Line array performance when the signal coherence is spatially dependent

Abstract

The effects of a signal coherence which decreases exponentially with sensor separation are examined for a number of line array processors. For the conventional beamformer the limiting gain against uncorrelated noise as the array is made infinitely long is simply (1 + ρ)/(1 − ρ), where ρ is the signal coherence between adjacent sensors. The gain of the optimum processor is also presented. A simple suboptimum processor which incoherently combines the outputs of a number of subarrays is found to provide near optimum performance. The performance of the split-beam multiplicative processor is shown to degrade rapidly as signal coherence decreases.