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National Geodetic Survey – Continuously Operating Reference Stations & Online Positioning User Service (CORS & OPUS) William Stone Southwest Region (UT,

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Presentation on theme: "National Geodetic Survey – Continuously Operating Reference Stations & Online Positioning User Service (CORS & OPUS) William Stone Southwest Region (UT,"— Presentation transcript:

1 National Geodetic Survey – Continuously Operating Reference Stations & Online Positioning User Service (CORS & OPUS) William Stone Southwest Region (UT, AZ, NM, NV) Geodetic Advisor william.stone@noaa.gov NOAA’s National Geodetic Survey User Conference San Diego – July 24, 2012

2 “ The location of anything is becoming everything.” Esri 2009 User Conference Opening Plenary “Geography is the platform for understanding the world.” Esri 2012 User Conference Opening Plenary

3 National Spatial Reference System

4 36 33 42.15986 N 105 12 15.67754 W ellipsoid ht. 1857.765 m orthometric ht. 1876.145 m (NAD83(2011) / NAVD88) CORS Coordinates CORS GNSS Observation Data Continuously Operating Reference Station

5 CORS Network  1950 sites  200 organizations

6 Red Butte (RBUT) CORS: 1997 - 2011 CORS Coordinate History Time Series  Long-term  60-day Red Butte (RBUT) CORS: Daily - Published IGS08

7 Why CORS? Provides direct tie to NSRS foundation Eliminates recon, staff, equipment needs @ control points Highly accurate – for all positioning requirements Coordinates/velocities in NAD83 & global reference frame Coordinates monitored daily & updated as required Preparation for transition to new national datums (2022)

8 CORS Applications Surveying GIS Geophysics / Crustal Motion / Subsidence Climate Change / Sea Level Rise Flood Risk Analysis / Management Precision Agriculture Land Management Meteorology (Water Vapor in Troposphere) Space Weather (Free Electrons in Ionosphere) Real-time Networks – NSRS Consistency NGS: Defining / Delivering NSRS Precise Orbits

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10 Maintaining Coordinate Accuracy - the Multi-Year CORS Solution 5 years in the making >>> new CORS coordinates & velocities Global Stations Global Stations + CORS global tracking network: –satellite orbits (15-min intervals) –terrestrial framework –Earth Orientation (EOPs) –global station positions (weekly averages) U.S. CORS tied to global framework via single baselines –minimizes frame distortions from local effects in dense regional networks 1994-2010.5 tracking history 90 billion double-difference eqs. relative >>> absolute antenna cals.  NAD83 (2011) epoch 2010.00  IGS08 epoch 2005.0  “few cm” change from previous

11 Change in NAD 83 Horizontal Position NAD 83(2011) epoch 2010.00 – NAD 83(CORS96) epoch 2002.0 Average shift:  E = 0.05 cm  5.25 cm  N = 2.12 cm  6.08 cm – combination of position and velocity differences – due mostly to updated velocities (including up to 8 more years of data) – plate movement in far West WA+OR 4.4E / 5N cm WA+OR 4.4E / 5N cm CA+NV -10.8E / 14.4N cm CA+NV -10.8E / 14.4N cm East 1.4E / -0.2N cm East 1.4E / -0.2N cm UT+CO+NM+AZ 0.5E /1.0N cm UT+CO+NM+AZ 0.5E /1.0N cm ID+MT+ND+SD+WY 1.7E / 0.5N cm ID+MT+ND+SD+WY 1.7E / 0.5N cm

12 CORS Coordinates – New Reference Frames IGS08 = International GNSS Service 2008 (GPS-only realization of ITRF2008) NAD83 (2011) epoch 2010.00 = North American Datum 1983 (2011 realization @ January 1, 2010) IGS08 Position >>> IGS08 Velocity >>> NAD83 Position >>> NAD83 Velocity >>>

13 NGS Real-time GNSS Data Service (BETA)

14 >15 min of L1/L2 GPS data >>> geodesy.noaa.gov/OPUS  OPUS-RS (Rapid Static) ----15 min to 2 hours  OPUS-S (Static) ---- 2 to 48 hours solution via email - in minutes options: publishing; OPUS-Projects (under development/testing) now using NAD83(2011) epoch 2010.00 & IGS08 epoch 2005.0 (from MYCS) now using GEOID12 for orthometric height computation fast, easy, consistent access to NSRS Online Positioning User Service (OPUS)

15 e-mail GPS file antenna antenna height in/exclude CORS extended solution SPCS zone project profile publish OPUS-RS or OPUS-Static (15 min-2 hr) (2-48 hr) Online Positioning User Service (OPUS) Submission Page

16 OPUS Solution Report

17 OPUS-RS Accuracy Estimator Tool

18 OPUS – Datasheet Publishing Publication Criteria: NGS-calibrated GPS antenna > 4 hour data span (OPUS-S) > 70% observations used > 70% fixed ambiguities < 0.04m H / 0.08m V peak-to-peak Applications: GPS on BMs (geoid modeling) PLSS / GCDB Data-sharing/archive

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20 CORS & OPUS INFO CORS Site Guidelines Future CORS Sites CORS Newsletter FAQs Papers Bibliography Presentations Contact Info GPS Calendar Resource Links Coordinates About OPUS geodesy.noaa.gov/CORS (& …/OPUS)

21 CORS Monograph CORS and OPUS for Engineers: Tools for Surveying and Mapping Applications sponsored by ASCE and NGS available on ASCE website useful to CORS & OPUS users working in many different types of GPS applications OPUS troubleshooting tips

22 see The American Surveyor vol 8 (no. 5,6,7)

23 NGS Real-time Guidelines: Single-base and Network

24 National Geodetic Survey Geodetic Advisors Geodetic Advisor Contact Info: http://geodesy.noaa.gov/ADVISORS/AdvisorsIndex.shtml

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