METHOD AND APPARATUS FOR DETERMINING THE VERTICAL SPEED OF AN AIRCRAFT

摘要

The vertical speed of an aircraft is determined in a manner independent of signals provided by an air data computer, an inertial reference system and an inertial navigation system. A first vertical velocity of the aircraft is determined based upon pressure altitude values obtained from a barometric altimeter. A second vertical velocity is obtained from GPS receiver. The first and second vertical velocities are then combined to determine the vertical speed of the aircraft by complimentarily filtering the first and second vertical velocities. More particularly, the first vertical velocity is typically low pass filtered to remove high frequency noise that is attributable to the relatively low resolution of the first vertical velocity value. Additionally, the second vertical velocity is typically high pass filtered to reduce errors due to long-term drift.