Spatial post-filter for linear hydrophone arrays with applications to underwater source localisation

This letter presents a spatial post-filter that can be employed in linear hydrophone arrays, commonly found in sonar systems, for the task of improving the bearing estimation and noise suppression capabilities of traditional beamformers. The proposed filter is computed in the time-frequency domain as the normalised cross-spectral density between two beamformed signals, which are generated by applying conventional beamforming to two adjacent non-overlapping sub-arrays. The evaluation on both simulated and real-world data demonstrates promising performance compared to other popular post-filters in some cases, especially for targets near the end-fire direction and in the presence of uncorrelated interferers or diffuse noise.