The authors would like to acknowledge support from the Centre for Maritime Research and Experimentation (CMRE), the Office of Naval Research (ONR), and Portland State University (PSU).
Journal of the Acoustical Society of America
Noise, Noise generators (Electronics), Sound, Oscillators -- Electric
A technique is presented for passively localizing multiple noise-producing targets by cross-correlating the elevation beams of a compact volumetric array on separate bearings. A target’s multipath structure inherently contains information about its range; however, unknown, random noise waveforms make time separation of individual arrivals difficult. Ocean ambient noise has previously been used to measure multipath delays to the seabed by cross-correlating the beams of a vertical line array [Siderius, Song, Gerstoft, Hodgkiss, Hursky, and Harrison, J. Acoust. Soc. Am. 127, 2193–2200 (2010)], but this methodology has not been applied to distant noise sources having non-vertical arrivals. The technique presented in this paper uses a compact volu-metric array mounted to an autonomous underwater vehicle to measure the three-dimensional directionality and time delays of multipath arrivals, while adaptively rejecting clutter and multi-target interference. This is validated with experimental results in a shallow ocean environment in which a small workboat maneuvered in the vicinity. Short ranges could be esti-mated reliably using straight ray paths, but longer ranges required accounting for ray refraction.
Gebbie, J., Siderius, M., Nielsen, P. L., & Miller, J. (2014). Passive localization of noise-producing targets using a compact volumetric array. Journal Of The Acoustical Society Of America, 136(1), 80-89. doi:10.1121/1.4881917