Results 171 to 180 of about 336,461 (224)

Beam steerable sonar array

The Journal of the Acoustical Society of America, 1984
A sonar array wherein the capacitance associated with the hydrophones of the array are utilized as shunt elements in an artificial transmission line in order to form an acoustic beam. Series inductance elements to the transmission line are variable with d.c.
Kenneth W. Groves, John D. Lea
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Sparse Cylindrical Sonar Arrays

IEEE Journal of Oceanic Engineering, 2008
Sparse arrays offer a means for reducing the cost and complexity of beamforming systems. Most of the work in the literature has focused on sparse linear arrays with isotropic transducer elements, which simplifies analysis greatly. In this paper, we will focus on multibeam cylindrical arrays using highly directive elements for use in fishery ...
J.E. Kirkebo, A. Austeng
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Parametric array Doppler sonar

IEEE Journal of Oceanic Engineering, 1977
A Doppler sonar technique capable of measuring ground speed and distance traveled at extreme ocean depths is described. The technique uses nonlinear acoustic effects to create the narrow beams required. Performance estimates are calculated and parameters for a test system chosen.
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Sonar array measurement facility

The Journal of the Acoustical Society of America, 1982
DED has developed a facility for the accurate calibration of towed line sonar arrays which is small and noise immune enough that it can be installed at any site requiring such measurements. The facility consists of a series of cylindrical transducers submerged in a water tank.
Frederick Reitz, Melvin Main
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The Directivity of Sonar Receiving Arrays

The Journal of the Acoustical Society of America, 1970
General expressions are developed for determining the beam patterns and directivity index of arbitrary configurations of hydrophones and results given in the special case of a cylindrical shell array. The limiting case of a continuous distribution of hydrophones is considered and integral relationships are derived for volume and shell distributed array.
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Shape and doppler correction for a towed sonar array

Oceans '04 MTS/IEEE Techno-Ocean '04 (IEEE Cat. No.04CH37600), 2005
Anti Submarine Warfare (ASW) is more and more focused toward shallow water environments. Many complications have come up for ASW sonar performance as a result of this. The problem that is tackled in this article is the performance loss due to the shape and motion of the sonar during a maneuver. Standard beamforming in towed sonar arrays is based on the
Groen, J., Beerens, S.P., Doisy, Y.
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An optimal sonar array for target localization and classification

Proceedings of the 1994 IEEE International Conference on Robotics and Automation, 2002
A novel sonar array for mobile robots is presented with applications to localization and mapping of indoor environments. The ultrasonic sensor localizes and classifies multiple targets in two dimensions to ranges of up to 8 meters. By accounting for effects of temperature and humidity, the system is accurate to within 1 mm and 6.1 degrees in still air.
Lindsay Kleeman, Roman Kuc
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Optical Processing for Sonar Arrays

1999
Abstract : We present an adaptation of the BEAMTAP (Broadband and Efficient Adaptive Method for True-time-delay Array Processing) algorithm, previously developed for wideband phased array radars, to lower bandwidth applications such as sonar. This system utilizes the emerging time or wavelength multiplexed optical hydrophone sensors and processes the ...
Lloyd Griffiths, Dana Anderson, Kelvin Wagner   +2 more
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Towed sonar receiving array

The Journal of the Acoustical Society of America, 1991
A mobile sonar surveillance system having a fully populated circular shapedorizontal receiving array steered in edgefired directions with overlapping coverage of beams. The array has a plurality of hydrophones randomly spaced and mounted on a series of parallel lines in the same horizontal plane and is suitable for towing by a single small ship.
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Optimized aberration correction for sonar arrays

Global Oceans 2020: Singapore – U.S. Gulf Coast, 2020
In this paper a method using simulated annealing is applied to the problem of array pattern synthesis subject to aberrations. For linear arrays an optimal suppression of the maximum sidelobe level can be achieved using a Dolph-Chebyshev window. However, the sensitivity of this window to position and phase aberrations means it has practical limitations ...
Jan Egil Kirkebo, Andreas Austeng
openaire   +1 more source