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.

HAUV 1b

HULS3

modified HULS3 with 3DFLS

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.

Typical imaging sonar data from open area of large ship hulls

Imaging sonar with extracted features from two frames aligned

We handle the complex areas of a ship differently by using profiling sonar.

Typical profiling sonar data from complex area

3D model of rudder and screw of a 180m long ship. Note the size of the ship in comparison to the HAUV (shown in yellow)

• Michael Kaess
• Hordur Johannsson

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

Imaging Sonar-Aided Navigation for AUVs (IROS 2010)