Browsing CMRE Publications by Issue Date
Now showing items 241-260 of 882
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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 ... -
Arctic ambient noise statistical measurement results and their implications to sonar performance improvements
(NATO. SACLANTCEN, 1982/06)Recent analyses of FRAM II arctic data have shown that under ice ambient noise can be at times highly impulsive and non-Gaussian. The analyses included time domain statistical measurements which were consistent with ... -
Site and frequency dependence of ambient noise in the North Eastern Pacific Ocean
(NATO. SACLANTCEN, 1982/06)One-hour averages of omnidirectional ambient noise measurements at 60 Hz and 165 Hz are analyzed for two nearby, deep ocean sites in the Northeastern Pacific during February and March 1981. Site A is a high noise site and ... -
Performance of three averaging methods for various distributions
(NATO. SACLANTCEN, 1982/06)The performance of three averaging methods, namely the sample median, the sample arithmetic mean, and the sample geometric mean, are analyzed in tenns of their bias, variance, and mean square error. The bias and variance ... -
Le programme Ulysse: réseau de bouées pour l'étude statistique du bruit ambiant sous-marin
(NATO. SACLANTCEN, 1982/06) -
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 . ... -
High-frequency normal-mode calculations in deep water
(NATO. SACLANTCEN, 1982/10)A method has been developed to perform high-frequency deep-water normal-mode calculations in the multikilohertz region in water depths of the order of 5 km. The results from this technique agree with fast field program ... -
Use of the towship for assessing towed-array performance and analyzing data quality
(NATO. SACLANTCEN, 1982/11)A series of relatively simple tests are presented and discussed, which used in conjunction with the noise received from the towship, can be used in real time to assess the performance of a towed array and the quality of ... -
Virtual beams from an FFT beamformer and their use to assess the quality of a towed-array system
(NATO. SACLANTCEN, 1983/01)Linear towed arrays with sophisticated signal processing systems have become popular for passive sonar and seismic prospecting. This is due to the ease of mobility and the large spatial gains achievable. However, because ... -
The optimum frequency of propagation in shallow-water environments
(NATO. SACLANTCEN, 1983/04)The optimum frequency of propagation in shallow water environments is the result of competing propagation and attenuation mechanisms at high and low frequencies. It is shown that the optimum frequency is strongly dependent ... -
Variable sea level and strait flows in the Mediterranean: a theoretical study of the response to meteorological forcing
(NATO. SACLANTCEN, 1983/05)Changes in atmospheric pressure over the Mediterranean are thought to account for a significant part of low frequency sea level changes and associated flow through the Strait of Gibraltar. However, Crepon's (1965) examination ... -
An evaluation of digitized APT data from the TIROS-N/NOAA-A, -J series of meteorological satellites
(NATO. SACLANTCEN, 1984/03)The TIROS-N/NOAA-A,-J series of meteorological satellites transmit imagery data to the Earth in both digital and analogue formats. The analogue data are a processed subset of the digital dat and have lower resolution. A ... -
Review of numerical models in underwater acoustics including recently developed fast-field program
(NATO. SACLANTCEN, 1984/12)Two papers given by SACLANTCEN personnel at the NATO Advanced Research Workshop on Hybrid Formulation of Wave Propagation and Scattering at Castel Gandolfo, Rome, Italy on 30 August to 3 September 1983 are published as a ... -
Incidence du bruit acoustique de thoniers ligneurs et senneurs français sur leurs performances de peche
(NATO. SACLANTCEN, 1985/01)Les auteurs présentents quelques expertises acoustiques provenant de deux études réalisées par le GERBAM: - la première, sur 95 thoniers ligneurs pratiquant la pêche du germon (Thunnus alalunga), -la second, sur 18 thoniers ... -
Mutual coherence and silence
(NATO. SACLANTCEN, 1985/01)In this paper we are developing the theoretical principle of a modification of the acoustical emission by a ship. Its objective is making inefficient the angular measurements achieved by a detector. More precisely, the ... -
Mobile range for measuring ship radiated acoustic noise
(NATO. SACLANTCEN, 1985/01)The Mobile Range described in this paper allows measurements of noise radiated from both surface ships and submarines in open seas with bottom depths from less than lOOm to 400 meters. The range is being developed and built ... -
Propeller leading edge trimming and maintenance effects on ship's noise operational performance
(NATO. SACLANTCEN, 1985/01)In the last ten years, considerable experience has been gathered at CEIMM's cavitation tunnel (Centra Esperienze Idrodinamiche Marina Militare) on the effects of propeller leading edge geometry on cavitation (and noise) ... -
Near field propeller radiated noise measurements: model and full scale experimental data comparison
(NATO. SACLANTCEN, 1985/01)The ever rising interest related to the underwater no1se originating from cavitating propellers prompted the Italian Navy to study this aspect of naval architecture in an experimental way. This was accomplished carrying ... -
Different approaches to economic cruising speeds on a CODOG frigate with due regard to radiated noise
(NATO. SACLANTCEN, 1985/01)All navies, in recent years, have been much more concerned in economic cruising speeds of ships. Frigate type naval ships are usually characterized by two shafts, by multiple propulsion engines per shaft, and by different ... -
Silent ship research applications and operation: proceedings of a conference held at SACLANTCEN on 2-4 October 1984 - volume 2: unclassified papers
(NATO. SACLANTCEN, 1985/01)Introduction: The project to construct an acoustically quiet research ship for the SACLANT ASW Research Centre provided a reason for SACLANTCEN to organize a conference on silent ships, their operation and applications. ...