Kinematics in four-dimensional atmospheric guidance

Abstract

The four-dimensional (4D) atmospheric guidance depict another point of view into the modern autopilot design. This type of guidance assures the tracking, with a pre-specified error, of a desired 4D trajectory. In this paper the 4D kinematics is analyzed, for the case of classical atmospheric vehicles control, in order to develop powerful guidance controllers. The solution of the inverse kinematics problem assures the conversion of the reference 4D primary trajectory in a sequence of required attitudes and speed magnitudes defined as functions of time. The control task was simplified by using the forced singular perturbation theory, the overall system dynamics being separated into reduced-order systems and independently controlled. The algorithm performance was evaluated for the case of a conventional transport aircraft that tracks a 4D trajectory defined by flight levels, waypoints and an estimated time of arrival. The test evolution was a final approach and landing. A version of a global guidance algorithm was implemented.