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Overview

Overview. Mission Overview and Significance History Challenges NGS 10-Year Plan NGS Programs Details on Programs and California Focus Marti Ikehara , State Geodetic Advisor Marti.ikehara@noaa.gov 916-227-7325. Detailed Topics. New datums from NGS in your future

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Overview

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  1. Overview Mission Overview and Significance History Challenges NGS 10-Year Plan NGS Programs Details on Programs and California Focus Marti Ikehara, State Geodetic Advisor Marti.ikehara@noaa.gov 916-227-7325

  2. Detailed Topics • New datums from NGS in your future • Development of a RTN backbone for California • Passive monumentation—who will maintain? • Legislative safeguards adequate? • Publication of GEOID09 • CBL usage, program

  3. Rationale for new Datums • Terminology • Horizontal becomes GEOMETRIC • Vertical becomes GEOPOTENTIAL • When? 2018, if GRAV-D program is complete • Why? But why?! • Primarily needed a better vertical datum for “vertical” data(geoid, ortho ht) not obtained by traditional leveling Airborne gravity observations will be used to develop next geoid • Geodetic Data collection relies upon navigation (GNSS) satellites orbiting around the mass center of the Earth • NAD83 reference frame/datum is not geocentric • NAD83 is not defined to include vertical velocities • Earth is not stable in all directions; reference frame must account for this to be as geodetically accurate as possible

  4. Z Earth-Centered Earth-Fixed (ECEF) Coordinate System XA, YA,ZA (not NAD83) Conventional Terrestrial Pole 1984.0 Bureau International de l'Heure (BIH) now the IERS -Y -X Greenwich Meridian Earth Mass Center X, Y, Z = 0 Y X GRS 80 Ellipsoid -Z

  5. ELLIPSOIDS used in the US(More than 60 have been used around the world) BESSEL 1841 (1848 – 1879) a = 6,377,397.155 m 1/f = 299.1528128 CLARKE 1866 (1879 – 1986) a = 6,378,206.4 m 1/f = 294.97869821 GEODETIC REFERENCE SYSTEM 1980 - (GRS 80) (1986 - Present) a = 6,378,137 m 1/f = 298.257222101 WORLD GEODETIC SYSTEM 1984 - (WGS 84) a = 6,378,137 m 1/f = 298.257223563

  6. Simplified Concept of NAD 83 vs. ITRF00 Datums h83 h00 Earth’s Surface ITRF 00 Origin 2.2 meters Identically shaped ellipsoids (GRS-80) a = 6,378,137.000 meters (semi-major axis) 1/f = 298.25722210088 (flattening) NAD 83 Origin

  7. Types of GEODETIC DATUMS HORIZONTAL 2 D (Latitude and Longitude) (e.g. NAD 27, NAD 83 (1986)) VERTICAL 1 D (Height) (e.g. Orthometric: NGVD 29, NAVD 88; Local Tidal) GEOMETRIC 3 D (Latitude, Longitude and Ellipsoid Height) Fixed and Stable - Coordinates seldom change (e.g. NAD 83 (1991), NAD 83 (2007)) also 4 D (Latitude, Longitude, Ellipsoid Height, Velocities) Coordinates change with time (e.g. ITRF00, ITRF08)

  8. Evolution of Geodetic Datums: from NAD27/NGVD29 to NAD83/NAVD88 to ?/ ? GPS H + V 2 + 1 27, 29 H + V 2 + 1 83(86), 88 H + VE+ VO 2 + 1 + 1 83(92), 88 +VELOCITIES (time) H + Ht+ VE +VO 2 + 2 + 1+ 1 83(07)+HTDP, 88 H + Ht+VE+ VEt 2 + 2 + 1+ 1 GEOMETRIC (VE+G)[+VEt]+ Gt 1 + 1 GEOPOTENTIAL H + Ht+VE+ VEt 2 + 2 + 1+ 1 ITRF00 (2002.00) + GRAVITY (geoid model)

  9. International Earth Rotation and Reference System Service (IERS)(http://www.iers.org) The International Terrestrial Reference System (ITRS) constitutes a set of prescriptions and conventions together with the modeling required to define origin, scale, orientation and time evolution ITRS is realized by the International Terrestrial Reference Frame (ITRF) based upon estimated coordinates and velocities of a set of stations observed by Very Long Baseline Interferometry (VLBI), Satellite Laser Ranging ( SLR), Global Positioning System (GPS) and GLONASS (GNSS), and Doppler Orbitography and Radio-positioning Integrated by Satellite (DORIS). ITRF89, ITRF90, ITRF91, ITRF92, ITRF93, ITRF94, ITRF95, ITRF96, ITRF97, ITRF2000, ITRF2005

  10. International Terrestrial Reference Frame 4 Global Independent Positioning Technologies International Global Navigation Satellite Systems Service (IGS) International Laser Ranging Service (ILRS) International Very Long Baseline Service (IVS) International DORIS Service (IDS)

  11. Tectonic Horizontal Motions

  12. Treatment of velocity in new datum • ITRF has velocities relative to the COM • Big question for our new datum is how is velocity treated: like ITRF OR “stable” North America like NAD83?

  13. Horizontal Velocities, relative to NAD83 datumreflected in HTDP model

  14. CORS Data allows for Monitoring Vertical Crustal Motion Vertical velocities associated with Glacial Isostatic Adjustment (rebound)

  15. Treatment of velocities in new datum • ITRF has velocities relative to the COM • Big question for our new datum is how is velocity treated: like ITRF OR “stable” North America like NAD83? • West Coast, esp CA, is accustomed to needing to account for velocity, at least horizontal • How do we incorporate vertical velocity? • How often would we change Coordinates? • ITRF: >1cm H, 2cm Eht; if ITRF changes, NAD83 too • Should it be 5mm, 10mm? At least annually??

  16. NGS CORS, as of Feb, 2010: 108 in CA

  17. Proposed Backbonefor a streaming RTN • Total statewide=154 • Funded, currently, by various programs=76 • Funded needed=78 • Partners being sought • $15,000 or $150,000 • Data streams • Regular: 20 • Sustaining: Unlimited • Not network solution

  18. Elements of CRTNCA Real Time Network • Currently, single base positioning available free • How do you get it? Contact Yehuda Bock, CSRC • Goal: RT data streaming to partners • Partners could be public agencies, private providers of RTN service • Funds needed to establish telemetry at 78 sites • Operational partners: MWD, USGS, SOPAC, Counties: LA, Orange, SD, and UNAVCO PBO

  19. Current status: http://sopac.ucsd.edu/projects/realtime

  20. NGS and RTNs • Draft RTN Guidelines indicate that RTN providers should incorporate some CORS (10%, minimum of 3) into their network • Doing so will enable connection with the NSRS or CSRS in the case of CRTN • NGS may ‘certify’ RTN providers, after reviewing practices, adjustment, etc • NGS long-term goal is to have national backbone of RT CORS that we operate • Maintenance of passive monuments is nil/low

  21. Passive monumentation • MAINTENANCE? • In LS Act, protected along R/W, transportation • Not protected on private property • Only actions by surveyors

  22. http://www.dca.ca.gov/pels/pls_act.pdf PROFESSIONAL LAND SURVEYORS’ ACT (Business and Professions Code §§ 8700 – 8805) INCLUDES AMENDMENTS MADE DURING THE 2007 LEGISLATIVE SESSION (Effective January 1, 2008, unless otherwise noted) CHAPTER 15. LAND SURVEYORS pg 20 of 31: NOTE, in (b): When monuments exist that "...provide horizontal or vertical survey control,"

  23. 8771. Record of survey - monumentation • (a) Monuments set shall be sufficient in number and durability and efficiently placed so as not to be readily disturbed, to assure, together with monuments already existing, the perpetuation or facile reestablishment of any point or line of the survey. • (b) When monuments exist that control the location of subdivisions, tracts, boundaries, roads, streets, or highways, or provide horizontal or vertical survey control, the monuments shall be located and referenced by or under the direction of a licensed land surveyor or registered civil engineer prior to the time when any streets, highways, other rights-of-way, or easements are improved, constructed, reconstructed, maintained, resurfaced, or relocated, and a corner record or record of survey of the references shall be filed with the county surveyor. They shall be reset in the surface of the new construction, a suitable monument box placed thereon, or permanent witness monuments set to perpetuate their location if any monument could be destroyed, damaged, covered, or otherwise obliterated, and a corner record or record of survey filed with the county surveyor prior to the recording of a certificate of completion for the project.

  24. Questions from reading PLS Act • If it’s on a superceded datum or has VERTCON elevations, does the monument still “provide” control? Or did it “used to provide” control? • Should monuments on private property or on public property that is NOT a road easement also be protected? • Do they need to be replaced or ‘merely’ referenced to something local? • This pertains to practice of licensed surveyors; there are many others capable of destruction

  25. GEOID09 published in Sept 09 • In California, GEOID03 considered 567 bench marks with GPS data (ellipsoid heights), and kept 549 • In GEOID09, there were 833 considered; 747 were included, a 36% increase

  26. GEOID09 compared to GEOID03 09: teal, good; yellow: State advisor-rejected; red: analysis-rejected 03 (underlying dots): dk blue, kept; orange: rejected

  27. From Helmer’s article in Winter 09/10 issue of California Surveyor

  28. Calibration Base Lines Possible CBLs to be measured • Briggsmore, Modesto: not done by NGS • Concord: usage shows discrepancy of 1cm • Camarillo: last monument knocked out • Sacramento: monuments about to be set Need to hear interest/POC for: • Inyokern: last measured in 1990! • Reno: re-measurement

  29. CBL Usage, Maintenance • Who has used one in the past 3 years? • Why? or Why not? • Distance from nearest one? • Bothersome to get key? • Usage procedures? • Forms needed for usage, filing with host? • Other issues??

  30. http://www.dot.ca.gov/hq/row/landsurveys/geodetic/geodetic_control.htmlhttp://www.dot.ca.gov/hq/row/landsurveys/geodetic/geodetic_control.html

  31. Kml’s and shapefiles downloadable

  32. 5 data types available/possible: HVL, H, CORS, VL and HVHM

  33. Using NGS DSWORLD software and Google earth to get the latest geodetic data for your project Start by downloading “Google earth” at: http://earth.google.com/download-earth.html Click here

  34. Open the NGS main page atwww.ngs.noaa.gov Mouse over the “Tools” button and then click on the “Download PC Software” link. Mouse-over the “TOOLS” button Click on “DOWNLOAD PC SOFTWARE”

  35. Next,clickonthe link: “UserContributedSoftwareisalsoavailable…..” Click here

  36. Next, click on the DSWORLD (Version *.**) link. A “file download” window will appear. Choose to save the file where you can easily find it. It will be a zip file, so you will need to unzip it and then double click on the setup.exe file. That will install the program for you. For additional information or assistance, please contact your NGS State Geodetic Advisor

  37. Anything Else?! • Marti.ikehara@noaa.gov • 916-227-7325 If you think of something: • ftp://ftp.ngs. noaa.gov/pub/marti

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