Broadband Robust Adaptive Beamforming in the Presence of Correlated interferences and DOA uncertainties

A novel method of broadband robust adaptive beamforming is proposed in this paper to deal with the signal cancellation caused by correlated interferences and DOA uncertainties. To achieve this goal, the classic techniques of spectral averaging and diagonal loading are integrated into the beamforming, with the former aiming at decorrelation and the latter at robustness against DOA uncertainties. Moreover, the optimal loading is selected based on worst-case performance optimization and a simple closed-form solution to it is suggested after some approximations. Besides its simplicity and low computational cost, this analytical solution reveals how different factors affect the optimal loading. Compared with many relevant methods, the proposed one achieves better robustness against DOA uncertainties, while suppressing both correlated and uncorrelated interferences effectively. Its excellent performance is confirmed via a number of numerical examples.