With the development of Radar technic, ARPA (Automatic Radar Plotting Aids) can display directly the course and speed of target ship and get the DCPA and the TCPA of the ship, so it is applied widely.

• 随着雷达技术的发展，ARPA(Automatic Radar Plotting Aids自动雷达标绘仪)由于可以直接显示目标船的航向、航速，同时可以直接得到目标船的DCPA和TCPA，因而得到了广泛的应用。