GPS MONITOR ALARM LIMITS FOR NONPRECISION APPROACHES

Robert Loh

Peer Reviewed

Abstract: The future navigation accuracy requirement for nonprecision approaches has been estimated to be 100 m. GPS can satisfy this requirement by limiting the 95 percent horizontal position determination accuracy for civil users to 100 m. The FAA is investigating GPS signal integrity monitoring and the associated monitor alarm limits in order to satisfy the integrity response time requirements for non-precision approaches. This paper documents a rationale for the 100 m GPS horizontal accuracy requirement and evaluates the impact of using GPS monitor alarm limits greater than 100 m. The GPS monitor alarm limit must be set above 100 m in order to reduce the number of potential alarms. The significant impact on nonprecision approaches, as defined in the Terminal Instrument Procedures, appears to be the size of the obstacle clearance areas and their effect on the minimum descent altitude.
Published in: NAVIGATION, Journal of the Institute of Navigation, Volume 36, Number 3
Pages: 253 - 264
Cite this article: Loh, Robert, "GPS MONITOR ALARM LIMITS FOR NONPRECISION APPROACHES", NAVIGATION, Journal of The Institute of Navigation, Vol. 36, No. 3, Fall 1989, pp. 253-264.
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