Airborne acoustic focusing system for land mine detection

Richard D. Rechtien; O. Robert Mitchell

doi:10.1117/12.357044

2 August 1999 Airborne acoustic focusing system for land mine detection

Richard D. Rechtien, O. Robert Mitchell

Proceedings Volume 3710, Detection and Remediation Technologies for Mines and Minelike Targets IV; (1999) https://doi.org/10.1117/12.357044
Event: AeroSense '99, 1999, Orlando, FL, United States

Abstract

A truncated ellipsoidal dish is used to translate a point source of acoustic energy, applied at the upper focal point, to a virtual source position at the lower focal pint, located within the truncated zone of the ellipsoid. The position of the lower focal point is, by definition, search depth. When this depth coincides with the depth of burial of a land mine, the height of the virtual source above the surface of the mine is, effectively, zero. Thus, questions relative to reflection efficiency that involve considerations of source wavelength and target size fall mute, since the Fresnel radius of the reflector essentially vanishes. Consequently, low frequencies can be used to detect small targets. Test results in sand, using plastic surrogate mines as targets, confirm realization of concept. The prototype enabled estimation of dish size and source characteristics required for a full-scale field system. The problem of anomalous nose associated with in-homogeneity of near-surface materials, undulations of the air-earth interface, and presence of surface objects was uncovered. 'False anomalies', as a result of these surface conditions, totally mask 'target anomalies'. For a field system to be viable, target discrimination, and/or noise suppression processing algorithms must be developed.

Citation Download Citation

Richard D. Rechtien and O. Robert Mitchell "Airborne acoustic focusing system for land mine detection", Proc. SPIE 3710, Detection and Remediation Technologies for Mines and Minelike Targets IV, (2 August 1999); https://doi.org/10.1117/12.357044

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