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Radio waves bouncing off ground surfaces provide accurate altitude readings during low visibility. The figure is taken from Federal Aviation Administration, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.

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Radar altimeters measure exact aircraft height above terrain using radio waves

Radio waves bouncing off ground surfaces provide accurate altitude readings during low visibility

Unlike barometric altimeters that calculate altitude from atmospheric air pressure, radar altimeters transmit downward microwave radio pulses to measure absolute distance to ground terrain. Introduced commercially by Bell Telephone Laboratories in 1938, radar altimeters provide essential altitude readings for terrain awareness warning systems and automated instrument landings.

Where this comes from

Federal Aviation Administration

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Tags: aviation, radar, altimeter

Radar altimeters measure exact aircraft height above terrain using radio waves: the short answers

Where does this come from, and can I check it?: Radio waves bouncing off ground surfaces provide accurate altitude readings during low visibility. The figure is taken from Federal Aviation Administration, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
Is this really a technology fact?: Yes. It sits on the Technology shelf, one of 1,090 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
What else can I read about it?: The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.