Results 211 to 220 of about 5,633 (244)
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The Journal of the Acoustical Society of America, 1991
A channel adaptive active sonar is disclosed, wherein the sonar transmit waveform is adaptively selected in accordance with the measured sonar channel scattering function to reduce the response of the sonar to unwanted reverberation while preserving the response to signal returns.
P. L. Feintuch, F. A. Reed
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A channel adaptive active sonar is disclosed, wherein the sonar transmit waveform is adaptively selected in accordance with the measured sonar channel scattering function to reduce the response of the sonar to unwanted reverberation while preserving the response to signal returns.
P. L. Feintuch, F. A. Reed
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The Journal of the Acoustical Society of America, 2001
The decomposition of the time reversal operator (DORT) is a single frequency method of spatially isolating scatterers with a multiple-source/multiple-receiver system [C. Prada et al., J. Acoust. Soc. Am. 99, 2067–2076 (1996)]. The application of the DORT technique to a broadband sonar system is explained by showing its relationship to the sonar ...
David M. Fromm, Charles F. Gaumond
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The decomposition of the time reversal operator (DORT) is a single frequency method of spatially isolating scatterers with a multiple-source/multiple-receiver system [C. Prada et al., J. Acoust. Soc. Am. 99, 2067–2076 (1996)]. The application of the DORT technique to a broadband sonar system is explained by showing its relationship to the sonar ...
David M. Fromm, Charles F. Gaumond
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Survey of active sonar simulations
The Journal of the Acoustical Society of America, 2004In lieu of well-characterized measured data sets, time series simulations are often employed for testing active sonar systems. This paper reviews the simulation techniques and models that are being employed today and discusses some of the issues of fidelity that may arise with regard to range dependence, bistatic geometries, reverberation statistics ...
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Continuous Active Sonars for Littoral Undersea Surveillance
IEEE Journal of Oceanic Engineering, 2019Recent advances in transducer and computing technology have pushed the concept of continuous active sonar (CAS) or high duty cycle sonar as an area of interest for application to antisubmarine warfare. Unlike conventional pulsed active sonars, CAS processing aims at detecting echoes while transmitting with a nearly 100% duty cycle. This paper describes
Andrea Munafo +2 more
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Active sonar clutter and auralization
The Journal of the Acoustical Society of America, 2008Target-like false alarms generically termed clutter are the primary hindrance to active sonar in shallow water operational areas. Clutter can arise from a myriad of sources with geologic, biologic and anthropogenic origin. The clutter-source echoes are often determined by automatic signal processing to be target-like and therefore potentially of ...
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Broadband DORT applied to bistatic active sonar
The Journal of the Acoustical Society of America, 2002The decomposition of the time reversal operator (DORT) is a single frequency method of spatially isolating scatterers with a multiple-source/multiple-receiver system [C. Prada et al., J. Acoust. Soc. Am. 99, 2067–2076 (1996)]. The DORT technique applied to the active sonar problem has demonstrated the ability to isolate scatterers at various depths and
David M. Fromm, Charles F. Gaumond
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Characterization of active sonar targets
2018<p>The problem of characterization of active sonar target response has important applications in many fields, including the currently cost-prohibitive recovery of unexploded ordinance on the ocean floor. We present a method for recognizing these objects using a multidisciplinary approach that fuses machine learning, signal processing, and feature
Daniel Schupp-Omid +3 more
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Waveguide Invariant Reverberation Mitigation for Active Sonar
2007 IEEE International Conference on Acoustics, Speech and Signal Processing - ICASSP '07, 2007Reverberation often limits the performance of active sonar systems. A method of target detection and bottom-feature suppression has been developed exploiting waveguide-invariant phenomena and the frequency-selective fading properties of broadband reverberation in shallow water channels.
Ryan A. Goldhahn +2 more
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Fundamentals of Bistatic Active SONAR
1989The purpose of this paper is to provide an introduction to bistatic active sonar. We consider only the simplest case of a single source and a single spatially-separated receiver. The extension to multiple sources and receivers is straightforward and involves the same concepts and principles.
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Frequency hopping waveforms for continuous active sonar
2015 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), 2015Due to the relatively low speed of sound long range active sonar has a low update rate compared to radar systems. A possible solution to mitigate this problem is continuous active sonar. The source transmits sound continuously resulting in a continuous return echo. A problem is separating the transmission from the (weaker) returns from the target. This
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