Browsing by Title
Now showing items 469-488 of 882
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Measurement and interpretation of angular spreading from multiple boundary interactions in a shallow water channel
(NATO. SACLANTCEN, 1997)The problem of angular spreading of sound that has undergone multiple boundary scattering (both sea surface and sea bed) in a shallow water channel is discussed. Measurements made of the horizontal spatial coherence along ... -
Measurement of the bubble population in coastal waters using combination frequencies of MHz order
(NATO. SACLANTCEN, 1997)This paper describes the use of a combinatron frequency technique to measure the size distribution of oceanic bubbles. Written between two sea trials, the paper describes how the apparatus cart be adapted to design tests ... -
Measurements and modelling of high-frequency acoustic scattering by a rough seafloor and sea surface
(NURC, 2009/12)Acoustic scattering by a rough, possibly dynamic interface is experimentally studied by insonifying the seabed and the sea surface at high frequency at various incidentangles. A directional source working at 300 kHz was ... -
Measurements and predictions of transmission loss at two sites in the Southwest Approaches to the English Channel
(NATO. SACLANTCEN, 1995/12)As part of a continuing series of measurements being made by -
Measurements for satellite validation made from the RV Alliance during October and November 1991
(NATO. SACLANTCEN, 1993/08)Measurements of sea-surface temperature, surface meteorology and atmospheric profiles were taken from the RV Alliance between 1 October -
Measurements of acoustic scattering from partially and completely buried spherical shells
(NATO. SACLANTCEN, 1999/04)Recent work at NATO SACLANT Undersea Research Centre has concentrated on investigating the use of low frequency sonars (2-20 kHz) in order to better exploit scattering features of buried targets that can contribute to their ... -
Measurements of correlation loss and time-spreading in linear FM sweeps and pseudo-random noise signals transmitted over long ranges in shallow water
(NATO. SACLANTCEN, 1986/12)The results of some transmission measurements made in shallow water are described. The ranges were about 15 km, 20 km, and 34 km, and the sound source was either suspended about 10 m above the bottom or was on the bottom ... -
Measurements of normal-mode amplitude functions in a nearly-stratified medium
(NATO. SACLANTCEN, 1975/10)In normal-mode treatments of acoustic propagation in nearly-stratified media, calculations are frequently based on the perfectly-stratified medium model, in which symmetry permits separation of the wave equationo In these ... -
Mechanisms for subcritical penetration into a sandy bottom: experimental and modelling results
(NATO. SACLANTCEN, 1998/05)This paper presents the results of a recent study whose overall objectives are to determine the mechanism(s) contributing to subcritical acoustic penetration into ocean sediments, and to quantify the results for use in ... -
Medium-induced low-frequency fluctuations in acoustic transmission loss: examples from measurements in selected geographical areas
(NATO. SACLANTCEN, 1986/06)The ocean is a complex, highly variable acoustic nedium. A propagating acoustic signal is affected by a host of phenomena, including the sea-surf ace and bottom, volume inhomogenei ties, internal waves and tides, and ... -
Methods used in France for the calculation of sound fields
(NATO. SACLANTCEN, 1971/12) -
METOC-driven Vessel Interdiction System (MVIS): supporting decision making in Command and Control (C2) systems
(CMRE, 2019/06)This paper presents a decision support system (DSS) to help Command and Control (C2) operators. Hereby, the METOC-driven vessel interdiction system (MVIS) is presented. It is aimed to help the decision-making process in ... -
Micro-bathymetry data acquisition for 3D reconstruction of objects on the sea floor
(CMRE, 2019/06)This paper describes an effort to capture micro-bathymetry data for the end purpose of 3D object reconstruction, using an AUV-borne multibeam echo sounder. Due to the combination of relatively narrow across-track coverage ... -
Mining maritime vessel traffic: promises, challenges, techniques
(CMRE, 2019/06)This paper discusses machine learning and data mining approaches to analyzing maritime vessel traffic based on the Automated Information System (AIS). We review recent efforts to apply machine learning techniques to AIS ... -
Mixed layer deepening and variability in the upperlayers if the central western Mediterranean, MILEX-82: final report
(NATO. SACLANTCEN, 1988/10)The 1982 Mixed-Layer Experiment (MILEX-82) is described in detail and the data are presented in ways designed to illustrate the spatial and temporal variability of the surface and deeper layers of the central western ... -
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 ... -
Mode and PE predictions of propagation in range-dependent environments: SWAM'99 workshop results
(NATO. SACLANTCEN, 2000/05)Three numerical acoustic models, a coupled normal-mode model (C-SNAP), -
Model for the frequency spread of backscattered underwater sound based on the facet model of the rough sea surface
(NATO. SACLANTCEN, 1978/11)A theoretical model for the doppler spread of backscattered acoustic waves from the rough sea surface is described on the basis of the decomposition of the continuous sea-surface spectrum that leads to the concept of facets. ... -
Model performance assessment for long-term vessel prediction using HFSW radar data
(CMRE, 2019/06)Vessels in open seas are seldom continuously observed. Thus, the problem of long-term vessel prediction becomes crucial. This paper focuses its attention on the performance assessment of the Ornstein- Uhlenbeck target ... -
Model statistics of inertial shear from multi- year simulations at weathership 'Mike': currents, atmospheric forcing, internal waves, mixed layer, Norwegian Sea)
(NATO. SACLANTCEN, 1990/12)In this memorandum we focus on one of the most important environmental