Browsing Technical Reports by Subject "Acoustic scattering - Seafloor and sea surface"
Now showing items 1-20 of 23
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A note on attenuation and dispersion in marine sediments
(NATO. SACLANTCEN, 1989/04)From the more recent investigations reported ill the literature, -
Benchmarking of SCARAB volume scattering versus OASES volume scattering
(NATO. SACLANTCEN, 2001/05)OASES uses wavenumber integration to solve for the backscattered pressure caused by sound speed and density inhomogeneity scatterers in the sediment; SCARAB uses a ray path technique to find the backscattered intensity. ... -
Bottom reverberation in shallow water: coherent properties as a function of bandwidth, waveguide characteristics and scatterer distribution
(NATO. SACLANTCEN, 1998/10)Scattering physics are often modeled using the Helmholtz equation for computational reasons. Likewise, propagation loss to and from scattering regions are often treated in a like manner. The usual approach for generating ... -
Bottom scattering measurements in shallow water
(NATO. SACLANTCEN, 1999/08)Sonar performance predictions of reverberation in shallow water rely upon good estimates of the bottom scattering strength. However, little is understood about bottom scattering in shallow water in -
Characteristics of the mediterranean seagrass Posidonia oceanica contributing to high-frequency acoustic scattering
(NATO. SACLANTCEN, 2000/05)Posidonia oceanica meadows are the most important ecosystem for the life cycle of coastal Mediterranean benthos with a fundamental role in the primary production of the neritic system and a decisive influence on other ... -
Detection of objects on a non Rayleigh background
(NATO. SACLANTCEN, 1995/12)Sector scanning sonar systems image the sea-bottom to detect objects that can be distinguished from the background structure of the seabottom. In current systems images are displayed and discarded as new image data become ... -
Development of a SACLANTCEN MCM sonar performance model
(NATO. SACLANTCEN, 1996/11)The report describes the Mine Countermeasures Sonar Performance -
GLider Acoustics Sensing of Sediments (GLASS): experiments and data analysis
(CMRE, 2013/12)Seabed characteristics (geoacoustic properties and scattering strength) are critical parameters for sonar performance predictions. However, this bottom information is considered very difficult and expensive to achieve in ... -
Measurements of acoustic scattering from partially and completely buried spherical shells
(NATO. SACLANTCEN, 1999/04)Recent work at NATO SACLANT Undersea Research Centre has concentrated on investigating the use of low frequency sonars (2-20 kHz) in order to better exploit scattering features of buried targets that can contribute to their ... -
Modelling of scattering by objects on the seabed
(NATO. SACLANTCEN, 1997/12)This paper describes some of the theory and implementation issues of modeling the backscattered -
Modelling scattering from partially buried cylinders = Acoustic scattering from cylindrical objects embedded between two half-spaces/The computation of the scattered pressure field from a cylinder embedded between two half-spaces = The computation of the scattered pressure field from a cylinder embedded between two half-spaces with different densities
(NATO. SACLANTCEN, 1996/12)1. A boundary integral equation method is presented for the computation of the acoustic field scattered from a cylindrical object which is totally within the water column, totally buried in sediment, or partially buried. ... -
Penetration of acoustic waves into sandy seafloors at low grazing angles: the Helmholtz-Kirchhoff approach
(NATO. SACLANTCEN, 1998/08)The Helmholtz-Kirchhoff integral is applied to model the penetration of sound waves into sandy seafloors at grazing angles above and below the critical angle. Although the conditions for the validity -
Scattering from a rough sedimental seafloor containing shear and layering, as determined by perturbation theory
(NATO. SACLANTCEN, 1993/07)First-order perturbation theory is applied to reverberation from a rough sedimental seafloor. In addition to existing approaches, the seafloor is allowed to be shear-supporting or to be layered. Scattering strengths are ... -
Spectral integral representations of monostatic backscattering from three dimensional distributions of sediment volume inhomogeneities
(NATO. SACLANTCEN, 2001/03)A theory is developed for generating short time, monostatic reverberation realizations caused by three dimensionally distributed volume inhomogeneities in stratified media. A spectral integral approach to treating the ... -
Spectral integral representations of scattering from volume inhomogeneities
(NATO. SACLANTCEN, 1999/07)In-situ measurements of scattering strength can be obtained by analyzing the early-time, high angle reverberation from bottom and sub-bottom features. In order to provide insight into the mechanisms which cause bottom ... -
Statistical characteristics of large-scale bottom reverberation
(NATO. SACLANTCEN, 1995/07)Simulation results from a statistical characterization of large-scale bottom reverberation from broadband signals are presented. The seafloor profile is parametrized via the surface root-mean-square height and correlation ... -
The reverberation of sound from smooth ocean floors
(NATO. SACLANTCEN, 1963/02)The reverberations produced by a completely flat surface separating two homogeneous isotropic fluids is investigated. There is no effort to include the effect of rough surfaces which would be a logical extension of the ...