##### Low Range Radar Altimeter (LRRA) A radar [[altimeter]] also called a radio altimeter (RALT or RADALT), electronic altimeter, reflection altimeter, or low-range radio altimeter (LRRA), measures [[altitude]] above the terrain presently beneath an aircraft by timing how long it takes a beam of [[Radio Wave|radio waves]] to travel to ground, reflect, and return to the craft. This type of altimeter provides the distance between the antenna and the ground directly below it, in contrast to a [[pressure altimeters|barometric altimeter]] which provides the distance above a defined vertical datum, usually mean [[Sea Level Pressure]]. Since the altitude information given by a radar altimeter is the [[absolute altitude]], it is also referred to as an absolute altimeter. >Covered in: >Mentioned in: >References: [[WP RADALT|🌍]] >Required by: > >Related to: >[[Radio Altimeter|🎞️]]