CORS, OPUS, and Reprocessing status … · GPS data collected since 1994 is being processed with...
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CORS, OPUS, and Reprocessing status Kevin Choi, Ph.D. Chief, Continuously Operating Reference Stations Branch National Geodetic Survey with significant contributions from the CORS and OPUS team (Francine Coloma, Don Haw, Jarir Saleh, Lijuan Sun, Sungpil Yoon, Joe Evjen) 1 NSPS/MAPPS 2017
Transcript of CORS, OPUS, and Reprocessing status … · GPS data collected since 1994 is being processed with...
CORS, OPUS, and Reprocessing status
Kevin Choi, Ph.D. Chief, Continuously Operating Reference Stations BranchNational Geodetic Survey
with significant contributions from the CORS and OPUS team (Francine Coloma, Don Haw, Jarir Saleh, Lijuan Sun, Sungpil Yoon, Joe Evjen) 1NSPS/MAPPS 2017
• National Spatial Reference System• CORS status• Accessing the NSRS using OPUS• Why Reprocessing?• Future of CORS
Contents
2NSPS/MAPPS 2017
• NOAA’s National Geodetic Survey (NGS) defines, maintains, and provides access to the National Spatial Reference System (NSRS)
• Consistent coordinate system that defines latitude, longitude, height, scale, gravity, and orientation throughout the United States
• Continuously Operating Reference Stations• Maintains and monitors 3-dimensional
coordinates of the ground stations and GPS orbits to provide direct access to NSRS
National Spatial Reference System
3NSPS/MAPPS 2017
U.S. CORS Network• ~2000 Continuously Operating Reference Stations
– Run by various agencies and research groups– Provide access to the U.S. National Spatial Reference System
– Also support Meteorology, Space Weather, and other Geophysical applications. 4NSPS/MAPPS 2017
yoursolution
sharing & projectsmark
description
O nlineP ositioningU serS ervice
free, fast, easy, consistent coordinates
geodesy.noaa.gov/OPUS
JGE 2016 v1
optional:
IGS & NGS base stations& site information files
IGS antenna calibrations& satellite orbits& reference frames
NGS geodetic toolkit, incl.PAGES (-S) processorRSGPS (-RS) processor
var. geophysical models& conversions
standard geodetic data
yourGPS data
5NSPS/MAPPS 2017
31,77072,190 79,284100,921
136,168136,450129,218134,339141,988129,234
199,158
5,29455,540
98,666126,058
165,945
201,550
181,754172,615170,816
205,607
285,483
231,125256,690
297,627311,692
432,609
354 8461,614
1,333
1,116
1,466
2,006
1,763 2,381
0
100,000
200,000
300,000
400,000
500,000
600,000
2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017
FY TotalsFY TotalsFY TotalsFY TotalsFY TotalsFY TotalsFY TotalsFY TotalsFY TotalsFY TotalsFY TotalsFY TotalsFY TotalsFY TotalsFY TotalsProjected
OPUS solutions / year OPUS annual usage
stacked bar graph
OPUS-S (solution shared)
OPUS-S (not shared)
OPUS-RS
JGE, Feb-2017
350,000 = NOS milestone
6NSPS/MAPPS 2017
Current CORS stations
1348 Computed Velocities1264 Estimated Velocities
7NSPS/MAPPS 2017
Reprocessing Campaigns
• Why reprocessing?– Consistent use of up-to-date geophysical models
(IERS convention)– Consistent processing strategies– Linearize plate rotation velocities– Refine station velocities by accommodating
earthquakes and equipment changes (discontinuities)
– Realign to the updated ITRF. • ITRF2014 and corresponding IGS14 has been released.
8NSPS/MAPPS 2017
Out-of-Tolerance CORS coordinates
• Stations outside of 2/4 cm (H/V) threshold– Excluded in the OPUS processing
• Sept 19 2013 – Mar 19, 2016 (2.5 years)– 24 Repro1 stations– 43 Modeled velocity stations (horizontal model only)
– Geophysically active area• Alaska, California
– Short data span– Subsidence area– ~900 new CORS stations since Repro1
9NSPS/MAPPS 2017
Out-of-Tolerance CORS coordinates
10NSPS/MAPPS 2017
Out-of-Tolerance CORS coordinates
11NSPS/MAPPS 2017
IGS Reprocessing Recommendations1st Reprocessing 2nd Reprocessing
Duration 1994 - 2007 1994 - 2014Reference Frame IGS05
(aligned to ITRF2005)IGb08 (aligned to ITRF2008)
IERS Convention IERS 2003 IERS 2010Geopotential Field
EGM96 EGM2008• time-variations of low-degree
coefficients• mean pole trajectory model
Antenna calibration
IGS05 ANTEX (absolute calibration)
IGS08 ANTEX (absolute calibration)
Tropospheric delay model
GPT / GMF GPT2 / VMF1_HT
Higher order Ionosphere
Not applied IERS 2010 & IGRF11(2nd order)
Ocean Pole Tide(Station Displ.)
Not applied IERS 2010
Orbit Dynamics No Earth Albedo model Earth Albedo model [1][2][3]Block specific SV thrusting (ERPFBOXW.f) 12NSPS/MAPPS 2017
NGS 2nd Reprocessing Campaign• NGS’ Orbit product
quality has been very stable in recent years,
• IGS Repro2 is completed and ITRF2014 was released in Jan. 2016– Periodic Signal
models– Post-Seismic
Deformation models
• IGS14 orbit/clock has been started since Jan 29, 2017 Image from P. Rebischung 2015
ITRF92ITRF93
ITRF94ITRF96
ITRF97IGS97
IGS00 IGb00 IGS05 IGS08 IGb08 IGS14
13NSPS/MAPPS 2017
NGS 2nd Reprocessing Campaign
0
500
1000
1500
2000
2500
1994 1999 2004 2009 2014
# Si
tes
Year
Global num_siteCORS num_site
14NSPS/MAPPS 2017
NGS 2nd Reprocessing Preliminary Orbit Quality
wrt. apriori orbits (ig1 +IGS Final) 15NSPS/MAPPS 2017
SUMMARY: NGS 2nd Reprocessing• Catching up the international standards
– ITRF2014 and IGS14• Utilized the new Cloud computing environment
– Faster distributed processes• 22 years of data (1994-2015)• Follow the Repro1 processing strategies with updated
models.• As of March 1, 2017, discontinuity detection by
stacking using CATREF – 3rd iteration.• Found some issues in some areas we will fix it!
16NSPS/MAPPS 2017
Current CORS stations
1348 Computed Velocities1264 Estimated Velocities
17NSPS/MAPPS 2017
Reprocessing Campaigns
2595 Computed Velocities (923 new!!)444 Estimated Velocities
18NSPS/MAPPS 2017
Future Plans: Foundation CORS
• CORS rely heavily on the partners.– NGS owns only ~40 stations
• Contribute more on the IGS Reference Frame Stations– Sites collocated with other techniques: VLBI,
SLR, DORIS– Locations with existing geophysical observatories
(gravity, seismic, atmospheric)– Adopt some/build others to cover geographically
deficient areas.19NSPS/MAPPS 2017
Foundation CORS
20NSPS/MAPPS 2017
Foundation CORS
21NSPS/MAPPS 2017
Summary and Conclusion• Uncertainty of the velocity model, Earthquakes, and
other regional deformations cause discrepancies in the propagated coordinates.
• 2nd reprocessing at NGS of global and U.S. CORS GPS data collected since 1994 is being processed with IGS08 Frame.
• Next step: Finalize discontinuity detection and align to IGS14 for the CORS stations once its ready
• On-going discussion with Canada and Mexico for the next NAREF definition
22NSPS/MAPPS 2017
Thank you!
23NSPS/MAPPS 2017
Backup slides
24NSPS/MAPPS 2017
Static: OPUS determines your position with a differential GPS static solution, using hours of data.
This process is repeated 4x from other CORS.
25NSPS/MAPPS 2017
Rapid-static: OPUS first creates an atmospheric delay model from surrounding CORS data.
Your position is then quickly determined by differential GPS static solution.
26NSPS/MAPPS 2017
Located in the SW corner of a 2 ft square concrete pad projecting 0.3 ft above ground, 3.3 ft S from S edge of sidewalk …
Shared solutions: describe the mark to share it.
requires 4+ hours on a permanent mark of public interest
http://geodesy.noaa.gov/marks/sharing/
27NSPS/MAPPS 2017
OPUS-projects: first, run OPUS to harvest all project data
OPUS automatically forms sessions from simultaneously observed marks, enabling multi-baseline processing and adjustment of redundant observations.
Improved solutions for simultaneous or repeated observationsharvest data from multiple observersshare upload & processing taskscustomize your processing using PAGES
simple data quality analysisimprove survey accuracyconstrain to local networkspublishing support (limited)
Bluebooking via OPUS projects is expected in 2017.
28NSPS/MAPPS 2017
Out-of-Spec CORS coordinates (AB37)
29NSPS/MAPPS 2017
Out-of-Tolerance CORS coordinates (P304)
30NSPS/MAPPS 2017
Out-of-Tolerance CORS coordinates (ASPA)
exp
31NSPS/MAPPS 2017
