RAIM AVAILABILITY FOR SUPPLEMENTAL GPS NAVIGATION

Karen L. Van Dyke

Peer Reviewed

Abstract:	This paper examines GPS receiver autonomous integrity monitoring (RAIM) availability for supplemental navigation based on the approximate radial-error protection (ARP) method. This method applies ceiling levels for the ARP figure of merit to screen out bad detection geometries under worst-case bias conditions. The ARP criterion value for each phase of flight is based on the integrity specifications stated in the RTCA Special Committee (X1-159 supplemental Minimum Operational Performance Standards (MOPS) for GPS. Applying the ARP criterion, extensive analysis was performed to determine the availability of RAIM over the conterminous United States, North Atlantic, Europe, Central East Pacific, and North Pacific during en route, terminal, and nonprecision approach phases of flight. The 21 primary, optimal 21, and optimized 21+ 3 GPS constellations were examined. The results demonstrate that RAIM is not available 100 percent of the time, even with 24 operational satellites. This is because there are times when only 4 satellites are visible, preventing RAIM detection altogether, and other times when the geometry of the visible satellites has an ARP that exceeds the ARP ceiling value.
Published in:	NAVIGATION: Journal of the Institute of Navigation, Volume 39, Number 4
Pages:	429 - 444
Cite this article:	Van Dyke, Karen L., "RAIM AVAILABILITY FOR SUPPLEMENTAL GPS NAVIGATION", NAVIGATION: Journal of The Institute of Navigation, Vol. 39, No. 4, Winter 1992-1993, pp. 429-444.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In