A two-stage beamformer with enhanced resistance against larger pointing errors

In this paper, a theoretical analysis on the output signal-to-interference-plus-noise ratio (SINR) for the eigenspace beamformer is carried out to examine the performance degradation due to larger pointing errors. As a remedy, a robust two-stage scheme is proposed for adaptive beamformer. A time-efficient algorithm is first developed to adjust the direction-of-arrival (DOA) estimate of the desired source. By exploiting the refined DOA estimate, an eigenspace beamformer incorporating with the spatial derivative constraints (SDC) is then used to further mitigate desired signal cancellation. Analysis and numerical results demonstrate the robustness against pointing errors and superiority over conventional methods.