Plain English Meaning

A special, very fast radar that lets controllers safely run two airplanes down to two parallel runways at the same time when those runways are close together. It updates much more often than normal radar so controllers can react quickly if one aircraft drifts toward the other.

Full Definition

PRM Radar is a high-update-rate surveillance radar system used by ATC to monitor simultaneous independent approaches to closely spaced parallel runways. It provides controllers with rapid position updates and high-resolution display of aircraft, allowing safe separation of two aircraft flying parallel approaches when the runway centerlines are too close for .