Pub Date : 2002-10-29DOI: 10.1109/OCEANS.2002.1192001
K. Hardy, M. Olsson, A. Yayanos, J. Prsha, W. Hagey
Recent developments in the manufacture of borosilicate glass housings offer scientific investigators and ocean engineers the opportunity to go "deep and cheap." The 17-inch OD spheres, manufactured By Schott Glasswerks in Jena, Germany, provide ample interior space and positive buoyancy. The clarity of the glass and manufacturing tolerance control make the housings useful for photographic imaging. Other sensors suites may be added or substituted. Multiple sphere configurations are achievable. Scripps Institution of Oceanography/UCSD researchers and its corporate partners recently completed sea trials of a 7km rated version of a baited camera inspired by the pioneering work of Scripps Professor John D. Isaacs. The project revisits great science of the past with today's technology in celebration of the 100/sup th/ birthday of Scripps Institution in 2003. Key components of a 10 km rated version have already been pressure tested.
{"title":"Deep Ocean Visualization Experimenter (DOVE): low-cost 10 km camera and instrument platform","authors":"K. Hardy, M. Olsson, A. Yayanos, J. Prsha, W. Hagey","doi":"10.1109/OCEANS.2002.1192001","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1192001","url":null,"abstract":"Recent developments in the manufacture of borosilicate glass housings offer scientific investigators and ocean engineers the opportunity to go \"deep and cheap.\" The 17-inch OD spheres, manufactured By Schott Glasswerks in Jena, Germany, provide ample interior space and positive buoyancy. The clarity of the glass and manufacturing tolerance control make the housings useful for photographic imaging. Other sensors suites may be added or substituted. Multiple sphere configurations are achievable. Scripps Institution of Oceanography/UCSD researchers and its corporate partners recently completed sea trials of a 7km rated version of a baited camera inspired by the pioneering work of Scripps Professor John D. Isaacs. The project revisits great science of the past with today's technology in celebration of the 100/sup th/ birthday of Scripps Institution in 2003. Key components of a 10 km rated version have already been pressure tested.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121425677","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 : 2002-10-29DOI: 10.1109/OCEANS.2002.1192102
G. Allen, J. Purpura, D. Overway
This paper is concerned with the early stage efforts to augment the AUV (autonomous underwater vehicle) with an enhanced magnetic detection/localization capability that is inherently unaffected by environmental conditions found in the shallow water environment. Prior to the placement of a sensitive magnetic sensor system on an actual AUV, the magnetic characteristics of the vehicle itself must be measured and their detrimental effects on the sensor mitigated. In particular, this paper discusses techniques for the magnetic characterization of several AUVs and a comparison of these results. It then briefly discusses proposed methods of mitigation and some of the surprising results obtained from candidate platforms. Detailed mitigation techniques and results are presented in a companion paper.
{"title":"Measurement of magnetic noise characteristics on select AUVs with some potential mitigation techniques","authors":"G. Allen, J. Purpura, D. Overway","doi":"10.1109/OCEANS.2002.1192102","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1192102","url":null,"abstract":"This paper is concerned with the early stage efforts to augment the AUV (autonomous underwater vehicle) with an enhanced magnetic detection/localization capability that is inherently unaffected by environmental conditions found in the shallow water environment. Prior to the placement of a sensitive magnetic sensor system on an actual AUV, the magnetic characteristics of the vehicle itself must be measured and their detrimental effects on the sensor mitigated. In particular, this paper discusses techniques for the magnetic characterization of several AUVs and a comparison of these results. It then briefly discusses proposed methods of mitigation and some of the surprising results obtained from candidate platforms. Detailed mitigation techniques and results are presented in a companion paper.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114334798","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 : 2002-10-29DOI: 10.1109/OCEANS.2002.1192137
M. Harris, W.E. Avera, L. Bibee
NRL demonstrated extraction of accurate single beam and multibeam bathymetry from a towed vehicle designed to locate mines in the water column. However, biases were encountered in measuring the static pressure depth of the moving vehicle. Water depth is calculated by simply adding tow vehicle depth, measured by a pressure sensor, to the multibeam ranges from the seafloor, measured acoustically from the vehicle. Comparisons of the tow vehicle bathymetry with ground truth showed a shallow bias in depth. The pressure sensor was suspected based on previous experience measuring multibeam bathymetry on the unmanned semi submersible ORCA. There were two contributing sources of error. The first was pressure sensor calibration; the sensor needs to be "zeroed" before entering the water. The second and more interesting was that the sensor was measuring variations in pressure caused from vehicle velocity in addition to changes in vehicle depth. The challenge is measuring static depth from a moving vehicle. The acoustic signal from the first water surface bounce was used to measure the bias and correct for pressure sensor error. This paper describes the sensors, data and techniques used to compensate for the depth bias.
{"title":"Tow vehicle depth verification","authors":"M. Harris, W.E. Avera, L. Bibee","doi":"10.1109/OCEANS.2002.1192137","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1192137","url":null,"abstract":"NRL demonstrated extraction of accurate single beam and multibeam bathymetry from a towed vehicle designed to locate mines in the water column. However, biases were encountered in measuring the static pressure depth of the moving vehicle. Water depth is calculated by simply adding tow vehicle depth, measured by a pressure sensor, to the multibeam ranges from the seafloor, measured acoustically from the vehicle. Comparisons of the tow vehicle bathymetry with ground truth showed a shallow bias in depth. The pressure sensor was suspected based on previous experience measuring multibeam bathymetry on the unmanned semi submersible ORCA. There were two contributing sources of error. The first was pressure sensor calibration; the sensor needs to be \"zeroed\" before entering the water. The second and more interesting was that the sensor was measuring variations in pressure caused from vehicle velocity in addition to changes in vehicle depth. The challenge is measuring static depth from a moving vehicle. The acoustic signal from the first water surface bounce was used to measure the bias and correct for pressure sensor error. This paper describes the sensors, data and techniques used to compensate for the depth bias.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121637999","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 : 2002-10-29DOI: 10.1109/OCEANS.2002.1191939
K. Matulewski
The Naval Oceanographic Office (NAVOCEANO) has continued to develop new capabilities in the area of near-real-time synoptic ocean observation. In the last year, the Navy has developed the ability to acquire and process near-real-time ocean color data. This has made possible the generation of satellite optical products that can be used for Naval fleet support. In this paper, we will present recent and near-future improvements in the areas of new data types, new products and product algorithms, atmospheric corrections, sensor calibrations, cloud masking techniques, validation issues, and timeliness of the data. We will also present the evolving method that NAVOCEANO is utilizing to acquire and process ocean color data. Present optical products available for Naval fleet support include diver visibility for fleet and diver guidance, attenuation fields for laser systems performance assessment, and turbidity and front/eddy information for physical circulation model performance assessments.
{"title":"Near-real-time processing of ocean color data for Naval fleet support -recent and future improvements","authors":"K. Matulewski","doi":"10.1109/OCEANS.2002.1191939","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1191939","url":null,"abstract":"The Naval Oceanographic Office (NAVOCEANO) has continued to develop new capabilities in the area of near-real-time synoptic ocean observation. In the last year, the Navy has developed the ability to acquire and process near-real-time ocean color data. This has made possible the generation of satellite optical products that can be used for Naval fleet support. In this paper, we will present recent and near-future improvements in the areas of new data types, new products and product algorithms, atmospheric corrections, sensor calibrations, cloud masking techniques, validation issues, and timeliness of the data. We will also present the evolving method that NAVOCEANO is utilizing to acquire and process ocean color data. Present optical products available for Naval fleet support include diver visibility for fleet and diver guidance, attenuation fields for laser systems performance assessment, and turbidity and front/eddy information for physical circulation model performance assessments.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127585278","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 : 2002-10-29DOI: 10.1109/OCEANS.2002.1191903
A. Gent
In 1989 the Oceanographer of the Navy approved the construction of a new class of multimission oceanographic survey ship for the Naval Oceanographic Office, the T-AGS 60 class. The initial focus of the survey mission was primarily blue water oceanography. In the intervening years mission focus has shifted towards the littoral. This paper presents the original class mission capability and discusses the mission evolution to the littoral and the incorporation of a hydrographic survey capability that meets International Hydrographic Organization requirements.
{"title":"T-AGS 60 class oceanographic survey ships: evolution of the hydrographic mission","authors":"A. Gent","doi":"10.1109/OCEANS.2002.1191903","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1191903","url":null,"abstract":"In 1989 the Oceanographer of the Navy approved the construction of a new class of multimission oceanographic survey ship for the Naval Oceanographic Office, the T-AGS 60 class. The initial focus of the survey mission was primarily blue water oceanography. In the intervening years mission focus has shifted towards the littoral. This paper presents the original class mission capability and discusses the mission evolution to the littoral and the incorporation of a hydrographic survey capability that meets International Hydrographic Organization requirements.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126455354","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 : 2002-10-29DOI: 10.1109/OCEANS.2002.1192134
K.J. Wydajewski, B. White
First responders are those elements of law enforcement, fire and rescue, emergency medical services, and national security personnel including military units who respond to emergency calls of service. In this paper, the maritime terrorist threat is introduced and an updated status of the U.S. government's response to the threat through organizational change is documented. Some of the more recent changes within the U.S. Coast Guard that affect the nation's posture against maritime terrorism are presented. A list of some of the first responders and supporting organizations to a maritime security incident is provided. A plausible incident scenario is used to illustrate the resulting flow of information and the need to rapidly disseminate data to the first responders to help them to be both safe and effective.
{"title":"Processes and techniques for providing critical data to first responders to maritime security incidents","authors":"K.J. Wydajewski, B. White","doi":"10.1109/OCEANS.2002.1192134","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1192134","url":null,"abstract":"First responders are those elements of law enforcement, fire and rescue, emergency medical services, and national security personnel including military units who respond to emergency calls of service. In this paper, the maritime terrorist threat is introduced and an updated status of the U.S. government's response to the threat through organizational change is documented. Some of the more recent changes within the U.S. Coast Guard that affect the nation's posture against maritime terrorism are presented. A list of some of the first responders and supporting organizations to a maritime security incident is provided. A plausible incident scenario is used to illustrate the resulting flow of information and the need to rapidly disseminate data to the first responders to help them to be both safe and effective.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128183821","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 : 2002-10-29DOI: 10.1109/OCEANS.2002.1191947
L. Bird
The Monterey Bay Aquarium Research Institute (MBARI) has committed to the novel and technically ambitious Canyon Dynamics Project. Canyon Dynamics represents a dual effort by science and engineering. Science, to understand the physical processes of submarine canyons as conduits for transporting materials from continents to the deep sea. Engineering, to develop the tools necessary to accomplish this goal. The key elements are instrumented platforms deployed in the axis of the Monterey Bay Canyon at depths of 250 and 500 meters, located 10 kilometers apart. These RINs (remote instrument nodes) and BINs (benthic inter connect nodes) will be connected with a fiber optic/power cable and establish a network that can measure the currents, suspended sediments concentrations, salinity, and temperature at these sites. This technology will act as building blocks for MOOS (MBARI Ocean Observatory System, MARS (Monterey Accessible Research System, and NEPTUNE projects. This presentation will deal specifically with the design, building, testing, and deployment of a ROV based tool sled constructed for the placement of this cable on the seabed and interconnections with the RIN/BIN platforms. The design includes; integration with the ROV Ventana, meet operational weight constraints, the ability to (pick up, drop, and reacquire the cable spool), support the vehicle's Schilling Titan III manipulator, monitor cable payout speed and distance and a variable ballast system controlled by the amount of cable deployed. Currently the core sled is complete and the peripherals are under construction. Testing has begun with the ROV Ventana and the cable laying tool sled, in the MBARI test tank, performing interconnects with an instrumented RIN platform. Further testing will continue through summer with RIN/BIN deployment taking place in June and cable laying scheduled for this fall.
{"title":"ROV based tool sled for the placement of fiber optic cable between benthic instrument nodes","authors":"L. Bird","doi":"10.1109/OCEANS.2002.1191947","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1191947","url":null,"abstract":"The Monterey Bay Aquarium Research Institute (MBARI) has committed to the novel and technically ambitious Canyon Dynamics Project. Canyon Dynamics represents a dual effort by science and engineering. Science, to understand the physical processes of submarine canyons as conduits for transporting materials from continents to the deep sea. Engineering, to develop the tools necessary to accomplish this goal. The key elements are instrumented platforms deployed in the axis of the Monterey Bay Canyon at depths of 250 and 500 meters, located 10 kilometers apart. These RINs (remote instrument nodes) and BINs (benthic inter connect nodes) will be connected with a fiber optic/power cable and establish a network that can measure the currents, suspended sediments concentrations, salinity, and temperature at these sites. This technology will act as building blocks for MOOS (MBARI Ocean Observatory System, MARS (Monterey Accessible Research System, and NEPTUNE projects. This presentation will deal specifically with the design, building, testing, and deployment of a ROV based tool sled constructed for the placement of this cable on the seabed and interconnections with the RIN/BIN platforms. The design includes; integration with the ROV Ventana, meet operational weight constraints, the ability to (pick up, drop, and reacquire the cable spool), support the vehicle's Schilling Titan III manipulator, monitor cable payout speed and distance and a variable ballast system controlled by the amount of cable deployed. Currently the core sled is complete and the peripherals are under construction. Testing has begun with the ROV Ventana and the cable laying tool sled, in the MBARI test tank, performing interconnects with an instrumented RIN platform. Further testing will continue through summer with RIN/BIN deployment taking place in June and cable laying scheduled for this fall.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133987837","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 : 2002-10-29DOI: 10.1109/OCEANS.2002.1193241
P. M. Oliveira, V. Lobo, V. Barroso, Femando Moura-Pires
Due to the complexity of underwater transients and background interference, model based approaches to transient detection/classification are often not practical. This has motivated an interest for data-driven, model-free methods. One such method was presented by Jones and Sayeed (see Proceedings of the 1995 IEEE International Conference on Acoustics, Speech and Signal Processing CASSP 95, Detroit, MI, p.1033-1036) and modified by Oliveira and Barroso (see Proc. of MTS/IEEE Oceans 2000, August 2000), where it was applied to the detection of underwater transients. We extend that approach, to allow its use in the more demanding environment of a brown water environment, where background noise is constituted by a multitude of different interferences, non-white, and highly non-stationary. Also, the assumption of linear separability amongst the transients and the background noise in the time-frequency or related domains will be discarded, leading to the use of an additional classifier stage. A technique to minimize the number of prototypes on this classifier is presented. The developed methods are used to detect and classify real underwater transients, recorded off the Portuguese coast. Estimation of the overall error rate of the method is obtained using cross-validation with the available data set, showing that these methods can effectively be used in real environment situations.
由于水下瞬态和背景干扰的复杂性，基于模型的瞬态检测/分类方法往往不实用。这激发了人们对数据驱动、无模型方法的兴趣。其中一种方法由Jones和Sayeed提出(参见1995年IEEE声学、语音和信号处理国际会议论文集，casp 95, Detroit, MI, p.1033-1036)，并由Oliveira和Barroso修改(参见Proc. of MTS/IEEE Oceans 2000, August 2000)，应用于水下瞬态检测。我们扩展了这种方法，以允许其在棕色水环境的更苛刻的环境中使用，其中背景噪声由多种不同的干扰组成，非白色，高度非平稳。此外，暂态和背景噪声在时频或相关域中的线性可分性假设将被丢弃，从而导致使用额外的分类器阶段。提出了一种最小化该分类器上的原型数量的方法。开发的方法用于检测和分类真实的水下瞬变，记录在葡萄牙海岸附近。通过与现有数据集的交叉验证，得到了该方法总体错误率的估计，表明该方法能够有效地应用于实际环境中。
{"title":"Detection and classification of underwater transients with data driven methods based on time-frequency distributions and non-parametric classifiers","authors":"P. M. Oliveira, V. Lobo, V. Barroso, Femando Moura-Pires","doi":"10.1109/OCEANS.2002.1193241","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1193241","url":null,"abstract":"Due to the complexity of underwater transients and background interference, model based approaches to transient detection/classification are often not practical. This has motivated an interest for data-driven, model-free methods. One such method was presented by Jones and Sayeed (see Proceedings of the 1995 IEEE International Conference on Acoustics, Speech and Signal Processing CASSP 95, Detroit, MI, p.1033-1036) and modified by Oliveira and Barroso (see Proc. of MTS/IEEE Oceans 2000, August 2000), where it was applied to the detection of underwater transients. We extend that approach, to allow its use in the more demanding environment of a brown water environment, where background noise is constituted by a multitude of different interferences, non-white, and highly non-stationary. Also, the assumption of linear separability amongst the transients and the background noise in the time-frequency or related domains will be discarded, leading to the use of an additional classifier stage. A technique to minimize the number of prototypes on this classifier is presented. The developed methods are used to detect and classify real underwater transients, recorded off the Portuguese coast. Estimation of the overall error rate of the method is obtained using cross-validation with the available data set, showing that these methods can effectively be used in real environment situations.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131480017","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 : 2002-10-29DOI: 10.1109/OCEANS.2002.1193310
F. Driscoll, W. Venezia, D. Curic, T. Pantelakis
The A-sized standard is adopted for many buoys used in ocean monitoring that are deployed from aircraft, helicopters, ships and submarines using pressure and gravity launch tubes, as well as charge-activated devices (CAD). Unfortunately, most existing A-sized systems are drifting buoys and acquiring relatively long term measurements from a fixed location in littoral waters is difficult because currents tend to move these drifting buoys on shore or out of the region of active interest. A novel air brake and mooring module is presented in this paper that provides a reliable air deployment and autonomous mooring capability for A-sized systems. The module consists of a combined air brake/anchor and an autonomous scope adjusting mooring line spool. In air, the combined air brake/anchor is rigidly attached to the sensor package to eliminate parachute entanglement. In water, the air brake/anchor is released and moors the system in bottom types ranging from mud and sand to broken rock. The mooring module supports different mooring lines, including embedded conductors, and self-locks the mooring line at preprogrammed scopes in depths ranging between 20 and 200 m. The electronic components are low power and potted to eliminate leaks. A structural finite element model is used to design the high strength lightweight anchor and the size of the mooring module and buoy are minimized using a finite element numerical simulation. The final package is small, consuming 1/3 of the available space, and its volume is equivalent to the combined space utilized by existing parachutes and sensor suspension and communication lines.
{"title":"A combination air deceleration and mooring module for A-sized buoys","authors":"F. Driscoll, W. Venezia, D. Curic, T. Pantelakis","doi":"10.1109/OCEANS.2002.1193310","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1193310","url":null,"abstract":"The A-sized standard is adopted for many buoys used in ocean monitoring that are deployed from aircraft, helicopters, ships and submarines using pressure and gravity launch tubes, as well as charge-activated devices (CAD). Unfortunately, most existing A-sized systems are drifting buoys and acquiring relatively long term measurements from a fixed location in littoral waters is difficult because currents tend to move these drifting buoys on shore or out of the region of active interest. A novel air brake and mooring module is presented in this paper that provides a reliable air deployment and autonomous mooring capability for A-sized systems. The module consists of a combined air brake/anchor and an autonomous scope adjusting mooring line spool. In air, the combined air brake/anchor is rigidly attached to the sensor package to eliminate parachute entanglement. In water, the air brake/anchor is released and moors the system in bottom types ranging from mud and sand to broken rock. The mooring module supports different mooring lines, including embedded conductors, and self-locks the mooring line at preprogrammed scopes in depths ranging between 20 and 200 m. The electronic components are low power and potted to eliminate leaks. A structural finite element model is used to design the high strength lightweight anchor and the size of the mooring module and buoy are minimized using a finite element numerical simulation. The final package is small, consuming 1/3 of the available space, and its volume is equivalent to the combined space utilized by existing parachutes and sensor suspension and communication lines.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130933330","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 : 2002-10-29DOI: 10.1109/OCEANS.2002.1191954
K. Briggs, D. Tang
The accuracy and resolution of sediment bulk density measurements are examined. Bulk density from cores is traditionally measured by weight loss of extruded and sectioned 2-cm-thick sediment disks. The actual bulk density is thus an average value for the volume of a 2-cm-long-x-cross-sectional-area sediment core disk. Thus, the values of the measurements as well as the estimates of the correlation lengths may be a function of the disk thickness (sampling interval) and estimation of correlation lengths may be distorted. From a bulk density power spectrum and correlation length estimated from existing data, Monte Carlo realizations of the density were obtained for the sediment volume. From such realizations, we re-applied the same procedures used in the actual core analysis on the simulated cores to obtain a "virtual" bulk density profile and then re-estimated the power spectrum. Because actual density is known from the original data in the simulation, the difference between the parameters used to generate the simulation and the "virtual" parameters is a measure of the distortion. As a result of numerous simulations run to achieve a robust estimate of "virtual" bulk density, we show that laboratory procedures bias (lower) the actual variance of the parameters by averaging or smoothing. In related work, however, the first-order autoregressive approach for estimating correlation length from contiguous disks indicates a bias toward a higher value of the parameter than is appropriate.
{"title":"Assessing the sediment volume contribution to scattering: bulk density fluctuations","authors":"K. Briggs, D. Tang","doi":"10.1109/OCEANS.2002.1191954","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1191954","url":null,"abstract":"The accuracy and resolution of sediment bulk density measurements are examined. Bulk density from cores is traditionally measured by weight loss of extruded and sectioned 2-cm-thick sediment disks. The actual bulk density is thus an average value for the volume of a 2-cm-long-x-cross-sectional-area sediment core disk. Thus, the values of the measurements as well as the estimates of the correlation lengths may be a function of the disk thickness (sampling interval) and estimation of correlation lengths may be distorted. From a bulk density power spectrum and correlation length estimated from existing data, Monte Carlo realizations of the density were obtained for the sediment volume. From such realizations, we re-applied the same procedures used in the actual core analysis on the simulated cores to obtain a \"virtual\" bulk density profile and then re-estimated the power spectrum. Because actual density is known from the original data in the simulation, the difference between the parameters used to generate the simulation and the \"virtual\" parameters is a measure of the distortion. As a result of numerous simulations run to achieve a robust estimate of \"virtual\" bulk density, we show that laboratory procedures bias (lower) the actual variance of the parameters by averaging or smoothing. In related work, however, the first-order autoregressive approach for estimating correlation length from contiguous disks indicates a bias toward a higher value of the parameter than is appropriate.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131260544","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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