Analysis of Reference Antenna Motion on the JPALS Shipboard Integrity Monitor

Michael Koenig, Demoz Gebre-Egziabher, Sam Pullen, Ung-Souk Kim, Per Enge, Boris S. Pervan, Fang Cheng Chan, and Glenn Colby

Abstract:	The Shipboard-Relative GPS (SRGPS) variant of the Joint Precision Approach and Landing System (JPALS) is being developed as a single navigation system and is intended to replace the existing multiple systems that provide navigation, precision approach and landing services to aircraft landing aboard ships. The required navigation system vertical accuracy is envisioned to be on the order of 0.3 m, and the vertical protection level is about 1.1 m with an associated integrity risk of approximately 10-7. In the SRGPS architectures currently being considered, the JPALS Shipboard Integrity Monitor (JSIM) is one of the reference station based integrity monitoring concepts under study. The function of JSIM is to detect, isolate, and alarm signal-in-space and reference receiver failures. In addition to its integrity monitoring functions, JSIM is responsible for generating and broadcasting high quality carrier- and code-phase corrections from multiple GPS frequencies. JSIM is a shipboard analog of the LAAS Ground Facility (LGF). Unlike the LGF, however, JSIM is a mobile system and has to deal with reference antennas that undergo rigid-body and relative motion. This paper presents the results of analyses which quantify the effect of antenna motion on the performance of one of the JSIM integrity monitors-Measurement Quality Monitor (MQM). The approach taken in this analysis is to model reference antenna motion as a source of additional wide-band and colored noise (i.e., correlated) that corrupts the fundamental GPS observables. Analytical expressions relating the effect of reference antenna motion to the JSIM protection limits are developed. These expressions are used to generate a set of design curves relating carrier-phase noise due to uncompensated antenna motion to the limits of the MQM.
Published in:	Proceedings of the 2002 National Technical Meeting of The Institute of Navigation January 28 - 30, 2002 The Catamaran Resort Hotel San Diego, CA
Pages:	382 - 389
Cite this article:	Koenig, Michael, Gebre-Egziabher, Demoz, Pullen, Sam, Kim, Ung-Souk, Enge, Per, Pervan, Boris S., Chan, Fang Cheng, Colby, Glenn, "Analysis of Reference Antenna Motion on the JPALS Shipboard Integrity Monitor," Proceedings of the 2002 National Technical Meeting of The Institute of Navigation, San Diego, CA, January 2002, pp. 382-389.
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