Results 151 to 160 of about 3,240 (206)

Waveguide invariance for active sonar.

The Journal of the Acoustical Society of America, 2009
Active sonar signal processing in shallow water has proven to be a challenging problem due to the strong interaction of sound with the boundaries of the channel and the dependence on typically unknown environmental parameters. This has motivated research on properties of acoustic propagation that are not sensitive to those factors, such as the ...
Jorge E. Quijano, Lisa M. Zurk
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LPI waveforms for active sonar?

2004 IEEE Aerospace Conference Proceedings (IEEE Cat. No.04TH8720), 2004
The idea of a low probability of intercept (LPI) waveform is that its form is chaotic. It can of course be recalled by the transmitter (platform), and matched to what is received; but to the target it appears only as noise, and consequently the robust target receiver can only detect a rise in energy.
P. Willett, J. Reinert, R. Lynch
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Diversity in multistatic active sonar

Oceans '99. MTS/IEEE. Riding the Crest into the 21st Century. Conference and Exhibition. Conference Proceedings (IEEE Cat. No.99CH37008), 2003
A multistatic network of autonomous active transmitters and receivers, such as deployable underwater surveillance systems, often provides multiple contacts of the same target. The present paper examines the effects of receiver diversity ("spatial diversity") on a multistatic system, where three independent, spatially separated sonar receivers detect ...
L. Mozzone, S. Bongi, F. Filocca
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DORT applied to active sonar

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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Active sonar ABF application issues

Conference Record of The Twenty-Ninth Asilomar Conference on Signals, Systems and Computers, 2002
This 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, 2004
In 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, 2019
Recent 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, Gaetano Canepa, Kevin D. LePage   +2 more
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Active sonar clutter and auralization

The Journal of the Acoustical Society of America, 2008
Target-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, 2002
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 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
openaire   +1 more source

Matched-field depth estimation for active sonar

The Journal of the Acoustical Society of America, 2004
This 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
openaire   +2 more sources