Ship Hull Inspection
We address the problem of navigation for underwater vehicles in harbor surveillance tasks including ship hull inspection. Maintaining accurate localization is important for navigation and ensuring coverage, but is difficult in cluttered environments such as harbors, where acoustic-based localization systems are difficult to employ.
For the open and locally flat areas of large ships, our approach uses onboard sensors in a simultaneous localization and mapping setting. We extract dense features from a forward looking imaging sonar and apply pair-wise registration between sonar frames. The registrations are combined with onboard velocity, attitude and acceleration sensors to obtain an improved estimate of the vehicle trajectory. We have successfully demonstrated hull search as well as closed-loop waypoint navigation on large Navy ships.
We handle the complex areas of a ship differently by using profiling sonar.
For the coverage planning aspects, see Franz Hover's group at MIT
For the camera-based navigation, see Ryan Eustice's PeRL lab at UMich