OCEANS '94. 'Oceans Engineering for Today's Technology and Tomorrow's Preservation.' Proceedings

13-16 Sept. 1994

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  • Performance of angle estimation methods applied to multibeam swath bathymetry

    Publication Year: 1994, Page(s):III/231 - III/236 vol.3
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (505 KB)

    The performance is assessed of standard angle estimation methods applied to the evaluation of the direction of arrival of the seafloor returns, in the context of multibeam swath bathymetry. It is shown to be limited not only by the electronic or ambient noise on the hydrophones, but also by two noise contributions which result from the angular extent of the resolution cell on the seafloor and the ... View full abstract»

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  • Hydrodynamic manoeuvrability data of a flatfish type AUV

    Publication Year: 1994, Page(s):III/425 - III/430 vol.3
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (452 KB)

    Hydrodynamic manoeuvrability data of the flatfish type autonomous underwater vehicle (AUV) “MARIUS” are presented. “MARIUS” was developed under the EC MAST Programme as a vehicle for seabed inspection and environmental surveys in coastal waters. The AUV has an overall length of 4.5 m and is driven by two propellers and four thrusters. The data comprise added mass and inerti... View full abstract»

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  • Dynamic properties of AUV “Typhlonus”

    Publication Year: 1994, Page(s):III/421 - III/424 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (220 KB)

    In the paper the questions of choice of Typhlonus autonomous underwater vehicle (AUV) hydrodynamic properties and features of the motion control system by velocity, depth and heading channels, are considered. The evaluation of vehicle dynamic properties is given, using sea tests results. The vehicle main properties, minimal hydrodynamic resistance and high maneuverability with stability, provides ... View full abstract»

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  • United States Navy operational oceanographic nowcast/forecast system

    Publication Year: 1994, Page(s):III/45 - III/50 vol.3
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (564 KB)

    The Commander, Naval Meteorology and Oceanography Command operates a system of meteorological and oceanographic models for continuous, realtime nowcast/forecast support to United States Department of Defense forces, particularly for Navy/Marine Corps safety of navigation, exploitation of oceanic fronts, and nearshore tactical employment of ships, aircraft and personnel for mine warfare, strike war... View full abstract»

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  • Oceanographic results from the assimilation of ERS-1 altimetric data in SOAP93 forecasting system

    Publication Year: 1994, Page(s):III/363 - III/367 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (404 KB)

    The French “Service Hydrographique et Oceanographique de la Maritime” (SHOM) is conducting a term program called SOAP. It aims at oceanic mesoscale variability, in real time. SOAP uses remote sensing data, in-situ data and ocean models. The authors present long time series of oceanographic results obtained during 1992 and 1993 assimilating ERS-1 altimeter data in a quasi-geostrophic mo... View full abstract»

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  • Autonomous navigation with sparse reference points

    Publication Year: 1994, Page(s):III/415 - III/420 vol.3
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (408 KB)

    This paper presents a navigation system for an autonomous underwater vehicle (AUV) that allows long range navigation by combining two distinct modes: local positioning with respect to a long baseline array of known localization (reference points) and autonomous mode in-between reference points, relying only on sonar/Doppler and depth information. In both modes, a Kalman based design approach was c... View full abstract»

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  • Simultaneous use of eulerian and lagrangian currents measured by VHF radars for estimating the horizontal diffusion coefficient in coastal circulation

    Publication Year: 1994, Page(s):III/40 - III/44 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (328 KB)

    A VHF radar has been used to locate a drifting transponder for measuring the lagrangian circulation in the coastal zone. It is expected that simultaneous use of several drifters will give an insight into small scale dispersion and diffusion phenomena. The paper describes the radar and transponder system, and outlines the method used to estimate the horizontal diffusion coefficient View full abstract»

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  • Description of the ocean prediction system SOAP 93

    Publication Year: 1994, Page(s):III/359 - III/362 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (256 KB)

    The French “Service Hydrographique et Oceanographique de la Marine” (SHOM) conducts a long term program called SOAP which aims at describing the oceanic mesoscale variability in real time using remote sensing data, in situ data and ocean models. The first phase of the program called SOAP 93 consists in assimilating satellite altimetric data into an eddy resolving multilayer open ocean ... View full abstract»

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  • Fisheries enforcement through vessel localization using AVHRR and SAR technology

    Publication Year: 1994, Page(s):III/313 - III/318 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (536 KB)

    Natural Resources Consultants, Western Resources Analysis and NASA are investigating the application of Advanced Very High Resolution Radiometer (AVHRR) and Synthetic Aperture Radar (SAR) technology to fisheries enforcement concerns. The goal of the project is to develop and market a surveillance system that can passively monitor fishing vessel locations in near real time. Work has been conducted ... View full abstract»

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  • Vehicle localisation in a poorly known environment

    Publication Year: 1994, Page(s):III/409 - III/414 vol.3
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (428 KB)

    The aim of this paper is to present an algorithm for the localisation of a vehicle in an unknown or partially known environment. The basic localisation algorithm uses extended Kalman filtering to fuse internal movement information and observations of absolute references. These references are artificial beacons or specific environment elements with known positions. In this paper we propose an exten... View full abstract»

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  • Lagrangian ambient noise drifter

    Publication Year: 1994, Page(s):III/34 - III/39 vol.3
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (420 KB)

    The Defence Research Establishment Atlantic has carried out an experiment to study the relationship between ambient noise and oceanographic features in regions of pronounced oceanic currents, such as the Gulf Stream or its eddies, using a field of purpose built, long life drifting buoys developed and maintained at sea by Seimac Limited, of Dartmouth, Canada. These Lagrangian Ambient Noise Drifters... View full abstract»

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  • FOAM-an operational forecasting ocean-atmosphere model for naval applications

    Publication Year: 1994, Page(s):III/353 - III/358 vol.3
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (500 KB)

    The paper describes the philosophy behind the development of FOAM, a forecasting ocean atmosphere model that is being developed for operational use by the Royal Navy View full abstract»

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  • A drifter for tracking oil spills using the Argos system

    Publication Year: 1994, Page(s):III/292 - III/297 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (404 KB)

    Several versions of oil spill markers have been developed to assist in the tracking of spills in the coastal waters of western Canada. The authors fitted the markers with a fabric skirt to slow their descent from aircraft and found that the skirt helped simulate the movement of an oil spill if it remained attached to the marker. The first operational version of these spill markers, incorporating a... View full abstract»

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  • Ocean forecast intervention using combined visualisation of oceanographic and remote sensed data

    Publication Year: 1994, Page(s):III/69 - III/74 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (448 KB)

    Current developments in oceanographic forecasting and remote sensing will provide potential users with such large volumes of data that it will be difficult to interpret and assimilate manually. One such user is that of the oceanographic forecaster who must control the assimilation of oceanographic data from a diverse range of sources to produce a single forecast sequence. This paper describes the ... View full abstract»

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  • Application of fluorescence synchronous spectra for oil pollution identification

    Publication Year: 1994, Page(s):III/308 - III/312 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (296 KB)

    It is shown that synchronous fluorescence spectra can be used for identification of oil type directly in water as well as in hexane extracts from water samples. Different oil products (gasoline, diesel fuel, kerosene, machine oil, some crude oils) and their water samples, hexane solutions and hexane extracts from water samples were studied. On the basis of obtained spectroscopic results it has bee... View full abstract»

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  • The design and performance of a compact underwater acoustic network node

    Publication Year: 1994, Page(s):III/467 - III/471 vol.3
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (428 KB)

    A major focus of the Acoustic Telemetry Group at Woods Hole Oceanographic Institution (WHOI) has been the development of underwater acoustic communication networks. Similar to a cellular telephone network, an acoustic network consists of a number of nodes or modems which adaptively route digital data packets between scientific sensors and a data collection or viewing point. A significant milestone... View full abstract»

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  • The feasibility of a very-long baseline acoustic positioning system for AUVs

    Publication Year: 1994, Page(s):III/403 - III/408 vol.3
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (540 KB)

    Positioning an AUV over a wide operational zone in deep water may be addressed through a very long baseline (VLB) acoustic positioning system. Ranges of 50 to 100 km can be obtained using modulated signals around 2-3 kHz, providing a sufficient signal-to-noise ratio and a good accuracy in time measurements for most environmental conditions. Nevertheless two major problems have to be solved if a go... View full abstract»

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  • Two-way solution of underwater sound propagation problem in two and three-dimensional environment by pseudodifferential parabolic equation technique

    Publication Year: 1994, Page(s):III/159 - III/162 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (208 KB)

    The paper presents some recipes for underwater sound calculations in 2D and 3D ocean models with sound speed and density slowly varying with horizontal coordinates and arbitrary in depth including a nonhomogeneous liquid model of bottom. These recipes are based on the idea of WKB-like factoring and the extensive use of high order Pade approximations for numerical solving of arising pseudodifferent... View full abstract»

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  • Underwater acoustic channel simulations for communication

    Publication Year: 1994, Page(s):III/495 - III/500 vol.3
    Cited by:  Papers (25)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (472 KB)

    Discusses communication from a transmitter to a receiver, one or both of which may be mobile. From recordings obtained regularly during the year in the Mediterranean Sea, the authors show in the first part the propagation modifications and their influence on the transmission conditions. From many experimental results already obtained in the authors' laboratory, they present briefly a general chara... View full abstract»

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  • Acoustic vorticity meter for benthic boundary layer flow measurements

    Publication Year: 1994, Page(s):III/250 - III/253 vol.3
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (540 KB)

    An acoustic travel-time flow-meter that had been configured to measure vorticity on scales of 15 and 45 centimeters has now been configured to measure benthic boundary layer vorticity over a scale of 1.5 meters. Closed square paths in each sensor define three orthogonal axes of vorticity. Originally constructed to measure shear in the presence of waves, the 15 cm and 45 cm sensors have an expected... View full abstract»

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  • Influence of mooring dynamics on current records

    Publication Year: 1994, Page(s):III/28 - III/33 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (360 KB)

    In order to evaluate some tidal records made during the GASTOM 90 oceanographic mission, a dynamic finite element simulation is used to study the behaviour of mooring lines. A theoretical approach, mainly a non-dimensional analysis and parametric study based on a simplified mesh, allows the authors to identify the relevant parameters for the modelisation and the accurate environmental constraints ... View full abstract»

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  • Data assimilation within the Forecasting Ocean Atmosphere Model (FOAM)

    Publication Year: 1994, Page(s):III/347 - III/352 vol.3
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (500 KB)

    FOAM, the Forecasting Ocean Atmosphere Model, is a system designed to produce analyses and short-range forecasts for the deep ocean. At the heart of FOAM is a standard numerical model of the ocean. The system uses the “analysis correction” scheme to analyse observations. The main advantages of this scheme are that it is relatively inexpensive (especially when compared with full variati... View full abstract»

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  • In-situ particle sizing at sea bottom interface

    Publication Year: 1994, Page(s):III/287 - III/291 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (424 KB)

    Particle size discrimination has been becoming practically available for direct underwater suspended matter quantification. At the bottom sediment water interface, it is particularly important to make relevant characterization of the sediment transport process in order to get good correlations between erosion and environmental stresses such as current or wind effects. The paper presents some exper... View full abstract»

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  • Coupling and propagation of elastic waves in Artic pack ice

    Publication Year: 1994, Page(s):III/600 - III/605 vol.3
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (400 KB)

    Acoustic sources under Arctic pack ice give rise to vibratory motion that travels in the ice sheet. These in-ice vibrations are detectable and can be used to localize the under-ice sources. This paper presents analysis of data from geophone and hydrophone arrays deployed during ICEX-I-90. Addressed are basic issues relating to the behavior of the waves. Primary interest was placed on characterizin... View full abstract»

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  • Fuel cell power systems for submersibles

    Publication Year: 1994, Page(s):III/449 - III/452 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (312 KB)

    International Fuel Cells Corporation (IFC) has successfully demonstrated a 10 kW prototype fuel cell power plant for a 44-inch submersible. The power plant features multiple proton exchange membrane (PEM) fuel cell stacks; a single stack is insertable into a 21-inch vehicle. Fueled by hydrogen and oxygen, it has demonstrated 68 percent energy efficiency at rated power. Fuel cells are attractive ca... View full abstract»

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