The content of this thesis comprises original research work on the investigations of new structures and algorithms to enhance robustness of array signal processing. To suppress the high sidelobe level of the Minimum Variance and Distortionless Response (MVDR) beamformer, two beamformers imposed with sparse constraint on the beampattern are proposed. In the first algorithm, the sparse constraint is imposed on the beampatterns of the beamformer with respect to interference directions, which results in a beamforming algorithm with lower sidelobe level and better robustness against look direction mismatch. When array imperfection is taken into account, a modified algorithm is proposed in order to improve the performance of the beamformer when the interference signals are not located perfectly at the presumed directions. The modified algorithm maintains distortionless response in a wide angular range. It has been demonstrated by computer simulations that the proposed algorithms are valid for sidelobe suppression. Their robustness against steering vector error is also verified.

223 p.