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Numerical modeling results for mode propagation in a wedge
(NATO. SACLANTCEN, 1987/11)
A PE (parabolic equation) code is used to study propagation in a shallow water wedge with a penetrable bottom. Particular attention is given to "wedge modes" that have wave fronts that are arcs of circles centered on the ...
Acoustic characterization of submerged aquatic vegetation
(NATO. SACLANTCEN, 1997)
The acoustic characteristics of submerged aquatic vegetation (SAV) were investigated in order to enhance the performance of mine-hunting and weapon sonars in littoral reglons. The specres of seagrass initially studied was ...
Channel-adapted source for shallow water
(NATO. SACLANTCEN, 1993/08)
In shallow water areas the utilization of active sonar is complicated by the fact that in these environments the performance of active systems is degraded by source signal interaction with channel boundaries. These boundary ...
Shallow water synthetic aperture sonar: an enabling technology for NATO MCM forces
(NURC, 2007/10)
The change in military focus from Cold War doctrine to expeditionary operations in shallower littoral water and the heightened terrorist threat to ports and their approaches, have put increased emphasis on countering ...
Modeling range-dependent, high-frequency, shallow-water torpedo reverberation data
(NATO. SACLANTCEN, 1997)
The high-frequency, forward bottom losses predicted by a lossy Rayleigh and a Biot poroelastic sediment model are substantially different. These differences will accumulate and become measurable in multiple bottom bounce ...
Sound propagation in shallow water: a detailed description of the acoustic field close to surface and bottom
(NATO. SACLANTCEN, 1982/02)
Experimental data are compared with normal-mode predictions for an isovelocity shallow-water propagation channel overlying a complicated layered bottom. Measurements were made close to both the sea surface and the sea floor ...
Site dependence of wind-dominated ambient noise in shallow water
(NATO. SACLANTCEN, 1982/06)
A survey of ambient noise data in shallow water taken under wind-dominated conditions shows substantial differences in spectrum level (often greater than 10 dB) under the same windspeerl and sea-state conditions. This ...
Achievable signal gains for line arrays in shallow water
(NATO. SACLANTCEN, 1993/08)
The well-documented conformance of signal gain to a 20 log n relationship for deep water, refracted paths, does not apply to shallow water where angular spreading effects from boundary roughness limit the signal gains that ...
Multipath pulse shapes in shallow water: theory and simulation
(NURC, 2007/04)
In shallow water propagation the steeper ray angles are weakened most by boundary losses. Regarding the sound intensity as a continuous function of angle it can be converted into a function of travel time to reveal the ...
High frequency matched field processing
(NATO. SACLANTCEN, 1997)
Results are discussed from a high frequency (0 9-5 7 kHz), very shallow water (<10 m) experiment exploring the feasibility of carrying out matched field processing in this frequency and water depth regime The data was ...