Implicit maneuver coordination: Issues and potential solutions

In earlier research projects, the depiction of airspace in which a loss of separation is predicted to occur has been explored as a means to increase conflict awareness. The computation of the conflict space is based on the current state of traffic and ownship. If the traffic maneuvers, the location and extent of the conflict space will change accordingly. Hence, if the other traffic also maneuvers to avoid the predicted loss of separation it is of fundamental importance that the maneuvers of ownship and traffic are complementary. To ensure that a conflict will indeed be avoided by such a maneuver and not accidentally made worse when both maneuver simultaneously, a form of coordination is necessary between the aircraft involved. Some research has been done in the area of implicit coordination between two aircraft, which provides coordinated resolution maneuvers to conflicting aircraft based on an epsilon criterion when only state information is periodically broadcast by the aircraft. This paper explores conflict scenarios that need additional rules to be safely resolved. Furthermore, a system is developed for analyzing the application of implicit maneuver coordination in scenarios that contain multiple intruders. This system is summarized in a decision tree that can be used to categorize scenarios according to the location of the closest point of approach of the intruders and the connectedness of the corresponding conflict areas. These factors determine the scenario complexity and the available or preferred conflict resolution options. The provided insight can be used to aid pilots in quickly assessing the most optimal maneuver in complex conflict scenarios. It can also be used in planning aircraft routes or in decisions on preventive maneuvers.