Results 171 to 180 of about 23,037 (220)

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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Processing of Noisy Passive Sonar Measurements

2007 International Conference on Signal Processing, Communications and Networking, 2007
In underwater an observer pre-processes the noisy bearing measurements available from passive sonar and then the data is used by Kalman filter to find out target motion parameters. The pre-processing reduces the amplitude of the noise, replaces the missed bearings with estimated bearings, supplies the estimated bearings if the bearing measurement is ...
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Range and Bearing Estimation in Passive Sonar

IEEE Transactions on Aerospace and Electronic Systems, 1980
Passive sonar systems are used for estimating the range and bearing of signal sources, such as ships or submarines. In this study, the Cramer-Rao bounds on estimation errors are used as measures of the accuracy of the estimates. The bounds show how parameters such as observation time, signal bandwidth, signal-to-noise ratio, and array geometry can be ...
S. Pasupathy, W. Alford
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Matched array processing for wideband passive sonar

ICASSP '81. IEEE International Conference on Acoustics, Speech, and Signal Processing, 2005
The Matched Array Processor (MAP) is quadratic adaptive matrix filter designed to optimize detection and bearing estimation of a desired wideband target signature in the presence of interferences. It is made adaptive in the spatial domain to remove interferences entering through the beam sidelobes and it is spectrally matched to the signal of interest.
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