A computationally efficient 'doubly-steered' approximation to the Frost beamformer for use with short observation times

It is demonstrated that it is possible to approach the performance of a Frost (1972) beamformer but with significantly less computational effort by pre-steering in only few primary directions equi-spaced in sin( theta ) terms, and using linear constraints to perform secondary steering about the primary directions. Various issues concerning the number of taps, the dimension of the constraint space statistical stability and time-bandwidth product are discussed. Results are shown using both simulated and real towed array data.<
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