Pub Date : 2015-10-01DOI: 10.23919/OCEANS.2015.7404355
W. Duan, Y. R. Zheng
A Soft Direct-Adaptive Turbo Equalization (Soft DA-TEQ) is proposed for robust MIMO UWA communications. The proposed Soft DA-TEQ is derived under on the general frame of Expectation Maximization (E.M.) algorithm, which utilize the a priori soft decisions from the decoder to direct the equalizer's coefficients adaptation. The a priori soft decisions directed adaptation effectively lower the error propagation, which often cause catastrophic performance degradation in Hard DA-TEQ. Besides, in each iteration of the E.M. based soft adaption, the reliability of the symbol estimation is updated and used in the next iteration of soft adaption, which further enhances the convergence of the DA-TEQ. Experimental results show that the proposed Soft DA-TEQ is capable of robust detection in fast time varying MIMO UWA channels, even with low pilot overhead.
{"title":"Soft Direct-Adaptive Turbo Equalization for MIMO underwater acoustic communications","authors":"W. Duan, Y. R. Zheng","doi":"10.23919/OCEANS.2015.7404355","DOIUrl":"https://doi.org/10.23919/OCEANS.2015.7404355","url":null,"abstract":"A Soft Direct-Adaptive Turbo Equalization (Soft DA-TEQ) is proposed for robust MIMO UWA communications. The proposed Soft DA-TEQ is derived under on the general frame of Expectation Maximization (E.M.) algorithm, which utilize the a priori soft decisions from the decoder to direct the equalizer's coefficients adaptation. The a priori soft decisions directed adaptation effectively lower the error propagation, which often cause catastrophic performance degradation in Hard DA-TEQ. Besides, in each iteration of the E.M. based soft adaption, the reliability of the symbol estimation is updated and used in the next iteration of soft adaption, which further enhances the convergence of the DA-TEQ. Experimental results show that the proposed Soft DA-TEQ is capable of robust detection in fast time varying MIMO UWA channels, even with low pilot overhead.","PeriodicalId":403976,"journal":{"name":"OCEANS 2015 - MTS/IEEE Washington","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126928402","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 : 2015-10-01DOI: 10.23919/OCEANS.2015.7404564
L. Christensen, C. Gaudig, F. Kirchner
In this paper we describe a new approach to deal with dynamic distortions of the ambient magnetic field often leading to errors in orientation estimation in confined unmanned underwater vehicles. In such systems, the space to mount magnetometer sensors is strictly limited and the sensors are often in the vicinity of distortion sources like ferromagnetic material, sonar transducers or strong electric currents flowing through nearby supply lines. In our paper we describe a threefold approach to deal with these magnetic field distortions: the use of multiple distributed magnetometers for robustness, the use of very small pressure-neutral sensors to get rid of mounting restrictions inside pressure compartments and the development and application of a multi-magnetometer fusion algorithm using von Mises-Fisher (vMF) distributions to compute undistorted orientation information.
{"title":"Distortion-robust distributed magnetometer for underwater pose estimation in confined UUVs","authors":"L. Christensen, C. Gaudig, F. Kirchner","doi":"10.23919/OCEANS.2015.7404564","DOIUrl":"https://doi.org/10.23919/OCEANS.2015.7404564","url":null,"abstract":"In this paper we describe a new approach to deal with dynamic distortions of the ambient magnetic field often leading to errors in orientation estimation in confined unmanned underwater vehicles. In such systems, the space to mount magnetometer sensors is strictly limited and the sensors are often in the vicinity of distortion sources like ferromagnetic material, sonar transducers or strong electric currents flowing through nearby supply lines. In our paper we describe a threefold approach to deal with these magnetic field distortions: the use of multiple distributed magnetometers for robustness, the use of very small pressure-neutral sensors to get rid of mounting restrictions inside pressure compartments and the development and application of a multi-magnetometer fusion algorithm using von Mises-Fisher (vMF) distributions to compute undistorted orientation information.","PeriodicalId":403976,"journal":{"name":"OCEANS 2015 - MTS/IEEE Washington","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126949502","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 : 2015-10-01DOI: 10.23919/OCEANS.2015.7404433
Vittorio Bichucher, Jeffrey M. Walls, P. Ozog, K. Skinner, R. Eustice
This paper reports on a factor graph simultaneous localization and mapping framework for autonomous underwater vehicle localization based on terrain-aided navigation. The method requires no prior bathymetric map and only assumes that the autonomous underwater vehicle has the ability to sparsely sense the local water column depth, such as with a bottom-looking Doppler velocity log. Since dead-reckoned navigation is accurate in short time windows, the vehicle accumulates several water column depth point clouds- or submaps-during the course of its survey. We propose an xy-alignment procedure between these submaps in order to enforce consistent bathymetric structure over time, and therefore attempt to bound long-term navigation drift. We evaluate the submap alignment method in simulation and present performance results from multiple autonomous underwater vehicle field trials.
{"title":"Bathymetric factor graph SLAM with sparse point cloud alignment","authors":"Vittorio Bichucher, Jeffrey M. Walls, P. Ozog, K. Skinner, R. Eustice","doi":"10.23919/OCEANS.2015.7404433","DOIUrl":"https://doi.org/10.23919/OCEANS.2015.7404433","url":null,"abstract":"This paper reports on a factor graph simultaneous localization and mapping framework for autonomous underwater vehicle localization based on terrain-aided navigation. The method requires no prior bathymetric map and only assumes that the autonomous underwater vehicle has the ability to sparsely sense the local water column depth, such as with a bottom-looking Doppler velocity log. Since dead-reckoned navigation is accurate in short time windows, the vehicle accumulates several water column depth point clouds- or submaps-during the course of its survey. We propose an xy-alignment procedure between these submaps in order to enforce consistent bathymetric structure over time, and therefore attempt to bound long-term navigation drift. We evaluate the submap alignment method in simulation and present performance results from multiple autonomous underwater vehicle field trials.","PeriodicalId":403976,"journal":{"name":"OCEANS 2015 - MTS/IEEE Washington","volume":"152 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131982895","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 : 2015-10-01DOI: 10.23919/OCEANS.2015.7404538
Pedro Caldeira Abreu, M. Bayat, J. Botelho, Pedro Góis, J. Gomes, A. Pascoal, J. Ribeiro, Miguel Ribeiro, Manuel Rufino, L. Sebastião, Henrique Silva
The EU MORPH project advances the use of a formation of five autonomous marine vehicles for mapping and scientific surveying of challenging, unstructured underwater environments as a means to overcome the limitations imposed by current single-vehicle based technology. We describe the test scenarios envisioned in the project and the requirements and constraints that they impose on the cooperative navigation and control systems that enable the concerted operation of the vehicle formation. We then provide a high-level description of each of the blocks that compose the final navigation and formation control architecture, developed at ISR/IST. We highlight how the systems take into account specific mission-related requirements and applications (e.g., typical trajectories employed for mapping and surveying). We describe the results of several trials at sea (involving multiple partners in the project and a group of heterogeneous vehicles) that illustrate the applicability of the MORPH concept in real operational scenarios as well as the limitations of the systems developed.
{"title":"Cooperative navigation and control: The EU MORPH project","authors":"Pedro Caldeira Abreu, M. Bayat, J. Botelho, Pedro Góis, J. Gomes, A. Pascoal, J. Ribeiro, Miguel Ribeiro, Manuel Rufino, L. Sebastião, Henrique Silva","doi":"10.23919/OCEANS.2015.7404538","DOIUrl":"https://doi.org/10.23919/OCEANS.2015.7404538","url":null,"abstract":"The EU MORPH project advances the use of a formation of five autonomous marine vehicles for mapping and scientific surveying of challenging, unstructured underwater environments as a means to overcome the limitations imposed by current single-vehicle based technology. We describe the test scenarios envisioned in the project and the requirements and constraints that they impose on the cooperative navigation and control systems that enable the concerted operation of the vehicle formation. We then provide a high-level description of each of the blocks that compose the final navigation and formation control architecture, developed at ISR/IST. We highlight how the systems take into account specific mission-related requirements and applications (e.g., typical trajectories employed for mapping and surveying). We describe the results of several trials at sea (involving multiple partners in the project and a group of heterogeneous vehicles) that illustrate the applicability of the MORPH concept in real operational scenarios as well as the limitations of the systems developed.","PeriodicalId":403976,"journal":{"name":"OCEANS 2015 - MTS/IEEE Washington","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132057675","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 : 2015-10-01DOI: 10.23919/OCEANS.2015.7404428
R. Forney, H. Roarty, S. Glenn
Ocean wave conditions impact many ways in which humans interact with the ocean, from the safety of recreation at the beach to the viability of offshore operations. Wave conditions are also topical from a research perspective, controlling processes such as coastal erosion and ocean mixing. Therefore, being able to characterize wave conditions on broad spatiotemporal scales is extremely valuable. A network of High-Frequency (HF) radar systems can provide measurements of wave conditions in near-real time along the coast where better observations are needed. Measurement of wave parameters such as significant wave height, wave period and wave direction is a secondary function of the SeaSonde HF radar. Waves are measured with SeaSonde HF radars from the second-order portion of the echo spectrum. The Doppler shift of the radio transmission from the SeaSonde contains information about the orbital velocity of the primary Bragg waves and the larger waves that they ride on. Since the wave data is dependent upon the occurrence of both Bragg and larger surface gravity waves, there is a minimum threshold for sea states in which reliable wave parameters can be determined. There is also a limiting factor for the radar in large sea states as the first-order spectra merge with the second-order and interpretation of the spectra becomes impossible with existing methods. We have tested methods for wave extraction and will present the results here. Our analysis explores the frequency-dependent threshold wave conditions for reliable wave parameter measurements, and which systems provide the best measurements. We also tested different radio waveform parameters to see which performed best in different environmental conditions. The study focuses on in-situ wave measurements from National Data Buoy Center (NOAA) buoys within the domain of the HF radar network, deployed offshore of Long Island and Delaware Bay, as well as mooring deployments of opportunity closer to the coast. Measurements will also be evaluated within the context of larger scale wave models routinely run in the area by NOAA. The threshold conditions determined by this study will guide the application of HF radar-based wave estimates to surf zone conditions by local weather forecast offices.
{"title":"Measuring waves with a compact HF radar","authors":"R. Forney, H. Roarty, S. Glenn","doi":"10.23919/OCEANS.2015.7404428","DOIUrl":"https://doi.org/10.23919/OCEANS.2015.7404428","url":null,"abstract":"Ocean wave conditions impact many ways in which humans interact with the ocean, from the safety of recreation at the beach to the viability of offshore operations. Wave conditions are also topical from a research perspective, controlling processes such as coastal erosion and ocean mixing. Therefore, being able to characterize wave conditions on broad spatiotemporal scales is extremely valuable. A network of High-Frequency (HF) radar systems can provide measurements of wave conditions in near-real time along the coast where better observations are needed. Measurement of wave parameters such as significant wave height, wave period and wave direction is a secondary function of the SeaSonde HF radar. Waves are measured with SeaSonde HF radars from the second-order portion of the echo spectrum. The Doppler shift of the radio transmission from the SeaSonde contains information about the orbital velocity of the primary Bragg waves and the larger waves that they ride on. Since the wave data is dependent upon the occurrence of both Bragg and larger surface gravity waves, there is a minimum threshold for sea states in which reliable wave parameters can be determined. There is also a limiting factor for the radar in large sea states as the first-order spectra merge with the second-order and interpretation of the spectra becomes impossible with existing methods. We have tested methods for wave extraction and will present the results here. Our analysis explores the frequency-dependent threshold wave conditions for reliable wave parameter measurements, and which systems provide the best measurements. We also tested different radio waveform parameters to see which performed best in different environmental conditions. The study focuses on in-situ wave measurements from National Data Buoy Center (NOAA) buoys within the domain of the HF radar network, deployed offshore of Long Island and Delaware Bay, as well as mooring deployments of opportunity closer to the coast. Measurements will also be evaluated within the context of larger scale wave models routinely run in the area by NOAA. The threshold conditions determined by this study will guide the application of HF radar-based wave estimates to surf zone conditions by local weather forecast offices.","PeriodicalId":403976,"journal":{"name":"OCEANS 2015 - MTS/IEEE Washington","volume":"126 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130226157","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 : 2015-10-01DOI: 10.23919/OCEANS.2015.7404555
F. Raimondi, M. Trapanese, V. Franzitta, V. Di Dio
The proposed project shows the results obtained in the implementation and testing in lacustrine and marine environment of a nautical remote controlled vehicle with surface navigation and innovative features Semi-Immergible (SI-USV). This vehicle is based on a pending patent belonging to Palermo University (Patent Pending RM2012A000209 and Patent RM2014Z000060) concerning innovative semi-immersible vehicles (SI-Drone), that can be remotely controlled from the ground, air, satellite and sea also during the semi-immersible operation. Given its low draft, the electric powered vehicle, coupled with jet propulsion, makes it possible to navigate in shallow waters, coastal shipping or sandbars. This complete system SI-Drone can solve the typical logistic problem occurring in very shallow water contexts (such as ports, rivers, lacustrine environment and marine coastal), where the low depth of the water column (generally less than 10 mt) presents several challenges, including near-field effect and operability difficulties. Then, the proposed system can be used for applications in the fields of ports, lakes monitoring, organic fish - marine, hydrography, geology / geophysics, oceanography, underwater acoustics and environmental monitoring with particular attention to climate change impact indicators. This paper deal with two dimensional motion control of DRONES based on merging of Fuzzy/Lyapunov and kinetic controllers. A fuzzy kinetic controller generates the surge speeds and the yaw rates of each DRONE, to achieve the objective of the planar motion planned by the decentralized algorithm, and it ensures robustness with respect to perturbations of the marine environment, forward surge speed control and saturation of the control signals, while the kinetic controller generates the thruster surge forces and the yaw torques of all the DRONE. The Lyapunov's stability of the equilibrium state of the closed loop motion control system is proved based on the properties of the Fuzzy maps for all the underwater vehicles, so that the stabilization of each semi-immergible vehicle in the planned trajectory is ensured. The validity of this control algorithm is also supported by simulation experiments. The procedures applied in the present article, as well as the main equations used, are the result of previous applications made in different technical fields that show a good replicability (1 - 4).
{"title":"Identification of the inertial model for innovative semi-immergible USV (SI-USV) drone for marine and lakes operations","authors":"F. Raimondi, M. Trapanese, V. Franzitta, V. Di Dio","doi":"10.23919/OCEANS.2015.7404555","DOIUrl":"https://doi.org/10.23919/OCEANS.2015.7404555","url":null,"abstract":"The proposed project shows the results obtained in the implementation and testing in lacustrine and marine environment of a nautical remote controlled vehicle with surface navigation and innovative features Semi-Immergible (SI-USV). This vehicle is based on a pending patent belonging to Palermo University (Patent Pending RM2012A000209 and Patent RM2014Z000060) concerning innovative semi-immersible vehicles (SI-Drone), that can be remotely controlled from the ground, air, satellite and sea also during the semi-immersible operation. Given its low draft, the electric powered vehicle, coupled with jet propulsion, makes it possible to navigate in shallow waters, coastal shipping or sandbars. This complete system SI-Drone can solve the typical logistic problem occurring in very shallow water contexts (such as ports, rivers, lacustrine environment and marine coastal), where the low depth of the water column (generally less than 10 mt) presents several challenges, including near-field effect and operability difficulties. Then, the proposed system can be used for applications in the fields of ports, lakes monitoring, organic fish - marine, hydrography, geology / geophysics, oceanography, underwater acoustics and environmental monitoring with particular attention to climate change impact indicators. This paper deal with two dimensional motion control of DRONES based on merging of Fuzzy/Lyapunov and kinetic controllers. A fuzzy kinetic controller generates the surge speeds and the yaw rates of each DRONE, to achieve the objective of the planar motion planned by the decentralized algorithm, and it ensures robustness with respect to perturbations of the marine environment, forward surge speed control and saturation of the control signals, while the kinetic controller generates the thruster surge forces and the yaw torques of all the DRONE. The Lyapunov's stability of the equilibrium state of the closed loop motion control system is proved based on the properties of the Fuzzy maps for all the underwater vehicles, so that the stabilization of each semi-immergible vehicle in the planned trajectory is ensured. The validity of this control algorithm is also supported by simulation experiments. The procedures applied in the present article, as well as the main equations used, are the result of previous applications made in different technical fields that show a good replicability (1 - 4).","PeriodicalId":403976,"journal":{"name":"OCEANS 2015 - MTS/IEEE Washington","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126397782","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 : 2015-10-01DOI: 10.23919/OCEANS.2015.7401902
R. Dziak, J. Haxel, H. Matsumoto, C. Meinig, N. Delich, J. Osse, M. Wetzler
We present the details of a unique deep-ocean instrument package and mooring that was deployed at Challenger Deep (10,984 m) in the Marianas Trench. The mooring is 45 m in length and consists of a hydrophone, RBRTM pressure and temperature loggers, nine Vitrovex® glass spheres and a mast with a satellite beacon for recovery. The mooring was deployed in January and recovered in March 2015 using the USCG Cutter Sequoia. The pressure logger recorded a maximum pressure of 10,956.8 decibars, for a depth of 10,646.1 m. To our knowledge, this is only the fourth in situ measurement of depth ever made at Challenger Deep. The hydrophone recorded for ~1 hour and stopped shortly after descending to a depth of 1,785 m (temperature of 2.4°C). The record at this depth is dominated by the sound of the Sequoia's engines and propellers.
{"title":"Deployment and recovery of a full-ocean depth mooring at Challenger Deep, Mariana Trench","authors":"R. Dziak, J. Haxel, H. Matsumoto, C. Meinig, N. Delich, J. Osse, M. Wetzler","doi":"10.23919/OCEANS.2015.7401902","DOIUrl":"https://doi.org/10.23919/OCEANS.2015.7401902","url":null,"abstract":"We present the details of a unique deep-ocean instrument package and mooring that was deployed at Challenger Deep (10,984 m) in the Marianas Trench. The mooring is 45 m in length and consists of a hydrophone, RBRTM pressure and temperature loggers, nine Vitrovex® glass spheres and a mast with a satellite beacon for recovery. The mooring was deployed in January and recovered in March 2015 using the USCG Cutter Sequoia. The pressure logger recorded a maximum pressure of 10,956.8 decibars, for a depth of 10,646.1 m. To our knowledge, this is only the fourth in situ measurement of depth ever made at Challenger Deep. The hydrophone recorded for ~1 hour and stopped shortly after descending to a depth of 1,785 m (temperature of 2.4°C). The record at this depth is dominated by the sound of the Sequoia's engines and propellers.","PeriodicalId":403976,"journal":{"name":"OCEANS 2015 - MTS/IEEE Washington","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122193083","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 : 2015-10-01DOI: 10.23919/OCEANS.2015.7404443
M. Algodon, Aaron T. Hilomen, M. Soriano
Area estimation of coral colonies from images can be improved by eliminating the distorting effect of camera rotation angle or reef slope. We propose a method that estimates the angle between reef and camera plane using the tracks formed by the movement of image features in the video. Estimates obtained from experimental setup show the effectiveness of the technique, with acceptable error for small angles. The technique can be used on benthos monitoring setups to provide good area estimates without any additional instrumentation.
{"title":"Estimating coral reef slope or camera pitch from video","authors":"M. Algodon, Aaron T. Hilomen, M. Soriano","doi":"10.23919/OCEANS.2015.7404443","DOIUrl":"https://doi.org/10.23919/OCEANS.2015.7404443","url":null,"abstract":"Area estimation of coral colonies from images can be improved by eliminating the distorting effect of camera rotation angle or reef slope. We propose a method that estimates the angle between reef and camera plane using the tracks formed by the movement of image features in the video. Estimates obtained from experimental setup show the effectiveness of the technique, with acceptable error for small angles. The technique can be used on benthos monitoring setups to provide good area estimates without any additional instrumentation.","PeriodicalId":403976,"journal":{"name":"OCEANS 2015 - MTS/IEEE Washington","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122284020","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 : 2015-10-01DOI: 10.23919/OCEANS.2015.7401889
R. Wright, Cheryl M. Zimmerman
This paper describes research to determine the effectiveness of forward-looking sonar as a means to safely navigate vessels in frontiers such as the Arctic and other regions that may be lacking recent or comprehensive hydrographic survey. Key elements of this investigation include the range at which valid measurements may be taken, uncertainty in measurement, confidence level of the measured value and resolution available to detect underwater hazards affixed to the bottom and suspended within the water column to provide time sufficient to enable the crew to take action to alter course and/or speed to avoid casualty. An additional factor involves examining forward-looking sonar measurements as a means to survey shallow sea bottom where hydrography data does not exist or is not accurate, potentially offering a valuable resource to supplement scarce national hydrographic office assets to accomplish this task. An assessment of viability is also made regarding compliance with the International Hydrographic Organization (IHO) standards for hydrographic surveys that form the basis for soundings that appear on navigation charts.
{"title":"Vector data extraction from forward-looking sonar imagery for hydrographic survey and hazard to navigation detection","authors":"R. Wright, Cheryl M. Zimmerman","doi":"10.23919/OCEANS.2015.7401889","DOIUrl":"https://doi.org/10.23919/OCEANS.2015.7401889","url":null,"abstract":"This paper describes research to determine the effectiveness of forward-looking sonar as a means to safely navigate vessels in frontiers such as the Arctic and other regions that may be lacking recent or comprehensive hydrographic survey. Key elements of this investigation include the range at which valid measurements may be taken, uncertainty in measurement, confidence level of the measured value and resolution available to detect underwater hazards affixed to the bottom and suspended within the water column to provide time sufficient to enable the crew to take action to alter course and/or speed to avoid casualty. An additional factor involves examining forward-looking sonar measurements as a means to survey shallow sea bottom where hydrography data does not exist or is not accurate, potentially offering a valuable resource to supplement scarce national hydrographic office assets to accomplish this task. An assessment of viability is also made regarding compliance with the International Hydrographic Organization (IHO) standards for hydrographic surveys that form the basis for soundings that appear on navigation charts.","PeriodicalId":403976,"journal":{"name":"OCEANS 2015 - MTS/IEEE Washington","volume":"26 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122299836","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}
Focused on underwater wireless acoustic communication and networks for data collection, this paper proposes a channel aware multichannel protocol for deep water pipeline monitoring system, where multiple sensor nodes report monitoring information to the drilling platform in the dynamically selected channel with subcarrier adaptive modulation. A two-stage channel selection and adaptive modulation protocol with both statistic and instantaneous channel information is proposed to optimize system performance. This scheme can be used in both vertical and horizontal pipeline monitoring system, and can be easily expanded to a common data collection network. Simulation results have shown its improvement compared to traditional FDMA scheme with random channel access.
{"title":"An OFDM based channel aware access protocol for underwater acoustic networks of submarine pipeline monitoring","authors":"Yuzhi Zhang, Haiyan Wang, Xiaohong Shen, Ruiqin Zhao","doi":"10.23919/OCEANS.2015.7404358","DOIUrl":"https://doi.org/10.23919/OCEANS.2015.7404358","url":null,"abstract":"Focused on underwater wireless acoustic communication and networks for data collection, this paper proposes a channel aware multichannel protocol for deep water pipeline monitoring system, where multiple sensor nodes report monitoring information to the drilling platform in the dynamically selected channel with subcarrier adaptive modulation. A two-stage channel selection and adaptive modulation protocol with both statistic and instantaneous channel information is proposed to optimize system performance. This scheme can be used in both vertical and horizontal pipeline monitoring system, and can be easily expanded to a common data collection network. Simulation results have shown its improvement compared to traditional FDMA scheme with random channel access.","PeriodicalId":403976,"journal":{"name":"OCEANS 2015 - MTS/IEEE Washington","volume":"212 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114150660","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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