A GPS Orbit and Clock Correction Analysis for Long Baseline High Performance DGPS

Yujie Zhang, Chris Bartone

Abstract:	"This paper focuses on a GPS orbit and clock correction analysis for long baseline high performance DGPS. An initial orbit accuracy assessment was pursued for the IGS ultra-rapid predicted product and WAAS corrected orbit/clock. The IGS ultra-rapid predicted orbit demonstrated about 10cm accuracy (total RMS 10.5cm based on limited data set tested) for real-time application. The limited data indicate that the IGS ultra-rapid predicted clock correction had about 3m accuracy where its performance is comparable to GPS broadcast clock correction. The WAAS corrected orbit demonstrated about 1.3m accuracy and the WAAS correct clock correction provides about 2m accuracy, based on the limited data assessment results. The WAAS Fast Correction in MT 2-5 was investigated to potentially improve the short term clock correction performance; however, based on this limited data set, it did not improve the overall clock error over just using the WAAS long-term clock correction provided in MT24-25. In comparison with the GPS broadcast orbit error, WAAS corrected orbit error improves by about 50% and the same improvement was show in the DD orbit error. The use of WAAS corrected orbit is recommended for NDGPS-HP architecture where both accuracy and integrity requirements exist. The IGS ultra-rapid predicted orbit demonstrated better accuracy performance than the WAAS corrected orbit, and may be applicable for some high accuracy, very long baseline NDGPS-HP applications if an appropriate overbound and monitor scheme can be developed to provide integrity."
Published in:	Proceedings of the 61st Annual Meeting of The Institute of Navigation (2005) June 27 - 29, 2005 Royal Sonesta Hotel Cambridge, MA
Pages:	1062 - 1072
Cite this article:	Zhang, Yujie, Bartone, Chris, "A GPS Orbit and Clock Correction Analysis for Long Baseline High Performance DGPS," Proceedings of the 61st Annual Meeting of The Institute of Navigation (2005), Cambridge, MA, June 2005, pp. 1062-1072.
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