Oceans '97. MTS/IEEE Conference Proceedings最新文献

{"title":"The Eastern Canada Shallow Water Ambient Noise experiment","authors":"M. Hazen, F. Desharnais","doi":"10.1109/OCEANS.1997.634410","DOIUrl":"https://doi.org/10.1109/OCEANS.1997.634410","url":null,"abstract":"In recent years the underwater acoustics community has shifted focus from oceanic to littoral water areas. Working with shallow water acoustics is extremely challenging since the environment can change dramatically in both time and space. The Eastern Canada Shallow-Water Ambient-Noise (EC-SWAN) experiment had the purpose of collecting data on the temporal and spatial variation of ambient noise in Eastern Canadian waters. One hour data samples were collected monthly from four sites across the Grand Banks of Newfoundland and the Scotian Shelf from December of 1995 to December of 1996. This paper describes the experimental process utilized, and presents samples of the data that demonstrate the temporal and spatial variability observed. In particular, the variability of the noise field due to biological, shipping and wind sources is explored.","PeriodicalId":259593,"journal":{"name":"Oceans '97. MTS/IEEE Conference Proceedings","volume":"224 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116123390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrated maritime surveillance (IMS) for the Grand Banks","authors":"R. Moutray, A. Ponsford","doi":"10.1109/OCEANS.1997.624124","DOIUrl":"https://doi.org/10.1109/OCEANS.1997.624124","url":null,"abstract":"June 1997 will see the launch of a new approach to surveillance of the 200 nautical mile Exclusive Economic Zone (EEZ). Work on a demonstration system off Canada's east coast began in March 1996. This collaborative project is the result of more than a decade of research and development. The demonstration system will provide continuous, all-weather surveillance of aircraft, surface vessels, icebergs and environmental conditions in the Grand Banks region to beyond the 200 mile limit. A shore based HF surface wave radar is the key sensor in the new system. This is the only technology that can provide continuous, cost effective, over-the-horizon surveillance at such long ranges. Re-using existing systems is a key element in the development strategy. These potentially include reports from Coast Guard and Fisheries patrol vessels, patrol aircraft, automatic dependent surveillance (ADS) reports from Coast Guard and fishing vessels and imaging satellite data, Surface wave radar provides the backbone picture by detecting and tracking all targets in the region but inputs from the other systems are essential in classifying and identifying the targets. Evaluation of the east coast system will include operation under extreme weather and sea state conditions, surveillance and management support to the east coast fisheries, enhanced visibility of tanker and support traffic to and from the Hibernia and Terra Nova oilfields, detection and tracking of icebergs and enhanced support for search and rescue and drug interdiction operations.","PeriodicalId":259593,"journal":{"name":"Oceans '97. MTS/IEEE Conference Proceedings","volume":"112 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126791181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-resolution near-seabed velocity and sediment transport profiling","authors":"R.F. van Unen, K.J.M. van Ruiten, J. Bosman","doi":"10.1109/OCEANS.1997.634412","DOIUrl":"https://doi.org/10.1109/OCEANS.1997.634412","url":null,"abstract":"In the Netherlands morphological studies are quite important because of the dynamics of the Dutch coastline and rivers. These types of processes require accurate and high resolution (both in time and space) measuring equipment, which so far was unavailable. Conventional Doppler profiling techniques (ADCPs) are hampered by the fact that the bottom 10-15% of the depth range cannot be measured. Non-acoustic methods for 'in-situ' and point current and/or concentration measurements disturb the actual phenomena under study. By this new acoustic method, based on incoherent cross-correlation techniques in the time domain, profiles now can be measured in these last few meters near the seabed. This remote sensing technique uses various pairs of vertical downward looking active acoustic transducers. This method has been developed and extensively tested for various conditions in the MAST VERTPARSE project. The experimental ranges varied for mean particle sizes from 50 /spl mu/m up to 500 /spl mu/m and for flow velocities in the range from 0.5 m/s up to 2.0 m/s. The experiment was focused on an upper river situation. In a dynamical process starting from a horizontal bed with a water flow velocity of 1.0 m/s sand dunes occurred with a typical height of 0.3 m and horizontal dimensions of 3.0 m. During this process particles with a mean diameter of 480 /spl mu/m were suspended by the current and observed by this method. The flume experiment provided a unique facility to observe these realistic morphological processes instantaneously. Additional measurements under realistic field conditions have already been preformed in a wave tunnel and in the Dutch coastal area near the Rotterdam Harbour. Velocity and concentration profiles have been measured with a vertical resolution of 0.015 m down to the very seabed. The mean and standard deviation of the flow velocity profiles are in agreement with reference measurements. The concentration profiles have not been checked yet in an absolute sense, but are looking very realistic compared to what is to be expected from theory and other experiments. This method proved itself robust for flow velocity measurements, so it can be implemented as a standard instrument in operational field experiments. The advantage of spatial resolutions to be selected by the observer and the facility of measurements down to the seabed including bottom tracks, give new opportunities in the development and calibration of morphological models.","PeriodicalId":259593,"journal":{"name":"Oceans '97. MTS/IEEE Conference Proceedings","volume":"151 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117346505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multibeam sonar bottom detection using multiple subarrays","authors":"Luren Yang, T. Taxt","doi":"10.1109/OCEANS.1997.624116","DOIUrl":"https://doi.org/10.1109/OCEANS.1997.624116","url":null,"abstract":"Two new bottom detection methods for multibeam bathymetric sonars are presented. Both of the methods are based on the early separate aperture method which combines amplitude and phase in the bottom detection. As a generalization of the separate aperture method, multiple subarrays are used to estimate the direction of arrival of the bottom echoes of oblique incident angles. An image transform is used to compute the bottom depth from the phase information. The methods were evaluated using Simrad EM3000 sonar data recorded from shallow water. The results show that both methods improve the bottom detection performance for oblique beams. The multiple subarray method is particularly useful for shallow water applications.","PeriodicalId":259593,"journal":{"name":"Oceans '97. MTS/IEEE Conference Proceedings","volume":"127 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117353458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An application of tapered, PZT composite lenses in an acoustic imaging sonar with 1-cm resolution","authors":"E. Belcher, D. C. Lynn","doi":"10.1109/OCEANS.1997.624135","DOIUrl":"https://doi.org/10.1109/OCEANS.1997.624135","url":null,"abstract":"This paper describes an experimental sonar with a resolution of 1 cm and a maximum range of 2.4 m. It was built to inspect hulls for fouling and damage in turbid water where optical systems fail. The system specifications called for a forward-looking sonar that could ensonify an area 0.6 m/spl times/1.5 m with 1-cm resolution. The sonar would mount on a remotely operated vehicle (ROV) that crawled systematically over the hull to assess fouling or to specific points to assess damage. The image needed to be refreshed rapidly enough that the sonar could also serve as a navigation aid for the ROV. Our solution was a mechanically scanned system with four transducers on a single shaft. The operating range and resolution allowed a refresh rate of two scans per second. The maximum range of 2.4 m allowed an operating frequency of 3 MHz, and thus a transducer aperture of only 12 cm was needed to obtain the 0.2/spl deg/ beamwidth. Each transducer was cut from a PZT composite. The cut transducers were given a tapered, diamond shape that significantly reduced the beampattern sidelobes in azimuth and elevation. Unfortunately, the calculated far field of the transducers was 22.6 m! The far field was shortened to 2 m by placing a plano-concave lens in front of each tapered PZT composite. The in-water electronics were connected to the surface electronics by a 150-m fiber optic cable. The system provided images with enough detail to allow the user to note individual barnacles or colonies of barnacles, peeling paint, and details on fixtures mounted on the hulls.","PeriodicalId":259593,"journal":{"name":"Oceans '97. MTS/IEEE Conference Proceedings","volume":"30 38","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120811815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seabottom roughness measurement by aquatic walking robot","authors":"J. Akizono, T. Tanaka, K. Nakagawa, T. Tsuji, M. Iwasaki","doi":"10.1109/OCEANS.1997.624200","DOIUrl":"https://doi.org/10.1109/OCEANS.1997.624200","url":null,"abstract":"Port construction works in Japan are now being done in deeper sea areas than before. Flattening of the rubble mound foundation in these deeper areas are carried out by machines because human divers' working time is very short at these depths. The authors developed a six-legged aquatic walking robot for underwater inspection. The robot named \"AQUAROBOT\" is navigated by an LBL ultrasonic transponder on the machine-leveled rubble mound foundation at up to 50 m depth. AQUAROBOT is able to walk on the uneven surface of the mound autonomously with its several sensors. Roughness is measured by the foot motion and pressure gauge during walking. The measured data is compensated for the tide.","PeriodicalId":259593,"journal":{"name":"Oceans '97. MTS/IEEE Conference Proceedings","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127836900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the development of an active vision system for 3-D scene reconstruction and analysis from underwater images","authors":"J. Strickrott, S. Negahdaripour","doi":"10.1109/OCEANS.1997.634438","DOIUrl":"https://doi.org/10.1109/OCEANS.1997.634438","url":null,"abstract":"Detection, localization and recognition of objects and nearby obstacles are critical in employing intelligent (autonomous) underwater vehicles for surveillance, collision- free navigation, target tracking, docking, surveying and mapping the ocean floor. Although deployment of video cameras onboard submersibles have become commonplace, computer processing of underwater images for scene reconstruction and interpretation is a technology yet to be developed. This paper describes steps toward the development of an active vision system for intelligent data acquisition and processing. This provides the capability to obtain information about the scene from video images online, and to exploit this knowledge in enhancing the data acquisition process; by achieving optimum parameters and geometry of the imaging system to improve image quality and information content.","PeriodicalId":259593,"journal":{"name":"Oceans '97. MTS/IEEE Conference Proceedings","volume":"31 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133613324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"EUROMAR-MERMAID: experimental operation of the prototype network","authors":"H. Knauth, F. Schroeder, D. Kohnke, F. Holzkamm","doi":"10.1109/OCEANS.1997.634448","DOIUrl":"https://doi.org/10.1109/OCEANS.1997.634448","url":null,"abstract":"The need for automated systems for the monitoring of chemical and biochemical parameters for which, however, appropriate instruments have not been available in the past, resulted in the definition of the EUREKA-EUROMAR project MERMAID. It is a joint project incorporating scientific and industrial partners from Germany, France, Norway, and Canada. In the first two phases of the MERMAID project several different modules with standard interfaces and standard data formats had been developed. Important components are automatic nutrient analysers and remote-controllable samplers for toxic trace substances (heavy metals and synthetic organic compounds) in addition to a high performance data management system with bidirectional telemetry units for remote-controlled network operation. These modules were implemented in a Marine Pollution Network (MERMAID-MAPONET) consisting of three sea stations, two of them built up in the Elbe estuary and one station which is at the same time part of the BSH network in the Elbe influenced coastal zone.","PeriodicalId":259593,"journal":{"name":"Oceans '97. MTS/IEEE Conference Proceedings","volume":"433 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116547837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A new instrument for optical forward scattering phase function surveys","authors":"L. Estes, G. Fain, J. Harris","doi":"10.1109/OCEANS.1997.634441","DOIUrl":"https://doi.org/10.1109/OCEANS.1997.634441","url":null,"abstract":"In order to predict the performance of in the water and through the surface laser communication systems, it is necessary to know the inherent optical properties of the water environment. In particular, knowledge of the absorption and scattering coefficients and the forward scattering phase function (FSPF) are required. Analytical models and photon Monte Carlo simulations can then make use of these inherent optical properties to predict system performance. In this paper the authors describe the design of a new device that can be used to conduct FSPF surveys. The device makes use of a green helium-neon laser operating at a 543.5 nanometer wavelength and thermoelectrically cooled CCD camera to make real time measurements. The system is powered from the deploying surface vessel and the data is recorded at each depth by a shipboard portable computer. In this manner vertical profiles of the FSPF can be obtained. The authors present some early results.","PeriodicalId":259593,"journal":{"name":"Oceans '97. MTS/IEEE Conference Proceedings","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128203132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"OASIS: ocean ambient sound system","authors":"L. Zedel, S. Osterhus, R.L. Gordon","doi":"10.1109/OCEANS.1997.634378","DOIUrl":"https://doi.org/10.1109/OCEANS.1997.634378","url":null,"abstract":"The Ocean Ambient Sound Instrument System (OASIS) consists of a conventional RD Instruments ADCP modified to allow the recording of high quality, ambient sound from 1-75 kHz. In addition to the usual capabilities of an ADCP, this combination of acoustic instrumentation allows wind direction and speed to be inferred from a subsurface platform. The method of wind speed determination from ambient sound levels is explained identifying some of the limitations. The design of both the hardware and software required to make combined ADCP and ambient sound recordings is discussed, the methods used to preserve the large dynamic range characteristic of ambient sound. Observations made in the Norwegian Sea at OWS Mike are presented.","PeriodicalId":259593,"journal":{"name":"Oceans '97. MTS/IEEE Conference Proceedings","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131615847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}