absolute altimeter meaning

[Defence]
(*) A type of altimeter which measures vertical distance to the surface below, using radio, radar, sonic, laser, or capacitive technology.

[Engineering]
"An instrument which employs radio, sonic, or capacitive technology to produce on its indicator the measurement of distance from the aircraft to the terrain below. Also known as terrain-clearance indicator."

Examples

1. The group also helped develop the radar altimeter, or absolute altimeter.