GPS Signal to Noise Measurement in Weak Signal and High Interference Environments

Paul D. Groves

Abstract:	In GPS receivers, measurement of the carrier power to noise density, C/N0, is important for determining whether the code and carrier tracking loops are in lock, controlling the response of the receiver to low signal to noise environments and determining the signal to noise environment in order to assess or predict receiver performance. However, in a weak signal or high interference environment, the C/N0 measurements can be very noisy. To mitigate this problem, an investigation has been conducted into methods of signal to noise measurement. Three C/N0 measurement techniques were investigated by theoretical analysis and simulation study and performance was compared with a range of different smoothing times. These were the established narrow to wide band power ratio method, a correlator comparison method and a discriminator output statistics method. All were found to be suitable in low signal to noise environments provided long averaging times of order 25 s or more are used
Published in:	Proceedings of the 18th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2005) September 13 - 16, 2005 Long Beach Convention Center Long Beach, CA
Pages:	643 - 658
Cite this article:	Groves, Paul D., "GPS Signal to Noise Measurement in Weak Signal and High Interference Environments," Proceedings of the 18th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2005), Long Beach, CA, September 2005, pp. 643-658.
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