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buoy trail The wake or plot trail made by a buoy on your radar screen, or more generally the trail left by any stationary target. This trail length is an important observation as it is effectively plotting your own motion on the screen. Any target with a longer trail has a relative speed faster than your speed, and any shorter trail has relative speed slower than you. Actual numerical values can be estimated from the lengths of moving-target trails relative to any buoy trail. All stationary targets seen on the radar will have the same trail length. Without any actual buoy trails on the radar screen, you can compute the length of the buoy trail as discussed in the text. The phrase "your buoy trail" means the trail length a buoy would make on your radar screen regardless of whether or not there is an actual buoy in range. In this sense, it is used as a reference length for judging the speeds of relative motion of all targets.

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