APPARATUS AND METHOD OF CHECKING RADIO ALTITUDE REASONABLENESS

摘要

In a ground proximity warning system for an aircraft, a signal representing clearance of the aircraft from the underlying terrain is produced from a sea level related altitude signal and a terrain database in addition to the radio altitude signal of the aircraft's radio altimeter. An indication of reasonableness of the aircraft radio altitude signal is formed jointly responsive to the aircraft radio altitude signal and the terrain clearance signal.