Fault Detection Methods And Testing For Marine GPS Receivers

G. MacGougan and J. Liu

Abstract:	A system fault is an undetected error in that system. In GNSS terms, reliability methods detect faults and measure the impact of undetected faults in a navigation system. Fault detection methods and testing provide necessary assessment of GNSS receiver performance in terms of reliability. The impact of an observation or design fault can be detrimental to dependable receiver function. As there are many classifications of GPS receivers, each with different performance characteristics and accuracy requirements, testing must focus on the weakest links in the navigation process for each receiver’s niche. This research focuses on the marine-grade GPS receiver. The focal point of receiver performance is most often judged in terms of precision requirements. The issue of reliability is often ignored as a receiver performance measure. Reliable navigation also depends upon proper navigation filter design. This paper not only demonstrates the need for fault detection but also exemplifies the need for proper design of a receiver’s navigation filter. As insufficient information is often provided concerning a receiver’s internal fault detection algorithms, a GPS hardware-in-the-loop simulator was used to construct fault detection scenarios. Investigative testing involved a selection of typical marine-grade GPS receivers. The receivers’ susceptibility to multipath or other fault inducing interference is revealed as only one of the receivers tested employed a fault detection algorithm. In addition, the receiver performance under high dynamics was determined. Using post-processed methods, the impact of an improper system model in a Kalman filter is reproduced and it is shown that a simple reliability algorithm greatly improves receiver reliability.
Published in:	Proceedings of the 15th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2002) September 24 - 27, 2002 Oregon Convention Center Portland, OR
Pages:	2668 - 2678
Cite this article:	MacGougan, G., Liu, J., "Fault Detection Methods And Testing For Marine GPS Receivers," Proceedings of the 15th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2002), Portland, OR, September 2002, pp. 2668-2678.
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