An advanced SSBL‐acoustic reference system using a planar hydrophone array

Abstract

AbstractSSBL (super‐short‐base‐line) is an acoustic reference system in which the angle of incidence (direction cosine) and the slant range of the acoustic wave are estimated to locate the source position. A new SSBL acoustic reference system differing from conventional systems is proposed. The new system uses a planar hydrophone array consisting of many hydrophone elements. When a maximum likelihood estimate is implemented for the direction cosine and slant range measured by a planar hydrophone array, the estimate is given so that the envelope of the spatial‐temporal correlation between the array output and the reference signals is maximized. When the short array condition is satisfied for a planar hydrophone array, this spatial‐temporal correlation is given by the temporal correlation, phase compensation and addition. We obtained the lower bound of the mean‐square error of estimates of the direction cosine and slant range and compared the performance of the system with that of conventional systems. For example, when a square planar array of 4 × 4 = 16 elements is used, system gains of about 16 dB for the direction cosine and 12 dB for the slant range are attainable.