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

Paul D. Groves

Peer Reviewed

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 was 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-wideband 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 on the order of 25s or more are used.
Published in:	NAVIGATION: Journal of the Institute of Navigation, Volume 52, Number 2
Pages:	83 - 94
Cite this article:	Groves, Paul D., "GPS Signal-to-Noise Measurement in Weak Signal and High-Interference Environments", NAVIGATION: Journal of The Institute of Navigation, Vol. 52, No. 2, Summer 2005, pp. 83-94.
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