Narrowband source localisation in the deep ocean using a near-surface array

A narrowband source at moderate range can be localised in a deep ocean using a near-surface vertical linear array without knowing the bottom properties. By casting the localisation as separate estimations of the source range and source depth, the performance is much better than that of the matched-field-processing (MFP) technique with the Bartlett processor. Source range estimation is based on the weighted subspace fitting technique with modification to consider the array tilt. Source depth estimation is based on the time delay of multipath arrivals. Experimental results using explosive sources are shown. The presented method shows a significant improvement in performance.