Effect of Narrowband Interference on GPS Code Tracking Accuracy

John W. Betz

Abstract:	The effect of narrowband interference on GPS code tracking accuracy is important, but has not been thoroughly evaluated. Theory shows that the effect of interference depends on details of receiver design, specially front-end bandwidth and early-late spacing in the discriminator, and that it has a different effect on code tracking accuracy than it does on some other aspects of GPS receiver performance. This paper compares theoretical predictions with experimental results to examine the effect of Gaussian interference on code tracking accuracy. Experimental results are obtained using MITRE’s real-time hardware testbed, measuring the effect of different interference frequencies on code tracking accuracy. Additional experimental results, obtained using a Novatel 3951-R 12 channel L1 C/A code receiver, are provided. The close correspondence between experimental results and theoretical predictions validates the theory, leading to better understanding of this important phenomenon. The results show that, for C/A code receivers, narrowband interference at frequencies away from band center can degrade code tracking accuracy more than interference having the same power at band center, even though the receiver’s measured signal-to-noise ratio degrades more when narrowband interference frequency is located at band center.
Published in:	Proceedings of the 2000 National Technical Meeting of The Institute of Navigation January 26 - 28, 2000 Pacific Hotel Disneyland Anaheim, CA
Pages:	16 - 27
Cite this article:	Betz, John W., "Effect of Narrowband Interference on GPS Code Tracking Accuracy," Proceedings of the 2000 National Technical Meeting of The Institute of Navigation, Anaheim, CA, January 2000, pp. 16-27.
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