An experimental evaluation of split-beam processing as a broadband bearing estimator for line array sonar systems

Abstract

This paper examines the potential improvements in bearing estimation performance of split-beam processing over full-aperture beamforming for broadband signals. It presents theoretical results in order to define the details of the signal flow in a split-beam processor, and it provides theoretical performance predictions by using Cramer–Rao lower bound (CRLB) analysis. The split-beam processing scheme was implemented in a real-time line array system. Good agreement between the theoretical performance predictions and the associated experimental broadband results were obtained. The experimental results indicate that the advantage of improved bearing estimation performance of the split-beamformer over the conventional full-aperture beamformer may be practically insignificant for passive line array applications because of the split-beamformer’s poor performance in detecting very weak broadband signals.