Conformal hull search using the harbor defense CetusII AUV

The deployment of high resolution sensors supporting the inspection of ship´s hulls requires an AUV to navigate in and around the hull of a ship or restricted berthing zone while maintaining a constant viewing aspect. This paper discusses the implementation of the highly maneuverable CetusII equipped with a unique upward looking sonar, three-point inverse stand-off altimetry, high-frequency long-baseline navigation and Doppler inertial guidance to support this mission. It describes the unique approach to hull following using a 3 upward looking sonar altimeters as well as the employment of a high-resolution fiber-optic gyroscope in heading maintenance near the large iron mass which comprises the ship´s hull. Adaptation of the vehicle control software to the unique aspects of hull inspection will be discussed as well as results from in-water ship hull inspection testing.