Ship Hull Inspection by Hull-Relative Navigation and Control

Attitude-Trajectory Estimation for Forward-Looking Multibeam Sonar Based on Acoustic Image Registration

“…While there are many technologies to assist in navigation for land or air based vehicles, these technologies do not necessarily transfer well to the underwater environment. Global Positioning System (GPS) may be referenced using underwater acoustic beacons [1], however a system may not always be available, or the accuracy good enough, for tasks such as exploration [2] or underwater inspection [3] [4]. Although inertial navigation systems are unaffected by being underwater, they are costly and subject to drift [5].…”

“…Throughout this text we will be using a numerical example related to a FLS inspection of a ship's hull. The dataset, captured by Bluefin Robotics Corp. [25], was using a hull inspection procedure described in [4]. In this context, the 'seabed' is the underside surface of a ship's hull.…”

An overview of AUV algorithms research and testbed at the University of Michigan

“…covariance form was published by McLauchlan and Murray [39], in the context of recursive structure-from-motion (SFM). This work was subsequently extended to realize a hybrid batch/recursive visual SLAM implementation that unified recursive SLAM and bundle adjustment [21]. McLauchlan recognized the potential increase in efficiency that can be gained via approximations to maintain sparsity of the information matrix:…”

“…To test our FBN algorithms in a real-hull environment, PeRL collaborated with Massachusetts Institute of Technology (MIT) and Bluefin Robotics to put one of our camera systems on the Hovering Autonomous Underwater Vehicle (HAUV) [21] at AUVFest'08 to collect imagery of the hull of the USS Saratoga-a decommissioned U.S. aircraft carrier stationed as Newport, RI (Fig. 9).…”

Dam wall detection and tracking using a Mechanically Scanned Imaging Sonar

“…As discussed in [5], in tasks such as dam survey, it is important to maintain a specified distance and specially a certain relative orientation with respect to the wall (usually orthogonal) in order to achieve a high resolution image mosaic. A similar problem was faced for ship hull inspection as reported in [6]. In that case, the DVL was looking towards the ship's hull and the range readings were used to compute the relative orientation of the robot with respect to the hull, while in our case, the robot is passively stable in roll and pitch and multiple range and bearing measurements of sonar are used to compute the robot's relative orientation and distance in front of the dam wall.…”