Effect of GPS III weighted voting on P(Y) receiver processing performance

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, producing a constantenvelope real-valued combination of the three biphase inputs with different useful received powers. Weighted voting introduces jitter into receivers' correlation functions, adding to jitter from noise and interference. This paper quantifies the effect of weighted voting on receiver input signal-to-noise ratio (SNR), then predicts the effect of weighted voting on carrier tracking by conventional, codeless, and semicodeless P(Y) receivers. Analysis and computer simulation results are supplemented by receiver measurements, providing conclusive evidence that degradation by weighted voting is evident only at high SNR, having an insignificant effect on receiver performance.

Blind Estimation of GPS M-Code Signals under Noncooperative Conditions

“…To establish effective warfare navigation capabilities while further improving system performance for both authorized and unauthorized users, the GPS modernization program has been implemented. The first phase of the GPS modernization program was the launch of the Block IIR-M satellites, which added a civilian L2C signal in the L2 band and broadcast a new military M-code signal in both the L1 and L2 bands [2]. The first GPS IIR-M satellite was launched on September 2, 2005.…”

Analysis of GPS P(Y) signal power enhancement based on the observations with a semi-codeless receiver

“…Borio et al (2013) and Borio (2019) also developed the method of codeless processing of the BOC (Binary Offset Carrier) signal, and other researchers analysed the performance of most codeless and semi-codeless tracking algorithms (Bakholdin et al, 2020;. Besides, the voting modulation method used in GPS III satellites may influence the performance of codeless tracking method and was analysed in Allen et al (2020). Based on these analyses, most tracking stations nowadays adapt the z-track method for L1P(Y) and L2P(Y) signal tracking because of its better C/N 0 performance.…”