Browsing Technical Reports by Type "Scientific Report (SR)"
Now showing items 61-80 of 83
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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 -
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 ... -
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 ... -
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 ... -
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 ... -
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 ... -
Single mode excitation, attenuation and backscatter in shallow water
(NATO. SACLANTCEN, 1995/10)Normal mode theory is used to illustrate that a vertical array of weighted sources driven in an -
Single ping clutter reduction: segmentation using Markov random fields
(NATO. SACLANTCEN, 1999/03)The use of low frequency active sonar in shallow water leads to large numbers of clutter detections. This high false alarm rate can overload automatic tracking and classification algorithms. Traditional detection algorithms ... -
Source localization in shallow water using multi-frequency processing of shot data
(NATO. SACLANTCEN, 1996/07)Multi-frequency processing methods are applied to real data generated by explosives to examine the -
Statistical evaluation of 80 kHz shallow-water seafloor reverberation
(NATO. SACLANTCEN, 1997/09)Knowledge of the background reverberation environment is a prerequisite for the design of any target detection scheme. While the problem of understanding and predicting high-frequency background reverberation level or mean ... -
Statistical normalization of non-Rayleigh reverberation
(NATO. SACLANTCEN, 2000/02)Low-frequency active sonar systems operating in shallow water are primarily limited by reverberation. -
Studies on information mechanics
(NATO. SACLANTCEN, 1987/04)Related issues connected with the transmission of information in a command and control environment -
Target localization with multiple sonar receivers
(NATO. SACLANTCEN, 2000/01)Deployable Underwater Surveillance Systems (DUSS) are a network of small multistatic transmitter/receiver sonar nodes. This study analyzes the contact localization capabilities of DUSS in term of range, time and bearing ... -
The effect of a layer of varying density on high-frequency acoustic reflection, forward propagation loss and backscattering strength
(NATO. SACLANTCEN, 1997/06)This report examines the impact that a thin layer of varying density would have on high-frequency reflection, forward loss and backscattering of acoustic plane waves from the seafloor. A functional form for density ... -
The effects of atmospheric and thermohaline variability on the validation of the GEOSAT altimeter oceanographic signal between Scotland and Iceland
(NATO. SACLANTCEN, 1987/10)Atmospheric and oceanographic profiles from the area between Scotland and Iceland are analysed in -
The GIN Sea: Review of physical oceanography and literature from 1972
(NATO. SACLANTCEN, 1988/07)A synthesis and review of the physical oceanography of the GIN Sea (Greenland, Iceland, and Norwegian Seas) is presented. An accompanying bibliography complete from 1972 is included. Emphasis is placed on describing the ... -
The magnetic dipole moment of RV Alliance
(NATO. SACLANTCEN, 1999/02)A SACLANTCEN magnetometry sea trial was performed in September 1998 in the northern Tyrrhenian Sea in the vicinity of the Formiche di Grosseto islands. One of the trial objectives -
The ocean wave dynamo: a source of magnetic ambient noise
(NATO. SACLANTCEN, 1997/09)The electromagnetic dynamo field of sea surface waves, a consequence of the Lorentz force, has been measured with two simultaneously operating, closely spaced tri-axial magnetometers. Measurements from a magnetometer located ... -
The sea surface as a random filter for underwater sound waves
(NATO. SACLANTCEN, 1974/06)In this dissertation the phenomenon of scattering and reflection of underwater sound waves from the sea surface is studied by considering the surface sound channel as a random, time-dependent filter. This filter can be ...