How do flight computers in planes know how high above the ground they are.
In:
There generally are two sources to pull from
The first is the barometric pressure of the air around the plane. When compared to the known value at ground level and adjusted for temperature, the current height can be determined.
The second is a set of radio altimeters that measure the time between the broadcast of a radio signal and it’s return to measure the height above local terrain. This information is mainly used for landing, or warning the aircraft that they are closing in on terrain at a worrisome rate (GPWS)
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