Results 131 to 140 of about 1,483 (184)

Passive sonar calibration spheres

The Journal of the Acoustical Society of America, 2001
The need for calibrated sonar targets is addressed with the development and testing of a set of thin-walled spheres filled with a high-density fluid. Using historical research information as a guide, a set of thin-walled metal spheres was developed and filled with a high-density fluid.
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Passive sonar processing using neural networks

[Proceedings] 1991 IEEE International Joint Conference on Neural Networks, 1991
The utilization of a two-stage neural network architecture for the detection of targets in a passive, listen-only sonar is discussed. The two-stage network consists of a first-stage Hopfield network to suppress noise, and a second stage using a bidirectional associative memory (BAM) to make the decision as to whether a target has been detected or not ...
P. Van-Houtte, K. Deegan, K. Khorasani
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Range-sensitive Bayesian passive sonar tracking

2010 13th International Conference on Information Fusion, 2010
Passive sonar arrays are commonly operated under a far-field assumption in which the only observable parameter regarding target location is the direction of arrival of the target's signal. Range can be observed, but only when a target is in the near-field region of the array.
B A Yocom, J M Aughenbaugh, B R La Cour
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Passive fiber optic sonar system

The Journal of the Acoustical Society of America, 1982
A fiber optic sonar system wherein first and second optical fibers are wound on a common mandrel and provided with a light energy beam. An acoustic signal differentially varies the index of refraction of the optical fibers to result in an interference pattern dependent upon the frequency of the received acoustic signal or signals.
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Handbook of sonar transducer passive materials

The Journal of the Acoustical Society of America, 1981
Some aspects of the engineering applications of elastomeric materials in sonar transducers are discussed. A sonar materials handbook being published as NRL Memorandum Report 4311 is also briefly reviewed.
R. N. Capps, F. J. Weber
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Psychoacoustics and Passive Sonar Detection

1974
Abstract : A review is made of the statistical theory of signal detection, followed by application of signal detection theory to psychoacoustics. The differences between relatively simple laboratory tests and the complex problems of passive sonar operating in the real world are explored.
C. B. Leslie, J. M. Stallard
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Passive Sonar Signal Processing

1981
An overview of applied research in passive sonar signal processing estimation techniques for naval systems is presented. The naval problem that motivates this work is the source state estimation problem. A discussion of this problem in terms of estimating the position of a moving acoustic source is presented.
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Optimum Design of Broadband Passive Sonar

IEEE Journal of Oceanic Engineering, 2016
In this paper, a new design principle is proposed for the frontend-hardware (FEHW) chain of broadband passive sonars. This principle embraces the ultimate purpose of broadband passive sonars, which is to maximize the detection of passive targets. FEHW chains were conventionally designed as noise whiteners to guarantee the data bit dynamic range in ...
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Site-specific passive sonar performance prediction

Conference Record of the Thirty-Sixth Asilomar Conference on Signals, Systems and Computers, 2002., 2003
A measurement-based plan and methodology are discussed for predicting a passive sonar performance dB-budget at a specific candidate site for which only single omnidirectional hydrophone data is available. Analysis of 24/7 calibrated hydrophone data supports detailed performance forecasting for a costly, large scale acoustic observatory.
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Panoramic audio device for passive sonar

The Journal of the Acoustical Society of America, 2005
The invention concerns panoramic audio devices to process the impulsive signals received by passive sonars. It consists in isolating, in each beam, impulsive signals in the frequency and time domains and then filtering them according to the characteristics of the human ear.
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