Decentralized self-propagating ground delay for UTM: Capitalizing on domino effect

We investigate a possible scheme for management of conflicts among autonomous unmanned aerial vehicles (UAVs) in high-density very low level (VLL) uncontrolled airspace. The drones are modeled as disks of a given radius, moving along prescribed trajectories planned without any centralized coordination. Thus, during the motion, the disks may potentially come into contact, which represents loss of separation between the drones. Two overlapping disks get enclosed by a larger disk serving as the protected zone for avoidance maneuvers of all the drones inside it. When the conflict is gone, the disk is deactivated and the UAVs continue towards their destinations. We simulate traffic demand and the evolution of the de-confliction zones over a geographic area and present statistics associated with functioning of the system with and without ground delay to avoid take offs into conflicts. The scheme shows promise and is a good approach to explore further in future work.