Browsing Technical Reports by Title
Now showing items 115-134 of 322
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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 ... -
EM phenomena in the ELF range: EM fields of submerged dipoles and finite antennas
(NATO. SACLANTCEN, 1965/06)The report is the first of a series of three that discusses various EM phenomena in the ELF range. The expressions for the various components of the EM field from submerged dipoles are presented. Although similar expressions ... -
EM phenomena in the ELF range: natural background noise and instrumentation for its measurement
(NATO. SACLANTCEN, 1965/06)The report is the second of a series of three that discusses various EM phenomena in the ELF range. A general outline of the natural background noise in the frequency range between 1 and 50 cps is given and the measurement ... -
Estimators for model-based passive localization
(NATO. SACLANTCEN, 1988/07)A comparative study is made of the performance of four different estimators as used in the matched field technique of passive localization. The study is based on both real and synthesized data. In the synthesized data case, ... -
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 ... -
Extended towed-array processor by overlapped correlator
(NATO. SACLANTCEN, 1988/11)The development of an algorithm for extended towed-array measurements, which could be used by matched-field estimators to obtain information about depth and range of a source, is studied. This algorithm combines coherently ... -
Fast Fourier transformation algorithms: experiments with microcomputers
(NATO. SACLANTCEN, 1986/07)We describe experiments intended to exploit the potential of modern -
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 ... -
Frequency deviation indicator
(NATO. SACLANTCEN, 1963/11)A new type of discriminator was developed to measure the frequency variation of electrical signals; it has the special feature to indicate without any delay the difference between the signal frequency and some fixed reference ... -
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 ... -
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 ... -
Geoacoustic models for selected shallow water areas
(NATO. SACLANTCEN, 1996/07)This report summarizes recent work on characterization of shallow water -
Geoenvironmental characterization of selected shallow-water sites on the western European continental shelf (SWAP)
(NATO. SACLANTCEN, 1995/04)Geoenvironrnental analyses for four experiment sites on the continental -
GLider Acoustics Sensing of Sediments (GLASS): experiments and data analysis
(CMRE, 2013/12)Seabed characteristics (geoacoustic properties and scattering strength) are critical parameters for sonar performance predictions. However, this bottom information is considered very difficult and expensive to achieve in ...