Browsing Reprints by Title
Now showing items 250-269 of 548
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Influence of background-noise spatial coherence on high-resolution passive method
(NATO. SACLANTCEN, 1982/06)New signal processing methods for passive listening have appeared recently : they are called "high resolution" methods because they have theoretically a better resolving power than conventional or adaptive beamforming . ... -
Influence of internal waves on sound propagation in the SOFAR channel
(NATO. SACLANTCEN, 1975/10)In this paper theoretical investigations due to the influence of internal waves to sound propagation in the SOFAR-channel are presented. The undisturbed acoustic field is described by a normal-mode model. The disturbance ... -
Information and source quality ontology in support of maritime situational awareness
(CMRE, 2019/05)To support situation awareness, the benefit of using a variety of sources is undeniable although it brings additional challenges related to possible conflicting information, heterogeneity in data formats, semantics, ... -
Intensity and phase fluctuations in low-frequency acoustic transmission through internal waves
(NATO. SACLANTCEN, 1975/10) -
Intensity at caustics
(NATO. SACLANTCEN, 1971/12)The classical divergence expressions predict an infinite intensity at caustics. This infinite intensity is a fundamental limitation of geometrical acoustics (ray theory). The intensity at a caustic is of primary concern ... -
Intensity calculations along a single ray
(NATO. SACLANTCEN, 1974/02)A method is presented for the calculation of sound intensity using only one ray. The sound-velocity profile is assumed to be continuous up to the second derivative and it is supposed that the ray equations are solved ... -
Intensity calculations along a single ray
(NATO. SACLANTCEN, 1971/12)A method is presented for the calculation of sound intensity using only one ray. The sound velocity profile is assumed to be continuous up to the second derivative and it is supposed that the ray equations are solved ... -
Intensity moments of underwater sound scattered by a Gaussian spectrum corrugated surface: measurements and comparison with a catastrophe theory approximation
(NATO. SACLANTCEN, 1997)An underwater forward-scattering investigation was undertaken with random rough corrugated pressure release surface manufactured out of Styrofoam. Measured wavefields associated with the reflection caustics agree with ... -
Intensity-range relations for shallow-water sound propagation
(NATO. SACLANTCEN, 1976/04)Convincing experimental evidence is presented to show that various "decay laws" for the decrease of sound intensity with increasing range can give high-quality representation for shallow water data. However, while a sequence ... -
Interactive tools for the exploration and analysis of multibeam and other seafloor acoustic data
(NATO. SACLANTCEN, 1997)The Ocean Mapping Group has developed a full suite of software tools for the real-time or near real-time display, editing, quality control, interpretation and visualization of multibeam sonar data. The combination of ... -
Interface wave studies on the Ligurian shelf usingan OBS array: experimental results and propagation models
(NATO. SACLANTCEN, 1986/06)Seismic waves travelling in the water/sediment or subbottom sediment/sediment interface have been the subject of considerable interest in recent years. Experiments have confirmed the existence of interface waves in different ... -
Intermediate water downstream of the Strait of Sicily
(NATO. SACLANTCEN, 1972/09)In July 1970 the ATLANTIS II sailed through the western Mediterranean providing an opportunity to make a quasi-synoptic observation of the Levantine Intermediate Water between the Strait of Gibraltar and the Strait of ... -
Internal oceanographic microstructure phenomena
(NATO. SACLANTCEN, 1975/10)This paper is concerned with the nature and causes of both fine structure and microstructure in the ocean. Following an account of the acoustic/oceanographic background to subject, the characteristics of fine structure are ... -
Inverse wave propagation in an inhomogeneous waveguide
(NATO. SACLANTCEN, 1975/10)A solution is given for the problem of inverse propagation in an inhomogeneous rectangular two-dimensional waveguide. The sound speed is assumed to vary in depth and inverse propagation means the calculation of the field ... -
Is power averaging the best estimator for undersea acoustic data?
(NATO. SACLANTCEN, 1982/06)The power average is the statistic which is commonly used in all types of acoustic data processing. It is an excellent estimator for "well behaved" Gaussian distributions when the central or average value is desired. ... -
JANUS-based services for operationally relevant underwater applications
(CMRE, 2017/11)This paper presents the design, test, and experimentation at sea of four JANUS-based services for operationally relevant underwater applications: 1) first contact and language switching; 2) transmission of automatic ... -
Joint probabilistic data association tracker for extended target tracking applied to X-band marine radar data
(CMRE, 2019/06)X-band marine radar systems are flexible and low-cost tools for monitoring multiple targets in a surveillance area. Although they may suffer from several sources of interference, e.g., sea clutter, they can provide ... -
Joint probabilistic data association tracker for extended target tracking applied to X-band marine radar data
(CMRE, 2017/11)X-band marine radar systems are flexible and low-cost tools for monitoring multiple targets in a surveillance area. Although they may suffer from several sources of interference, e.g., sea clutter, they can provide ... -
Knowledge-based ship tracking applied to HF surface wave radar data
(CMRE, 2019/06)In recent years, low-power high-frequency surface-wave radars have received significant attention thanks to their over-the-horizon coverage capability and the continuous-time operation mode. These radars have become effective ... -
Knowledge-based ship tracking applied to HF surface wave radar data
(CMRE, 2019/06)In recent years, low-power high-frequency surface-wave radars have received significant attention thanks to their over-the-horizon coverage capability and the continuous-time operation mode. These radars have become effective ...