Evaluation of Assisted GPS (AGPS) Performance Using Simulator and Field Tests

S. Singh

Abstract:	The Federal Communications Commission (FCC) E-911 mandate, Location-Based Services (LBS), as well as personal and vehicular navigation applications are driving the need for navigation capability in degraded signal environments such as in urban areas and indoors. Since the position accuracy yielded by GPS methods is better than other positioning technologies, most wireless carriers are looking at Assisted GPS (AGPS) as the solution to meet the FCC criteria. The purpose of this paper is to compare the effects of various aiding parameters such as satellite ephemeris or almanac, and varying timing or horizontal positioning uncertainties on AGPS signal acquisition by using a hardware simulator and under different field test conditions. A SiRFLocTM evaluation kit is used to investigate the performance of the AGPS receiver. Acquisition tests showed the importance of aiding data such as satellite ephemeris and good timing or position accuracy under significantly weak signal conditions, e.g. the concrete basement or less than -142 dBm (Ephemeris aiding). Comparison of field and simulation testing showed similarities when the effects of different aiding data were analyzed at various simulated signal power levels or different field test sites thus illustrating that simulation tests which can be cheaper than field testing in terms precious resources such as time or cost could provide valuable first-hand knowledge before conducting field tests.
Published in:	Proceedings of the 19th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2006) September 26 - 29, 2006 Fort Worth Convention Center Fort Worth, TX
Pages:	2956 - 2967
Cite this article:	Singh, S., "Evaluation of Assisted GPS (AGPS) Performance Using Simulator and Field Tests," Proceedings of the 19th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2006), Fort Worth, TX, September 2006, pp. 2956-2967.
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