Spatial processing beyond adaptive beamforming

Underlying assumptions of classical directivity pattern application are identified. Adaptive beamforming principles are related to relaxation of these assumptions, and the limitations of adaptive beamformers are developed in terms of lack of a priori knowledge of source distribution and medium propagation parameters. Progress in spatial processing beyond current adaptive beamforming is discussed in terms of estimating jointly source distribution and medium properties using the outputs of an N‐element array of sensors.