Optimal Robust Beamforming for Interference and Multipath Mitigation in GNSS Arrays

In this paper, we introduce an optimal robust beamformer for detecting a desired signal in presence of noise, strong interferers of unknown directions-of-arrival (DOA), and multipath. The proposed approach achieves the highest possible signal-to-interference plus noise ratio (SINR) by optimally estimating the interference DOA, followed by a triply constrained robust Capon beamformer. More specifically, we maximize the SINR subject to nulling strong interferers and offer robustness against multipath and steering vector uncertainty. Unlike existing techniques, we examine explicitly the use of robust beamforming for multipath mitigation to enhance acquisition and tracking performance of GPS receivers.