Browsing by Subject "Acoustic reverberation"
Now showing items 1-20 of 46
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A shallow water system for maximizing echo to reverberation ratio
(NATO. SACLANTCEN, 1993/08)A method for increasing incident energy on mid-depth targets while at the same range reducing boundary reverberation for shallow water ducts has been devised. The basis of the approach is couched in range dependant normal ... -
A theoretical model for doppler spread of backscattered sound from a composite roughness sea surface
(NATO. SACLANTCEN, 1975/10)For calculating the Doppler spread of acoustical reverberation from the sea surface, good results are achieved by applying a composite-roughness model. The small wavelets primarily responsible for the backscattering are ... -
Acoustic characterization of a shallow water site
(NATO. SACLANTCEN, 1993/08)Results are presented from an exercise aimed at providing a low frequency active sonar environmental characterization of a specific shallow water site in the Gulf of Mexico. Downward refracting acoustic transmission and ... -
Analysis of basin backscattering in the Levantine Sea
(NATO. SACLANTCEN, 1989/12)Research has been conducted in the Levantine Sea basin to measure low-frequency basin reverberation and relate the measurements to backscattering strength. The receivers were a towed horizontal array and a suspended vertical ... -
Application of ray tracing with horizontal gradient to monostatic boundary reverberation
(NATO. SACLANTCEN, 1971/12)Presented is the current work being done at the Naval Research Laboratory (NRL) on the development of a series of computer programs to predict long range, low frequency, monostatic boundary reverberation. The emphasis is ... -
Benchmarking scattering in ocean waveguides
(NATO. SACLANTCEN, 1995/07)Accurate numerical solutions are presented for benchmark problems -
Bottom reverberation in shallow water: coherent properties as a function of bandwidth, waveguide characteristics and scatterer distribution
(NATO. SACLANTCEN, 1998/10)Scattering physics are often modeled using the Helmholtz equation for computational reasons. Likewise, propagation loss to and from scattering regions are often treated in a like manner. The usual approach for generating ... -
Calculation of reverberation and average intensity of broadband acoustic signals in the ocean by means of the RAIBAC computer model
(NATO. SACLANTCEN, 1976/04)Based on the conventional ray-tracing principle, a fast numerical algorithm is developed that calculates averaged propagation loss and reverberation of underwater sound. The averaging is performed by summing incoherently ... -
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 -
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 measured reverberation on the transmission loss data with modelled results on the West Florida continental shelf
(NATO. SACLANTCEN, 1993/08)Acoustic data from the September, 1992 Area Characterization Test (ACT I) are compared to ADAM (Advanced Development Acoustic Model) output. Conduct of harsh shallow water acoustic exercises, and data interpretation mandates ... -
Effect of different bandwidths for the detection of extended targets in reverberation
(NATO. SACLANTCEN, 1993/08)In this paper, firstly the theoretical background of bandwidth effects on detection in noise and reverberation is presented in some detail, and secondly the relevant results of sea. trials with a low frequency active sonar ... -
Effects of sea bed structure on high frequency acoustic reverberation in shallow water
(NATO. SACLANTCEN, 1997)Although undoubtedly sea bed structures, patterns, and composition affect the reverberation of high-frequency acoustic energy, the extent of their influence is not well known. The effects of varying selected bedform ... -
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 ... -
High resolution feature extraction from reverberation data
(NATO. SACLANTCEN, 1997)A new method of signal approximatzon is presented which has the capability to model complex active returns due to reverberation. The method explored herein is data adaptive in the sense that high resolution processing is ... -
Low frequency active sonar: a NATO Conference held by SACLANTCEN on 24-28 May 1993 - collection of unclassified papers - volume 1 of 2
(NATO. SACLANTCEN, 1993/08)A conference on Low Frequency Active Sonar was held at SACLANTCEN from 24th to 28th May 1993. The conference was attended by over 100 delegates from NATO countries, and the topics presented ranged from environmental aspects, ... -
Low frequency active sonar: a NATO Conference held by SACLANTCEN on 24-28 May 1993 - collection of unclassified papers - volume 2 of 2
(NATO. SACLANTCEN, 1993/08)A conference on Low Frequency Active Sonar was held at SACLANTCEN from 24th to 28th May 1993. The conference was attended by over 100 delegates from NATO countries, and the topics presented ranged from environmental aspects, ... -
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 modelling of high-frequency acoustic scattering by a rough seafloor and sea surface
(NURC, 2009/12)Acoustic scattering by a rough, possibly dynamic interface is experimentally studied by insonifying the seabed and the sea surface at high frequency at various incidentangles. A directional source working at 300 kHz was ... -
Model-aided data adaptive suppression of reverberation
(NATO. SACLANTCEN, 1993/08)We propose a processing methodology which is based on the piece-wise modeling, adaptive estimation, and removal of reverberation components. An important feature of this approach is that backscatter models and information ...
