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Stone national spatial reference system heights
- 1. Grand Junc*on September 24, 2014
- 2. U.S. Department of Commerce Na*onal Oceanic & Atmospheric Administra*on Na$onal Geode$c Survey Mission: To define, maintain & provide access to the Na(onal Spa(al Reference System (NSRS) to meet our Na*on’s economic, social & environmental needs Na$onal Spa$al Reference System • Latitude • Longitude • Height • Scale • Gravity • Orientation & their (me varia(ons (& Na*onal Shoreline, etc.)
- 3. National Geodetic Survey Geodetic Advisors ! SW Region (AZ, NV, NM, UT) Bill Stone ! Colorado Pam Fromhertz ! Oregon Mark Armstrong ! Wyoming Mike Londe (BLM) Geode*c Advisor Contact Info: hLp://geodesy.noaa.gov/ADVISORS/AdvisorsIndex.shtml
- 4. Establishing accurate eleva*ons (heights)… 1. is important 2. can be expensive 3. can be technically challenging
- 5. Con*nuously Opera*ng Reference Sta*ons (CORS) ! 2000 sites (including 400 PBO) ! 225 organiza$ons
- 6. U.S. CORS Velocity Field -‐ NAD83(2011) epoch 2010.0
- 7. CORS 90-‐day Coordinate Plots
- 8.
- 9. NAD 83(2011) epoch 2010.00
- 10. NORTH AMERICAL VERTICAL DATUM 1988 (NAVD88)
- 11. ` BM with Scaled Posi*on Datasheet
- 12. ` Scaled Orthometric Height Datasheet
- 13. GPS-‐derived Orthometric Height Datasheet
- 14. NEW Na*onal Geode*c Survey Ten-‐Year Plan " By 2022, reduce all defini*onal & access-‐related errors in geometric reference frame to 1 cm when using 15 min of GNSS data “Replace NAD83” " By 2022, reduce all defini*onal & access-‐related errors in orthometric heights in geopoten*al reference frame to 2 cm when using 15 min of GNSS data “Replace NAVD88”
- 15. NAD83 Shortcomings o2.2 m offset – NAD83 vs. Interna$onal Terrestrial Reference Frame (ITRF) o CORS & passive network inconsistency vs.
- 16. Future Geometric (3-‐D) Datum # replace NAD83 with new geometric datum – by 2022 # CORS-‐based, accessed via GNSS observa$ons # coordinates & veloci$es in ITRF & official US datum & rela$onship (NAD83 replacement: plate-‐fixed or “ITRF-‐like”?) # passive control $ed to new datum; not a component of new datum # address user needs of datum coordinate constancy vs. accuracy
- 17. New geometric datum minus NAD 83 (horizontal)
- 18. New geometric datum minus NAD 83 (ellipsoid height)
- 19. NAVD88 Shortcomings oCross-‐country errors (1-‐m $lt) o 0.5 m bias in reference surface vs. global mean sea level geoid o Subsidence, uplif, freeze/thaw invalidate BM eleva$ons Approximate Geoid Mismatch in the NAVD88 H=0 surface
- 20. The Rela$onship of Heights
- 21. Gravity for the Redefini$on of the American Ver$cal Datum (GRAV-‐D) • $38.5M over 10 years • Replace the na*onal ver*cal datum (NAVD88) by 2022 with a 1 cm accurate gravimetric geoid • Orthometric heights accessed via GNSS accurate to 2 cm • Thrusts of project: – Airborne gravity survey of en*re country and its holdings – Long-‐term geoid change monitoring – Partnership surveys Gravity and Heights are inseparably connected
- 22. GRAV-D Status •10 km spaced data lines • 70 km spaced cross lines • 20,000 m al*tude • 230 kt flight speed • 35% of US complete (Q1-‐2014)
- 23. Geoid Slope Valida*on Surveys – 2011 & 2014 GPS DoV Leveling Gravity LIDAR/ Imagery
- 24. Future Geopoten*al (Ver*cal) Datum # replace NAVD88 – by 2022 # accessed by GNSS & gravimetric geoid # monitor $me-‐varying nature of gravity field # most accurate con$nental gravimetric geoid model, ever
- 26. Hybrid Geoid Model (GEOID12A) & Gravimetric Geoid Model (USGG2012) Conversion Surfaces using GPS on BM data Earth’s Surface h h h h h H H H H H N N N N N Ellipsoid Hybrid Geoid H ~ h -‐ N
- 27.
- 29. Online Posi$oning User Service (OPUS) • upload L1/L2 GPS data # OPUS-‐RS (Rapid Sta*c) -‐-‐-‐-‐15 min to 2 hr (per CORS) # OPUS-‐S (Sta*c) -‐-‐-‐-‐ 2 to 48 hr (anywhere) • solu*on via email -‐-‐-‐-‐ in minutes • op*onal sharing (formerly “publishing”) • OPUS-‐Projects (coming soon) >>> fast, easy NSRS access
- 30. OPUS – Share (aka OPUS-‐DB) ! Sharing Criteria: • NGS-calibrated antenna • > 4 hour data span • > 70% observations used • > 70% fixed ambiguities • < 0.04m H peak-to-peak • < 0.08m V peak-to-peak ! Uses: • GPS on BMs • PLSS / GCDB • Data archive • Data sharing
- 31.
- 32. Height Modernization Height Modernization -faster -cheaper -more accessible
- 33. Height Moderniza*on Regions Western Regional States
- 34. Height Moderniza*on Program Page: Mee*ngs, Presenta*ons
- 35. NGS homepage: geodesy.noaa.gov • Data access • Geode*c Toolkit • Publica*ons • Height Moderniza*on • Training opps • Educa*on resources • Presenta*ons • CORS, OPUS, …
- 36. Accurate positioning begins with accurate coordinates Source: Zurich-American Insurance Group