Meaning of ALTIMETER in English
Instrument that measures the altitude of the land surface or of any object, such as an airplane.
The mechanical pressure altimeter measures atmospheric pressure relative to sea level through a series of bellows, gears, and springs, which move pointers on a dial. Radio altimeters measure the distance of an aircraft above the ground rather than above sea level by indicating the time a pulse of radio energy takes to travel from the aircraft to the ground and back; they are used in automatic navigation and blind-landing systems.
Britannica Concise Encyclopedia. Краткая энциклопедия Британика. 2012