Browsing by Title
Now showing items 840-859 of 882
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Time-frequency representation of model based high frequency broad band scattering from a rough interface
(NATO. SACLANTCEN, 1997)A formulism for scattering a broad band high frequency pulse from a randomly rough surface of n penetrable oceanic sediment is developed and used to investiyate the ability of local cosine transform (LCT) rime-frequency ... -
Toeplitz constrained adaptive beamforming with auxiliary data
(NATO. SACLANTCEN, 1997/02)Submarine and mine detection using active sonar face similar problems when adaptive beamforming is required to provide high angular resolution or to suppress angularly isolated interferences. Both -
Toward the development of secure underwater acoustic networks
(CMRE, 2019/05)Underwater acoustic networks (UANs) have been recognized as an enabling technology for various applications in the maritime domain. The wireless nature of the acoustic medium makes UANs vulnerable to various malicious ... -
Towards fully autonomous underwater vehicles in ASW scenarios: an adaptive data driven AUV mission management layer
(CMRE, 2019/06)We present an adaptive, data driven Mission Management Layer (MML) to manage the phases (surveillance, track prosecution and target reacquisition) of the mission of AUVs operating as receiver nodes in a multistatic network ... -
Tracking an unknown number of targets using multiple sensors: a belief propagation method
(CMRE, 2019/06)We propose a multisensor method for tracking an unknown number of targets. Low computational complexity and very good scalability in the number of targets, number of sensors, and number of measurements per sensor are ... -
Transmission-loss characteristics and geoacoustic model for an outer Albanian continental shelf platform in the south-east Adriatic sea
(NATO. SACLANTCEN, 1996/03)Transmission-loss experiments have been canied out on the outer Albanian Shelf. The acoustic measurements were performed together with a combined oceanographic and geological-geophysical survey which identified the different ... -
Transmission-time variability, vertical spatial and temporal analysis of NAPOLI'85, an experiment in the Tyrrhenian Sea
(NATO. SACLANTCEN, 1989/09)An acoustic propagation experiment (NAPOLI '85) was carried out in the Tyrrhenian Sea in October 1985 in which signals from a broadband source were recorded at a range of 5 km with a vertical 62-m hydrophone array over a ... -
Twenty years of research at the SACLANT ASW Research Centre: 1959-1979
(NATO. SACLANTCEN, 1980/01) -
Two dimensional internal-wave spectra
(NATO. SACLANTCEN, 1975/10)Although spatial fluctuations of the sound speed in the ocean have a variety of causes, internal waves are thought to produce most of the fluctuations over horizontal scales ranging from several tens of metres to several ... -
Two-dimensional space-series analysis for sea-floor roughness
(NATO. SACLANTCEN, 1979/10)For a quantitative description of the sea-floor roughness, a numerical method has been developed to obtain the two-dimensional power spectrum and the autocorrelation function. The determination of these parameters gives ... -
Underwater acoustics - modelling: keynote address
(NATO. SACLANTCEN, 1975/10) -
Underwater ambient noise: proceedings of a conference held at SACLANTCEN on 11-14 May 1982, vol. 2 - Unclassified Papers, part 2
(NATO. SACLANTCEN, 1982/06)Contents: PROCESSING TECHNIQUES--A method of estimating the influence of ship's noise on ambient noise measurements; Optimal detection and tracking of acoustical noise sources in a time-varying environment; Influence of ... -
Underwater communications research and development at CMRE
(CMRE, 2019/06)A key to developing autonomous maritime systems for NATO is communication among data gathering platforms below and above the water. However, unlike the mature technologies that are used for terrestrial networks, underwater ... -
Underwater intruder detection sonar for harbour protection: state of the art review and implications
(NURC, 2006/08)Sonar is the sensor of choice for wide-area underwater surveillance because sonar (based on sound waves) typically provides a much larger area of coverage than radar (electromagnetic waves) or video (visible light) can ... -
Underwater optical and acoustic imaging: a time for fusion? a brief overview of the state-of-the-art
(CMRE, 2019/06)Underwater optical imaging has several drawbacks inherent to the physical medium such as light attenuation and turbidity. Sonars try to obviate those issues although, typically, they have lower resolutions. Combining visual ... -
Underwater photography for quantitative description of bottom roughness
(NATO. SACLANTCEN, 1985/04)Knowledge of the roughness of the sea floor is obviously of great importance in marine geology for understanding the processes of the ocean bottom, and in underwater acoustics for understanding the scattering process. The ... -
Underwater source localization using a hydrophone-equipped glider
(CMRE, 2014/01)Buoyancy-driven underwater gliders are autonomous underwater vehicles that were originally developed to collect oceanographic data. CMRE is studying the use of this technology for the characterization of denied areas, ... -
Underwater target classification in synthetic aperture sonar imagery using deep convolutional neural networks
(CMRE, 2019/06)Deep convolutional neural networks are used to perform underwater target classification in synthetic aperture sonar (SAS) imagery. The deep networks are learned using a massive database of real, measured sonar data collected ... -
Uniqueness problems in extracting environmental parameters from high-frequency shallow-water reverberation measurements
(NATO. SACLANTCEN, 1997)Inversion techniques that extract environmental parameters from measured reverberation often lead to mathematical problems that are not well-posed. Two examples illustrate this possibility. The first hows how a model can ...