Separability of Multipath Arrivals by Conventional Beamforming and Its Use for Source Localization

Source localization can be achieved by matching the arrival angles of the direct (D) path and surface-reflected (SR) path with a vertical line array (VLA) in deep water. This source localization method works at regions where multipath arrivals are resolved as separate, while it fails at regions where multipath arrivals are indistinguishable. The separability of multipath arrivals by conventional beamforming (CBF) and the applicable region of the source localization method under one experimental configuration with water depth equal to 1507 m and a VLA deployed at depth from 1335.5 m to 1448 m are analyzed, based on the approximate expression of the half-power (−3 dB) beamwidth of CBF. Experimental results of explosive sources with nominal depth of 200 m and 300 m are also presented.