ASA 130th Meeting - St. Louis, MO - 1995 Nov 27 .. Dec 01

3aSA1. Benchmarking the Kirchhoff approximation for specular scatter from a finite length cylindrical scatterer.

Kevin D. LePage

Bolt Beranek and Newman Inc., 70 Fawcett St., Cambridge, MA 02138

Recent work at BBN has been directed toward understanding and parametrizing the low- to mid-frequency, broadband scattered signature of submarines in terms of a small set of physical mechanisms. These mechanisms include parametrized dispersion curves, end-cap reflection coefficients, and end-cap radiation and excitation coefficients. Here, the Kirchhoff approximation is applied to model the early time portion of the backscattered signal. Two issues present themselves with this approach: (1) What is the correct frequency-dependent background impedance of the hull; and (2) for what frequencies and range of bistatic angles does the Kirchhoff approximation provide adequate performance. Here, the later issue is addressed by benchmarking the approximate results against consistent SARA calculations for a locally reacting finite length body of revolution. [Work supported by ONR.]