Development and analysis of a two-stage beamformer for multiple correlatedinterferers using rectangular array

A two-stage two-dimensional (2-D) beamformer is proposed for signal enhance ment in an environment of multiple correlated interferers using a rectangul ar array. In the first stage, subarray beamformers are constructed which ex hibit reliable interference cancellation using difference preprocessed and spatially smoothed data. A secondary combining of all possible subarray bea mformers is then performed to fully exploit the array aperture. It is shown that, compared to the conventional one-stage optimum beamformer, the two-s tage beamformer performs equally well and requires a much lower complexity of implementation when a suitable subarray size is chosen. (C) 1999 Acousti cal Society of America. [S0001-4966(99)04701-3].