Formal Verification of COLREG-Based Navigation of Maritime Autonomous Systems.

Along with the very actively progressing field of autonomous ground and aerial vehicles, the advent of autonomous vessels has brought up new research and technological problems originating from the specifics of marine navigation. Autonomous ships are expected to navigate safely and avoid collisions following COLREG navigation rules. Trustworthy navigation of autonomous ships presumes applying provably correct navigation algorithms and control strategies. We introduce the notion of maritime game as a special case of Stochastic Priced Timed Game and model the autonomous navigation using UPPAAL STRATEGO. Furthermore, we use the refinement technique to develop a game model in a correct-by-construction manner. The navigation strategy is verified and optimized to achieve the goal to safely reach the manoeuvre target points at a minimum cost. The approach is illustrated with a case study inspired by COLREG Rule 15.