Measurement of Backscattered GPS Signals

Tore Lindgren, Eric Vinande, Dennis Akos, Dallas Masters and Penina Axelrad

Abstract:	States Department of Commerce’s National Geodetic Survey (NGS) has developed a nationwide network of continuously operating reference stations (CORS) designed to support the broad spectrum of post-processed, relative Global Positioning System (GPS) techniques and applications. This network now comprises more than 900 permanent, geodetic-quality GPS receivers, in various installation configurations. The network was established through an exemplary cooperative effort, involving nearly 200 organizations from various government levels, academia, and the private sector. CORS GPS observational data are freely provided to the user community via the Internet and are capable of supporting high-accuracy positioning requirements. In addition to enhancing geospatial positioning, applications of CORS data include the following: a critical role in defining the nation’s geodetic reference system; the ability to characterize the free electron content of the ionosphere; and an important source of precipitable water vapor input to meteorological forecasts. Associated with the CORS network, the Online Positioning User Service (OPUS) is a free, automated Web-based utility that processes submitted GPS observation data with respect to the CORS network, providing corresponding positional coordinates, via email, usually in minutes. This powerful tool has proven to be very popular with the geospatial community and is changing the way NGS is able to provide access to the National Spatial Reference System. Abstract—This paper describes a technique utilizing GPS ground reflections (GPS bistatic radar) to detect objects with a significant radar cross section located on the surface of the earth. GPS bistatic radar has been shown to be effective as a radar altimeter and for characterization of the reflection surface but has thus far not been shown to be effective for object detection. The technique uses ground reflections with longer path delay than the shortest path specular reflection. Data was collected using a COTS software receiver and post-processed using an in-house tool. Regions with ground reflections were overlayed on aerial imagery to identify possible sources.
Published in:	Proceedings of IEEE/ION PLANS 2006 April 25 - 27, 2006 Loews Coronado Resort Hotel San Diego, CA
Pages:	664 - 669
Cite this article:	Lindgren, Tore, Vinande, Eric, Akos, Dennis, Masters, Dallas, Axelrad, Penina, "Measurement of Backscattered GPS Signals," Proceedings of IEEE/ION PLANS 2006, San Diego, CA, April 2006, pp. 664-669. https://doi.org/10.1109/PLANS.2006.1650659
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