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dc.contributor.advisorLarraza, Andres|Mitchell N. Shipley
dc.contributor.authorStokely, John P.
dc.dateJune 2001
dc.date.accessioned2012-08-22T15:34:12Z
dc.date.available2012-08-22T15:34:12Z
dc.date.issued2001-06
dc.identifier.urihttp://hdl.handle.net/10945/10903
dc.description.abstractAs the United States Navy considers operation closer to shore, it must account for the impact of shallow water ocean environments on the performance of active sonar. Multi-path propagation and high ambient noise in these areas pose a unique detection challenge for current sonar systems. A possible solution for this problem involves the use of processing that is actually enhanced by multi-path propagation, and can perform in the presence of in-band noise. Time-Reverse Acoustics (TRA) has been used with many transducer elements to focus acoustic energy in a very small region. Used as a single element active sonar, it can focus the return of an active pulse at the receiver location. To test the performance of a TRA-based sonar in the presence of noise, ultrasonic signals were used in a laboratory waveguide, so that the scale of wavelength to water depth approximates a shallow channel with a flat, lossy bottom. Several sequences of a traditional sinusoidal pulse and the time- reversed reception were performed with varying noise levels. The gain in detection signal-to-noise ratio (SNR) was on average +7.3+0.8dB using TRA. Further, the TRA processing provided a noticeable detection when noise had completely obscured the reception of the initial pulse.en_US
dc.format.extentxii, 43 p. ; 28 cm.en_US
dc.rightsThis publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. As such, it is in the public domain, and under the provisions of Title 17, United States Code, Section 105, may not be copyrighted.en_US
dc.titleExperimental studies of two-way single element time reversal in a noisy waveguideen_US
dc.typeThesisen_US
dc.contributor.departmentApplied Physics
etd.thesisdegree.nameM.S. in Applied Physicsen_US
etd.thesisdegree.levelMastersen_US
etd.thesisdegree.disciplineApplied Physicsen_US
etd.thesisdegree.grantorNaval Postgraduate School (U.S.)en_US


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