Airborne Mitigation of Constellation Wide Faults

Todd Walter, Juan Blanch

Peer Reviewed

Abstract:	Advanced Receiver Autonomous Integrity Monitoring (ARAIM) is being investigated as a promising method to provide vertical guidance for aircraft. One of the most significant concerns raised for ARAIM, is the possibility of multiple simultaneous faults being present on one of the constellations. This threat can be mitigated by forming position solutions that exclude each constellation in turn. Unfortunately, if the remaining constellations are not sufficiently strong, the resulting subset can lead to a significant loss of availability. This paper examines some additional airborne consistency checks that can identify some of these feared events. A simple idea is compare broadcast data sets to prior information in order to identify erroneous ephemeris data. Another idea is to use periods of strong geometry to be able to help get through subsequent periods of weak geometry. Further, by validating broadcast ephemeris messages when constellation cross-checks are available, it may be possible to view the messages as trusted when the cross-checks are no longer available. Such an approach may be able to dramatically improve overall system availability. This paper examines the real constellation fault that occurred on April 1-2, 2014 as well as more difficult to detect constellation fault modes.
Published in:	Proceedings of the 2015 International Technical Meeting of The Institute of Navigation January 26 - 28, 2015 Laguna Cliffs Marriott Dana Point, California
Pages:	676 - 686
Cite this article:	Walter, Todd, Blanch, Juan, "Airborne Mitigation of Constellation Wide Faults," Proceedings of the 2015 International Technical Meeting of The Institute of Navigation, Dana Point, California, January 2015, pp. 676-686.
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