Comprehensive Study on Route Flight Separation and Control Frequency of Urban UAV

Focusing on urban UAVs route flight, in order to ensure the safety of operation, it is necessary to equip the UAVs with appropriate separation. For the longitudinal flight scenario of the same route, a separation regulation model that considers the conflict frequency and collision probability and complies with the ICAO separation principle is investigated. By considering only the collision risk of UAVs positioning error, the longitudinal separation is obtained, which is used as the benchmark for the subsequent separation calculation. By considering the position uncertainty caused by both positioning error and velocity error, the collision risk along with the flight progress of UAVs is calculated. Increasing the longitudinal separation will delay the time to break through the target level of safety, but as the flight progresses, the collision risk will eventually overstep the target level of safety. Based on this finding, the method of UAV position regulation mechanism is proposed, and the distance between two aircraft is calibrated periodically. For a given target level of safety, a curve of longitudinal separation and position control frequency can be obtained, and a game relationship is found to exist between them. Implementation of high-frequency control, a smaller route separation is needed. Otherwise, the required route separation should be increased. In order to take into account, the double constraints of urban airspace and position control ability, a compromise scheme to select the separation and the control frequency at the maximum curvature is presented. It is found that the more stringent the safety target level requirements, the greater the required frequency of regulation and flight separation. The experimental analysis finds that when the target level of safety is 5×10^－9 times/flight hour, the required control frequency is 87 times/hour and the required longitudinal separation is 90 m. At the same time, in the actual operating environment, the application of the above evaluation models and methods can objectively select the required separation and regulation frequency. The research in this paper can consider the safety of urban logistics UAV air operation and improve urban airspace utilization and delivery efficiency.