Automatic radar plotting aids are essentially utilized to improve the standard of collision avoidance at sea. Primarily designed as anti-collision radar, the ARPA technology removed the chore of plotting targets manually on a reflection plotter or separate plotting aid. The system is able to acquire automatically and constantly monitor number of targets, plot their speeds and courses, present these as vectors on the display screen, updated with each sweep of the antenna, and calculate their closest points of approach to own ship and the time before that will occur.