Pub Date : 2010-05-24DOI: 10.1109/OCEANSSYD.2010.5603618
S. Shankar, M. Chitre, Melani Jayasuria
The design of a communication system is closely linked to assumptions about the nature of the channel. A vast majority of the components of a modern communication system are implemented in software, affording us the ability to fine tune their parameters during operation. The objective for tuning the parameters could be to optimize data rates, protect against errors, minimize power, and so on. If the physics of the channel is completely known, it is possible to determine the values of these parameters for a given objective. However in practice, it is quite difficult to know the state of the channel completely. The parameters usually interact with each other, so tuning them in isolation is often not possible. We present a data driven approach for tuning the physical layer parameters of a communication link to optimize data rates, assuming the channel remains static over the course of a file transfer. Our approach does not need any knowledge of the physics of the channel. We illustrate the application of our approach in the context of an underwater communication link.
{"title":"Data driven algorithms to tune physical layer parameters of an underwater communication link","authors":"S. Shankar, M. Chitre, Melani Jayasuria","doi":"10.1109/OCEANSSYD.2010.5603618","DOIUrl":"https://doi.org/10.1109/OCEANSSYD.2010.5603618","url":null,"abstract":"The design of a communication system is closely linked to assumptions about the nature of the channel. A vast majority of the components of a modern communication system are implemented in software, affording us the ability to fine tune their parameters during operation. The objective for tuning the parameters could be to optimize data rates, protect against errors, minimize power, and so on. If the physics of the channel is completely known, it is possible to determine the values of these parameters for a given objective. However in practice, it is quite difficult to know the state of the channel completely. The parameters usually interact with each other, so tuning them in isolation is often not possible. We present a data driven approach for tuning the physical layer parameters of a communication link to optimize data rates, assuming the channel remains static over the course of a file transfer. Our approach does not need any knowledge of the physics of the channel. We illustrate the application of our approach in the context of an underwater communication link.","PeriodicalId":129808,"journal":{"name":"OCEANS'10 IEEE SYDNEY","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116976456","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 : 2010-05-24DOI: 10.1109/OCEANSSYD.2010.5603944
D. Ogburn, Thomas Q. Zeng
It is a common understanding that coastal wetland plays an important role in marine fisheries recruitment. However, mechanistic detail of the processes that link the two ecosystems is not well defined. This study aims to describe and map ecological landscape features of a saltmarsh-estuary ecotone at the entrance to Mambo Creek in Salamander Bay, at Port Stephens, on the southeast coast of Australia. The creek drains from 175 ha of estuarine-freshwater area which forms part of the Tomaree Wetland complex. Based on field surveyed data and GIS analysis, a dynamical system is depicted of a tidal salt-wedge that results from the interaction of the wetland and estuary water. The creek entrance lies inside the extensive Posidonia seagrass beds of Salamander Bay. It is constricted by a shallow sandbar at the entrance and is fringed by mangroves that stabilize the creek channel. Analysis of the ebb-tide outflow from the wetland shows it contains micro-particles (10–100 µm diameter) at densities >20,000 particles ml−1, high levels of H2S, low pH, lows-alinity and low dissolved oxygen and is thus adverse for most fish fry. In the vicinity of the entrance channel to the creek: i) the outflow from the wetland forms a tidal salt wedge and disperses across the water surface where it meets denser saline estuary water; ii) the micro-particles sink out of the surface layer at the tip of the salt wedge in a sharp, readily observable boundary, due to flocculation effects. At this boundary or ecotone, the continuous presence of a “feeding prism” which contains very large numbers of at least three species of marine fish fry <20 mm total length, particularly in warmer months, was observed. The fry remain only within this creek area and feed on the ad-libitum supply of outwelling wetland micro-food particles while swimming in near oceanic condition water below the salt wedge; iii) the seston material varies with season; in warmer months it is principally a mixture of purple and green bacteria coated micro-particles and in cooler months detritus predominates; iv) the location of the halocline is dynamic and is related to the morphology of the creek and tide; and, v) the creek entrance also contains a deeper area in which small numbers of large apparently gravid fish were regularly observed. The fish fry aggregations are mapped in relation to the halocline in space and time during summer and winter seasons and linked to tidal sea-level and the morphology of the creek. The authors suggest the “feeding prism” ecotone is an important link between wetland process functions and marine fish recruitment for at least three commercially and recreationally important coastal fish species and perhaps others. It is this ecotone that needs to be considered as a focus of management measures and environmental impact assessment associated with adjoining developments and landscape modifications that may affect coastal processes in the vicinity of the creek. For example, the sand-dune syst
{"title":"Mapping the fish fry feeding prism in a saltmarsh-estuary ecotone","authors":"D. Ogburn, Thomas Q. Zeng","doi":"10.1109/OCEANSSYD.2010.5603944","DOIUrl":"https://doi.org/10.1109/OCEANSSYD.2010.5603944","url":null,"abstract":"It is a common understanding that coastal wetland plays an important role in marine fisheries recruitment. However, mechanistic detail of the processes that link the two ecosystems is not well defined. This study aims to describe and map ecological landscape features of a saltmarsh-estuary ecotone at the entrance to Mambo Creek in Salamander Bay, at Port Stephens, on the southeast coast of Australia. The creek drains from 175 ha of estuarine-freshwater area which forms part of the Tomaree Wetland complex. Based on field surveyed data and GIS analysis, a dynamical system is depicted of a tidal salt-wedge that results from the interaction of the wetland and estuary water. The creek entrance lies inside the extensive Posidonia seagrass beds of Salamander Bay. It is constricted by a shallow sandbar at the entrance and is fringed by mangroves that stabilize the creek channel. Analysis of the ebb-tide outflow from the wetland shows it contains micro-particles (10–100 µm diameter) at densities >20,000 particles ml−1, high levels of H2S, low pH, lows-alinity and low dissolved oxygen and is thus adverse for most fish fry. In the vicinity of the entrance channel to the creek: i) the outflow from the wetland forms a tidal salt wedge and disperses across the water surface where it meets denser saline estuary water; ii) the micro-particles sink out of the surface layer at the tip of the salt wedge in a sharp, readily observable boundary, due to flocculation effects. At this boundary or ecotone, the continuous presence of a “feeding prism” which contains very large numbers of at least three species of marine fish fry <20 mm total length, particularly in warmer months, was observed. The fry remain only within this creek area and feed on the ad-libitum supply of outwelling wetland micro-food particles while swimming in near oceanic condition water below the salt wedge; iii) the seston material varies with season; in warmer months it is principally a mixture of purple and green bacteria coated micro-particles and in cooler months detritus predominates; iv) the location of the halocline is dynamic and is related to the morphology of the creek and tide; and, v) the creek entrance also contains a deeper area in which small numbers of large apparently gravid fish were regularly observed. The fish fry aggregations are mapped in relation to the halocline in space and time during summer and winter seasons and linked to tidal sea-level and the morphology of the creek. The authors suggest the “feeding prism” ecotone is an important link between wetland process functions and marine fish recruitment for at least three commercially and recreationally important coastal fish species and perhaps others. It is this ecotone that needs to be considered as a focus of management measures and environmental impact assessment associated with adjoining developments and landscape modifications that may affect coastal processes in the vicinity of the creek. For example, the sand-dune syst","PeriodicalId":129808,"journal":{"name":"OCEANS'10 IEEE SYDNEY","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115469877","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 : 2010-05-24DOI: 10.1109/OCEANSSYD.2010.5603548
Hongmei Zhang, Jianhu Zhao, Kun Yang, Chunhe Tian
Seabed topographic match is a very important work for fulfilling the blend of different-source sounding data and the underwater positioning and navigation. Contour match is a classic method for the seabed topographic match. However, the traditional contour match algorithm will lead to obvious time consuming and mismatch, especially in the longer contour match. Thus, a kind of contour match algorithm based on angle code technique is presented and studied in this paper. Firstly, the principle of this match method is detailed. Then some key problems are studied, and the matching procedure is given out. Besides, the method was used for a simulation experiment of underwater topographic matching navigation, the satisfying results are achieved.
{"title":"Seabed topographic contour match based on angle code technique","authors":"Hongmei Zhang, Jianhu Zhao, Kun Yang, Chunhe Tian","doi":"10.1109/OCEANSSYD.2010.5603548","DOIUrl":"https://doi.org/10.1109/OCEANSSYD.2010.5603548","url":null,"abstract":"Seabed topographic match is a very important work for fulfilling the blend of different-source sounding data and the underwater positioning and navigation. Contour match is a classic method for the seabed topographic match. However, the traditional contour match algorithm will lead to obvious time consuming and mismatch, especially in the longer contour match. Thus, a kind of contour match algorithm based on angle code technique is presented and studied in this paper. Firstly, the principle of this match method is detailed. Then some key problems are studied, and the matching procedure is given out. Besides, the method was used for a simulation experiment of underwater topographic matching navigation, the satisfying results are achieved.","PeriodicalId":129808,"journal":{"name":"OCEANS'10 IEEE SYDNEY","volume":"243 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121122123","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 : 2010-05-24DOI: 10.1109/OCEANSSYD.2010.5603584
J. Thredgold, M. Fewell, S. Lourey, H. Vu
This paper describes a study of the effect of networking active sonars on tracking performance in a scenario with explicit inclusion of false detections, using two false-detection models and detection-probability curves with two levels of tailing. We compare the tracking performance when sonars share detections (centralized tracking) with the performance when sonars share tracks (distributed tracking). Provided that the sonar layout and detection probabilities are such that multiple sonars have a reasonable probability of obtaining detections from a target, we show that centralized tracking decreases the time to confirm a track on a target and improves the continuity of the target track, but increases the false track rate. Results for other metrics are also presented.
{"title":"Performance assessment of sonar-system networks for anti-submarine warfare","authors":"J. Thredgold, M. Fewell, S. Lourey, H. Vu","doi":"10.1109/OCEANSSYD.2010.5603584","DOIUrl":"https://doi.org/10.1109/OCEANSSYD.2010.5603584","url":null,"abstract":"This paper describes a study of the effect of networking active sonars on tracking performance in a scenario with explicit inclusion of false detections, using two false-detection models and detection-probability curves with two levels of tailing. We compare the tracking performance when sonars share detections (centralized tracking) with the performance when sonars share tracks (distributed tracking). Provided that the sonar layout and detection probabilities are such that multiple sonars have a reasonable probability of obtaining detections from a target, we show that centralized tracking decreases the time to confirm a track on a target and improves the continuity of the target track, but increases the false track rate. Results for other metrics are also presented.","PeriodicalId":129808,"journal":{"name":"OCEANS'10 IEEE SYDNEY","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123546664","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 : 2010-05-24DOI: 10.1109/OCEANSSYD.2010.5603878
K. Asakawa, Makoto Ito, T. Hyakudome
We have designed and produced small models of ceramic pressure housings for use in a free-fall floating ocean-bottom seismometer that is useful at up to 11,000 m water depth. We also present a new design method of plural through-holes for underwater connectors on ceramic hemispheres. Its design concept and the results of finite element analysis (FEA) are presented along with results of hydraulic pressure tests using 1/4-scale models. Actual-size ceramic pressure housing will be completed soon.
{"title":"Evaluation of small models of ceramic housings for 11,000 m ocean bottom seismometers","authors":"K. Asakawa, Makoto Ito, T. Hyakudome","doi":"10.1109/OCEANSSYD.2010.5603878","DOIUrl":"https://doi.org/10.1109/OCEANSSYD.2010.5603878","url":null,"abstract":"We have designed and produced small models of ceramic pressure housings for use in a free-fall floating ocean-bottom seismometer that is useful at up to 11,000 m water depth. We also present a new design method of plural through-holes for underwater connectors on ceramic hemispheres. Its design concept and the results of finite element analysis (FEA) are presented along with results of hydraulic pressure tests using 1/4-scale models. Actual-size ceramic pressure housing will be completed soon.","PeriodicalId":129808,"journal":{"name":"OCEANS'10 IEEE SYDNEY","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124191141","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 : 2010-05-24DOI: 10.1109/OCEANSSYD.2010.5603542
Xinke Zhu, Jiancheng Yu, Shenzhen Ren, Xiaohui Wang
When monitoring spatial phenomena, we are not just interested in measurements at sensed locations but also at locations where no sensors were placed. To estimate the scalar field where no sensors are deployed, we need to interpolate the data. We are interested in how the best sampling design is to be found and best used to draw conclusions about the field as whole. First of all, a performance metric is defined to quantify how well the sampling network collecting data in a given region. Secondly, near-optimal collecting data strategy proposed minimizes the integral of the Kriging variance over the area of interest. Thirdly, several approaches proposed make the optimization more computationally efficient. Finally, the proposed methods are verified respectively by simulation.
{"title":"Near-optimal collecting data strategy based on ordinary Kiriging variance","authors":"Xinke Zhu, Jiancheng Yu, Shenzhen Ren, Xiaohui Wang","doi":"10.1109/OCEANSSYD.2010.5603542","DOIUrl":"https://doi.org/10.1109/OCEANSSYD.2010.5603542","url":null,"abstract":"When monitoring spatial phenomena, we are not just interested in measurements at sensed locations but also at locations where no sensors were placed. To estimate the scalar field where no sensors are deployed, we need to interpolate the data. We are interested in how the best sampling design is to be found and best used to draw conclusions about the field as whole. First of all, a performance metric is defined to quantify how well the sampling network collecting data in a given region. Secondly, near-optimal collecting data strategy proposed minimizes the integral of the Kriging variance over the area of interest. Thirdly, several approaches proposed make the optimization more computationally efficient. Finally, the proposed methods are verified respectively by simulation.","PeriodicalId":129808,"journal":{"name":"OCEANS'10 IEEE SYDNEY","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124407169","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 : 2010-05-24DOI: 10.1109/OCEANSSYD.2010.5603896
Arjuna Balasuriya, S. Petillo, H. Schmidt, M. Benjamin
This paper discusses the autonomy framework proposed for the mobile instruments such as Autonomous Underwater Vehicles (AUVs) and gliders. Paper focuses on the challenges faced by these clusters of mobile platform in executive tasks such as adaptive sampling in the hostile underwater environment. Collaborations between these mobile instruments are essential to capture the environmental changes and track them for time-series analysis. This paper looks into the challenges imposed by the underwater communication infrastructure and presents the nested autonomy architecture as a solution to overcome these challenges. The autonomy architecture is separated from the low-level control architecture of these instruments, which is called the ‘backseat driver’. The back-seat driver paradigm is implemented on the Mission Oriented Object Suite (MOOS) developed at MIT. The autonomy is achieved by generating multiple behaviors (multiple objective functions) linked to the internal state of the platform as well as the environment. Optimization engine called the MOOS-IvP is used to pick the best action for the given instance based on the mission at hand. At sea operational scenarios and results are presented to demonstrate the proposed autonomy architecture for Ocean Observatory Initiative (OOI).
{"title":"Behavior-based planning and prosecution architecture for Autonomous Underwater Vehicles in Ocean Observatories","authors":"Arjuna Balasuriya, S. Petillo, H. Schmidt, M. Benjamin","doi":"10.1109/OCEANSSYD.2010.5603896","DOIUrl":"https://doi.org/10.1109/OCEANSSYD.2010.5603896","url":null,"abstract":"This paper discusses the autonomy framework proposed for the mobile instruments such as Autonomous Underwater Vehicles (AUVs) and gliders. Paper focuses on the challenges faced by these clusters of mobile platform in executive tasks such as adaptive sampling in the hostile underwater environment. Collaborations between these mobile instruments are essential to capture the environmental changes and track them for time-series analysis. This paper looks into the challenges imposed by the underwater communication infrastructure and presents the nested autonomy architecture as a solution to overcome these challenges. The autonomy architecture is separated from the low-level control architecture of these instruments, which is called the ‘backseat driver’. The back-seat driver paradigm is implemented on the Mission Oriented Object Suite (MOOS) developed at MIT. The autonomy is achieved by generating multiple behaviors (multiple objective functions) linked to the internal state of the platform as well as the environment. Optimization engine called the MOOS-IvP is used to pick the best action for the given instance based on the mission at hand. At sea operational scenarios and results are presented to demonstrate the proposed autonomy architecture for Ocean Observatory Initiative (OOI).","PeriodicalId":129808,"journal":{"name":"OCEANS'10 IEEE SYDNEY","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121572785","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 : 2010-05-24DOI: 10.1109/OCEANSSYD.2010.5603857
J. Vitorino, S. Larangeiro, Francisco Silva, J. Pinto, S. Almeida
We describe the development of an operational forecast system for the NAzare Canyon area (W Portugal) which is presently being conducted at Instituto Hidrografico (IHPT). The system integrates a number of numerical models aimed to simulate and forecasts the wave conditions, the circulation promoted in the canyon area by wind forcing, interactions with the deep sea circulation or tides, and the littoral processes. The forecast system is planned to make an extensive use of the real-time observations collected by multi-parametric platforms maintained by IH in the Nazare Canyon area as part being developed sic guidelines for preparing papers for conference proceedings.
{"title":"An operational system for the forecasting of oceanographic conditions in the Nazare Canyon area (W Portugal)","authors":"J. Vitorino, S. Larangeiro, Francisco Silva, J. Pinto, S. Almeida","doi":"10.1109/OCEANSSYD.2010.5603857","DOIUrl":"https://doi.org/10.1109/OCEANSSYD.2010.5603857","url":null,"abstract":"We describe the development of an operational forecast system for the NAzare Canyon area (W Portugal) which is presently being conducted at Instituto Hidrografico (IHPT). The system integrates a number of numerical models aimed to simulate and forecasts the wave conditions, the circulation promoted in the canyon area by wind forcing, interactions with the deep sea circulation or tides, and the littoral processes. The forecast system is planned to make an extensive use of the real-time observations collected by multi-parametric platforms maintained by IH in the Nazare Canyon area as part being developed sic guidelines for preparing papers for conference proceedings.","PeriodicalId":129808,"journal":{"name":"OCEANS'10 IEEE SYDNEY","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121974326","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 : 2010-05-24DOI: 10.1109/OCEANSSYD.2010.5603966
K. Lo, B. Ferguson
Acoustic sensors deployed on the sea floor can be localized using a broadband sound source travelling along a linear trajectory at a constant velocity and a constant depth below the sea surface. The absolute positions (X- and Y-coordinates) of the sensors are estimated in two steps, assuming that the XY-plane coincides with the (flat) sea surface. First, a local Cartesian x-y coordinate system is set up in such a way that, when the sensors and the moving source are projected onto the local xy-plane, its origin coincides with the projection of one of the sensors (called the reference sensor) and the x-axis is parallel to the projection of the source's linear trajectory which intersects the positive y-axis. The projection of the source trajectory onto the xy-plane is described by three motion parameters: the source speed together with the time and horizontal range at which the source is at the closest point of approach (CPA) to the reference sensor. The relative positions (x- and y-coordinates) of all other sensors, along with the three motion parameters, are estimated by measuring the temporal variation of the differential time-of-arrival (DTOA) of the signal emitted by the moving source at each pair of sensors and then minimizing the sum of the squared deviations of the noisy DTOA estimates from their predicted values over a sufficiently long period of time for all pairs of sensors. This relative position estimation assumes a priori knowledge of the source depth, the sensor depths and the side (either left or right) on which the source transits past the reference sensor. In the second step, the relative position estimate of each sensor is converted into an absolute position estimate by rotating the x- and y-axes by an angle equal to the source bearing at CPA, followed by a translational displacement determined by the absolute position of the reference sensor. The source bearing at CPA can be estimated if either the direction of travel of the source or the absolute position of another sensor is known. It can also be derived together with the absolute position of the reference sensor if the absolute position of the moving source is known as a function of time (e.g. from a GPS receiver attached to the source). The proposed sensor localization method is applied to real acoustic data recorded in a shallow water experiment where a small vessel travelled at a constant speed (at zero depth) past a wide-aperture linear horizontal array of eight hydrophones mounted 1 m above the sea bed. Assuming that the absolute positions of two of the sensors are known, the effectiveness of the method is verified by comparing the estimated absolute positions of the other six sensors with their nominal values.
{"title":"Underwater acoustic sensor localization using a broadband sound source in uniform linear motion","authors":"K. Lo, B. Ferguson","doi":"10.1109/OCEANSSYD.2010.5603966","DOIUrl":"https://doi.org/10.1109/OCEANSSYD.2010.5603966","url":null,"abstract":"Acoustic sensors deployed on the sea floor can be localized using a broadband sound source travelling along a linear trajectory at a constant velocity and a constant depth below the sea surface. The absolute positions (X- and Y-coordinates) of the sensors are estimated in two steps, assuming that the XY-plane coincides with the (flat) sea surface. First, a local Cartesian x-y coordinate system is set up in such a way that, when the sensors and the moving source are projected onto the local xy-plane, its origin coincides with the projection of one of the sensors (called the reference sensor) and the x-axis is parallel to the projection of the source's linear trajectory which intersects the positive y-axis. The projection of the source trajectory onto the xy-plane is described by three motion parameters: the source speed together with the time and horizontal range at which the source is at the closest point of approach (CPA) to the reference sensor. The relative positions (x- and y-coordinates) of all other sensors, along with the three motion parameters, are estimated by measuring the temporal variation of the differential time-of-arrival (DTOA) of the signal emitted by the moving source at each pair of sensors and then minimizing the sum of the squared deviations of the noisy DTOA estimates from their predicted values over a sufficiently long period of time for all pairs of sensors. This relative position estimation assumes a priori knowledge of the source depth, the sensor depths and the side (either left or right) on which the source transits past the reference sensor. In the second step, the relative position estimate of each sensor is converted into an absolute position estimate by rotating the x- and y-axes by an angle equal to the source bearing at CPA, followed by a translational displacement determined by the absolute position of the reference sensor. The source bearing at CPA can be estimated if either the direction of travel of the source or the absolute position of another sensor is known. It can also be derived together with the absolute position of the reference sensor if the absolute position of the moving source is known as a function of time (e.g. from a GPS receiver attached to the source). The proposed sensor localization method is applied to real acoustic data recorded in a shallow water experiment where a small vessel travelled at a constant speed (at zero depth) past a wide-aperture linear horizontal array of eight hydrophones mounted 1 m above the sea bed. Assuming that the absolute positions of two of the sensors are known, the effectiveness of the method is verified by comparing the estimated absolute positions of the other six sensors with their nominal values.","PeriodicalId":129808,"journal":{"name":"OCEANS'10 IEEE SYDNEY","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122080950","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 : 2010-05-24DOI: 10.1109/OCEANSSYD.2010.5603867
D. Guériot, C. Sintes
Simulating realistic sonar data is crucial for tuning detection and classification algorithms according to environment and acquisition characteristics. Moreover, robustness of performances estimation and prediction applications can be greatly enhanced as soon as such a simulation tool provides both a modular underwater world representation (multiple sensors, environments and acquisition conditions) and a selection of several computational engines (ray theory, parabolic equation, …). Therefore, we developed such a framework for simulators, allowing both scene design and computational engine choice. Within it, two engines (one for rays, one for tubes) has been successfully implemented and realistic simulations obtained, as shown in the presented simulated sonar images. This paper introduces the simulation of a new imaging sensor (DIDSON acoustic camera) showing the extensibility of the proposed framework while providing realistic and specific front-looking simulated images. Moreover, in order to bypass the scene resolution given by the facet sizes, some georeferenced perturbations are introduced in order to model sub-facet behaviors and produce more realistic responses from the scene with micro and macro textures on the output images.
{"title":"Forward looking sonar data simulation through tube tracing","authors":"D. Guériot, C. Sintes","doi":"10.1109/OCEANSSYD.2010.5603867","DOIUrl":"https://doi.org/10.1109/OCEANSSYD.2010.5603867","url":null,"abstract":"Simulating realistic sonar data is crucial for tuning detection and classification algorithms according to environment and acquisition characteristics. Moreover, robustness of performances estimation and prediction applications can be greatly enhanced as soon as such a simulation tool provides both a modular underwater world representation (multiple sensors, environments and acquisition conditions) and a selection of several computational engines (ray theory, parabolic equation, …). Therefore, we developed such a framework for simulators, allowing both scene design and computational engine choice. Within it, two engines (one for rays, one for tubes) has been successfully implemented and realistic simulations obtained, as shown in the presented simulated sonar images. This paper introduces the simulation of a new imaging sensor (DIDSON acoustic camera) showing the extensibility of the proposed framework while providing realistic and specific front-looking simulated images. Moreover, in order to bypass the scene resolution given by the facet sizes, some georeferenced perturbations are introduced in order to model sub-facet behaviors and produce more realistic responses from the scene with micro and macro textures on the output images.","PeriodicalId":129808,"journal":{"name":"OCEANS'10 IEEE SYDNEY","volume":"4 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121000003","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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