Results 181 to 190 of about 48,682 (230)
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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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Active sonar ABF application issues
Conference Record of The Twenty-Ninth Asilomar Conference on Signals, Systems and Computers, 2002This paper discusses several issues which arise when designing algorithms for adaptive beamforming (ABF) as applied to active sonar. Adaptation on match-filtered data and the necessity for pre-steering are clarified. The validity of narrowband beamforming and the use of short data blocks are considered.
J.M. Alsup, X. Zabal
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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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Matched-field depth estimation for active sonar
The Journal of the Acoustical Society of America, 2004This work concerns the problem of estimating the depth of a submerged scatterer in a shallow-water ocean by using an active sonar and a horizontal receiver array. As in passive matched-field processing (MFP) techniques, numerical modeling of multipath propagation is used to facilitate localization.
Granger, Hickman, Jeffrey L, Krolik
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Non-recurrent wideband continuous active sonar
2012 Oceans, 2012This paper presents a continuous active sonar (CAS) waveform which enables high revisit rates and wideband processing gains to be achieved with suppression of range-ambiguous returns. Non-recurrent wideband linear FM signals with circular Costas frequency-staggering across chirp repetition intervals is shown to provide ambiguity functions with good ...
G. Hickman, J. L. Krolik
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Antisubmarine Warfare: Passive vs. Active Sonar
The Two-Year College Mathematics Journal, 1983(1983). Antisubmarine Warfare: Passive vs. Active Sonar. The Two-Year College Mathematics Journal: Vol. 14, No. 5, pp. 434-435.
L. Whitt, K. Wilk
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A Theory of Active Sonar Detection
Proceedings of the IRE, 1959The results of a theory of echo detection developed for radar are extended to sonar for the case of narrow-banid transmitted signals. The exposition specifically omits discussion of the decision problem and the statistical nature of the whole process of detection.
J. Stewart, E. Westerfield
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