Browsing Technical Reports by Issue Date
Now showing items 261-280 of 322
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A review of the application of UUV technology to mine countermeasures
(NATO. SACLANTCEN, 1999/03)The emphasis on littoral warfare, the proliferation of low cost mines available to potentially hostile countries, high exercise costs and risks related to the operation of present NATO MCM units, require the development ... -
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 ... -
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 ... -
Deployable underwater surveillance systems: analysis of experimental results: part III
(NATO. SACLANTCEN, 1999/04)Deployable Underwater Surveillance Systems (DUSS) are a new active sonar concept based on a distributed network of small multistatic transmitter / receiver nodes. This study analyzes data acquired during the period 29 June ... -
Nowcasting and forecasting of sound velocity structure by ocean modelling
(NATO. SACLANTCEN, 1999/04)The Harvard Ocean Prediction System (HOPS) is applied to an observed oceanographic data set in -
A classification technique combining aspect dependence and elastic properties of target scattering
(NATO. SACLANTCEN, 1999/04)Discrimination between man-made and natural underwater objects and between man-made objects of different characteristics are the key objectives of target classication. The current approach is mainly based on the analysis ... -
A high resolution seismic sequence analysis of the Malta Plateau
(NATO. SACLANTCEN, 1999/05)A high resolution seismic study of the Malta Plateau was conducted to characterize the Quaternary sediment layers, mapping their regional extent and determining the environmental conditions during their deposition. Seismic ... -
Broad-band geoacoustic inversion in shallow water from waveguide response measurements on a single hydrophone: theory and YELLOW SHARK experimental results
(NATO. SACLANTCEN, 1999/05)Executive summary: Performance models such as the Allied Environmental Support System (AESS) require environmental input parameters such as the geoacoustic properties of the battlespace. The models ingest the input parameters ... -
Data communication and data fusion architecture for RAPID RESPONSE 96-98
(NATO. SACLANTCEN, 1999/06)Executive Summary: The concept of Rapid Environmental Assessment (REA) has emerged in recent years as one of the most interesting research topics in Military Oceanography (MILOC): REA in a military environment is defined ... -
A neural-network-fusion architecture for automatic extraction of oceanographic features from satellite remote sensing imagery
(NATO. SACLANTCEN, 1999/06)This report describes an approach for automatic feature detection from fusion of remote sensing imagery using a combination of neural network architecture and the Dempster-Shafer (DS) theory of -
Time series variability in fluctuating ocean waveguides
(NATO. SACLANTCEN, 1999/07)The variability of signals propagating through an uncertain sound speed structure is addressed. Signals are assumed to travel in a narrow band adiabatically in modes and to experience fluctuations in sound speed which are ... -
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 ... -
Performance assessment of propagation models in AESS-6.0
(NATO. SACLANTCEN, 1999/08)A set of AESS propagation-loss predictions has been generated for typical operational scenarios in both deep and shallow water, for two sonar frequencies (500 and 3500 Hz) and for several source-receiver combinations. ... -
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 -
The application of spread-spectrum communications to REA tactical networks and deployable underwater surveillance systems
(NATO. SACLANTCEN, 1999/08)The present document is a part of an ongoing study on advanced communication techniques in support of Rapid Environmental Assessment (REA) and Deployable Undersea Surveillance Systems (DUSS). It aims at the definition of ... -
Long range, large throughput radio data links for DUSS (Deployable Underwater Surveillance Systems)
(NATO. SACLANTCEN, 1999/10)Two mono-directional radio telemetry systems are described operating from a buoy to NRV Alliance at frequencies of 0.4 and 2.28 GHz. Digital data at 2 Mbps were transmitted close to the sea surface, collecting information ... -
Annual Progress Report 1999
(NATO. SACLANTCEN, 2000) -
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 ... -
Geo-acoustic inversion of the PROSIM'97 experimental data using simplex simulated annealing
(NATO. SACLANTCEN, 2000/01)In the spring of 1997 SACLANTCEN performed an experiment near the Elba island in the Mediterranean Sea. The PROSIM'97 experiment was designed for the validation of a broadband acoustic propagation model. During the period ... -
Statistical normalization of non-Rayleigh reverberation
(NATO. SACLANTCEN, 2000/02)Low-frequency active sonar systems operating in shallow water are primarily limited by reverberation.