CPA Closest Point of Approach

CPA, closest point of approach, indicates the point where two ships will be closest, in the projection of their course.

In the nautical sector, this measurement can be calculated by radar, AIS or marine GPS instruments. These devices show the position of the CPA on the display and often also how much time is left for the CPA (TCPA Time to CPA).

The CPA highlights the probability of a collision between two boats, highlighting the proximity of the two boats at this point.