The 2 SOPS User Range Accuracy (URA) Improvement and Broadcast Inter-Frequency Bias (TGD) Updates

Michael H. Rivers

Abstract:	Over the last two years, 2 SOPS has participated in two significant improvements to the GPS navigation signal. One of them was an improvement to the broadcast URA index. This index was designed to be a statistical indicator of space and control segment errors, but was significantly skewed due to an out-dated general modeling factor included in each URA calculation. Once this was recognized, an effort was initiated to remove this overly conservative factor and study the impacts. The second improvement was the implementation of the Jet Propulsion Laboratory's new TGD values. Although 2 SOPS was not significantly involved in the derivation of the new TGD values, it was instrumental in coordinating and implementing these values. As part of the process, 2 SOPS receives updated values on a quarterly basis and changes the broadcast values as needed. The author will present a description of each improvement and how these changes can affect users.
Published in:	Proceedings of the 13th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2000) September 19 - 22, 2000 Salt Palace Convention Center Salt Lake City, UT
Pages:	2551 - 2555
Cite this article:	Rivers, Michael H., "The 2 SOPS User Range Accuracy (URA) Improvement and Broadcast Inter-Frequency Bias (TGD) Updates," Proceedings of the 13th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2000), Salt Lake City, UT, September 2000, pp. 2551-2555.
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