Adaptive ground collision avoidance system

A ground collision avoidance system for use by a pilot in an aircraft that has a mission control system, a navigation system, a digital terrain elevation database, active terrain sensors and a radar altimeter, the ground collision avoidance system comprising:

• a local terrain awareness system that fuses inputs from the mission control system, the navigation system, the active terrain sensors, and the radar altimeter with terrain information in the digital terrain elevation database to generate a current profile of the elevation and character of the terrain over which the aircraft is operating;
• a flight envelope prediction system attached to the mission control system for providing first and second flight path envelopes, wherein the first flight path envelope is a first prediction of the aircraft's flight path based on a current flight path and the second flight path envelope is a second prediction of the aircraft's flight path based on the first path envelope and a flight path angle that is necessary to avoid the terrain which may exist in the first path envelope, the second flight path envelope being determined by iteratively and simultaneously determining a ground collision point and a ground avoidance point, the ground collision point being a predicted point of collision with the terrain and the ground avoidance point being a predicted point with respect to the ground collision point at which the aircraft's path should be modified to avoid the terrain;
• a ground correlation system attached to the local terrain awareness system and the flight envelope prediction system for correlating terrain elevation data with the first and second flight path envelopes for providing pathway elevation data indicative of specific ground elevation data over which the aircraft travels;
• a collision control and guidance system attached to the ground correlation system and the flight envelope prediction system which determines that a ground collision condition exists when the generation of the second flight path envelope by the flight envelope prediction system is no longer possible, and then uses the terrain information to calculate at least one standard replanning maneuver to avoid collision with the terrain;
• and
• a collision warning system attached to the collision control and guidance system for producing an alarm if the ground collision condition exists as determined by the collision control and guidance system.