Performance evaluation of operational modes in terminal airspace of UAV takeoff and landing areas

The terminal airspace of UAV takeoff and landing areas serves as the foundation for ensuring the safe and efficient operation of UAVs. Within this area, the air traffic environment is highly complex, making UAVs prone to collisions, delays, and other issues. However, research on terminal airspace and flight rules for UAV takeoff and landing areas remains scarce. This study designs a terminal airspace for small UAVs with a multi-layered annular frustum structure based on a hovering holding mode and proposes two operational modes for the terminal area: the Open Queue Approach (OQA) and the Directed Queue Approach (DQA). Mathematical models for performance evaluation metrics of these operational modes are developed. By establishing and solving a Mixed Integer Nonlinear Programming (MINP) model and developing a simulation environment for UAV terminal airspace operations using the SimPy library, the study proposes optimization-based and statistics-based methods for operational mode performance evaluation, quantitatively assessing the performance of different terminal area operational modes from the perspectives of volume, operational efficiency, and safety. In addition, controlled simulation experiments are conducted to compare the operational performance of the proposed hovering holding mode with a representative loitering holding mode under high-traffic scenarios. The results show that the hovering holding mode proposed in this paper can reduce UAV waiting time by 47.9Â % compared to the loitering holding mode; the minimum airspace volume under the OQA operational mode is smaller than that of the DQA mode; the OQA mode demonstrates superior efficiency, while the DQA mode exhibits better performance from the perspective of safety.