Browsing by Type "Scientific Memorandum (SM)"
Now showing items 41-60 of 159
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Broadband geo-acoustic inversion from sparse data using genetic algorithms: results from the 1997 Geo-Acoustic Inversion Workshop
(NATO. SACLANTCEN, 1998/03)Matched field acoustic inversion techniques were investigated -
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 -
C-SNAP: Coupled SACLANTCEN Normal mode propagation loss model
(NATO. SACLANTCEN, 1993/12)On the basis of a widely used and efficient range-independent normal mode code, SNAP, and a numerical solution technique for one-way mode coupling obtained from KRAKEN, we have built a range-dependent propagation loss model ... -
Celtic Duet - a joint SACLANTCEN/NRL shallow-water sea trial in Celtic Sea during July 1992: data summary
(NATO. SACLANTCEN, 1996/10)In July 1992 a joint shallow-water sea trial was conducted in the -
Channel sensitive processor: real data processing
(NATO. SACLANTCEN, 1998/02)The CSP is applied to data collected during the DUSS97 sea trial. A one-way geometry is used and the transmitted signal propagation time is known a priori. As predicted by analytical and simulation studies, the CSP detector ... -
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 ... -
Comparison of a time domain spectral collocation method and the time-evolution backscatter model BORIS
(NATO. SACLANTCEN, 1997/11)A model based on the time-domain spectral collocation method has been implemented at Forsvarets -
Comparison of satellite-retrieved sea-surface temperatures with drifter and ship-borne measurements
(NATO. SACLANTCEN, 1996/01)Sea-surface temperatures (SST) retrieved from satellite imagery are compared with in-situ measured data. The satellite data are from the Advanced Very High Resolution Radiometer (AVHRR) of the series of NOAA satellites, ... -
Coupled-mode modelling of acoustic scattering from three-dimensional, axisymmetric objects
(NATO. SACLANTCEN, 1997/01)In this memorandum a coupled-mode method for computing the wavefield scattered by three-dimensional, axisymmetric objects is presented. The method provides a unified approach to solving three-dimensional scattering problems ... -
Decay of large underwater bubble oscillations
(NATO. SACLANTCEN, 1999/02)Pressure - time series from breathing mode oscillation of large (centimeter scale or larger) underwater bubbles reveal much higher decay rates than can be explained using viscous, thermal, or radiative mechanisms which ... -
Deconvolution by homomorphic and Wiener filtering
(NATO. SACLANTCEN, 1988/09)This study is concerned with deconvolution methods applied to underwater propagation in shallow -
Deep water mass circulation in the Alboran Basin: Measurements - August to November'83: ALBORAN III
(NATO. SACLANTCEN, 1988/02)The circulation of the deep water mass in the western Alboran Sea is studied. Interaction between the -
Deep water mass circulation in the Alboran basin: measurements - January to April '82 ALBORAN II
(NATO. SACLANTCEN, 1987/09)Alboran Sea circulation between 220 m and 1100 m depth is studied. Interaction between three water types, Atlantic water, Levantine water, and western Mediterranean Deep water cause a complicated flow pattern. Atlantic ... -
Delay-Doppler resolution performance of large time-bandwidth product linear FM signals in a multi- path ocean environment
(NATO. SACLANTCEN, 1989/04)Active sonar systems that transmit large time-bandwidth (TW)-product linear frequency modulated (LFM) waveforms and receive echoes from targets of unknow~r~an ge and speed can suffer considerable correlation losses that ... -
Detection of narrow-band low-level signals: simulated performance of high-resolution eigenstructure methods versus conventional beamforming
(NATO. SACLANTCEN, 1988/08)In this report the detection of narrow-band low-level signals by passive sonar is addressed, -
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 -
Development of barotropic models for the GIN Sea
(NATO. SACLANTCEN, 1991/03)Barotropic ocean models are developed for deep oceans, with arbitrary topography and basin geometry, on a sphere. A special adaptation is made for the Greenland-Iceland-Norwegian (GIN) Seas with closed lateral boundaries. ... -
Digital map and linked data (DMap) implementation at SACLANTCEN as an aid to sea-going research
(NATO. SACLANTCEN, 1995/08)DMaps (data maps), consisting of a geographical informatiorl system -
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 ...