GPS Performance Evaluation and WAGE

Michael D. Menn, William A. Feess, and Harold Bernstein

Abstract:	GPS Signal in Space (SIS) error has been significantly reduced by the Ephemeris Enhancement Endeavor (EEE) retuning effort. The Wide Area GPS Enhancement (WAGE), which allows specially equipped user sets to reduce radial minus clock errors, has been implemented in the control segment. The primary objective of this study is to assess accuracy with and without a WAGE equipped receiver. This work expands the focus of previous investigations by including an evaluation of WAGE accuracy. Actual control segment uploaded messages are compared to National Imagery and Mapping Agency (NIMA) Best Fit Ephemeris to generate orbit plane coordinate figures of merit. Smoothed measurements formed by both the GPS control segment and NIMA receivers are used to compute measurement domain error statistics. The results show that EEE without WAGE reduces the SIS error by about 20%. Before EEE, WAGE reduced the SIS error for a properly equipped user by only about 8%. After EEE, WAGE provides an additional improve-ment of about 20%. EEE and WAGE combined yield an improvement of about 36%.
Published in:	Proceedings of the 54th Annual Meeting of The Institute of Navigation (1998) June 1 - 3, 1998 The Adams Mark Hotel Denver, CO
Pages:	593 - 599
Cite this article:	Menn, Michael D., Feess, William A., Bernstein, Harold, "GPS Performance Evaluation and WAGE," Proceedings of the 54th Annual Meeting of The Institute of Navigation (1998), Denver, CO, June 1998, pp. 593-599.
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