Conflict-Aware Flight Planning for Avoiding Near Mid-Air Collisions

We present a novel conflict-aware flight planning approach that avoids the possibility of near mid-air collisions (NMACs) in the flight planning stage. Our algorithm computes a valid flight-plan for an aircraft (ownship) based on a starting time, a set of discrete way-points in 3D space, discrete values of ground speed, and a set of available flight-plans for traffic aircraft. A valid solution is one that avoids loss of standard separation with available traffic flight-plans. Solutions are restricted to permutations of constant ground speed and constant vertical speed for the ownship between consecutive way-points. Since the course between two consecutive way-points is not changed, this strategy can be used in situations where vertical or lateral constraints due to terrain or weather may restrict deviations from the original flight-plan. This makes our approach particularly suitable for unmanned aerial systems (UAS) integration into urban air traffic management airspace. Our approach has been formally verified using the Athena proof assistant. Our work, therefore, complements the state-of-the-art pairwise tactical conflict resolution approaches by enabling an ownship to generate strategic flight-plans that ensure standard separation with multiple traffic aircraft, while conforming to possible restrictions on deviation from its flight path.