Multiple Level Integrity Monitoring in Assisted GPS

Hanna Sairo, Jari Syrjärinne, and Jarmo Takala

Abstract:	Monitoring GPS integrity is mainly about finding the possibly error causing signals, and then deciding about further actions in position computation. In this paper, a method for integrity monitoring for wireless-assisted GPS (AGPS) is proposed. The method is based on sequential, different integrity checks. These checks form a method that is now named multiple level integrity monitoring, which includes both signal condition checks and verification of satellite combination geometry. The proposed procedure is the following: First, signals that are very likely, if not certainly, erroneous are excluded. Then, if geometry is acceptable, weighted positioning is carried out. The features of wireless assisted GPS are considered in the integrity issues. The proposed method is tested with Matlab simulations, in which erroneous conditions are artificially created. The obtained results show that the proposed method usually prevents usage of faulty signals. The proposed method presents novelty especially by suggesting an angle value check for ephemeris data verification in assisted GPS.
Published in:	Proceedings of the 15th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2002) September 24 - 27, 2002 Oregon Convention Center Portland, OR
Pages:	2129 - 2134
Cite this article:	Sairo, Hanna, Syrjärinne, Jari, Takala, Jarmo, "Multiple Level Integrity Monitoring in Assisted GPS," Proceedings of the 15th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2002), Portland, OR, September 2002, pp. 2129-2134.
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