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Now showing items 11-20 of 48
Impact of uncertain environmental knowledge on the shallow-water transfer function
(NATO. SACLANTCEN, 1992/12)
It is assumed that the acoustic channel can be modeled as a linear time-invariant space-variant filter. In this case, from linear systems theory, it is known that the filter output, that is the predicted source signal ...
An acoustic, high resolution, sediment profiler
(NATO. SACLANTCEN, 1966/11)
An acoustic sediment profiler is described that utilizes short 50 kHz pulses to achieve a high range resolution. In trials in shallow water, penetration depths of about 9 m and resolution of about 25 cm were obtained. ...
The application of coupled-mode theory to propagation in shallow water with randomly varying sound speed
(NATO. SACLANTCEN, 1987/06)
Sound propagation in the Baltic Sea cannot be described correctly by range independent propagation
Passive localization using propagation models
(NATO. SACLANTCEN, 1987/06)
Passive ranging using propagation models can be effected in two different ways: forward modeling
Horizontal array gain in shallow water
(NATO. SACLANTCEN, 1980/12)
Some results of a comprehensive model study on the use of horizontal hydrophone arrays in shallow water are presented. Well-known signal processing techniques are applied to a shallow-water sound propagation model in order ...
A note on convergent zones
(NATO. SACLANTCEN, 1962/02)
An exact solution for ray paths near a sound channel with parabolic velocity profile is given for rays crossing the sound channel axis at small angles. The convergent zone for such rays for a source on axis is compared ...
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 ...
Deconvolution by homomorphic and Wiener filtering
(NATO. SACLANTCEN, 1988/09)
This study is concerned with deconvolution methods applied to underwater propagation in shallow