Automatic Guidance through 4D Waypoints with time and spatial margins

This paper presents a new algorithm for 4D Automatic Guidance, enabling the automatic capture of 4D waypoints (i.e. 3D points in the space with a requested time of arrival), while satisfying navigation constraints coming from both Air Traffic Management (i.e. time and space constraints on the waypoints to reach) and vehicle performance limitations. The proposed guidance strategy mainly relies on the continuous re-generation of the geometric reference trajectory and, in case this is not sufficient to guarantee the requested time of arrival, airspeed reference is adjusted to compensate for the difference between estimated and requested time of arrival of waypoint. The effectiveness of the proposed approach has been demonstrated by means of numerical simulations, including vehicle model and simplified autopilot/autothrust system that ensure tracking of the reference 4D trajectory. This paper was developed in the framework of 4DCoGC, a research project funded by European Commission under the Seventh Framework Programme whose objective is to address the aircraft 4D guidance and control principle.