A new robust quadratic constraint beamforming against array steering vector errors

A new robust adaptive beamforming based on quadratic constraint is presented; it is a robust extension of Capon´s minimum variance distortionless response (MVDR) beamforming algorithm. The quadratic constraint is added to the weighted least squared error between the desired and the actual beam patterns over a small region near the array steering direction, which makes the array less sensitive to steering vector errors and nonstationary data snapshots. Thus, robustness is achieved. Furthermore, a computationally efficient data dependent approach based on eigenvalue decomposition is proposed to determine the robust control parameter in this algorithm properly; computer simulations and sonar experimental data indicate that this method is effective and applicable in practice.