Robust Adaptive Beamforming Based on Generalized Sidelobe Cancellation

If the desired signal is present in training snapshots, conventional adaptive beamformer is quite sensitive even to slight mismatches between the presumed and actual signal steering vectors (spatial signatures). Such mismatches can occur as a result of environmental nonstationarities, look direction errors, imperfect array calibration, distorted antenna shape, as well as distortions caused by near-far mismatch, source spreading, and local scattering. It induces signal cancellation in the traditional adaptive beamforming and severely degrades the beamforming performance. In this paper, we develop a new approach to robust GSC (generalized sidelobe cancellation) - based adaptive beamforming in the presence of an arbitrary unknown signal steering vector mismatch. The proposed method involves two steps: the first step is to use a nulling broadened blocking matrix to exclude the desired signal component from the auxiliary channels, and the second step is to obtain optimal weight by sidelobe cancellation method. Finally, simulation results demonstrate that the proposed structure can considerably enhance the overall performance. It has greatly improved robustness as compared with existing adaptive beamforming algorithms, and enjoys simple implementation.