Effect of GPS III Weighted Voting on P(Y) Receiver Processing Performance

David William Allen, Alberto Arredondo, Daniel R. Barnes, John W. Betz, Alessandro P. Cerruti, Benjamin Davidson, Karl L. Kovach, Alexander Utter

Abstract:	Signal generation in the GPS III satellites employs weighted voting to combine the baseband P(Y) signal with both components of the baseband L1C signal on the in-phase part of the L1 carrier. Weighted voting employs majority voting with pseudorandom time multiplexing of pure signals to produce a constant envelope real-valued combination of the three biphase inputs with different useful received power levels. Both majority voting and pseudorandom insertion of pure signals introduce jitter into correlation functions computed by a receiver, in addition to the jitter caused by received noise and interference. This paper quantifies the effect of weighted voting on receiver input signal-to-noise ratio, and then uses results from a companion paper to predict the effect of weighted voting on the performance of carrier tracking in conventional, codeless, and semi-codeless P(Y) receivers. The results from analysis and computer simulations in both this paper and the companion paper are supplemented by laboratory measurements on actual receivers, providing conclusive evidence that degradation due to weighted voting is only evident at high signal-to-noise ratios, and has an insignificant effect on receiver performance.
Published in:	Proceedings of the 2019 International Technical Meeting of The Institute of Navigation January 28 - 31, 2019 Hyatt Regency Reston Reston, Virginia
Pages:	936 - 950
Cite this article:	Updated citation: Published in NAVIGATION: Journal of the Institute of Navigation
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