Projection-based tapering for conventional beamforming on nonlinear sonar arrays

We propose a projection-based tapering method for conventional beamforming on nonlinear sonar arrays. The method is shown to be robust to modelling errors, in contrast to previously proposed array interpolation methods. Simulations using the LASAR40 diver detection sonar as an example show that the sidelobe level is decreased compared to direct application of a standard tapering function to the array or part of it. In locations with considerable amount of reverberation, the decreased sidelobe level translates directly into increased detection range. The proposed method can be applied to any nonlinear array, e.g. circular array configurations.