Definitions for "Radar altimeter"
Airborne radar that measures the distance of the aircraft above the ground.
a small radar mounted on the underside of an aircraft that constantly measures the altitude above ground
(Also called radio altimeter.) An onboard radar for determining the altitude of an aircraft above an underlying surface. Pulse-radar techniques measure altitude in terms of the transit time of the radar pulse; continuous-wave radar measures altitude in terms of the phase difference between the transmitted and received signals.