The ability to avoid shorelines, reefs and moving ships or obstacles is the premise of automatic navigation. For achieving the goal, conventional A star algorithm is improved to plan route globally. The safety distance is set between planning route and obstacles. Additionally, the planning route is further optimized to remove unnecessary waypoints, and only vital waypoints are retained for conforming to navigation practice and track keeping control. Besides, minimum course alteration algorithm (MCA) is proposed to avoid moving ships or obstacles constrained by COLREGs. The proposed algorithms are validated in simulation. The results show that the algorithms are credible in two and multi ships encounter situations, even the targets ships take unexpected course alteration and the own ship could well avoid collision with shorelines, reefs and moving ships or obstacles under external disturbance.

能够避开海岸线、暗礁和移动的船只或障碍物是自动导航的前提。为实现这一目标，对传统的A星算法进行了改进，以全局规划路线。规划路线与障碍物之间设置安全距离。此外，进一步优化规划路线，去除不必要的航点，仅保留重要航点，以符合导航实践和航迹控制。此外，提出了最小航向改变算法（MCA）来避免受COLREGs约束的移动船舶或障碍物。所提出的算法在仿真中得到验证。结果表明，该算法在两艘和多艘船舶相遇情况下是可信的，即使目标船舶发生意外航向改变，本船也能很好地避免与海岸线碰撞，