Logical Shepherd Assisting Air Traffic Controllers for Swarm UAV Traffic Control Systems

Abstract

In recent years, Unmanned Aerial Vehicles (UAVs) have attracted attentions from almost every industry. Their low cost, high accessibility, and low-risk compared to human-operated vehicles, created a unique opportunity for a variety of use cases in many application domains. The addition of these tele-operated, and sometimes autonomous, vehicles to the air traffic control environment imposed significant challenges and has been calling for appropriate UAV traffic control systems. The complexity of this situation increases manyfold when the UAVs need to work together as a swarm. Air traffic controllers are used to manage 20 or so aircraft separated according to strict guidelines. A highly dynamic, adaptive, fast, and large swarm of UAVs present unprecedented complexity. Shepherding offers an opportunity to provide a concept of a single sheepdog simultaneously guiding a large sheep flock. We present a logical shepherd that could act both in an autonomous mode or in a tele-operation mode by simply sitting in the hands of a swarm traffic controller. Due to the safety critical nature of the environment, we modified the concept of shepherding by designing an asynchronous shepherding algorithm coupled with a digital twin environment to assess consequences. Once the logical shepherd location and orientation is chosen by the human operator, the influence force vectors start to propagate asynchronously from one aircraft to another, maintaining separation assurance and safety constraints. The updated trajectory intent information of the UAVs gets displayed on the screen for the human operator to see if the change is acceptable or not. If acceptable, the recommendation is made and the UAVs commence to follow the new path.