Robust beamforming with array shape distortion dependent diagonal loading

A simple method to adaptively determine the diagonal loading factor for robust beamforming is proposed. The loading factor is acquired based on the information of the steering vector error caused by the array shape distortion, which can be extracted from the received data covariance matrix. Lagrange multiplier and root-finding method are used to optimize the diagonal loading factor. Accordingly, the proposed method is efficient in computation. Simulation and sonar experiment results showed the effectiveness of the proposed method.