J Acoust Soc Am. 2007 Nov;122(5):2706-14. doi: 10.1121/1.2783127.

Comparison of a subrank to a full-rank time-reversal operator in a dynamic ocean.

The Journal of the Acoustical Society of America

Geoffrey F Edelmann, Joseph F Lingevitch, Charles F Gaumond, David M Fromm, David C Calvo

PMID: 18189563 DOI: 10.1121/1.2783127

Abstract

This paper investigates the application of time-reversal techniques to the detection and ensonification of a target of interest. The focusing method is based on a generalization of time-reversal operator techniques. A subrank time-reversal operator is derived and implemented using a discrete set of transmission beams to ensonify a region of interest. In a dynamic ocean simulation, target focusing using a subrank matrix is shown to be superior to using a full-rank matrix, specifically when the subrank matrix is captured in a period shorter than the coherence time of the modeled environment. Backscatter from the point target was propagated to a vertical 64-element source-receiver array and processed to form the sub-rank time-reversal operator matrix. The eigenvector corresponding to the strongest eigenvalue of the time-reversal operator was shown to focus energy on the target in simulation. Modeled results will be augmented by a limited at-sea experiment conducted on the New Jersey shelf in April-May 2004 measured low-frequency backscattered signal from an artificial target (echo repeater).

Publication Types

• Journal Article
• Research Support, U.S. Gov't, Non-P.H.S.