Adaptive beamforming or matched field processing in media with uncertain propagation conditions

Abstract

Adaptive beamforming or matched field processing provides high resolution with sidelobe control if accurate replica fields can be generated. The generation of these replica fields is a formidable problem requiring knowledge of the complex ocean propagation environment. On the other hand, the detection problem in the ocean may not require high resolution, whereas sidelobe control is still an important issue. Relaxing resolution requirements suggest that a certain tolerance incorporating uncertainty of the propagation conditions is permissible, or even desirable, because of the difficulties both in specifying the medium exactly and in identifying global peaks. This possibility of lowering the requirements on our knowledge of the environment is investigated with two methods: (1) by constructing multiple beam (constraint) algorithms and (2) by considering stochastic blurring by the medium. These two approaches are applied to plane‐wave beamforming and matched field processing.