Browsing Technical Reports by Title
Now showing items 237-256 of 322
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Reduction of low frequency active sonar clutter through image processing
(NATO. SACLANTCEN, 1997/12)Large numbers of false clutter detections arise in the use of low frequency active sonar for the detection of low Doppler submarine targets in shallow water. Traditional detection algorithms operate individually on each ... -
Remote sensing of topographically-induced upwelling in the southern coastal region of Sicily
(NATO. SACLANTCEN, 1998/09)Upwelling signatures caused by variations in bottom topography along the southeastern Sicilian coast are identified, using spaceborne remote sensing Advanced Very High Resolution Radiometer (AVHRR) imagery, ERS-1 and ... -
Resonance analysis of the acoustic response of a water-filled cylindrical shell
(NATO. SACLANTCEN, 1998/09)The resonance analysis approach developed for characterizing free-field air-filled cylindrical shells in terms of geometrical and mechanical pararneters is extended to fluid-filled shells either in the freefield or proud ... -
Resonance scattering analysis by autoregressive models applied to air-filled, cylindrical, thin walled shells in water
(NATO. SACLANTCEN, 1997/10)Autoregressive (AR) parametric spectral estimation of the scatterer transfer function is applied to the analysis of acoustic scattering by elastic objects. In accordance with Resonance Scattering Theory (RST), the specular ... -
Results on the detection of narrow-band low-level signals in a ship-induced noise field using high-resolution beamforming
(NATO. SACLANTCEN, 1988/07)In this report the performance of a high-resolution beamformer is compared to that of the conventional -
Reverberation suppression
(NATO. SACLANTCEN, 1995/05)We propose a processing methodology for shallow-water reverberation -
Robust broadband matched-field processing: performance in shallow water by simulation
(NATO. SACLANTCEN, 1993/11)An issue of concern for matched-field processing is the strong dependence between performance and -
Robust normalization algorithms for low-frequency active sonar signals
(NATO. SACLANTCEN, 1995/12)Two normalization processors of active sonar signals are presented. Due to their specific design, these algorithms are particulary good candidates to normalize the data stream before applying postprocessing methods based ... -
SACLANT Undersea Research Centre - Research and Accomplishments 1975-1989
(NATO. SACLANTCEN, 1992/12)The SACLANT Undersea Research Centre, originally the SACLANT ASW Research Centre, was established in 1959 to provide scientific and technical advice and assistance to the Supreme Allied Commander Atlantic in the field of ... -
SAFARI Seismo-Acoustic Fast field Algorithm for Range-Independent environments: user's guide
(NATO. SACLANTCEN, 1988/09)An efficient algorithm has been developed for solving the depth-separated wave equation in general fluid/solid horizontlly stratified media. The algorithm has been built into a general-purpose package of computer codes ... -
SAGA User Manual 2.0: an inversion software package
(NATO. SACLANTCEN, 1997/07)The purpose of many experiments is to identify environmental parameters -
Satellite measurements of sea surface temperature: some consequences of variability on validation and applications
(NATO. SACLANTCEN, 1990/07)Sea-surface temperature (SST) measurements from both spaceborne and in situ sensors are analysed to determine likely temperature differences that can arise between two measurements separated in space and time. This has ... -
Scattering by spheres buried in sediment
(NATO. SACLANTCEN, 1997/01)In this report the scattering of acoustic energy by an elastic sphere buried in sediment is examined. The geoacoustic model consists of two homogeneous fluid halfspaces separated by an intermediate layer. The source field ... -
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 ... -
Scintillation instrument for remote environmental analysis (SIREN)
(NATO. SACLANTCEN, 1999/02)A high frequency acoustic propagation instrument which was developed to study ocean variability in the Strait of Istanbul (Bosporus) is described. The scintillation instrument for remote environmental analysis (SIREN) was ... -
Sea-surface winds in the Iceland-Faeroe area, as derived from the ERS-1 scatterometer
(NATO. SACLANTCEN, 1994/04)This report presents measurements of surface meteorological data taken during three cruises of R/V Alliance to the Iceland-Faeroe frontal area during August 1991 (NORDIC'91), March 1992 (NORDIC'92a) and October 1992 ... -
Sediment shear waves: a comparison of in situ and laboratory measurements
(NATO. SACLANTCEN, 1989/03)Surficial sediment shear wave velocity measurements were made at eight sites (water depths 7-22 m) -
Seismic stratigraphy of the Capraia basin, Northern Tyrrhenian Sea
(NATO. SACLANTCEN, 2001/01)The distribution and thickness of sediments within the Capraia Basin, Northern Tyrrhenian Sea, have been mapped using high-resolution seismic reflection data. The data were studied within the geologic framework determined ... -
Shallow seafloor geology and sediment character ofthe western Mallorca Platform
(NATO. SACLANTCEN, 1995/03)A site survey of the seabottom west of Mallorca in the central Balearic Islands has characterized the bottom and the immediate sub-bottom. High resolution seismic reflection Uniboom, deeper penetrating (about 5x Uniboom) ...