Performance of Receiver Autonomous Integrity Monitoring (RAIM) in the Presence of Simultaneous Multiple Satellite Faults

Young C. Lee

Abstract:	After discontinuing the use of Selective Availability (SA) in May 2000, thereby improving the accuracy of civil signals, the United States plans to launch GPS satellites with second and third civil signals over the next several years. The European Galileo satellites are also planned to be available each with multiple-frequency signals in the next several years. With a large number of satellites and new signals, receiver autonomous integrity monitoring (RAIM) can achieve significantly better performance. This may enable one potential new capability, LPV, which is an approach procedure that can be used with WAAS. However, such navigation capability requires significantly tighter alert limits for RAIM. Consequently, even small errors would be considered significant. For this reason, the probability of two or more simultaneous satellite faults having significant ranging errors might not be negligible as assumed in past RAIM designs for nonprecision approach (NPA) through en route phases of flight. This paper investigates the effect of simultaneous multiple satellite faults on RAIM integrity performance and shows that the requirement for RAIM to provide integrity in the presence of two simultaneous satellite faults severely degrades RAIM availability. It is recommended to re-examine the multiple satellite fault probability to see if it can reasonably be ignored.
Published in:	Proceedings of the 60th Annual Meeting of The Institute of Navigation (2004) June 7 - 9, 2004 Dayton Marriott Hotel Dayton, OH
Pages:	687 - 697
Cite this article:	Lee, Young C., "Performance of Receiver Autonomous Integrity Monitoring (RAIM) in the Presence of Simultaneous Multiple Satellite Faults," Proceedings of the 60th Annual Meeting of The Institute of Navigation (2004), Dayton, OH, June 2004, pp. 687-697.
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