Title: An Analysis of Near-band Harmful Interference on Civilian GPS Receivers
Author(s): Connor L. Brashar
Published in: Proceedings of the 29th International Technical Meeting of The Satellite Division of the Institute of Navigation (ION GNSS+ 2016)
September 12 - 16, 2016
Oregon Convention Center
Portland, Oregon
Pages: 3123 - 3132
Cite this article: Brashar, Connor L., "An Analysis of Near-band Harmful Interference on Civilian GPS Receivers," Proceedings of the 29th International Technical Meeting of The Satellite Division of the Institute of Navigation (ION GNSS+ 2016), Portland, Oregon, September 2016, pp. 3123-3132.
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Abstract: Due to the demand for available radio frequency space, the GPS L1 near-band region has become increasingly noisy. With the importance of continued GPS operation and the lack of information regarding near-band signal effects, an investigation of harmful interference on a variety of receivers can provide valuable information on the impacts on GPS activity. In an analysis of near-band interference of four types (constant waveform (CW), 1.1MHz swept CW, 2MHz swept CW, and 1.1MHz broadband) on four civilian GPS receivers, interference response characteristics were evaluated to within 2dB for a minimum 40MHz bandwidth centered at the L1 frequency. The study revealed that all receivers had a lower resistance to wider interference types than for narrow bandwidth signals such as CW, but more variable response to narrow interference. Individual receivers also experienced different regions of nonlinearity, providing variable and often beneficial resistance characteristics unique to a single receiver. By determining the characteristic curvature of each receiver within a 40MHz bandwidth, receiver response to interference in ranges beyond the near-band tested could then be inferred. This was performed through the approximation of interference response across all receivers and signal types, in order to create a unified equation by which interference response of the average GPS receiver could be approximated. By using this equation for receiver response in all ranges around the L1 frequency, safe margins for the operational capacity of GPS receivers in an interference environment can be ensured, both in the near-band and beyond.