In-Depth Coordination and Extension: Decentralized Onboard Conflict Resolution of UAVs in the Low Altitude Airspace.

The wide applications of Unmanned Aerial Vehicles (UAVs) in the low altitude airspace have brought about the requirement for online conflict resolution coordination. In this study, we propose the decentralized onboard in-depth coordination method. As a premise, we anticipate that each UAV could receive the states of the neighboring UAVs in a wide range with advanced wireless communication devices. Therefore, each UAV is able to determine the surroundings of itself and the UAVs that conflict with it. A two-layered in-depth coordination method is proposed. In the first layer, each conflict-involved UAV determines the maneuver constraints and conflict avoidance responsibilities of itself and its neighbors based on the rules-based coordination method. In the second layer, each UAV determines appropriate conflict avoidance maneuvers according to the in-depth coordination mechanism independently. The safe separation requirements of the neighboring UAVs are considered. Furthermore, we extend the in-depth coordination method to the bio-inspired UAV flocks coordination method with reference to the behaviors of biological flocks. The virtual UAVs are constructed to promote the connections between UAVs in terms of conflict resolution, so that the boundary UAVs would take appropriate heading maneuvers to make room for the practical conflict-involved UAVs. We validate our approach on representative scenarios, and the results demonstrate that our method is beneficial in reducing the impact on the air traffic, and is capable of dealing with complex conflict scenarios.