CES-515 Towards Localization and Mapping of Autonomous Underwater Vehicles: A Survey

Autonomous Underwater Vehicles (AUVs) have been used for a huge number of tasks ranging from commercial, military and research areas etc, while the fundamental function of a successful AUV is its localization and mapping ability. This report aims to review the relevant elements of localization and mapping for AUVs. First, a brief introduction of the concept and the historical development of AUVs is given; then a relatively detailed description of the sensor system used for AUV navigation is provided. As the main part of the report, a comprehensive investigation of the simultaneous localization and mapping (SLAM) for AUVs are conducted, including its application examples. Finally a brief conclusion is summarized

Dynamic sonar perception

Thesis (Ph. D. in Marine Robotics)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 2003.Includes bibliographical references (leaves 183-192).Reliable sonar perception is a prerequisite of marine robot feature-based navigation. The robot must be able to track, model, map, and recognize aspects of the underwater landscape without a priori knowledge. This thesis explores the tracking and mapping problems from the standpoint of observability. The first part of the thesis addresses observability in mapping and navigation. Features are often only partially observable from a single vantage point; consequently, they must be mapped from multiple vantage points. Measurement/feature correspondences may only be observable after a lag, and feature updates must occur after a delay. A framework is developed to incorporate temporally separated measurements such that the relevant quantities are observable. The second part of the thesis addresses observability in tracking. Although there may be insufficient information from a single measurement to estimate the state of a target, there may be enough information to observe correspondences. The minimum information necessary for a dynamic observer to track locally curved targets is derived, and the computational complexity is determined as a function of sonar design, robot dynamics, and sonar configuration. Experimental results demonstrating concurrent mapping and localization (CML) using this approach to early sonar perception are presented, including results from an ocean autonomous underwater vehicle (AUV) using a synthetic aperture sonar at the GOATS 2002 experiment in Italy.Richard J. Rikoski.Ph.D.in Marine Robotic

Radius of curvature estimation and localization of targets using multiple sonar sensors

Acoustic sensors have been widely used in time-of-flight ranging systems since they are inexpensive and convenient to use. One of the most important limitations of these sensors is their low angular resolution. To improve the angular resolution and the accuracy, a novel, flexible, and adaptive three- dimensional (3-D) multi-sensor sonar system is described for estimating the radius of curvature and location of cylindrical and spherical targets. Point, line, and planar targets are included as limiting cases which are important for the characterization of typical environments. Sensitivity analysis of the curvature estimate with respect to measurement errors and certain system parameters is provided. The analysis and the simulations are verified by experiments in 2-D with specularly reflecting cylindrical and planar targets, using a real sonar system. Typical accuracies in range and azimuth are 0.18 mm and 0.1°, respectively. Accuracy of the curvature estimation depends on the target type and system parameters such as transducer separation and operating range. The adaptive configuration brings an improvement varying between 35% and 45% in the accuracy of the curvature estimate. The presented results are useful for target differentiation and tracking applications.A flexible and adaptive three-dimensional multisensor sonar system capable of estimating the location and radius of curvature of spherical and cylindrical targets is presented. The performance radius of curvature estimation is analyzed to provide information for differentiating reflectors with different radii. Results showed that the adaptive configuration improved the accuracy of the curvature estimate between 35% and 45%

AN INTEGRATED SIMULATION APPROACH FOR AUV IMAGE-BASED SLAM NAVIGATION

This thesis develops a simulation framework for undersea feature-based navigation. Using an autonomous underwater vehicle (AUV) to locate an item of interest on the seafloor is a capability that would greatly benefit the Navy. AUVs provide a gateway toward removing the workforce requirement; however, they are still costly both in acquisition and maintenance. A solution to this problem is using two AUVs, one with increased capability and charged with finding and marking seafloor items with a beacon. An expendable AUV outfitted with cost-effective sensors would relocate, identify and neutralize the threat. Using undersea imaging to correlate seafloor images to an a priori image mosaic together with a ultra short baseline (USBL) beacon allows the AUV to complete challenging mission objectives without traditional navigation systems. Incremental Smoothing and Mapping 2 (iSAM2) is a Simultaneous Localization and Mapping (SLAM) technique that can be used by the AUV for position localization and is an appropriate technique, with image and USBL sensing, for real-time navigation operations. A simulation framework provides the ability to evaluate an AUV's performance while minimizing the risk of real-world operations. The framework is composed of a software architecture that allows for testing using the same software applied in real-world operations. This thesis demonstrates this framework and provides analysis for its usability for image-based SLAM.Lieutenant, United States NavyApproved for public release. Distribution is unlimited

Sensory Communication

Contains table of contents for Section 2, an introduction and reports on twelve research projects.National Institutes of Health Grant 5 R01 DC00117National Institutes of Health Contract 2 P01 DC00361National Institutes of Health Grant 5 R01 DC00126National Institutes of Health Grant R01-DC00270U.S. Air Force - Office of Scientific Research Contract AFOSR-90-0200National Institutes of Health Grant R29-DC00625U.S. Navy - Office of Naval Research Grant N00014-88-K-0604U.S. Navy - Office of Naval Research Grant N00014-91-J-1454U.S. Navy - Office of Naval Research Grant N00014-92-J-1814U.S. Navy - Naval Training Systems Center Contract N61339-93-M-1213U.S. Navy - Naval Training Systems Center Contract N61339-93-C-0055U.S. Navy - Naval Training Systems Center Contract N61339-93-C-0083U.S. Navy - Office of Naval Research Grant N00014-92-J-4005U.S. Navy - Office of Naval Research Grant N00014-93-1-119

A sonar-based mapping system for an unmanned undersea vehicle

Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.Includes bibliographical references (p. 115-118).An unmanned undersea vehicle (UUV) must operate autonomously in a complex, dynamic environment and react intelligently to changing tactical, environmental, and mission variables with no outside intervention. To support these real-time, adaptive mission capabilities, the building and updating of an efficient and accurate map of the tactical scene is critical. The challenges are to obtain useful and comprehensive information about the environment, to represent and fuse this data into an on-board map, to update the map in real-time when new data is discovered, and to save the map for future use while maintaining both efficiency and accuracy. This thesis presents the design and implementation of a sonar-based mapping system for a UUV, and discusses the elements of the mapping system design: representation of static and dynamic obstacles in a mapping system, the need for efficient data structures, the incorporation of sonar measurement uncertainty, and the assimilation of new information into the map. The mapping system consists of a static obstacle map that stores information about stationary objects and a dynamic obstacle map that stores information about moving objects in the underwater environment. The static obstacle map consists of a local map that represents the immediate mission area and a global map that represents the entire mission area. The combination of the separate maps forms an integrated mapping system that represents the UUV's tactical scene, supports a query for the presence or absence of an obstacle at any location, time, and level of certainty, and as such, can be used to support the UUV's mission objectives. This thesis also discusses modeling of noise in the sonar measurements. Since the mapping system must handle noisy sonar measurements, a model of a noisy sonar measurement is an imperative part of the sonar simulation and the validation of the mapping system.by Margaret F. Nervegna.M.Eng

Adaptive sampling in autonomous marine sensor networks

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2006In this thesis, an innovative architecture for real-time adaptive and cooperative control of autonomous sensor platforms in a marine sensor network is described in the context of the autonomous oceanographic network scenario. This architecture has three major components, an intelligent, logical sensor that provides high-level environmental state information to a behavior-based autonomous vehicle control system, a new approach to behavior-based control of autonomous vehicles using multiple objective functions that allows reactive control in complex environments with multiple constraints, and an approach to cooperative robotics that is a hybrid between the swarm cooperation and intentional cooperation approaches. The mobility of the sensor platforms is a key advantage of this strategy, allowing dynamic optimization of the sensor locations with respect to the classification or localization of a process of interest including processes which can be time varying, not spatially isotropic and for which action is required in real-time. Experimental results are presented for a 2-D target tracking application in which fully autonomous surface craft using simulated bearing sensors acquire and track a moving target in open water. In the first example, a single sensor vehicle adaptively tracks a target while simultaneously relaying the estimated track to a second vehicle acting as a classification platform. In the second example, two spatially distributed sensor vehicles adaptively track a moving target by fusing their sensor information to form a single target track estimate. In both cases the goal is to adapt the platform motion to minimize the uncertainty of the target track parameter estimates. The link between the sensor platform motion and the target track estimate uncertainty is fully derived and this information is used to develop the behaviors for the sensor platform control system. The experimental results clearly illustrate the significant processing gain that spatially distributed sensors can achieve over a single sensor when observing a dynamic phenomenon as well as the viability of behavior-based control for dealing with uncertainty in complex situations in marine sensor networks.Supported by the Office of Naval Research, with a 3-year National Defense Science and Engineering Grant Fellowship and research assistantships through the Generic Ocean Array Technology Sonar (GOATS) project, contract N00014-97-1-0202 and contract N00014-05-G-0106 Delivery Order 008, PLUSNET: Persistent Littoral Undersea Surveillance Network

Supply Chain Planning with Incremental Development, Modular Design, and Evolutionary Updates

Proceedings Paper (for Acquisition Research Program)The policy specified by DoDI 5000.02 (DoD, 2008, December 8) prescribes an evolutionary acquisition strategy. Products with long lifecycles such as torpedoes, evolutionary updates via incremental development, modular design updates, technology refreshes, technology insertions, and Advanced Processor Builds are all in play at the same time. Various functional elements of the weapon system are often redesigned during the lifecycle to meet evolving requirements. Component obsolescence and failures must also be anticipated and addressed in upgrade planning. Within each weapon system''s evolutionary acquisition, cycle-changing requirements may expose weaknesses that have to be rectified across the inventory. New acquisition paradigms such as modular design have to be introduced into the supply chain while maintaining inventory levels of previously designed weapons at a high level of readiness. Thus, a diverse set of requirements must be satisfied with a finite set of resources. The acquisition policy does not provide guidance on how to address cross-coordination and optimization of project resources. This paper explores decision models for balancing conflicting demands and discusses the application of how these models address cross-coordination and optimization of project resources in the torpedo acquisition process while keeping the weapon''s efficiency and inventory effectiveness at or above minimum specified levels.Naval Postgraduate School Acquisition Research ProgramApproved for public release; distribution is unlimited