Theoretical Bounds and Reliable C/N0 Estimation for Modernized GPS Signals

K. Muthuraman

Abstract:	With the increasing interest in weak signal tracking and GNSS modernization efforts for improving receiver sensitivity, it is important to have a reliable technique for estimating the Carrier-to-Noise density ratio (C/N0). The paper aims at providing a comprehensive theoretical analysis of the C/N0 estimation process with emphasis on the use of both data and pilot channels as input. A theoretical bound on the gain achievable by using both the data and pilot channel is derived. The derivation and the use of this bound for the analysis of C/N0 estimators are considered one of novel contributions of this work. The effect of coherent integration time on the C/N0 estimates is also considered and analyzed. Maximum Likelihood (ML) estimators that use either the data channel alone or both data and pilot channels are derived with a detailed analysis on the bias levels and noise variance under weak signal conditions. A novel iterative method for C/N0 estimation is proposed first for data channel only and then extended to use both channels. The proposed method which uses both channels is shown to be reliable down to 17 ????????-???????? when applied to the GPS L2C signals. Further, the algorithm provides gain in noise variance
Published in:	Proceedings of the 22nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2009) September 22 - 25, 2009 Savannah International Convention Center Savannah, GA
Pages:	3260 - 3270
Cite this article:	Updated citation: Published in NAVIGATION: Journal of the Institute of Navigation
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