An Overview on Systems and Algorithms for On-Board 3D/4D Trajectory Management

In recent years, significant emphasis has been devoted to progresses in the field of on-board trajectory generation and tracking for aircraft guidance along specified waypoints. Research in this area was mainly driven by the request of improved on-board autonomy for both unmanned aerial systems and manned civil aircrafts. Several algorithms and systems have been developed and patented in this field, addressing both 3D waypoints, which are specified in terms of their three dimensional coordinates and, more recently, 4D waypoints, which also include a required time to arrival. Of course, patents proposed for 3D/4D trajectory management systems are characterized by their key features (use of 3D or 4D constraints, of different waypoint capture concepts, and so on) and by different applications and algorithms. In this paper, a review is performed of the most relevant patents presented in recent years in this field. This review considers the various problems, emphasizing main advantages and weaknesses of the proposed solutions and suggesting some possible future developments.