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Now showing items 61-69 of 69
Statistical characterization of shallow-water bistatic sonar reverberation and noise
(NATO. SACLANTCEN, 1993/08)
Shallow-water, low-frequency bistatic sonar measurements often exhibit high noise caused by bathymetric reverberation and other sources. Understanding the noise statistics is an essential first step in developing filters ...
Spatial variability of surficial shallow water sediment geoacoustic properties
(NATO. SACLANTCEN, 1986/06)
Variability of surficial sediment geoacoustic properties was determined from cores collected at eight shallow-water continental shelf regions in the U.S., Italy and Australia. Highly porous muds found in low energy ...
An experimental investigation of the contribution of sediment volume scattering to acoustic backscatter measured in the shallow waters of the Florida Strait
(NATO. SACLANTCEN, 1997)
Experiments were conducted in the Florida Strait region of the United States in July 1995 for the purpose of investigating the contribution of sediment volume scattering to measured backscatter levels at frequencies between ...
Small scale volumetric inhomogeneities of shallow water sediments: measurements and discussion
(NATO. SACLANTCEN, 1997)
There is a consensus that high-frequency acoustic scattering by the ocean bottom is partly due to sediment volumetric inhomogeneities, r e., random fluctuations in sediment sound speed and density. Understanding the spatial ...
Measurement and interpretation of angular spreading from multiple boundary interactions in a shallow water channel
(NATO. SACLANTCEN, 1997)
The problem of angular spreading of sound that has undergone multiple boundary scattering (both sea surface and sea bed) in a shallow water channel is discussed. Measurements made of the horizontal spatial coherence along ...
Multipath field representation for seabed parameter extraction using backscatter data from shadow zones
(NATO. SACLANTCEN, 1997)
Inversion strategies for bottom parameter estimation in shallow water impose stringent requirements on accuracy and speed of acoustic models. We highlight the importance of second order effects as first order determinants ...
A solution of of the wave sound equation in shallow water for real speed profiles and solid bottom under sediment
(NATO. SACLANTCEN, 1975/10)
The wave equation has been solved by using normal mode theory. The medium is assumed to be horizontally stratified. A closed form solution has been found in the case of GANS - PEDERSEN types of density and sound-speed ...
The optimum frequency of propagation in shallow-water environments
(NATO. SACLANTCEN, 1983/04)
The optimum frequency of propagation in shallow water environments is the result of competing propagation and attenuation mechanisms at high and low frequencies. It is shown that the optimum frequency is strongly dependent ...
High frequency acoustic propagation in coastal waters
(NATO. SACLANTCEN, 1997)
High Frequency Acoustic Propagation experiments were performed with bottom-mounted sources and receivers at different coastal sites. A measurement technique has been developed and propagation loss data have been taken using ...