A robust adaptive Capon beamforming

Adaptive beamforming suffers from performance degradation in the presence of mismatch between the actual and presumed array steering vector of the desired signal. We propose a novel approach to adaptive beamforming that is robust to array errors. The proposed method involves two steps: the first step is to estimate the actual steering vector of the desired signal, and the second is to obtain optimal weight by utilizing the estimated steering vector. Our method belongs to the class of diagonal loading, but the optimal amount of diagonal loading level can be precisely calculated based on the uncertainty set of the steering vector. Moreover, the proposed robust Capon beamforming has an explicit closed-form solution. Computer simulation results demonstrate its excellent performance.