Patent ID: 8676403

Claim:
A method of guiding an aircraft to follow a predetermined four-dimensional flight path, comprising: monitoring an actual along-track position and an actual vertical position of the aircraft relative to corresponding desired along-track and vertical positions on the predetermined flight path; generating throttle commands based on deviations of the actual vertical position of the aircraft from the desired vertical position; and generating elevator commands based on an along-track position deviation of the actual along-track position from the desired along-track position, a vertical position deviation of the actual vertical position from the desired vertical position, and a ground speed deviation of the actual ground speed of the aircraft from the desired ground speed of the aircraft, wherein said generating elevator commands comprises: obtaining a current calibrated airspeed from flight data; converting said ground speed deviation to an equivalent calibrated airspeed deviation; modifying said current calibrated airspeed by an amount that is a function of said calibrated airspeed deviation to form a first calibrated airspeed command; modifying said first calibrated airspeed command by an amount that is a function of said along-track position deviation to form a second calibrated airspeed command; modifying said second calibrated airspeed command by an amount that is a function of said vertical position deviation to form a third calibrated airspeed command; and commanding actuations of elevators in accordance with said third calibrated airspeed command.