Broadband Source Imaging in a Shallow Water Wedge by an Array of Receivers
Abstract
The combination of time domain source imaging techniques and arrays to consider the localization of an impulsive source in a wedge waveguide, with a free surface and rigid bottom, is investigated. An impulsive signal is transmitted from an unknown location, received by an array of hydrophones, and stored. The signals are time reversed and transmitted into the model wedge by a transducer at each receiver location. Model transmission functions are used to compute the pressures at a set of locations. The field calculations use an image construction from D. Chu's exact solution for a density contrast wedge (J. Acoust. Soc. Am. 86,1883-1896(1989)). A map of the peak pressures gives an image of the source location. Particular attention is given to the peak amplitudes, sidelobe amplitudes, and spatial resolution as a function of the number and placement of receivers. Source localization is enhanced by the range dependency of the environment, which eliminates 'range' sidelobes, even for a single hydrophone. Adding receivers along an arc eliminates 'angle' sidelobes; but adding receivers along an arc or radial gives little reduction in overall background level. Adding receivers parallel to the wedge axis gives sharp, unambiguous azimuthal Shallow-water, Algorithms, Hydrophone arrays, Source imaging techniques.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1994
- Accession Number
- ADA284227
Entities
People
- Christopher Feuillade
- Clarence S. Clay
Organizations
- United States Naval Research Laboratory