Pub Date : 2001-11-05DOI: 10.1109/OCEANS.2001.968233
G. Reader, I. Potter, E. Clavelle
Diver propulsion vehicles (DPVs) are used by recreational and military divers. For the latter divers there is a need for special DPVs which have low magnetic and acoustic signatures so that they can operate in areas were mines are known or suspected to exist or dumped munitions. The possibility of constructing a power system for such a DPV was investigated. Since commercial off-the-shelf (COTS) products are being used increasingly in military systems a survey and evaluation of existing power systems technologies was conducted. One of the most viable options identified was the use of a Stirling engine. As part of the military specification was the use of a liquid hydrocarbon fuel it was necessary to explore ways in which the necessary oxidant could be provided, using a commercial product, if possible. In the latter case the use of oxygen candles was identified as a viable option. Thus, a Stirling engine system was designed and a breadboard unit constructed and experimental studies of a COTS oxygen candle were conducted. It was determined that such a combination of oxygen source and energy convertor was worthy of further investigation.
{"title":"Power and oxygen sources for a diver propulsion vehicle","authors":"G. Reader, I. Potter, E. Clavelle","doi":"10.1109/OCEANS.2001.968233","DOIUrl":"https://doi.org/10.1109/OCEANS.2001.968233","url":null,"abstract":"Diver propulsion vehicles (DPVs) are used by recreational and military divers. For the latter divers there is a need for special DPVs which have low magnetic and acoustic signatures so that they can operate in areas were mines are known or suspected to exist or dumped munitions. The possibility of constructing a power system for such a DPV was investigated. Since commercial off-the-shelf (COTS) products are being used increasingly in military systems a survey and evaluation of existing power systems technologies was conducted. One of the most viable options identified was the use of a Stirling engine. As part of the military specification was the use of a liquid hydrocarbon fuel it was necessary to explore ways in which the necessary oxidant could be provided, using a commercial product, if possible. In the latter case the use of oxygen candles was identified as a viable option. Thus, a Stirling engine system was designed and a breadboard unit constructed and experimental studies of a COTS oxygen candle were conducted. It was determined that such a combination of oxygen source and energy convertor was worthy of further investigation.","PeriodicalId":326183,"journal":{"name":"MTS/IEEE Oceans 2001. An Ocean Odyssey. Conference Proceedings (IEEE Cat. No.01CH37295)","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126031621","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}
Pub Date : 2001-11-05DOI: 10.1109/OCEANS.2001.968039
J. Bailey–Brock, B. Paavo, B. M. Barrett, J. Dreyer
Comparison of benthic communities off the Sand Island Ocean Outfall was undertaken to recognize pollution indicator species for Hawaiian waters. The primary treatment sewage is discharged off the south shore of Oahu at 70 m depth. A historical data set spanning 15 years for seven sites at 70 m (4 ZID and 3 far field) and two studies at 20, 50, and 100 m were compared. Polychaetes collected with a 7.6 cm diameter sediment core were sorted and five indicator species tentatively identified. Neanthes arenaceodentata (F. Nereididae) and Ophryotrocha adherens (F. Dorvilleidae) have been dominant at ZID stations. Since 1993, N. arenaceodentata has virtually disappeared from the ZID while o. adherens became abundant and continues to flourish there. The well known indicators within the Capitella capitata complex (F. Capitellidae) are present at ZID and far field sites. Two sabellids, Euchone sp. B and Augeneriella dubia are inversely distributed, the smaller Euchone sp. B at the far field stations and larger A. dubia at the ZID. The former is most likely restricted to the greater proportion of fine sediment particles at two far field sites. Pionosyllis heterocirrata (F. Syllidae) is the most abundant and widespread polychaete off Oahu's south shore. These indicator species share life history and feeding traits that lead to rapid growth and onset of reproduction, and produce benthic juveniles that recruit to the parent population leading to high levels of abundance. The success of indicator species is due to rapid use of available food resources and resulting increase in abundance. O. adherens is the most abundant indicator species at the ZID, P heterocirrata is the most ubiquitous species at all sites and should always be present in these sediments. No pollution level effects on the benthic assemblages seem to be present, but fluctuations in indicator abundances may indicate a response to organic materials such as sewage outfalls. Future changes in benthic assemblages on Oahu's south shore need to consider all possible organic sources including sewage effluent, fish farm wastes, land run off, canal and harbor drainage and the effects of beach nourishment projects.
对沙岛海洋出口的底栖生物群落进行了比较，以识别夏威夷水域的污染指标物种。初级处理污水在瓦胡岛南岸70米深度处排放。在70米的7个地点(4个ZID和3个远场)和20、50和100米的两项研究中，对15年的历史数据集进行了比较。对直径7.6 cm沉积物岩心收集的多毛菌进行了分类，初步鉴定出5种指示种。在ZID站点中，沙齿小蚁(Neanthes arenaceodentata, F. Nereididae)和粘眼鼠(Ophryotrocha adens, F. Dorvilleidae)为优势种。自1993年以来，砂齿犀实际上已经从ZID消失，而粘齿犀却在那里大量繁殖并继续繁荣。在小头藻复合体(小头藻科)中众所周知的指示物出现在ZID和远场地点。Euchone sp. B和dubia Augeneriella dubia是反向分布的，Euchone sp. B在远场站较小，dubia A.在ZID站较大。前者很可能仅限于两个远场地点的较大比例的细沉积物颗粒。瓦胡岛南岸是最丰富和广泛分布的多毛纲动物。这些指示物种具有共同的生活史和摄食特征，从而导致快速生长和开始繁殖，并产生底栖动物幼崽，这些幼崽会招募亲本种群，从而产生高水平的丰度。指标物种的成功是由于对现有食物资源的迅速利用，从而使丰度增加。O. adherens是ZID中最丰富的指示物种，P . heterocirrata是所有站点中最普遍存在的物种，应该始终存在于这些沉积物中。似乎没有污染水平对底栖生物组合的影响，但指标丰度的波动可能表明对污水排放等有机物质的反应。未来欧胡岛南岸底栖生物群落的变化需要考虑所有可能的有机来源，包括污水排放、养鱼场废物、土地流失、运河和港口排水以及海滩营养项目的影响。
{"title":"Changes in pollution indicators at the Sand Island sewage outfall","authors":"J. Bailey–Brock, B. Paavo, B. M. Barrett, J. Dreyer","doi":"10.1109/OCEANS.2001.968039","DOIUrl":"https://doi.org/10.1109/OCEANS.2001.968039","url":null,"abstract":"Comparison of benthic communities off the Sand Island Ocean Outfall was undertaken to recognize pollution indicator species for Hawaiian waters. The primary treatment sewage is discharged off the south shore of Oahu at 70 m depth. A historical data set spanning 15 years for seven sites at 70 m (4 ZID and 3 far field) and two studies at 20, 50, and 100 m were compared. Polychaetes collected with a 7.6 cm diameter sediment core were sorted and five indicator species tentatively identified. Neanthes arenaceodentata (F. Nereididae) and Ophryotrocha adherens (F. Dorvilleidae) have been dominant at ZID stations. Since 1993, N. arenaceodentata has virtually disappeared from the ZID while o. adherens became abundant and continues to flourish there. The well known indicators within the Capitella capitata complex (F. Capitellidae) are present at ZID and far field sites. Two sabellids, Euchone sp. B and Augeneriella dubia are inversely distributed, the smaller Euchone sp. B at the far field stations and larger A. dubia at the ZID. The former is most likely restricted to the greater proportion of fine sediment particles at two far field sites. Pionosyllis heterocirrata (F. Syllidae) is the most abundant and widespread polychaete off Oahu's south shore. These indicator species share life history and feeding traits that lead to rapid growth and onset of reproduction, and produce benthic juveniles that recruit to the parent population leading to high levels of abundance. The success of indicator species is due to rapid use of available food resources and resulting increase in abundance. O. adherens is the most abundant indicator species at the ZID, P heterocirrata is the most ubiquitous species at all sites and should always be present in these sediments. No pollution level effects on the benthic assemblages seem to be present, but fluctuations in indicator abundances may indicate a response to organic materials such as sewage outfalls. Future changes in benthic assemblages on Oahu's south shore need to consider all possible organic sources including sewage effluent, fish farm wastes, land run off, canal and harbor drainage and the effects of beach nourishment projects.","PeriodicalId":326183,"journal":{"name":"MTS/IEEE Oceans 2001. An Ocean Odyssey. Conference Proceedings (IEEE Cat. No.01CH37295)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123316452","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}
Pub Date : 2001-11-05DOI: 10.1109/OCEANS.2001.968350
D. Green, F. Blackmon
The Surf Zone Acoustic Telemetry Experiment (SZATE) was conducted during August and September 2000 alongside the pier at Scripps Institution of Oceanography. The goal was to characterize the relationships between the performance of acoustic communications and observable oceanographic and acoustic conditions. As part of our participation in SZATE, we designed and transmitted messages by means of both non-coherent signaling methods, and channel-equalized, coherent methods. The latter involved a 3220 bps QPSK message with accompanying channel probes. More than 20,000 such waveforms were processed and analyzed, with channel conditions ranging from benign to unusable. Channel equalization was accomplished with decision feedback equalizers based on the LMS, RLS, and fast RLS implementations. Due to rapid temporal variations in the channel impulse response, the basic LMS algorithm was generally ineffective. The RLS and fast RLS algorithm performance were comparable, with the latter providing slightly superior performance in terms of residual uncorrected channel symbol errors. Equalizer tap placement was determined from a heuristic algorithm which provided excellent results. The presence of bubbles may dominate signaling performance by blocking the channel. Bubbles are either injected into the water column from breaking waves, or are advected by along-shore currents. However, the channel is generally "open" and in such cases the percent of successful messages ranged from approximately 50% to 98%, with an average of approximately 80%. Temporal diversity is shown to substantially improve this success rate. The performance in the absence of bubbles is correlated with the temporal coherence of each of the major multipath arrivals.
{"title":"Performance of channel-equalized acoustic communications in the surf zone","authors":"D. Green, F. Blackmon","doi":"10.1109/OCEANS.2001.968350","DOIUrl":"https://doi.org/10.1109/OCEANS.2001.968350","url":null,"abstract":"The Surf Zone Acoustic Telemetry Experiment (SZATE) was conducted during August and September 2000 alongside the pier at Scripps Institution of Oceanography. The goal was to characterize the relationships between the performance of acoustic communications and observable oceanographic and acoustic conditions. As part of our participation in SZATE, we designed and transmitted messages by means of both non-coherent signaling methods, and channel-equalized, coherent methods. The latter involved a 3220 bps QPSK message with accompanying channel probes. More than 20,000 such waveforms were processed and analyzed, with channel conditions ranging from benign to unusable. Channel equalization was accomplished with decision feedback equalizers based on the LMS, RLS, and fast RLS implementations. Due to rapid temporal variations in the channel impulse response, the basic LMS algorithm was generally ineffective. The RLS and fast RLS algorithm performance were comparable, with the latter providing slightly superior performance in terms of residual uncorrected channel symbol errors. Equalizer tap placement was determined from a heuristic algorithm which provided excellent results. The presence of bubbles may dominate signaling performance by blocking the channel. Bubbles are either injected into the water column from breaking waves, or are advected by along-shore currents. However, the channel is generally \"open\" and in such cases the percent of successful messages ranged from approximately 50% to 98%, with an average of approximately 80%. Temporal diversity is shown to substantially improve this success rate. The performance in the absence of bubbles is correlated with the temporal coherence of each of the major multipath arrivals.","PeriodicalId":326183,"journal":{"name":"MTS/IEEE Oceans 2001. An Ocean Odyssey. Conference Proceedings (IEEE Cat. No.01CH37295)","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123432481","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}
Pub Date : 2001-11-05DOI: 10.1109/OCEANS.2001.968137
D. Lemon, J. Gower, M. Clarke
Measuring acoustic backscatter in the water column is a low-cost, reliable method for examining the long-term behaviour and distribution of zooplankton populations. Backscatter at acoustic frequencies above 20 kHz is useful for profiling those quantities, which, when tracked over long periods of time, can provide a valuable contribution to understanding and monitoring the state of marine ecosystems. The Water Column Profiler/sup TM/ is a self-contained echo-sounder, designed for long-term, autonomous operation. The instrument can be used in either downward-looking mode, from a moored surface buoy, or in upward-looking mode from a submerged mooring. The instrument has selectable parameters for pulse length and sampling interval. The data are recorded in digital form, and averaging in both time and range is available. On-board storage of up to 64 Mbytes of non-volatile Flash RAM allows operation for periods up to 6 months in length for 150 m water depth sampled at 1m intervals every minute. Interfacing to a real-time data link is possible for buoy-mounted installations. A 200 kHz Water Column Profiler/sup TM/ has been operating on a moored buoy in Saanich Inlet, British Columbia, since September 1999. In June, 2000, a 50 kHz unit was added. Time series of acoustic backscatter at both frequencies many months long have been collected, showing the evolution of the behaviour and abundance of the dominant species of zooplankton (Euphausiids and Amphipods) in the inlet over time scales from diurnal to seasonal. Examples of these data are presented and discussed, comparing the results at the two frequencies and the implications for acoustically discriminating size with a multi-frequency instrument.
{"title":"The acoustic water column profiler: a tool for long-term monitoring of zooplankton populations","authors":"D. Lemon, J. Gower, M. Clarke","doi":"10.1109/OCEANS.2001.968137","DOIUrl":"https://doi.org/10.1109/OCEANS.2001.968137","url":null,"abstract":"Measuring acoustic backscatter in the water column is a low-cost, reliable method for examining the long-term behaviour and distribution of zooplankton populations. Backscatter at acoustic frequencies above 20 kHz is useful for profiling those quantities, which, when tracked over long periods of time, can provide a valuable contribution to understanding and monitoring the state of marine ecosystems. The Water Column Profiler/sup TM/ is a self-contained echo-sounder, designed for long-term, autonomous operation. The instrument can be used in either downward-looking mode, from a moored surface buoy, or in upward-looking mode from a submerged mooring. The instrument has selectable parameters for pulse length and sampling interval. The data are recorded in digital form, and averaging in both time and range is available. On-board storage of up to 64 Mbytes of non-volatile Flash RAM allows operation for periods up to 6 months in length for 150 m water depth sampled at 1m intervals every minute. Interfacing to a real-time data link is possible for buoy-mounted installations. A 200 kHz Water Column Profiler/sup TM/ has been operating on a moored buoy in Saanich Inlet, British Columbia, since September 1999. In June, 2000, a 50 kHz unit was added. Time series of acoustic backscatter at both frequencies many months long have been collected, showing the evolution of the behaviour and abundance of the dominant species of zooplankton (Euphausiids and Amphipods) in the inlet over time scales from diurnal to seasonal. Examples of these data are presented and discussed, comparing the results at the two frequencies and the implications for acoustically discriminating size with a multi-frequency instrument.","PeriodicalId":326183,"journal":{"name":"MTS/IEEE Oceans 2001. An Ocean Odyssey. Conference Proceedings (IEEE Cat. No.01CH37295)","volume":"220 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123447237","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}
Pub Date : 2001-11-05DOI: 10.1109/OCEANS.2001.968714
R. Wyber
By use of a broadband synthetic aperture sonar it has been possible to measure the reverberation with a resolution in the order of 1 cm along the sonar axis and 4 cm in the transverse direction. With such high resolution measurements it is possible to measure the acoustic response of low wavenumber structural features of the sediment which contribute to the scattering. While the wavenumbers of these features lie outside the band of the transmitted signal they can be observed via their modulation of the high wavenumber components in the backscattered signal. Using models developed to incorporate the modulation terms, together with the deterministic measurements of the bottom structure, it was shown that at the site where the measurements were carried out these terms did not significantly contribute to the variance of the backscattered signal for a sonar using a real array. For a broadband synthetic aperture sonar however these modulation components dominated the variance of the backscattered signal. This resulted in strong structure being present in the reverberation against which additional processing gain was realised by adaptively matching the filtering applied to the signal and the reverberation. This gain is additional to that predicted by the classical theory, which arises from the reduction in the insonified area of the bottom realised with a high resolution sonar.
{"title":"The reverberation for a broadband synthetic aperture sonar","authors":"R. Wyber","doi":"10.1109/OCEANS.2001.968714","DOIUrl":"https://doi.org/10.1109/OCEANS.2001.968714","url":null,"abstract":"By use of a broadband synthetic aperture sonar it has been possible to measure the reverberation with a resolution in the order of 1 cm along the sonar axis and 4 cm in the transverse direction. With such high resolution measurements it is possible to measure the acoustic response of low wavenumber structural features of the sediment which contribute to the scattering. While the wavenumbers of these features lie outside the band of the transmitted signal they can be observed via their modulation of the high wavenumber components in the backscattered signal. Using models developed to incorporate the modulation terms, together with the deterministic measurements of the bottom structure, it was shown that at the site where the measurements were carried out these terms did not significantly contribute to the variance of the backscattered signal for a sonar using a real array. For a broadband synthetic aperture sonar however these modulation components dominated the variance of the backscattered signal. This resulted in strong structure being present in the reverberation against which additional processing gain was realised by adaptively matching the filtering applied to the signal and the reverberation. This gain is additional to that predicted by the classical theory, which arises from the reduction in the insonified area of the bottom realised with a high resolution sonar.","PeriodicalId":326183,"journal":{"name":"MTS/IEEE Oceans 2001. An Ocean Odyssey. Conference Proceedings (IEEE Cat. No.01CH37295)","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123457325","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}
Pub Date : 2001-11-05DOI: 10.1109/OCEANS.2001.968254
M. Soriano, S. Marcos, C. Saloma, M. Quibilan, P. Aliño
The purpose of this study is to automate coral reef assessment, that is, to classify coral images into benthic categories from digitized underwater video using a computer-based classifier such that coral reef analysis becomes less subjective, less tedious and more precise. Corals exhibit a variety of color, texture and structure which are the visual cues used by marine scientists for their classification. In computer vision, color is a point property of a picture element while texture is a property of an area. Color and texture have been combined as color-texture which is a feature that describes the spatial organization of colors in an area. As inputs to a classifier, the authors extract color, texture and color-texture descriptors from coral images and measure recognition rates using each feature. Corals are 3D structures and, when imaged, are prone to varying resolutions, perspective projection and lighting conditions. Therefore, an additional objective of this study is to address the problem of illumination, rotation and scale invariance in pattern recognition of underwater images. Images were classified into one of five benthic categories: alive coral, dead coral, dead coral with algae, algae and abiotics. Overall, texture was found to be more discriminating than using color alone or color and texture combined. Dead coral was the most successfully recognized class using color features.
{"title":"Image classification of coral reef components from underwater color video","authors":"M. Soriano, S. Marcos, C. Saloma, M. Quibilan, P. Aliño","doi":"10.1109/OCEANS.2001.968254","DOIUrl":"https://doi.org/10.1109/OCEANS.2001.968254","url":null,"abstract":"The purpose of this study is to automate coral reef assessment, that is, to classify coral images into benthic categories from digitized underwater video using a computer-based classifier such that coral reef analysis becomes less subjective, less tedious and more precise. Corals exhibit a variety of color, texture and structure which are the visual cues used by marine scientists for their classification. In computer vision, color is a point property of a picture element while texture is a property of an area. Color and texture have been combined as color-texture which is a feature that describes the spatial organization of colors in an area. As inputs to a classifier, the authors extract color, texture and color-texture descriptors from coral images and measure recognition rates using each feature. Corals are 3D structures and, when imaged, are prone to varying resolutions, perspective projection and lighting conditions. Therefore, an additional objective of this study is to address the problem of illumination, rotation and scale invariance in pattern recognition of underwater images. Images were classified into one of five benthic categories: alive coral, dead coral, dead coral with algae, algae and abiotics. Overall, texture was found to be more discriminating than using color alone or color and texture combined. Dead coral was the most successfully recognized class using color features.","PeriodicalId":326183,"journal":{"name":"MTS/IEEE Oceans 2001. An Ocean Odyssey. Conference Proceedings (IEEE Cat. No.01CH37295)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123720326","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}
Pub Date : 2001-11-05DOI: 10.1109/OCEANS.2001.968799
W. Shi-cai, Yang Zijie, Wen Bi-yang, Shi Zhenhua, Tian Jian-sheng, Gao Huotao, Wu Xiongbin, K. Hengyu
OSMAR2000 is a HF ground wave radar system developed by the Wuhan University of China. The system has adopted a phased array antenna with the unique working mode of "one element transmitting and eight elements receiving". The experiment of bi-stational radar detection of oceanic surface dynamics was accomplished for the first time in the mainland of China, successfully mapping the surface currents. Verification tests against in situ measurements by traditional marine instruments indicate that OSMAR2000's detecting range is 200 km for currents and wind, and 120 km for waves.
{"title":"Test of HF ground wave radar OSMAR2000 at the Eastern China Sea","authors":"W. Shi-cai, Yang Zijie, Wen Bi-yang, Shi Zhenhua, Tian Jian-sheng, Gao Huotao, Wu Xiongbin, K. Hengyu","doi":"10.1109/OCEANS.2001.968799","DOIUrl":"https://doi.org/10.1109/OCEANS.2001.968799","url":null,"abstract":"OSMAR2000 is a HF ground wave radar system developed by the Wuhan University of China. The system has adopted a phased array antenna with the unique working mode of \"one element transmitting and eight elements receiving\". The experiment of bi-stational radar detection of oceanic surface dynamics was accomplished for the first time in the mainland of China, successfully mapping the surface currents. Verification tests against in situ measurements by traditional marine instruments indicate that OSMAR2000's detecting range is 200 km for currents and wind, and 120 km for waves.","PeriodicalId":326183,"journal":{"name":"MTS/IEEE Oceans 2001. An Ocean Odyssey. Conference Proceedings (IEEE Cat. No.01CH37295)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122523022","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}
Based on detailed analysis of causes resulting in phase errors in synthetic aperture sonar (SAS), this paper points out that the primary factors to affect our developing SAS can be ascribed to the shifts of Doppler center ( f/sub dc/) and Doppler rate (f/sub r/) for the irregular motion of the underwater carrier. Successively f/sub dc/ and f/sub r/ estimating methods in the image field based on multi-look processing are analyzed, and it is proved that these approaches are the better selections for SAS in the presence of both range migrant and partial aperture. A compensating and imaging complete SAS systemic design based on auto-focusing method is provided together with a modified range-Doppler imaging algorithm and a refined compensating step based on the PGA algorithm, and it is proved that this design is effective by real lake trial results.
{"title":"Synthetic aperture sonar imaging based on auto-focusing method","authors":"Jia Xu, Xingzhou Jiang, Jinsong Tang, Cunhua Zhang","doi":"10.1109/OCEANS.2001.968253","DOIUrl":"https://doi.org/10.1109/OCEANS.2001.968253","url":null,"abstract":"Based on detailed analysis of causes resulting in phase errors in synthetic aperture sonar (SAS), this paper points out that the primary factors to affect our developing SAS can be ascribed to the shifts of Doppler center ( f/sub dc/) and Doppler rate (f/sub r/) for the irregular motion of the underwater carrier. Successively f/sub dc/ and f/sub r/ estimating methods in the image field based on multi-look processing are analyzed, and it is proved that these approaches are the better selections for SAS in the presence of both range migrant and partial aperture. A compensating and imaging complete SAS systemic design based on auto-focusing method is provided together with a modified range-Doppler imaging algorithm and a refined compensating step based on the PGA algorithm, and it is proved that this design is effective by real lake trial results.","PeriodicalId":326183,"journal":{"name":"MTS/IEEE Oceans 2001. An Ocean Odyssey. Conference Proceedings (IEEE Cat. No.01CH37295)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114281672","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}
Pub Date : 2001-11-05DOI: 10.1109/OCEANS.2001.968363
J. M. Hemsley
According to the authors of "Long Time Series Measurements in the Coastal Ocean: A Workshop" (C.L. Vincent, T.C. Royer, and K.H., Brink, Woods Hole Oceanographic Institution, November, 1993), "Long time series measurements (in excess of 10 years duration) in the coastal ocean are important to science and society. They provide a measure of the health of the coastal ocean and are essential to distinguish long-term trends, caused by anthropogenic effects or climate change for example, from natural variability. They provide a basis for a new hypothesis about processes operating in the coastal ocean and a range of conditions for testing predictive capabilities. In addition, they document rare and/or catastrophic events that may play a critical role in coastal processes." When that report was written, 8 years ago, The National Data Buoy Center (NDBC) had 55 stations in the 10 to 100 years of data category. NDBC buoys and Coastal-Marine Automated Network (C-MAN) stations, because of their continued importance to the National Weather Service (NWS), can be assumed to be long-term. That means that the manager engaged in maritime commerce, scientist involved in marine research, commercial fisherman, and recreational boater can depend on NDBC data when making decisions. The value of these data is validated by the three million hits on NDBC's Web site in an average month. NDBC has a history of providing high-quality data in a timely manner to the users of its data. That group, originally comprised primarily of forecasters, has expanded many times over as a result of the Internet. It has been a challenge to meet the needs of such a diverse group of real-time users, but NDBC has accepted that challenge and continues to respond to the needs of those who rely on the data. This paper reviews the quantity and quality of NDBC data. It discusses how and where the data are collected, and it explains how it can be obtained. It also evaluates how successful NDBC has been in collecting quality data and discusses what is being done to maintain, even improve, the quantity of data made available to those who depend on it.
{"title":"The long-term marine data set collected by The National Data Buoy Center","authors":"J. M. Hemsley","doi":"10.1109/OCEANS.2001.968363","DOIUrl":"https://doi.org/10.1109/OCEANS.2001.968363","url":null,"abstract":"According to the authors of \"Long Time Series Measurements in the Coastal Ocean: A Workshop\" (C.L. Vincent, T.C. Royer, and K.H., Brink, Woods Hole Oceanographic Institution, November, 1993), \"Long time series measurements (in excess of 10 years duration) in the coastal ocean are important to science and society. They provide a measure of the health of the coastal ocean and are essential to distinguish long-term trends, caused by anthropogenic effects or climate change for example, from natural variability. They provide a basis for a new hypothesis about processes operating in the coastal ocean and a range of conditions for testing predictive capabilities. In addition, they document rare and/or catastrophic events that may play a critical role in coastal processes.\" When that report was written, 8 years ago, The National Data Buoy Center (NDBC) had 55 stations in the 10 to 100 years of data category. NDBC buoys and Coastal-Marine Automated Network (C-MAN) stations, because of their continued importance to the National Weather Service (NWS), can be assumed to be long-term. That means that the manager engaged in maritime commerce, scientist involved in marine research, commercial fisherman, and recreational boater can depend on NDBC data when making decisions. The value of these data is validated by the three million hits on NDBC's Web site in an average month. NDBC has a history of providing high-quality data in a timely manner to the users of its data. That group, originally comprised primarily of forecasters, has expanded many times over as a result of the Internet. It has been a challenge to meet the needs of such a diverse group of real-time users, but NDBC has accepted that challenge and continues to respond to the needs of those who rely on the data. This paper reviews the quantity and quality of NDBC data. It discusses how and where the data are collected, and it explains how it can be obtained. It also evaluates how successful NDBC has been in collecting quality data and discusses what is being done to maintain, even improve, the quantity of data made available to those who depend on it.","PeriodicalId":326183,"journal":{"name":"MTS/IEEE Oceans 2001. An Ocean Odyssey. Conference Proceedings (IEEE Cat. No.01CH37295)","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114391538","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}
Pub Date : 2001-11-05DOI: 10.1109/OCEANS.2001.968249
G. White, R. Johnson
The University of Washington has begun employing a heavy-duty release that can be attached to a ship's amagraph cable enabling the user to release underwater packages up to 20000 lbs to full ocean depth. A deck unit allows the operator to remotely release the package with feedback indicators. The release mechanism uses an internal motor that is oil filled and pressure compensated to open and close the clevis. There are electrical limit switches built into the unit to automatically stop motor action in the fully open (released) or fully closed (latched) position. Utilization of this device will give operators another tool for gentle and precise deployments of increasingly complex and expensive seafloor instrumentation.
{"title":"Electronic activated pelican hook","authors":"G. White, R. Johnson","doi":"10.1109/OCEANS.2001.968249","DOIUrl":"https://doi.org/10.1109/OCEANS.2001.968249","url":null,"abstract":"The University of Washington has begun employing a heavy-duty release that can be attached to a ship's amagraph cable enabling the user to release underwater packages up to 20000 lbs to full ocean depth. A deck unit allows the operator to remotely release the package with feedback indicators. The release mechanism uses an internal motor that is oil filled and pressure compensated to open and close the clevis. There are electrical limit switches built into the unit to automatically stop motor action in the fully open (released) or fully closed (latched) position. Utilization of this device will give operators another tool for gentle and precise deployments of increasingly complex and expensive seafloor instrumentation.","PeriodicalId":326183,"journal":{"name":"MTS/IEEE Oceans 2001. An Ocean Odyssey. Conference Proceedings (IEEE Cat. No.01CH37295)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128711118","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}
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