Technical Reports: Recent submissions
Now showing items 21-40 of 322
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A study of the uncertainty in estimate seabed properties as a result of goeacoustic inversion algorithms
(NATO. SACLANTCEN, 2003/10)This paper investigates the inherent uncertainty in estimated seabed properties derived from matched-field geoacoustic inversion algorithms. This algorithm-induced uncertainty must be considered when interpreting inversion ... -
Signal and reverberation formulae including refraction
(NATO. SACLANTCEN, 2003/04)Because reverberation is an incoherent process it is possible to base realistic solutions on very simple flux theory. This report extends the closed-form signal and reverberation formulae of an earlier report [SACLANTCEN ... -
Project 03F - 1: phase 1 completion report
(NATO. SACLANTCEN, 2002/12)This report describes the results of Phase I of Project 03F-1. The overall aim of this project is to -
Broadband signal simulation in shallow water
(NATO. SACLANTCEN, 2002/12)Today's minimum requirements for ocean acoustic models are to be able to simulate broadband signal transmissions in 2D varying environments with an acceptable computational effort. Standard -
Formulae for bistatic signal and reverberation
(NATO. SACLANTCEN, 2002/12)This report demonstrates that it is possible to obtain closed-form solutions for signal and reverberation in a wide variety of bistatic scenarios including ducts and bottom bathymetry. These formulae adapt earlier monostatic ... -
Bottom reflection properties deduced from an ambient noise: simulation of a processing technique
(NATO. SACLANTCEN, 2002/11)A promising new method has already been proposed [SACLANTCEN SM-387] to calculate bottom reflection loss from ambient noise directionality. Although this method has been tried experimentally at more than 11 sites under ... -
The characterization of a range-dependent environment using towed horizontal array data from the MAPEX 2000 experiment
(NATO. SACLANTCEN, 2002/11)The characterization of ocean environments using geoacoustic inversion techniques has received a -
SUPREMO: a multistatic sonar performance model
(NATO. SACLANTCEN, 2002/11)Multistatic sonars introduce new problems to the modeller such as mutual interference from multiple sources and variable target aspect in a background of range-dependent bistatic reverberation. A multistatic sonar performance ... -
Noise measurements during MAPEX 2000
(NATO. SACLANTCEN, 2002/03)During MAPEX2000 some simultaneous ambient noise measurements with an HLA and satellite SAR images were collected. The aim was to predict shipping and wind noise from the satellite radar and to compare results with acoustic ... -
Real-and synthetic-array signal processing of buried targets
(NATO. SACLANTCEN, 2002/01)Results from two field experiments aimed at investigating the detection and classification of buried targets are presented. In both experiments a 2-16 kHz parametric source was used. In the first experiment the source was ... -
Water masses, sound velocity structure and circulation between the eastern Algerian Basin and the Strait of Sicily in October 1996
(NATO. SACLANTCEN, 2002/01)The investigation is based on data collected between the eastern Algerian Basin and the Strait of Sicily and in the southern Tyrrhenian Sea. The major pathways of water masses are identified by the -
Bathymetric imaging with wideband interferometric synthetic aperture sonar
(NATO. SACLANTCEN, 2001/11)A new approach to interferometric sonar is presented, based on time delay estimation using shortterm correlation of the seafloor backscatter. It is most suited to signals with large relative bandwidths and long interferometric ... -
Annual Progress Report 1999
(NATO. SACLANTCEN, 2000) -
Performance assessment of the LYBIN - 2.0 propagation-loss model
(NATO. SACLANTCEN, 2001/07)A new acoustic model LYBIN has been proposed for inclusion in the AESS model set. In order to determine this model's prediction accuracy and computational efficiency, SACLANTCEN was tasked to test LYBIN on exactly the same ... -
Direct observation of the angle of intromission in marine sediment
(NATO. SACLANTCEN, 2001/06)High porosity marine sediments like silty clays have the curious property that the speed of sound through its bulk medium is lower than that of the interstitial pore fluid. When a high porosity sediment is at the water ... -
Predicting underwater ambient noise with an evolutionary signal processing method
(NATO. SACLANTCEN, 2001/06)In this report we employ recent developments in non-linear physics and time series prediction to study the physical characteristics of measured underwater ambient sounds. Specifically, we examine the predictability of a ... -
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 ... -
An automatic approach to ship detection in spaceborne synthetic aperture radar imagery: an assessment of ship detection capability using RADARSAT
(NATO. SACLANTCEN, 2000/12)This report describes a methodology for automated ship and wake detection in space-based synthetic aperture radar (SAR) imagery. The methodology incorporates a multistage approach involving several algorithms which can ... -
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. ...