A Distributed Conflict Detection and Resolution Method for Unmanned Aircraft Systems Operation in Integrated Airspace

Recently, with the rapid development of related avionics, Unmanned Aircraft Systems (UAS) have been widely used in various fields. The current segregated operations cannot meet their increasing demand and it is expected that UAS could operate in the integrated airspace with manned aircraft. However, full integration of UAS into civil airspace is confronted with the safety challenge because their Detect and Avoid (DAA) ability is not equivalent with that of manned aircraft. As the number of aircraft grows in the shared airspace, the possibility of flight conflicts will inevitably increase. In order to ensure the safe operation of various types of aircraft, a distributed Conflict Detection and Resolution (CD&R) method for integrated operation is proposed in this paper. First, a dynamic protect zone based on time threshold in the presence of uncertainty is designed to obtain efficient separation criteria. Based on the established protect zone, the Closest Point of Approach (CPA) strategy is employed to detect potential conflicts. Additionally, two conflict risk ranking mechanisms are specifically introduced to guarantee the efficiency of subsequent multi-aircraft conflict resolution. Finally, the mixed integer programming models have been built to minimize the conflict-free trajectory deviation via the Velocity Obstacle (VO) method. Numerical results have shown the superior performance of proposed method in different scenarios.