The direction of the target's movement relative to the own ship.
Calculated by dividing the relative distance projection by the relative speed. Ocean CPA method.pdf
More details on reliability in CPA calculations The direction of the target's movement relative to
): The vector difference between the own ship’s velocity and the target's velocity. a collision is possible
The is the estimated position where the distance between two ships (the "own ship" and a "target vessel") reaches its absolute minimum. It is the primary metric used by Watchkeeping Officers to assess the Risk of Collision (ROC) . If the CPA is too small, a collision is possible, requiring immediate maneuvering according to COLREGs . 2. Core Parameters The method relies on two primary mathematical outputs: