Examination of time-reversal acoustic application to shallow water active sonar systems
Winter, Thomas A.
Smith, Kevin B.
MetadataShow full item record
The ability to employ effectively an active sonar system in the littoral regions is of great interest to the United States Navy. Time-varying multipath propagation introduces significant problems that must be overcome in the employment of shallow water active sonar. The phenomenon of time-reversal acoustics (TRA) has provided hope for a solution to this problem by undoing much of the multipath spreading without the need to have knowledge of the environment in these littoral regions. When an active sonar return is time-reversed (phase- conjugated in the frequency domain) and retransmitted, this second signal focuses in time and space back at the original source location. This thesis investigates the phenomenon of TRA as it applies to an idealized shallow water environment. Numerical modeling was performed for a variety of source and target apertures and ranges. Results demonstrate a significant enhancement in received active sonar signal strength due to the TRA acoustic field focusing effect. Furthermore, the signal strength enhancement remains significant even when the source to target range changes between active sonar transmissions. The results presented in this thesis demonstrate that the use of TRA may provide substantial signal to noise ratio improvements over current active sonar systems. Further modeling and real world experiments could ultimate lead to the development of a practical active TRA sonar system
Showing items related by title, author, creator and subject.
Therrien, Charles; Oppenheim, Alan V.; Baggeroer, Arthur B.; Chandrakasan, Anantha P.; Wornell, Gregory W.; Aliberti, Giovanni; Gold, Bernard; Isabelle, Steven H.; Kschischang, Frank; Nawab, Hamid S.; Preisig, James C.; Weinstein, Ehud; Amirtharajah, Rajeevan; Barron, Richard J.; Beheshti, Soosan; Chan, Albert; Chen, Brian; Draper, Stark; Hadjicostis, Christoforos N.; Laneman, Nicholas J.; Lee, Li; Lopez, Michael J.; Ooi, James M.; Papadopoulos, Haralabos C.; Secor, Matthew J.; Seefeldt, Alan J.; Verbout, Shawn M.; Wage, Kathleen E.; Wang, Alex Che-Wei; Said, Maya R.; Chupp, Darla J.; Zaganjori, Janice M.; Eggen, Trym H.; Ludwig, Jeffrey T.; Sestok, Charles K.; Torres, Wade P. (Monterey, California. Naval Postgraduate School, 1997);The field of digital signal processing grew out of the flexibility afforded by the use of digital computers in implementing signal processing algorithms and systems. It has since broadened into the use of a variety of ...
Blau, Joseph A.; Johnson, Bonnie W.; Cohn, Keith; Green, John (Monterey, California: Naval Postgraduate SchoolMonterey, California. Naval Postgraduate School, 2019-12); NPS-19-N003-ADirected Energy Weapons (DEW) will proliferate and become a threat exploited by adversaries due to high potential mission success and low cost compared to traditional weapons. Counter DEW (CDEW) methods and capabilities ...
The Shelf-edge frontal structure in the central East China Sea and its impact on low-frequency acoustic propagation Ramp, Steven R.; Chiu, Ching-Sang; Bahr, Frederick L.; Qi, Yiquan; Dahl, Peter H.; Miller, James H.; Lynch, James F.; Zhang, Renhe; Zhou, Ji-Xun (IEEE, 2004-10);Two field programs, both parts of the Asian Seas International Acoustics Experiment (ASIAEX), were carried out in the central East China Sea (28 to 30 N, 126 30 to 128 E) during April 2000 and June 2001. The goal of these ...