Pub Date : 1993-10-18DOI: 10.1109/OCEANS.1993.326123
H. Wong, A. Antoniou
The application of 2D signal processing to profiles collected in airborne laser bathymetry is investigated. The processing involves a type of 2D filtering for the suppression of impulsive noise and the application of a sophisticated 2D interpolation technique for the reconstruction of bathymetric data. The reconstructed profiles are further enhanced by two adaptive procedures: one involves 2D power spectral analysis of the data on a block-by-block basis and the other concerns the estimation of the data on a point-by-point basis. Results show that each type of filtering enhances the accuracy of bathymetric measurement quite significantly.<>
{"title":"Reconstruction and enhancement of sea-bed topography by using 2-D signal processing","authors":"H. Wong, A. Antoniou","doi":"10.1109/OCEANS.1993.326123","DOIUrl":"https://doi.org/10.1109/OCEANS.1993.326123","url":null,"abstract":"The application of 2D signal processing to profiles collected in airborne laser bathymetry is investigated. The processing involves a type of 2D filtering for the suppression of impulsive noise and the application of a sophisticated 2D interpolation technique for the reconstruction of bathymetric data. The reconstructed profiles are further enhanced by two adaptive procedures: one involves 2D power spectral analysis of the data on a block-by-block basis and the other concerns the estimation of the data on a point-by-point basis. Results show that each type of filtering enhances the accuracy of bathymetric measurement quite significantly.<<ETX>>","PeriodicalId":130255,"journal":{"name":"Proceedings of OCEANS '93","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130363039","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 : 1993-10-18DOI: 10.1109/OCEANS.1993.326147
J. Illman, H. Milburn, R. Macdonald
The NOAA Vents program and Canada's Pacific Geoscience Centre and Institute of Ocean Sciences have recently collaborated in an effort to utilize Canada's HYSUB 5000 ROV in the study of hydrothermal venting and seafloor processes along a mid-ocean ridge. A navigation system has been developed to geodetically position the ROV over rough terrain in deep water using a long baseline acoustic net, differential GPS and software tailored to the needs of the operators and scientists. Ship positioning and station-keeping is a vital part of successful ROV operations and special considerations were given for operation from a non-dynamically positioned research vessel. With the growing acceptance of remotely operated vehicles for performing tasks previously allocated to manned submersibles, the demands on the navigation system have increased. To date, the navigation system has produced good geodetic results while the ROV has successfully sampled hot water vents, connected to a deeply moored instrument package for data retreival, collected biological samples and photographed large areas of the seafloor-all tasks previously performed by ALVIN in the VENTS and RIDGE research programs.<>
{"title":"An integrated system for navigation and positioning of an ROV for scientific exploration","authors":"J. Illman, H. Milburn, R. Macdonald","doi":"10.1109/OCEANS.1993.326147","DOIUrl":"https://doi.org/10.1109/OCEANS.1993.326147","url":null,"abstract":"The NOAA Vents program and Canada's Pacific Geoscience Centre and Institute of Ocean Sciences have recently collaborated in an effort to utilize Canada's HYSUB 5000 ROV in the study of hydrothermal venting and seafloor processes along a mid-ocean ridge. A navigation system has been developed to geodetically position the ROV over rough terrain in deep water using a long baseline acoustic net, differential GPS and software tailored to the needs of the operators and scientists. Ship positioning and station-keeping is a vital part of successful ROV operations and special considerations were given for operation from a non-dynamically positioned research vessel. With the growing acceptance of remotely operated vehicles for performing tasks previously allocated to manned submersibles, the demands on the navigation system have increased. To date, the navigation system has produced good geodetic results while the ROV has successfully sampled hot water vents, connected to a deeply moored instrument package for data retreival, collected biological samples and photographed large areas of the seafloor-all tasks previously performed by ALVIN in the VENTS and RIDGE research programs.<<ETX>>","PeriodicalId":130255,"journal":{"name":"Proceedings of OCEANS '93","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117023268","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 : 1993-10-18DOI: 10.1109/OCEANS.1993.326198
M. Chaffey, A. Pearce, R. Herlien
MBARI is currently developing an electrically propelled remotely operated vehicle (ROV) designed to carry science payloads to 4000 meters ocean depth. Mission requirements for accurate navigation, precision maneuvering and extensive sensor capabilities place large demands on the data gathering and control system. The ROV must operate reliably in an extremely hostile ocean environment while retaining enough flexibility to support varied scientific missions for a decade or more. An ROV system architecture has been implemented that incorporates Hewlett Packard UNIX workstations, shipboard and vehicle mounted VMEbus and microcontroller based computers all linked to form a distributed data gathering and control network. In-water tests of the ROV have shown that a distributed, multiple processor system shows promise as a practical solution for interfacing the large number of sensors and actuators on a research ROV and provides considerable system adaptability.<>
{"title":"Distributed data and computing system on an ROV designed for ocean science","authors":"M. Chaffey, A. Pearce, R. Herlien","doi":"10.1109/OCEANS.1993.326198","DOIUrl":"https://doi.org/10.1109/OCEANS.1993.326198","url":null,"abstract":"MBARI is currently developing an electrically propelled remotely operated vehicle (ROV) designed to carry science payloads to 4000 meters ocean depth. Mission requirements for accurate navigation, precision maneuvering and extensive sensor capabilities place large demands on the data gathering and control system. The ROV must operate reliably in an extremely hostile ocean environment while retaining enough flexibility to support varied scientific missions for a decade or more. An ROV system architecture has been implemented that incorporates Hewlett Packard UNIX workstations, shipboard and vehicle mounted VMEbus and microcontroller based computers all linked to form a distributed data gathering and control network. In-water tests of the ROV have shown that a distributed, multiple processor system shows promise as a practical solution for interfacing the large number of sensors and actuators on a research ROV and provides considerable system adaptability.<<ETX>>","PeriodicalId":130255,"journal":{"name":"Proceedings of OCEANS '93","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117029292","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 : 1993-10-18DOI: 10.1109/OCEANS.1993.326007
M. Deffenbaugh, H. Schmidt, J. Bellingham
In the Spring of 1994, the dynamical and mechanical behavior of the Artic ice cover was studied from an ice camp deployed in the Beaufort Sea, 2-300 nm north of Prudoe Bay. The periodic measurement of the under-ice topography is a key component of the experiment, and the authors make use of autonomous underwater vehicle (AUV) technology to provide a cost effective alternative to the use of nuclear submarines. As a proof of concept, the AUV Odyssey was used to obtain ice-topographic data from areas located up to 10 km from the base camp. Accurate and reliable navigation is crucial to successful completion of the mission and recovery of the vehicle. The planned mission is described together with the associated requirements for vehicle technology, with particular emphasis on the development of a robust, very long baseline acoustic navigation system.<>
{"title":"Acoustic navigation for Arctic under-ice AUV missions","authors":"M. Deffenbaugh, H. Schmidt, J. Bellingham","doi":"10.1109/OCEANS.1993.326007","DOIUrl":"https://doi.org/10.1109/OCEANS.1993.326007","url":null,"abstract":"In the Spring of 1994, the dynamical and mechanical behavior of the Artic ice cover was studied from an ice camp deployed in the Beaufort Sea, 2-300 nm north of Prudoe Bay. The periodic measurement of the under-ice topography is a key component of the experiment, and the authors make use of autonomous underwater vehicle (AUV) technology to provide a cost effective alternative to the use of nuclear submarines. As a proof of concept, the AUV Odyssey was used to obtain ice-topographic data from areas located up to 10 km from the base camp. Accurate and reliable navigation is crucial to successful completion of the mission and recovery of the vehicle. The planned mission is described together with the associated requirements for vehicle technology, with particular emphasis on the development of a robust, very long baseline acoustic navigation system.<<ETX>>","PeriodicalId":130255,"journal":{"name":"Proceedings of OCEANS '93","volume":"196 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132522141","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 : 1993-10-18DOI: 10.1109/OCEANS.1993.326001
P. Mikhalevsky, R. Muench, A. Baggeroer
Several climate models suggest that the Arctic Ocean may be one of the more sensitive indicators of global climate change. In addition to changes in the Arctic Ocean temperature, the ice pack will also respond to these changes; for example, its mean thickness, roughness and the percentage of open water will all be modulated. Low frequency acoustic propagation in the Arctic is strongly influenced by the ice pack properties since the SOFAR axis is at or near the surface. In addition to the travel time and phase changes that could be observed due to changes in the Arctic Ocean temperature; phase and amplitude coherence, travel times, transmission losses, modal coupling are just a few of the observables which would respond to changes in the pack ice. Current understanding as well as future work and possibilities for acoustic thermometry of Arctic Ocean climate are reviewed.<>
{"title":"Acoustic thermometry for Arctic Ocean climate","authors":"P. Mikhalevsky, R. Muench, A. Baggeroer","doi":"10.1109/OCEANS.1993.326001","DOIUrl":"https://doi.org/10.1109/OCEANS.1993.326001","url":null,"abstract":"Several climate models suggest that the Arctic Ocean may be one of the more sensitive indicators of global climate change. In addition to changes in the Arctic Ocean temperature, the ice pack will also respond to these changes; for example, its mean thickness, roughness and the percentage of open water will all be modulated. Low frequency acoustic propagation in the Arctic is strongly influenced by the ice pack properties since the SOFAR axis is at or near the surface. In addition to the travel time and phase changes that could be observed due to changes in the Arctic Ocean temperature; phase and amplitude coherence, travel times, transmission losses, modal coupling are just a few of the observables which would respond to changes in the pack ice. Current understanding as well as future work and possibilities for acoustic thermometry of Arctic Ocean climate are reviewed.<<ETX>>","PeriodicalId":130255,"journal":{"name":"Proceedings of OCEANS '93","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128104495","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 : 1993-10-18DOI: 10.1109/OCEANS.1993.326191
R. B. Huseby, O. Milvang, A. Solberg, K. W. Bjerde
The development of reliable methods for automatic seabed classification enjoys widespread interest at the present time. In this article, statistical methods for seabed classification from backscatter sonar data are investigated. The classification rule is derived from the Bayes decision rule and involves a probability model of the features extracted from multibeam echosounder data. The features are based on the backscatter distribution, the spectral distribution, and the backscatter-level co-occurence. The authors also present procedures for detection of seabed of unknown type and classification of pixels as a mixture of two different classes. Raw backscatter data from the Simrad EM 1000 Multibeam Echo Sounder are used. The results show that it is possible to differentiate between seabeds of various sediment types.<>
{"title":"Seabed classification from multibeam echosounder data using statistical methods","authors":"R. B. Huseby, O. Milvang, A. Solberg, K. W. Bjerde","doi":"10.1109/OCEANS.1993.326191","DOIUrl":"https://doi.org/10.1109/OCEANS.1993.326191","url":null,"abstract":"The development of reliable methods for automatic seabed classification enjoys widespread interest at the present time. In this article, statistical methods for seabed classification from backscatter sonar data are investigated. The classification rule is derived from the Bayes decision rule and involves a probability model of the features extracted from multibeam echosounder data. The features are based on the backscatter distribution, the spectral distribution, and the backscatter-level co-occurence. The authors also present procedures for detection of seabed of unknown type and classification of pixels as a mixture of two different classes. Raw backscatter data from the Simrad EM 1000 Multibeam Echo Sounder are used. The results show that it is possible to differentiate between seabeds of various sediment types.<<ETX>>","PeriodicalId":130255,"journal":{"name":"Proceedings of OCEANS '93","volume":"621 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114058608","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 : 1993-10-18DOI: 10.1109/OCEANS.1993.326158
C. Blyth, M. A. Caldwell, T. Fyles, B. Smiley
The Continental and Oceanographic Data Information System (CODIS) is a custom software/database application developed to provide an on-line computer catalogue or inventory of scientific data gathered during environmental studies in Canadian West Coast and Arctic waters and in the Fraser River. CODIS was developed in conjunction with Fisheries and Oceans Canada and the University of Victoria. Information about the disciplines: ocean chemistry, physical oceanography, fish, mammals, zoobenthos, plankton and continental chemistry, with the intent of including more disciplines in the future. The purpose of the inventory was to assemble, condense and appraise all available documentation in order to assist the researcher or environmental manager in identifying and locating the most suitable data sets for specific applications. The system includes data from the Fisheries and Oceans Canada, Arctic Data Compilation and Appraisal and West Coast Data Compilation and Appraisal catalogues and data collected by the University of Victoria. The information has been assembled from a variety of sources. The system includes information concerning data quality based on suitability of methods and completeness of documentation. The data quality rating is an objective scale that grades data according to their ability to be compared to data described in other data sets. The purpose of the data rating is to provide users with a guide to the level of confidence they can place on conclusions drawn from the data and it provides an indication of how applicable the data are for other purposes. CODIS permits the data to be edited while maintaining strict adherence to data quality protocols.<>
{"title":"The Continental and Oceanographic Data Information System (CODIS)","authors":"C. Blyth, M. A. Caldwell, T. Fyles, B. Smiley","doi":"10.1109/OCEANS.1993.326158","DOIUrl":"https://doi.org/10.1109/OCEANS.1993.326158","url":null,"abstract":"The Continental and Oceanographic Data Information System (CODIS) is a custom software/database application developed to provide an on-line computer catalogue or inventory of scientific data gathered during environmental studies in Canadian West Coast and Arctic waters and in the Fraser River. CODIS was developed in conjunction with Fisheries and Oceans Canada and the University of Victoria. Information about the disciplines: ocean chemistry, physical oceanography, fish, mammals, zoobenthos, plankton and continental chemistry, with the intent of including more disciplines in the future. The purpose of the inventory was to assemble, condense and appraise all available documentation in order to assist the researcher or environmental manager in identifying and locating the most suitable data sets for specific applications. The system includes data from the Fisheries and Oceans Canada, Arctic Data Compilation and Appraisal and West Coast Data Compilation and Appraisal catalogues and data collected by the University of Victoria. The information has been assembled from a variety of sources. The system includes information concerning data quality based on suitability of methods and completeness of documentation. The data quality rating is an objective scale that grades data according to their ability to be compared to data described in other data sets. The purpose of the data rating is to provide users with a guide to the level of confidence they can place on conclusions drawn from the data and it provides an indication of how applicable the data are for other purposes. CODIS permits the data to be edited while maintaining strict adherence to data quality protocols.<<ETX>>","PeriodicalId":130255,"journal":{"name":"Proceedings of OCEANS '93","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122465649","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 : 1993-10-18DOI: 10.1109/OCEANS.1993.326146
F. Parthiot, J. Denis
IFREMER-French Institute for Sea Exploration and Exploitation-is currently operating manned submersibles, towed sonars and ROVs down to 6000 m. IFREMER are replacing their positioning system resting on long base line (LBL) by a new positioning system called POSIDONIA which is under development at the company group Thomson Sintra ASM and Mors Environment. This replacement aims to reduce operators time and overall costs by improving accuracy, reliability and flexibility in comparison with the existing systems. To achieve these characteristics, the POSIDONIA positioning system is of a new breed which combines a short base line (SBL) and an ultra short base line (USBL). It has been designed to operate in noisy environments and get rid of multipath effects, to compensate for the lack of precise radio navigation, and generally to comply with the various task requirements. Therefore, not only has the acoustic signal processing been optimized, but also the beacon functionalities to give full versatility. In addition, the need of a high precision vertical and heading reference unit (VHRU), to make up for the vessel attitude, has induced the definition of a hybrid VHRU based on both GPS and inertial sensors.<>
{"title":"A better way to navigate on deep sea floors","authors":"F. Parthiot, J. Denis","doi":"10.1109/OCEANS.1993.326146","DOIUrl":"https://doi.org/10.1109/OCEANS.1993.326146","url":null,"abstract":"IFREMER-French Institute for Sea Exploration and Exploitation-is currently operating manned submersibles, towed sonars and ROVs down to 6000 m. IFREMER are replacing their positioning system resting on long base line (LBL) by a new positioning system called POSIDONIA which is under development at the company group Thomson Sintra ASM and Mors Environment. This replacement aims to reduce operators time and overall costs by improving accuracy, reliability and flexibility in comparison with the existing systems. To achieve these characteristics, the POSIDONIA positioning system is of a new breed which combines a short base line (SBL) and an ultra short base line (USBL). It has been designed to operate in noisy environments and get rid of multipath effects, to compensate for the lack of precise radio navigation, and generally to comply with the various task requirements. Therefore, not only has the acoustic signal processing been optimized, but also the beacon functionalities to give full versatility. In addition, the need of a high precision vertical and heading reference unit (VHRU), to make up for the vessel attitude, has induced the definition of a hybrid VHRU based on both GPS and inertial sensors.<<ETX>>","PeriodicalId":130255,"journal":{"name":"Proceedings of OCEANS '93","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124029768","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 : 1993-10-18DOI: 10.1109/OCEANS.1993.326226
R. Coates
The paper first attempts to provide a framework for the underwater acoustic communication system. An acoustic frequency band allocation, analogous to that used by radio engineers, is proposed. Similarly, the "shallow" channel is defined and the conditions pertaining to "high" bit rate explored. Finally the paper, using this framework, discusses the performance of a range of communication systems developed at the University of Birmingham, UK.<>
{"title":"Underwater acoustic communications","authors":"R. Coates","doi":"10.1109/OCEANS.1993.326226","DOIUrl":"https://doi.org/10.1109/OCEANS.1993.326226","url":null,"abstract":"The paper first attempts to provide a framework for the underwater acoustic communication system. An acoustic frequency band allocation, analogous to that used by radio engineers, is proposed. Similarly, the \"shallow\" channel is defined and the conditions pertaining to \"high\" bit rate explored. Finally the paper, using this framework, discusses the performance of a range of communication systems developed at the University of Birmingham, UK.<<ETX>>","PeriodicalId":130255,"journal":{"name":"Proceedings of OCEANS '93","volume":"99 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124194336","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 : 1993-10-18DOI: 10.1109/OCEANS.1993.326059
B. Nutzel, H. Herwig, A. Schmidt
Results of the experiment SAXON Phase 2 which was conducted in November 1991 at the German Research Platform NORDSEE are presented. The experiment was designed to measure the acoustic and electromagnetic backscattering strength of the sea surface simultaneously and at the same sonar and radar wavelength. The grazing angle dependence was investigated at angles from 20/spl deg/ to 70/spl deg/. Backscattering from the same spot of the sea surface was measured at a grazing angle of 18/spl deg/ for both systems. The sonar frequencies were 50, 26.5, and 5 kHz corresponding to radar frequencies of 10, 5.3, and 1 GHz (X-, C-, and L-band), respectively. Data were collected at wind speeds ranging from 0 to 21 m/s. The results exhibit excellent correlation between sonar and radar backscattering in the low wind speed regime at all frequencies. At higher wind speeds, bubbles caused by breaking waves are the dominant acoustic backscattering mechanism at high sonar frequencies. In this case both systems no longer see the same scatterers and the correlation decreases. The parameter combinations of wind speed and sonar and radar frequency, for which the backscatter occurs from the sea surface only, are given for a grazing angle of 45.<>
{"title":"Acoustic and microwave backscattering of the sea surface","authors":"B. Nutzel, H. Herwig, A. Schmidt","doi":"10.1109/OCEANS.1993.326059","DOIUrl":"https://doi.org/10.1109/OCEANS.1993.326059","url":null,"abstract":"Results of the experiment SAXON Phase 2 which was conducted in November 1991 at the German Research Platform NORDSEE are presented. The experiment was designed to measure the acoustic and electromagnetic backscattering strength of the sea surface simultaneously and at the same sonar and radar wavelength. The grazing angle dependence was investigated at angles from 20/spl deg/ to 70/spl deg/. Backscattering from the same spot of the sea surface was measured at a grazing angle of 18/spl deg/ for both systems. The sonar frequencies were 50, 26.5, and 5 kHz corresponding to radar frequencies of 10, 5.3, and 1 GHz (X-, C-, and L-band), respectively. Data were collected at wind speeds ranging from 0 to 21 m/s. The results exhibit excellent correlation between sonar and radar backscattering in the low wind speed regime at all frequencies. At higher wind speeds, bubbles caused by breaking waves are the dominant acoustic backscattering mechanism at high sonar frequencies. In this case both systems no longer see the same scatterers and the correlation decreases. The parameter combinations of wind speed and sonar and radar frequency, for which the backscatter occurs from the sea surface only, are given for a grazing angle of 45.<<ETX>>","PeriodicalId":130255,"journal":{"name":"Proceedings of OCEANS '93","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124576125","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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