Conflict Detection and Resolution Strategy for eVTOLs in Low-Altitude Urban Environments Based on the Geodetic Coordinate System

Conflict detection and resolution (CD&R) based on trajectory prediction will support operations for unmanned aircraft systems operating in low-altitude airspace. Especially in the context of four-dimensional trajectory-based operation, the characteristics of complex low-altitude urban environments and the uncertainty associated with aircraft movements must be considered. This study is divided into three primary parts: trajectory tracking and extrapolation, conflict detection, and conflict resolution. First, the motion of electric vertical takeoff and landing (eVTOL) is decoupled into independent motion in three directions based on the geodetic coordinate system. The interacting multimodel algorithm is applied based on a posteriori modification to the temporal confidence. Second, we propose a dynamic conflict detection method based on Gilbert–Johnson–Keerthi algorithm in a spatial grid system. Third, an improved artificial potential field method is used for avoiding collisions in real time. Automatic dependent surveillance–broadcast information served as the input of the scheme, and the simulation is divided into three distinct phases. We evaluated the accuracy of trajectory tracking in two coordinate systems and performed conflict detection within the airspace. The proposed method facilitated simulated conflict resolution by coordinating the flight plans of six eVTOLs. The results demonstrated that the CD&R scheme based on the geodetic coordinate system can improve the flight efficiency and safety of eVTOLs.