Browsing Technical Reports by Type "Scientific Report (SR)"
Now showing items 21-40 of 83
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Deployable underwater surveillance systems(DUSS): localization and fusion of multistatic contacts: evaluation of feasibility using experimental data
(NATO. SACLANTCEN, 1998/12)Active sonar deployable underwater surveillance systems (DUSS) are based on a distributed network -
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 ... -
Detection of buried mines using Rayleigh-scattered second-derivative Gaussian pulses
(NATO. SACLANTCEN, 1995/10)Large ground mines which are intentionally or unintentionally buried in the sediment have proven to -
Detection of buried objects at low grazing angles: preliminary experimental results
(NATO. SACLANTCEN, 1998/06)This report considers the acoustic detection of objects buried in the seabed, and especially the possibility of using subcritical insonification geometries in order to increase coverage rate. -
Detection of buried objects in the seabed: a simple model study
(NATO. SACLANTCEN, 1998/10)The problem of detecting an object buried in the seabed is studied by means of a simple model. In this model, the object is a rigid sphere buried in a bottom modelled as a fluid half space. The scattered field is determined ... -
Distributions of magnetic field variations, differences and residuals
(NATO. SACLANTCEN, 1999/02)Temporal and spatial variations of the geomagnetic field were recorded in different geographic areas, -
Effects of intrinsic medium inhomogeneities on long-range acoustic transmission
(NATO. SACLANTCEN, 1993/10)Duda et al. [J. Acoust. Soc. Am. 92(2), 939-955, 1992] have measured wavefront arrival times over a -
Efficient global matrix approach to the computation of synthetic seismograms
(NATO. SACLANTCEN, 1986/05)A numerically efficient global matrix approach to the solution of the wave equation in horizontally stratified environments is presented. The field in each layer is expressed as a superposition of the field produced by the ... -
EVA - an evaluator of vague evidence in ASW situations: an expert system prototype
(NATO. SACLANTCEN, 1987/10)This paper presents an example of how an expert system can contribute to the creation and updating -
Experimental demonstration of the focused acoustic field in the ocean
(NATO. SACLANTCEN, 1998/10)An experiment conducted in the Mediterranean Sea in April1996 demonstrated that a time reversal mirror (or phase conjugate array) can be implemented to spatially and temporally refocus an incident acoustic field back to ... -
Finite difference modelling of scattering by objects in the seabed
(NATO. SACLANTCEN, 1996/07)In this report we describe the theory and some implementation issues of a finite difference code used at SACLANT Centre. In particular, we consider the modelling of attenuation and the excitation of a remote incident field ... -
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 ... -
Generic Oceanographic Array Technologies (GOATS)'98: bi-static seabed scattering measurements using autonomous underwater vehicles
(NATO. SACLANTCEN, 1998/10)The GOATS'98 experiment was performed May 5-29, 1998 in shallow water off Marciana Marina, on the island of Elba, Italy. The experiment addressed some of the fundamental issues associated with using the new Autonomous Ocean ... -
High-resolution beamforming techniques performance analysis
(NATO. SACLANTCEN, 1986/11)Seven different beamforming techniques (including both conventional and high-resolution types) have been analyzed and compared in order to develop a quantitative relationship between resolution performance on the one hand ... -
Infrared detection of marine mammals
(NURC, 2005/12)An infrared (IR) binocular, designed for in-the-field military applications, was tested using in situ marine mammals during the Mar Ligure Joint Experiment 2003 (MLJX03) that took place in August-September 2003 onboard the ... -
Inversion for geometric and geoacoustic parameters in shallow water: experimental results
(NATO. SACLANTCEN, 1994/12)Experimental results on the estimation of both geometric and geoacoustic parameters in shallow water are presented. Genetic algorithms are used for estimation of the forward model parameters, the -
Logarithmic least mean square sound-field estimation
(NATO. SACLANTCEN, 1987/03)The report deals with narrowband beamforming techniques for passive sonar applications. In particular, the Least Mean Square fit parameter estimation technique is used to estimate the spatial sound-field power density. To ... -
Low-frequency reverberation measurements with an activated towed array: Scattering strengths and statistics
(NATO. SACLANTCEN, 1987/10)Results of reverberation measurements made with a low-frequency activated towed array sonar system in two deep-water locations of the Mediterranean Sea are presented. Measurements took -
Measurements and predictions of transmission loss at two sites in the Southwest Approaches to the English Channel
(NATO. SACLANTCEN, 1995/12)As part of a continuing series of measurements being made by -
Mechanisms for subcritical penetration into a sandy bottom: experimental and modelling results
(NATO. SACLANTCEN, 1998/05)This paper presents the results of a recent study whose overall objectives are to determine the mechanism(s) contributing to subcritical acoustic penetration into ocean sediments, and to quantify the results for use in ...