Download or read book Navigation and Localization of an Autonomous Underwater Vehicle Fleet for Magnetic Field Measurements written by Jordan Stringfield and published by . This book was released on 2012 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development and Testing of Navigation Algorithms for Autonomous Underwater Vehicles written by Francesco Fanelli and published by Springer. This book was released on 2019-04-16 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on pose estimation algorithms for Autonomous Underwater Vehicles (AUVs). After introducing readers to the state of the art, it describes a joint endeavor involving attitude and position estimation, and details the development of a nonlinear attitude observer that employs inertial and magnetic field data and is suitable for underwater use. In turn, it shows how the estimated attitude constitutes an essential type of input for UKF-based position estimators that combine position, depth, and velocity measurements. The book discusses the possibility of including real-time estimates of sea currents in the developed estimators, and highlights simulations that combine real-world navigation data and experimental test campaigns to evaluate the performance of the resulting solutions. In addition to proposing novel algorithms for estimating the attitudes and positions of AUVs using low-cost sensors and taking into account magnetic disturbances and ocean currents, the book provides readers with extensive information and a source of inspiration for the further development and testing of navigation algorithms for AUVs.

Download or read book Navigation and Collaboration of Autonomous Underwater Vehicles when Measuring Magnetic Fields written by Jesse Pentzer and published by . This book was released on 2010 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Underwater Vehicle Localization Using Range Measurements written by Georgios Papadopoulos and published by . This book was released on 2010 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis investigates the problem of cooperative navigation of autonomous marine vehicles using range-only acoustic measurements. We consider the use of a single maneuvering autonomous surface vehicle (ASV) to aid the navigation of one or more submerged autonomous underwater vehicles (AUVs), using acoustic range measurements combined with position measurements for the ASV when data packets are transmitted. The AUV combines the data from the surface vehicle with its proprioceptive sensor measurements to compute its trajectory. We present an experimental demonstration of this approach, using an extended Kalman filter (EKF) for state estimation. We analyze the observability properties of the cooperative ASV/AUV localization problem and present experimental results comparing several different state estimators. Using the weak observability theorem for nonlinear systems, we demonstrate that this cooperative localization problem is best attacked using nonlinear least squares (NLS) optimization. We investigate the convergence of NLS applied to the cooperative ASV/AUV localization problem. Though we show that the localization problem is non-convex, we propose an algorithm that under certain assumptions (the accumulative dead reckoning variance is much bigger than the variance of the range measurements, and that range measurement errors are bounded) achieves convergence by choosing initial conditions that lie in convex areas. We present experimental results for this approach and compare it to alternative state estimators, demonstrating superior performance.

Download or read book Autonomous Underwater Vehicles written by Jing Yan and published by Springer Nature. This book was released on 2021-11-01 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: Autonomous underwater vehicles (AUVs) are emerging as a promising solution to help us explore and understand the ocean. The global market for AUVs is predicted to grow from 638 million dollars in 2020 to 1,638 million dollars by 2025 – a compound annual growth rate of 20.8 percent. To make AUVs suitable for a wider range of application-specific missions, it is necessary to deploy multiple AUVs to cooperatively perform the localization, tracking and formation tasks. However, weak underwater acoustic communication and the model uncertainty of AUVs make achieving this challenging. This book presents cutting-edge results regarding localization, tracking and formation for AUVs, highlighting the latest research on commonly encountered AUV systems. It also showcases several joint localization and tracking solutions for AUVs. Lastly, it discusses future research directions and provides guidance on the design of future localization, tracking and formation schemes for AUVs. Representing a substantial contribution to nonlinear system theory, robotic control theory, and underwater acoustic communication system, this book will appeal to university researchers, scientists, engineers, and graduate students in control theory and control engineering who wish to learn about the core principles, methods, algorithms, and applications of AUVs. Moreover, the practical localization, tracking and formation schemes presented provide guidance on exploring the ocean. The book is intended for those with an understanding of nonlinear system theory, robotic control theory, and underwater acoustic communication systems.

Download or read book Improving AUV Localization Accuracy by Combining Ultra short baseline and Long baseline Measurement Systems in a Post processing Extended Kalman Filter written by David Halverson Pick (II) and published by . This book was released on 2019 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: The University of Idaho (UI), partnered with the Office of Naval Research (ONR), is developing the capability to perform oceanographic survey measurements conducted by autonomous underwater vehicles (AUVs). Accurate spatial and temporal localization of these measurements is essential to properly correlate electric and magnetic field measurements to the desired reference frame. Previous work at UI has investigated the use of long baseline (LBL), moving short baseline (MSBL), and hybrid baseline (HBL) for navigation and localization. LBL navigation systems can have a high degree of accuracy but have a limited operating range and are not easily re-deployed and surveyed. Field testing operations at the University of Idaho continue to expand, including consideration of ultra-short baseline (USBL) localization and navigation as an alternative or augmentation to existing LBL navigation systems due to advantages in deployability. The acoustic ranging from these systems are used in an extended Kalman filter (EKF) to estimate orientation and position. This information is utilized by the AUV to navigate along a waypoint course and stored in a log for post-process analysis and further study. This paper presents a series of Monte Carlo simulations that were performed to compare the measurement uncertainty between conventional LBL and USBL systems. The simulated North and East position measurements from the USBL were used as additional measurements in a new post-processing EKF. This was performed in several different cases, allowing for the comparison between the legacy EKF and differing variants of a post-processing EKF using USBL measurements. Each of these simulations utilized historic UI field testing LBL range and AUV sensor measurements in addition to simulated USBL measurements.Results from Monte Carlo simulations suggest that USBL localization uncertainty is better than that of LBL, albeit for a smaller operating range. This smaller operating range comes from poor depth uncertainty and a lack of depth telemetry. Additionally, it was found that the addition of USBL measurements to the existing EKF greatly improved the state estimate uncertainty for AUV position over the legacy EKF. USBL systems often provide a telemetry-based depth measurement, which communicates depth from the AUV to the USBL transceiver and greatly improves the uncertainty of the USBL system. When depth telemetry is implemented, the USBL has a lower uncertainty than the EKF does, but the EKF provides additional confidence in the state estimates due to the combination of independent measurement systems and the addition of the AUV kinematic model.

Download or read book Sensor Based Navigation and Localization Methods for Autonomous Underwater Vehicles written by and published by . This book was released on 1995 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt: An algorithm designed to navigate an Autonomous Underwater Vehicle (AUV) within a charted environment is presented. The algorithm processes sensor inputs from the AUV high resolution scanning sonar, compass and velocimeter. The operating environment is modeled with a suitable three dimensional potential function and its gradient which form an attractive field. This algorithm provides performance comparable to the Kalman Filter with the advantage of reduced computational requirements facilitated by precomputation and table look up of correction factors. Applications of data smoothing filters and sliding mode theory are also investigated. The applicability and robustness of this approach are demonstrated with actual test data obtained with the NPS Phoenix submersible and extended simulation of complex environments including unmodeled obstacles.

Download or read book Long Range Underwater Navigation Using Gravity Based Measurements written by Parth Pasnani and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this thesis is to demonstrate feasibility of a gravity-based system for long range underwater localization. Such a system is demonstrated, in simulations, with the use of particle filter-based localization and Rao-Blackwellized particle filter SLAM (simultaneous localization and mapping). This system allows an autonomous underwater vehicle (AUV) to operate submerged for extended periods without the use of an active sensor, thus widening the variety of missions that an AUV can be tasked with. Additionally, this thesis demonstrates how information theory techniques can be used to plan a path through a region such that SLAM data association within that region is improved thus improving the performance of SLAM. The results from this work also indicate that characteristic value can be used to evaluate the "SLAMability" of an environment. Combining the characteristic value with information theory techniques improves the performance of SLAM at extended ranges enabling long range underwater localization.

Download or read book Technology and Applications of Autonomous Underwater Vehicles written by Gwyn Griffiths and published by CRC Press. This book was released on 2002-11-28 with total page 369 pages. Available in PDF, EPUB and Kindle. Book excerpt: The oceans are a hostile environment, and gathering information on deep-sea life and the seabed is incredibly difficult. Autonomous underwater vehicles are robot submarines that are revolutionizing the way in which researchers and industry obtain data. Advances in technology have resulted in capable vehicles that have made new discoveries on how th

Download or read book Long Range Gravity Aided Autonomous Underwater Vehicle Navigation written by Franz Heubach and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Autonomous underwater vehicles (AUV) are a mobile platform for underwater sensing, an environment relatively unexplored. Georeferencing measurements is difficult due to the challenge of AUV localization. The rapid attenuation of radio frequencies underwater restricts AUVs from using the global position system (GPS), the above-water solution to localization. Underwater localization relies on dead-reckoning, the integration of vehicle inertia measurements to arrive at a position estimate. However, the dead-reckoned position error is unbounded. This error can be bounded using a source of position feedback. Terrain aided navigation (TAN) - using georeferenced geophysical terrain maps can provide that feedback. TAN shows significant promise as a method for long-range, passive underwater AUV navigation, especially gravity-aided navigation (GAN). This thesis presents a TAN algorithm that uses a gravity gradiometer and gravity gradient maps to successfully limit dead-reckoning error by a factor of 25 over a 500 km long AUV mission, with a localization accuracy of 1 km. The TAN algorithm exploits the correlation between terrain and the gravity anomaly to use a global database of bathymetry maps (GEBCO) with 400 m resolution. The mission was simulated in the AUV navigation testbed (ANT), a collection of tooling developed during this thesis to accelerate research in TAN. Among the contributions made by the ANT, is a inertial navigation system (INS) that emulates the uncertainty characteristics of a commercial navigation grade INS (Kearfott Seanav) \textemdash~to simulate dead-reckoning error growth. Parts of the ANT have been released to the research community as open-source, and are being used by researchers in the Intelligent Systems Laboratory (ISL) at Dalhousie University.

Download or read book Absolute Positioning of an Autonomous Underwater Vehicle Using GPS and Coustic Measurements written by Neil Harvey Kussat and published by . This book was released on 2004 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Navigation and Target Localization Performance of the AUV Remote Environmental Measuring UnitS written by Christopher John Cassidy and published by . This book was released on 2000 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A High Rate Virtual Instrument of Marine Vehicle Motions for Underwater Navigation and Ocean Remote Sensing written by Chrystel Gelin and published by Springer Science & Business Media. This book was released on 2012-08-22 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dead-Reckoning aided with Doppler velocity measurement has been the most common method for underwater navigation for small vehicles. Unfortunately DR requires frequent position recalibrations and underwater vehicle navigation systems are limited to periodic position update when they surface. Finally standard Global Positioning System (GPS) receivers are unable to provide the rate or precision required when used on a small vessel. To overcome this, a low cost high rate motion measurement system for an Unmanned Surface Vehicle (USV) with underwater and oceanographic purposes is proposed. The proposed onboard system for the USV consists of an Inertial Measurement Unit (IMU) with accelerometers and rate gyros, a GPS receiver, a flux-gate compass, a roll and tilt sensor and an ADCP. Interfacing all the sensors proved rather challenging because of their different characteristics. The proposed data fusion technique integrates the sensors and develops an embeddable software package, using real time data fusion methods, for a USV to aid in navigation and control as well as controlling an onboard Acoustic Doppler Current Profiler (ADCP). While ADCPs non-intrusively measure water flow, the vessel motion needs to be removed to analyze the data and the system developed provides the motion measurements and processing to accomplish this task.

Download or read book Cooperative Localization for Autonomous Underwater Vehicles written by Alexander Bahr and published by . This book was released on 2009 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Self-localization of an underwater vehicle is particularly challenging due to the absence of Global Positioning System (GPS) reception or features at known positions that could otherwise have been used for position computation. Thus Autonomous Underwater Vehicle (AUV) applications typically require the pre-deployment of a set of beacons.This thesis examines the scenario in which the members of a, group of AUVs exchange navigation information with one another so as to improve their individual position estimates. We describe how the underwater environment poses unique challenges to vehicle navigation not encountered in other environments in which robots operate and how cooperation can improve the performance of self-localization. As intra-vehicle communication is crucial to cooperation, we also address the constraints of the communication channel and the effect that these constraints have on the design of cooperation strategies. The classical approaches to underwater self-localization of a single vehicle, as well as more recently developed techniques are presented. We then examine how methods used for cooperating land-vehicles can be transferred to the underwater domain. An algorithm for distributed self-localization, which is designed to take the specific characteristics of the environment into account, is proposed. We also address how correlated position estimates of cooperating vehicles can lead to overconfidence in individual position estimates. Finally, key to any successful cooperative navigation strategy is the incorporation of the relative positioning between vehicles. The performance of localization algorithms with different geometries is analyzed and a distributed algorithm for the dynamic positioning of vehicles, which serve as dedicated navigation beacons for a fleet of AUVs, is proposed.

Download or read book An Underwater Vehicle Navigation System Using Acoustic and Inertial Sensors written by Khalid M. Alzahrani and published by . This book was released on 2018 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unmanned Underwater Vehicles (UUVs) have become an essential tool for different underwater tasks. Compared with other unmanned systems, the navigation and localization for UUVs are particularly challenging due to the unavailability of Global Positioning System (GPS) signals underwater and the complexity of the unstable environment. Alternative methods such as acoustic positioning systems, Inertial Navigation Systems (INS), and the geophysical navigation approach are used for UUV navigation. Acoustic positioning systems utilize the characteristics of acoustic signals that have a lower absorption rate and a more extended propagation distance than electromagnetic signals underwater. The significant disadvantage of the INS is the "drift," the unbounded error growth over time in the outputs. This thesis is aimed to study and test a combined UUV navigation system that fuses measurements from the INS, Doppler Velocity Log (DVL), and Short Baseline (SBL) acoustic positioning system to reduce the drift. Two Kalman filters are used to do the fusion: the Extended Kalman Filter (EKF) and the Unscented Kalman Filter (UKF). After conducting the experiments and simulation, the results illustrated the INS/SBL fusion navigation approach was able to reduce the drift problems in the INS. Moreover, UKF showed a better performance than the EKF in the INS.

Download or read book Advanced Sensing Navigation and Autonomy for Unmanned Underwater Vehicles written by Eric Curtis Gallimore and published by . This book was released on 2019 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research results that advance the capabilities of autonomous underwater vehicles (AUVs) to conduct seabed surveys are described. These include the creation of a software framework to enable research and development in sensing and adaptive autonomy, a novel synthetic baseline navigation technique, and a magnetic sensing system that incorporates sense and react behaviors. Field experiments were conducted globally in a wide range of littoral environments to test hypotheses associated with the emerging field of autonomy as applied to underwater systems. To facilitate sensor integration and provide a testbed for autonomous sense and react research, an onboard sensor processing and autonomy system was developed for the REMUS AUV using the Robot Operating System (ROS) that provides high-level control of the vehicle. Multiple vehicles outfitted with this system were used for seabed surveys, sensor evaluation, and engineering tests. This framework enabled the development of novel techniques for undersea navigation and magnetic sensing. A synthetic baseline navigation technique that self-localizes an AUV using intermittent acoustic communications signals received by a single transducer is presented. The methodology is found to offer advantages over traditional acoustic-based navigation, in that it can operate with or without synchronized clocks, does not require acoustic transmissions dedicated to navigation, and can provide faster navigation solution convergence. The method uses the phase measurement at the output of a second-order phase-locked loop (PLL) to create fine-scale pseudo-range estimates in addition to, or in the absence of, a one-way travel time (OWTT) measurement based on the arrival time of the acoustic data packet. These range measurements are incorporated by an adaptive particle filter. This technique allows the vehicle navigation system to take advantage of multiple phase-derived range measurements made over the duration of a communication packet. To enable geophysical and archaeological survey capabilities, a scalar magnetometer system has been developed and integrated into an AUV. Real-time signal processing mitigates platform effects of the vehicle. Development of autonomy for on-board processing and target detection, coupled with reacquisition behaviors, is found to increase the effective survey coverage rate by nearly 300% when searching for magnetic dipole targets. The compact system collects data from a Micro-Fabricated Atomic Magnetometer (MFAM, Geometrics Corporation, San Jose, CA, USA), a total-field atomic magnetometer, and data from the sensor is both streamed to storage and made available to an onboard autonomy engine for real-time sense and react behaviors. Following characterization both in controlled laboratory conditions and at sea to determine its performance limits, methodologies for processing the magnetometer data to correct for interference and error introduced by the AUV platform were developed to improve sensing performance. When conducting seabed surveys, the developed autonomy is found to reliably detect and characterize targets of interest using physics-based algorithms designed to operate in real-time within the computational constraints of the AUV. Over the course of this research, the system was advanced to drive both single- and multiple-vehicle autonomous target reacquisition behaviors. Detailed results from surveys searching for submerged World-War II aircraft wrecks at locations worldwide are presented.

Download or read book Scientific and Environmental Data Collection with Autonomous Underwater Vehicles written by John Moore (Jr.) and published by . This book was released on 1992 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: