Acoustic motion estimation and guidance for unmanned underwater vehicles

The problem of navigation, guidance and control of Unmanned Underwater Vehi cles (UUVs) is addressed in this paper. A task-function based guidance syst em and an acoustic motion estimation module have been integrated with a con ventional UUV autopilot within a two-layered hierarchical architecture for closed-loop control. The design of the guidance system is based on suitable Lyapunov functions that can handle the different manoeuvres involved in ap proaching a target. Range and bearing information provided by a pencil beam profiling sonar are processed by an Extended Kalman Filter based algorithm for motion estimation in a structured environment. The resulting Navigatio n Guidance and Control (NGC) system has been tested on Roby2, the UUV testb ed developed at the Istituto Automazione Navale of Italy's National Researc h Council. The experimental set-up as well as modalities and results are di scussed.