Robust response control for adaptive beamformers against arbitrary array imperfections

The recently proposed robust adaptive beamformers, which utilize the autocorrelation sequence of array weight, were formulated as linear optimization problems. With the constraints on magnitude response (CMRs), we are able to control the robust response region of these adaptive beamformers with specified beamwidth and response ripple. Hence, they are robust against large steering direction errors. In practice, many array imperfections may cause the violation of the CMRs, which results in target signal cancellation. In this paper, a novel adaptive beamformer is proposed with new robust CMRs that are derived based on the worst-case optimization. With the robust CMRs, the proposed beamformer is formulated as a linear programming problem with linear and second-order conic constraints. It possesses superior robustness against arbitrary array imperfections and high performance on signal-to-interference-plus-noise ratio (SINR) enhancement. Simple implementation, flexible performance control as well as high SINR enhancement support the practicability of the proposed method. (c) 2008 Elsevier B.V. All rights reserved.