| 释义 |
laser altimeter
laser altimeter[′lā·zər al¦tim·əd·ər] (navigation) An altimeter in which a laser beam, modulated by radio frequencies, is directed downward from an aircraft, and the laser light reflected from the terrain is picked up by a telescope system, sensed by a photomultiplier, and phase-compared with the transmitted signal to obtain the round-trip propagation time; the height above ground equals one-half the product of the propagation time and the speed of light. laser altimeterAn altimeter that measures the time it takes for a laser pulse to return from the ground directly below the aircraft. This time is converted into height above the ground, and this is what the altimeter indicates. It is more accurate than a radio or radar altimeter. A laser altimeter measures and indicates absolute altitude.AcronymsSeeALT-L |