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Statistical evaluation of 80 kHz shallow-water seafloor reverberation
(NATO. SACLANTCEN, 1997)
In this work a comparison is presented between 80 kHz reverberation statistics obtained at shallow water sites around Sardinia and Sicily. The data include measurements from several distinct bottom provinces, including ...
A noise directionality model including variable bathymetry
(NATO. SACLANTCEN, 1997)
In this paper we investigate the noise directionality due to distributed surface sources m several envtronments with a uniformly sloping sea bed. Of particular interest are frequency dependence and the question of the ...
Shallow-water seafloor characterization for high-frequency multibeam echosounder: image segmentation using angular backscatter
(NATO. SACLANTCEN, 1997)
Sonar images from multibeam echosounders are submitted to various degradations, partly due to the sensor itself: Signal artefacts and corresponding corrections are presented, both for signal processing and for array ...
Determination of velocity profile and sea bed characteristics from high frequency pulse propagation in a shallow water Mediterranean environment
(NATO. SACLANTCEN, 1997)
Time-domain features of shallow water Mediterranean and Yellow Sea data are simulated for frequency band widths of 0.8 kHz with a centralfrequency of 3.2 kHz. Contour plots of pulse arrivals in time and depth are analyzed ...
The effect source movements on shallow water bottom backscatter
(NATO. SACLANTCEN, 1997)
The time-evolution model BORIS is used to study the effects of source movements on bottom backscatter. Changes in the backscattend time domain signals as functions of source depth, position and incident angles are simulated ...
The effect of suspended particulate matter on the performance of high frequency sonars in turbid coastal waters
(NATO. SACLANTCEN, 1997)
Shallow coastal environments are characterised by high levels of suspended mineral particles relative lo the open ocean and such suspensions can have a significant effect on the performance of high frequency sonars operating ...
Retrodirective array performance case studies and implications for mine countermeasures
(NATO. SACLANTCEN, 1997)
The use of focused acoustic fields for the mechanical destruction of fluid-borne targets is applied zn. the medical field for the comminution of kidney stones by lithotripsy. Inhomogeneities in the propagation medzum are ...
Multistatic bottom reverberation in shallow water
(NATO. SACLANTCEN, 1997)
A wavenumber integration approach to modeling of the full multistatic reverberant field produced by small-scale bottom roughness in stratified shallow water waveguides has been developed. A perturbation approach to rough ...
Sound absorption by suspended particulate matter
(NATO. SACLANTCEN, 1997)
A series of experiments has been performed to study the viscous absorption of sound by particulate suspensions typical of those found in coastal waters. The effect due to the particles in the frequency range of 50 - 150 ...