Non-Plane-Wave noise source localization for horizontal arrays at low frequency in very shallow water (VSW)

Localizing low frequency noise sources in shallow water using a horizontal array is complicated by waveguide dispersion and maneuverability constraints. If the dispersive properties of the sound propagation channel are well known, waveguide effects can be used advantageously for the purpose of localizing sources without requiring a relative change in bearing to the target. Here we propose to investigate the feasibility of using optimal waveguide source localization (OWSL). In this approach, the approximate bearing of a source is first obtained using plane-wave beamforming. Sophisticated processing techniques exploiting broadband waveguide physics and waveguide invariant theory are then used to efficiently refine the bearing estimate and simultaneously estimate the range of the source. Our Phase I effort will include development of a high fidelity system simulation to determine the expected performance of OWSL for representative scenarios assuming expected uncertainties in both the important environmental (e.g., sound speed) and system (e.g., noise levels and sensor locations) parameters. Utilizing a new statistical methodology, we will determine measurement system requirements, such as synthetic array aperture length and measurement sample size, necessary to attain desired design accuracy. A detailed evaluation and demonstration process required for Fleet implementation will also be developed.