TCPA stands for which term in radar navigation?

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Multiple Choice

TCPA stands for which term in radar navigation?

TCPA is about when two moving objects will be closest to each other if they keep their current speeds and courses. It’s the predicted moment in time, measured from now, at which the distance between your vessel and the other object will be the smallest. Think of your own vessel and the other object with a relative position vector and a relative velocity vector. The distance between them over time is D(t) = |r + v t|. The time to reach the closest point occurs when the rate of change of that distance is zero, which gives t = - (r · v) / |v|^2 (assuming there is relative motion, so |v| ≠ 0). If t is positive, the closest approach will happen in the future; if it’s negative, it already happened. If there’s no relative motion, TCPA is undefined or infinite because the distance won’t change. In practice, TCPA helps you assess collision risk alongside the Closest Point of Approach distance. A small positive TCPA with a small CPA distance signals you should consider action to avoid a near pass. The other, less standard phrases do not describe this specific prediction in radar navigation.

TCPA is about when two moving objects will be closest to each other if they keep their current speeds and courses. It’s the predicted moment in time, measured from now, at which the distance between your vessel and the other object will be the smallest.

Think of your own vessel and the other object with a relative position vector and a relative velocity vector. The distance between them over time is D(t) = |r + v t|. The time to reach the closest point occurs when the rate of change of that distance is zero, which gives t = - (r · v) / |v|^2 (assuming there is relative motion, so |v| ≠ 0). If t is positive, the closest approach will happen in the future; if it’s negative, it already happened. If there’s no relative motion, TCPA is undefined or infinite because the distance won’t change.

In practice, TCPA helps you assess collision risk alongside the Closest Point of Approach distance. A small positive TCPA with a small CPA distance signals you should consider action to avoid a near pass. The other, less standard phrases do not describe this specific prediction in radar navigation.

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