WLC26-6: C/No Estimation in a GPS Software Receiver in the Presence of RF Interference Mitigation via Null Steering for the Multipath Limiting Antenna

Estimation of the carrier-to-noise ratio C/N_o is an important aspect of the functionality of global positioning system (GPS) receivers. This estimate is used to weight the measurements obtained from each satellite in order to improve the accuracy of the position calculation. The multipath limiting antenna (MLA) has shown promising results in combating ground multipath errors. Radio frequency interference (RFI) is a major error source for GPS receivers. Such interference can be reduced by using null steering at the antenna side. In this work, we present a novel null steering approach for the MLA, and demonstrate its effect on the estimation of the C/N_o in a GPS software receiver. Two types of RFI sources are investigated; narrow band continuous wave (CW) and wide band pulsed wave (PPS). Performance of two C/N_o estimation algorithms is compared under different RFI and directions of arrivals.