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

{"title":"World geodetic system 1984-a summary of enhancements through the development of the new geopotential model EGM96","authors":"P. Fell","doi":"10.1109/OCEANS.1997.624220","DOIUrl":"https://doi.org/10.1109/OCEANS.1997.624220","url":null,"abstract":"Summary form only given, substantially as follows. EGM96 is a geopotential model of the Earth consisting of spherical harmonic coefficients complete to degree and order 360. This model is the result of a collaboration between the National Imagery and Mapping Agency, the NASA Goddard Space Flight Center and the Ohio State University, supported by the Naval Surface Warfare Center. The joint project took advantage of new surface gravity data from many different regions of the globe, including data newly released from the NIMA archives. Major terrestrial gravity acquisitions by NIMA since 1990 include airborne gravity surveys over Greenland and parts of the Arctic and the Antarctic, surveyed by the Naval Research Laboratory, and cooperative gravity collection projects, several which were undertaken with the University of Leeds. These collection efforts improved data holdings over many of the world's land areas, including Africa, Canada, parts of South America and Africa, Southeast Asia, Eastern Europe, and the former Soviet Union. EGM96 also included altimeter derived anomalies derived from the U.S. Navy's GEOSAT geodetic mission and from ERS-1 over portions of the Arctic and Antarctic, as well as the altimeter derived anomalies over the Weddell Sea. Other data that contributed to EGM96 were direct satellite altimetry from TOPEX/POSEIDON, ERS-1 and GEOSAT, and satellite tracking to over 20 satellites using satellite laser ranging (SLR), the Global Positioning System, DORIS, Tracking and Data Relay Satellite System, and TRANET. In addition, a new topographic data base was assembled from all available sources in order to reduce raw surface gravity data and prepare the 30'/spl times/30' gravity anomalies. This database was also used to calculate isostatic values in the roughly 3 percent of the globe where surface gravity data was not available. This new geopotential model is being used as a geodetic reference to update WGS 84. In addition, it will serve as a state of the art model for precise orbit, oceanographic, and geophysical studies. The paper will summarize the results of the EGM96 development.","PeriodicalId":259593,"journal":{"name":"Oceans '97. MTS/IEEE Conference Proceedings","volume":"45 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":"125254700","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 bathymetric data for regional assessment of marine geology","authors":"R. Parrott, G. Fader, J. Shaw, J. Hughes-Clarke","doi":"10.1109/OCEANS.1997.624214","DOIUrl":"https://doi.org/10.1109/OCEANS.1997.624214","url":null,"abstract":"Digital multibeam bathymetry has become the primary reconnaissance mapping tool used by the Geological Survey of Canada for marine geology surveys. Multibeam bathymetry and backscatter intensity data were collected as the first stage of several recent multiparameter geophysical surveys. The multibeam bathymetric data were used to create shaded relief images that depict seafloor morphology. Acoustic backscatter intensity measurements are used to determine the general distribution of coarse and fine sediments. The maps and images form the basis for the preliminary interpretation of geological processes and features, and are used to plan subsequent surveys using higher resolution sidescan sonar and seismic reflection systems to better define features identified on the multibeam data. Examples are presented from recent surveys in Atlantic Canada.","PeriodicalId":259593,"journal":{"name":"Oceans '97. MTS/IEEE Conference Proceedings","volume":"12 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":"127783202","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":"Spectral identification of coral biological vigour","authors":"H. Holden, E. LeDrew","doi":"10.1109/OCEANS.1997.634400","DOIUrl":"https://doi.org/10.1109/OCEANS.1997.634400","url":null,"abstract":"No quantitative means of remotely determining the biological vigour of corals exists. In an effort to find a quantitative measure, the spectral reflectance of healthy and bleached corals were measured in situ with a hand-held spectroradiometer. Principal components analysis revealed that there is a spectral distinction based on biological vigour. This spectral distinction was largely based on magnitude of reflectance. Spectral derivative analysis was then used to determine the particular wavelength ranges that could be used to identify biological vigour of coral samples.","PeriodicalId":259593,"journal":{"name":"Oceans '97. MTS/IEEE Conference Proceedings","volume":"61 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":"123753859","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 MFSK acoustic modem for operation in adverse underwater channels","authors":"K. Scussel, J. Rice, S. Merriam","doi":"10.1109/OCEANS.1997.634370","DOIUrl":"https://doi.org/10.1109/OCEANS.1997.634370","url":null,"abstract":"With US Navy SBIR funding, Datasonics has teamed with Delphi Communication Systems and Naval Command, Control & Ocean Surveillance Center, RDT&E Division (NRaD) to develop a new acoustic telemetry and ranging (telesonar) modem. Periodic transmission of digital message packets satisfies most telesonar applications, including data reporting from oceanographic sensors, controlling autonomous devices, monitoring offshore-oil equipment, and communicating with undersea vehicles. These applications are well served by robust, low-data-rate, noncoherent, multiple frequency shift keying (MFSK) signaling offering greater affordability, networkability, and energy conservation than coherent modems. Well designed MFSK signaling furthermore provides superior reliability in noisy, doubly spread, forward-scattered, horizontal channels such as those found in littoral ocean environments. This paper describes the design of the new telesonar type-A MFSK acoustic modem providing communication rates of 100 to 2400 bit/s. Improved performance in adverse transmission channels is obtained from increased signaling diversity and stronger coding techniques based on symbol sets derived from Hadamard matrices. The new product also preserves the 1-of-4 MFSK modulation mode used in the Datasonics ATM-850 modem. The parallel goal of reduced cost is achieved by the new modem electronics design and packaging.","PeriodicalId":259593,"journal":{"name":"Oceans '97. MTS/IEEE Conference Proceedings","volume":"46 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":"123755721","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":"Standard local area networks for high-performance measurements systems","authors":"J. Walrod","doi":"10.1109/OCEANS.1997.634371","DOIUrl":"https://doi.org/10.1109/OCEANS.1997.634371","url":null,"abstract":"Local area network (LAN) technologies such as Ethernet and asynchronous transfer mode (ATM) are being used to build data acquisition and telemetry systems which provide higher performance, greater modularity, easier reconfiguration, and less cost than traditional architectures. This paper discusses the use of various LAN technologies in ocean measurement system applications.","PeriodicalId":259593,"journal":{"name":"Oceans '97. MTS/IEEE Conference Proceedings","volume":"38 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":"121749263","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":"The discovery of shipwrecks through marine geological mapping","authors":"G. Fader, R. Miller","doi":"10.1109/OCEANS.1997.634352","DOIUrl":"https://doi.org/10.1109/OCEANS.1997.634352","url":null,"abstract":"Summary form only given. Systematic marine geological mapping of the inner continental shelf off southeast Atlantic Canada has lead to the discovery of up to 80 shipwrecks that represent a substantial archaeological resource as well as a potential hazard to seabed engineering and bottom fishing activity. New technologies such as multibeam bathymetric mapping systems, high-resolution sidescan sonars and magnetometers, together with advances in positioning, have allowed the Canadian Hydrographic Service and the Geological Survey of Canada to build a data base for their discovery. A few shipwrecks have been positively identified on the basis of positional knowledge at the time of sinking or design characteristics of the vessel which allow for comparison with survey data. The shipwrecks range from wooden eighteenth century, to First and Second World War vessels, and include several ships sunk during the past 40 years. In addition to their cultural value, they represent time markers on the seabed and can be used to understand sediment dynamics and the long-term effects of storms and currents on seabed stability. They can also be used to study the effects of metal corrosion over time. For example, rusticles from HMCS Clayoquoi, similar to those found on the RMS Titanic, are presently under study. Many of the military vessels contain a variety of unexploded ordinance which represents a seabed hazard to a broad range of activities. Submersible and survey investigations are continuing to identify each of the shipwrecks, as they collectively represent a substantial resource for archaeological research and ecotourism, and as such, must be considered in models of sustainable resource management for the coastal zone. The Acorn, Trongate, Governor Cornwallis, Gertrude de Costa, Havana, Good Hope, British Freedom, HMCS Clayoquot and the Athel Viking are shipwrecks which are presented and discussed. Due to sensitive archaeological and military aspects of some of the shipwrecks discussed in this presentation, a formal paper will not be prepared. Many of the shipwrecks have recently been discovered and a proper assessment has not been conducted.","PeriodicalId":259593,"journal":{"name":"Oceans '97. MTS/IEEE Conference Proceedings","volume":"23 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":"122190063","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":"Wideband passive mechanical mounting systems for disk drives on boats in rough seas","authors":"N. Dennis","doi":"10.1109/OCEANS.1997.624216","DOIUrl":"https://doi.org/10.1109/OCEANS.1997.624216","url":null,"abstract":"The paper addresses the problem of wideband mechanical isolation of some oceanographic computer systems with magnetic and optical disk drives in boats with large translational and rotational motions in rough seas. Isolation is required against a wide spectrum of vibration due to propeller cavitation and engine dynamics, and shock due to hull slams and docking. Troubles such as a head crash can occur. Such troubles are difficult to predict not only because of the complex variety of wave trains in a \"rough\" sea, but also because of disk drive specifications that are inappropriate. More than a decade of experience has shown that there is no such widespread problem for larger ships. The shipboard frequencies of structural vibration (usually less than 100 Hz) are generally much lower than the resonant mechanical frequencies of computer systems with magnetic disk drives which, with some exceptions, are above 2 kHz. Moreover, shocks and ship motions of larger oceanographic vessels are of less consequence.","PeriodicalId":259593,"journal":{"name":"Oceans '97. MTS/IEEE Conference Proceedings","volume":"41 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":"131616817","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":"Performance comparison of RDI ADCPs: broadband versus narrowband","authors":"T. C. Wilson, K. Lwiza, G. L. Allen","doi":"10.1109/OCEANS.1997.634347","DOIUrl":"https://doi.org/10.1109/OCEANS.1997.634347","url":null,"abstract":"The \"broadband\" acoustic Doppler current profiler (ADCP) manufactured by RD Instruments of San Diego CA can potentially greatly enhance the temporal and spatial resolution of underway current measurements relative to older \"narrowband\" ADCP technology. Despite this, adoption of broadband ADCPs has been slow in the US national research vessel fleet operated by the University-National Oceanographic Laboratory System (UNOLS). Narrowband ADCPs are now considered \"standard equipment\" in UNOLS intermediate and large class vessels. Adoption of the potentially superior newer technology has been delayed by a lack of rigorous intercomparison studies between the narrowband and broadband ADCP, plus some anecdotal evidence of decreased performance when substituting a broadband for a narrowband (such as significantly decreased profiling range). A series of intercomparison experiments were performed aboard the Research Vessel Seward Johnson during month-long cruises in May 1996 and May 1997 in the vicinity of Barbados, West Indies. The instruments involved were narrowband 150 kHz and broadband 150 kHz vessel mounted ADCPs. The two ADCPs were set up in as similar a manner as possible to provide the most valid intercomparison. In order to avoid any possible interference between ADCP systems experiments were run in time-interleaved fashion. Results showed that the broadband ADCP produced data quality superior to the narrowband under similar conditions. Profiling range in broadband water profiling mode 7 was equal to that of the narrowband. In broadband modes 4 and 1, profiling ranges averaged 78% and 75% of narrowband ranges respectively. Ensemble to ensemble variation of speed at 57 meters depth averaged 13.26 cm/sec for the narrowband versus 6.16 cm/sec for broadband mode 7 and 4.80 cm/sec for broadband mode 4. Broadband water profiling mode 7 provides profiling ranges equal to a narrowband of the same frequency with increased data accuracy, while water profiling mode 4 provides even greater data accuracy with only a loss of 20-25% in range.","PeriodicalId":259593,"journal":{"name":"Oceans '97. MTS/IEEE Conference Proceedings","volume":"8 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":"131859305","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":"The development of SEAPUP (a light work class ROV)","authors":"Qiong Wu","doi":"10.1109/OCEANS.1997.634360","DOIUrl":"https://doi.org/10.1109/OCEANS.1997.634360","url":null,"abstract":"ROV (remotely operated vehicle) is an important equipment for offshore industry. RACAL Techno-Transfer Industries Pte Ltd. (TTI) is one of the leading ROV companies in the world. SEAPUP is the new member in the SEALION ROV family which has been developed, manufactured and operated by TTI. The operation system of SEAPUP has been developed from the SEALION operation system. There are three parts in SEAPUP system: surface control unit, vehicle control unit and telemetry system. Reliability, robustness and compatibility are three main design principles for SEAPUP.","PeriodicalId":259593,"journal":{"name":"Oceans '97. MTS/IEEE Conference Proceedings","volume":"28 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":"125761872","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 peer-to-peer communication protocol for underwater acoustic communication","authors":"S.M. Smith, J.C. Park, A. Neel","doi":"10.1109/OCEANS.1997.634374","DOIUrl":"https://doi.org/10.1109/OCEANS.1997.634374","url":null,"abstract":"The Advanced Marine Systems (AMS) group at Florida Atlantic University has developed a peer-to-peer communication protocol for use with acoustic communication systems interfaced with the Ocean Explorer (OEX) autonomous underwater vehicles (AUVs). The protocol does not require a master-slave control structure between telemetry units and is applicable to arbitrary signaling formats. This architecture allows the communication channel to remain open such that any telemetry unit in the network can have channel access, and therefore insures the opportunity to transmit important data that may become available. The protocol has been implemented in an acoustic modem (AM) capable of transmitting binary data through the shallow-water acoustic waveguide. Data transmitted from an OEX AUV to a surface ship using this protocol in the ocean are presented.","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":"130712434","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}