Analysis of Nine Years of North American CORS Data
Abstract
Data from a network of 350 Continuously Operating GPS Reference Stations (CORS) located across the U.S. were homogeneously analyzed together with about 130 globally distributed stations for the period from 1994 through 2002. Every third day was included for computational efficiency. The final orbits of the International GPS Service (IGS) were used without adjustment, after applying transformations to a consistent IGS00 reference frame (closely aligned to ITRF2000); the reported satellite accuracy codes were applied for each day. Our double-differenced carrier phase analysis methods are generally consistent with the IERS 1996 Conventions, using 30-second sampling and a 15-degree elevation cutoff. Data for each day were processed in three interlocking subnetworks that were combined at the normal equations level, then the days were combined to determine the station coordinates and linear velocities of all stations. Results were carefully edited to delete spans of bad data and to introduce position discontinuities where necessary, usually due to equipment changes or nearby earthquakes. The combined solution was aligned to the IGS00 reference frame by minimizing the differences for 53 of the 54 IGS fiducial stations. To determine the daily station repeatabilities, we re-solved each day using a subset of constrained coordinates taken from the overall 9-year solution. Using the global solution and the station repeatabilities, we plan to examine the intra-plate stability of N. America and to assess the feasibility of realizing a horizontal reference frame for eastern N. America stable at the 1-mm level or better. This work anticipates the requirements of the Plate Boundary Observatory (PBO) currently under construction. This solution will also improve our understanding of local and regional vertical motions across N. America. In the future, PBO will dramatically improve the spatial resolution of long-term GPS solutions of this type, at least in the western U.S.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2003
- Bibcode:
- 2003AGUFM.G31B0701D
- Keywords:
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- 1206 Crustal movements: interplate (8155);
- 1208 Crustal movements: intraplate (8110);
- 1243 Space geodetic surveys;
- 1247 Terrestrial reference systems;
- 8155 Plate motions: general