Hours of dataResults not shared
FLAVORS OF OPUS
LOCUSLeveling Online Computing Service
Integration with GPS?Results shared or not
Ten-Year Milestones (2018)
1) NGS will compute a pole-to-equator, Alaska-to-Newfoundland geoid model, preferably inconjunction with Mexico and Canada as well asother interested governments, with an accuracyof 1 cm in as many locations as possible
2) NGS redefines the vertical datum based onGNSS and a gravimetric geoid
3) NGS redefines the national horizontal datumto remove disagreements with the ITRF
Predicted Positional Changes in 2018Vicinity of Trenton, NJ.
(Computed at DOT SOUTH pid KV6044)
HORIZONTAL = 1.30 m (4.3 ft)ELLIPSOID HEIGHT = - 1.25 m (- 4.1 ft)
Predicted with HTDP
ORTHOMETRIC HEIGHT = - 0.39 m (- 1.3 ft)Predicted with HTDP and USGG2009
http://www.ngs.noaa.gov/corbin/calendar.shtml
GOOD COORDINATION BEGINS WITHGOOD COORDINATES
GEOGRAPHY WITHOUT GEODESY IS A FELONY
