title: Passive localization of noise-producing targets using a compact volumetric array.
abstract: 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 volumetric 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 estimated reliably using straight ray paths, but longer ranges required accounting for ray refraction.
authors.affiliation: Northwest Electromagnetics and Acoustics Research Laboratory, Department of Electrical and Computer Engineering, Portland State University, 1900 SW 4th Avenue, Suite 160, Portland, Oregon 97201.
authors.forename: John
authors.initials: J
authors.lastname: Gebbie
authors.affiliation: Northwest Electromagnetics and Acoustics Research Laboratory, Department of Electrical and Computer Engineering, Portland State University, 1900 SW 4th Avenue, Suite 160, Portland, Oregon 97201.
authors.forename: Martin
authors.initials: M
authors.lastname: Siderius
authors.affiliation: Centre for Maritime Research and Experimentation, Viale S. Bartolomeo 400, La Spezia, Italy.
authors.forename: Peter L
authors.initials: PL
authors.lastname: Nielsen
authors.affiliation: Centre for Maritime Research and Experimentation, Viale S. Bartolomeo 400, La Spezia, Italy.
authors.forename: James
authors.initials: J
authors.lastname: Miller