SUMMARY

Locating and tracking sound sources underwater has utility in many fields whose interest lies in the ocean, particularly military defense and environmental research. A passive, mobile array of directional vector sensors is a promising platform suited for this task, provided the locations of the sensors can be accurately known, especially to reach the achievable array gain offered by coherent processing methods. However, a submerged sensor which must rely on dead-reckoning often lacks such positional accuracy. Coherent processing of the recorded ambient noise (including both diffuse background ambient noise and discrete sources of opportunity) between sensors could provide a means to localize an inaccurate array, ultimately improving the array’s tracking performance. To investigate this approach, the proposed research will focus on three aspects of the tracking problem: 1) the at-sea validation of a mobile volumetric vector sensor array platform, composed of drifting nodes, suitable for recordings of ambient noise, 2) the signal-processing methodology to perform self-element localization of this mobile volumetric array using ambient noise, and 3) the performance study of this array for source localization and tracking using coherent processing.