Location of GPS Interferers

John E. Wohlfiel, Bereket Tanju

Abstract:	Growing GPS use, particularly for safety-of-life applications (i.e. flight in controlled airspace, harbor navigation etc), has placed considerable attention on the risks associated with using a low-signal power radio navigation system. Safety-of-life applications require a high degree of accuracy, availability, continuity, and integrity service, and in the case of GPS, radio frequency (RF) interference can potentially degrade and/or disrupt one or more of these critical parameters causing an unwanted and potentially hazardous situation. Detecting GPS interference and an ability to locate interference source(s) can be a powerful way of dealing with the interference risks associated with GPS. In this paper, we describe a project that was directed by congress starting in 1997 to detect and locate sources of collateral interference and intentional jamming, and to assess the technical feasibility and utility of this concept on an airborne platform. Under this demonstration project titled LOCO GPSI (Location of GPS Interferers), SPAWAR and FALON Incorporated began working towards a high sensitivity, rapid scanning receiver employing short baseline interferometry for precision direction finding (DF). LOCO GPSI system hardware and software which consists of a state-of-the-art signal processor, DF processors, a three channel DF receiver, and multiple antennas have been prototyped and packaged in a flight qualified pod. Initial anechoic chamber tests have shown good promise towards achieving project goals. Further anechoic chamber tests, pedestal tests of a full-scale aircraft, and flight tests are planned for the near future. The technology used in this project is seen to have a great dual-use potential for satisfying the GPS situational awareness/interference monitoring desires of the civil and military communities. This concept can be used for surveying the RF environment around airfields and ports prior to commencing GPS based operations. The airborne concept can also be adapted to a static implementation around airfields and ports for a continuous monitoring/surveillance capability.
Published in:	Proceedings of the 12th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1999) September 14 - 17, 1999 Nashville, TN
Pages:	143 - 148
Cite this article:	Wohlfiel, John E., Tanju, Bereket, "Location of GPS Interferers," Proceedings of the 12th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1999), Nashville, TN, September 1999, pp. 143-148.
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