Pre-processing of GNSS Signals Subject to Interference

John Cooper and Peter Daly

Abstract:	Increasingly, interference effects on GNSS receivers are becoming important as more safety-critical appli-cations such as civil aviation are employing the sys-tem. The inherent interference rejection capability of the GNSS spread-spectrum modulating technique is now no longer considered adequate to remove the ef-fects of very strong jammers. These can be generated intentionally, as in jamming situations, or unintention-ally by systems such as mobile satcomms. Continuous satellite tracking through this interference is essential for high integrity applications. The paper presents a new hardware based GNSS inter-ference mitigation scheme which is particularly effec-tive against CW and pulsed CW interference. Interfer-ers with some degree of frequency or amplitude modulation can also be reduced. The core hardware can remove two CW interferers from anywhere within the GPS P code bandwidth or the GLONASS fre-quency spectrum and further interferers can be re-moved by cascading modules. Simulation and actual data is presented. Due to the wideband nature of the signal processing, the module introduces very little additional phase distortion and thus, group delay to the GLONASS band which has been shown to be advanta-geous to differential GLONASS processing.
Published in:	Proceedings of the 10th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1997) September 16 - 19, 1997 Kansas City, MO
Pages:	1437 - 1446
Cite this article:	Cooper, John, Daly, Peter, "Pre-processing of GNSS Signals Subject to Interference," Proceedings of the 10th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1997), Kansas City, MO, September 1997, pp. 1437-1446.
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