Performance analysis of narrowband interference mitigation and near-far resistance scheme for GNSS receivers

This paper presents a method to mitigate the interferences against pseudolite-type and continuous-wave interferences in a global navigation satellite system (GNSS) environment. Ground-based pseudolites can transmit GPS-liked signals and augment GNSS constellations to enhance the accuracy, integrity, and availability. Unfortunately, a nearby pseudolite may induce a strong interference to GPS receivers. As a result, the receiver may fail to acquire and track signals from satellites. In order to account for such a problem, a mitigation scheme that combines the use of frequency domain excision method and direct reconstruction method is proposed to effectively nullify continuous-wave and pseudolite-type interferences, so that the GPS signals can still be tracked in the presence of strong interferences. Experiment results show that with the removal of interferences, the measured narrow-to-wide power ratio for all satellites can be enhanced. A sensitivity analysis is then conducted to assess the performance of the proposed algorithm in the presence of errors in the estimation of the signal power, Doppler frequency and code delay. Finally, the problem of combined interferences of pseudolites and continuous-wave sources is investigated both theoretically and experimentally. It is shown that the method is applicable to mitigate narrowband continuous-wave interferences and pseudolite-type interferences.