GPS Anomalous Event Monitor (GAEM)

Christopher A. Snyder, Gang Feng, and Frank van Graas

Abstract:	When a GPS receiver reports a bad measurement, it is often difficult to analyze the anomaly due to a lack of detailed data surrounding the event. A system that samples the GPS radio frequency signal at a rate that preserves all the pertinent signal information allows for off-line processing to determine the cause of the anomaly. The GPS Anomalous Event Monitor (GAEM) is designed to capture GPS data at a rate of 5 mega samples per second for several seconds surrounding the event. New block processing techniques are used on the 12-bit samples to assess the quality of the received GPS signal in terms of signal power, code-carrier divergence, correlation function shape, step errors, and interference. The method for capturing the data, validation of this process, and a description of the implemented system will be discussed. An example configuration is presented where the GAEM is interfaced with a prototype Local Area Augmentation System (LAAS), which provides real-time alerts that trigger the GAEM.
Published in:	Proceedings of the 55th Annual Meeting of The Institute of Navigation (1999) June 27 - 30, 1999 Royal Sonesta Hotel Cambridge, MA
Pages:	185 - 189
Cite this article:	Snyder, Christopher A., Feng, Gang, van Graas, Frank, "GPS Anomalous Event Monitor (GAEM)," Proceedings of the 55th Annual Meeting of The Institute of Navigation (1999), Cambridge, MA, June 1999, pp. 185-189.
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