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Proceedings Paper

Near and far EMI field analyses in a conducting environment to enhance underwater UXO detection
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Paper Abstract

The underlying physics of low frequency EMI scattering phenomena in underwater environments from highly conducting and permeable metallic objects is analyzed using an approach that combines the method of auxiliary sources and a surface impedance boundary condition. The combined algorithm solves EMI boundary-value problems by representing the electromagnetic fields in each domain of the structure under investigation by a finite linear combination of analytical solutions of the relevant field equations, corresponding to elementary sources situated a small distance away from the boundaries of each domain. Numerical experiments are conducted for homogeneous and multilayer targets of canonical (spheroidal) shapes subject to frequency- or time-domain illumination, as well as for heterogeneous UXO like targets, to demonstrate: (a) how marine environments change EMI sensor performance and associated processing approaches for detecting highly conducting and permeable metallic objects underwater, and (b) what are the EMI sensors detectability limits. Near and far EMI field and induced eddy-current distributions are presented to help gain insight into underwater EMI scattering phenomena. Particularly, the results illustrate coupling effects between the object and its surrounding conductive medium, especially at high frequencies (early times for time-domain sensors). The results also suggest that this coupling depends on the object's material properties, the conductivity of the medium, and the distance between the sensor and the object's center.

Paper Details

Date Published: 5 May 2009
PDF: 11 pages
Proc. SPIE 7303, Detection and Sensing of Mines, Explosive Objects, and Obscured Targets XIV, 73030D (5 May 2009); doi: 10.1117/12.819059
Show Author Affiliations
Fridon Shubitidze, Dartmouth College (United States)
Sky Research, Inc. (United States)
Ben Barrowes, U.S. Army Engineer Research and Development Ctr. (United States)
Irma Shamatava, Dartmouth College (United States)
Sky Research, Inc. (United States)
Juan Pablo Fernández, Sky Research, Inc. (United States)
Kevin O'Neill, Sky Research, Inc. (United States)
U.S. Army Engineer Research and Development Ctr. (United States)


Published in SPIE Proceedings Vol. 7303:
Detection and Sensing of Mines, Explosive Objects, and Obscured Targets XIV
Russell S. Harmon; J. Thomas Broach; John H. Holloway, Editor(s)

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