Research on the assessment method of urban airspace zoning based on obstacle threat levels

In order to ensure the safe operation of urban airspace, this paper proposes an innovative approach to delineate urban airspace using obstacle threat levels. It suggests evaluating the safety margin between unmanned aerial vehicles (UAVs) and obstacles based on the concept of risk transition zones. Taking the example of Liuhe District in Nanjing City, obstacle expansion boundaries are formed with the application of convex hull algorithm, and the expanded area is considered as the risk transition zone between high and low-risk areas in urban airspace. Based on obstacle threat levels, the research area can be roughly categorized into no-fly zones, high-risk zones, high-risk transition zones, medium-risk zones, and low-risk zones. Micro, light, and small UAV airspace environmental risk maps are generated using inverse distance weighting interpolation. Experimental results indicate that the proportion of risk transition zones in the study area for micro, light, and small UAVs is 3.0%, 11.0%, and 3.7%, respectively. This can be used to assess the safety margin between UAVs and obstacles, providing a scientific basis for the safe operation of different types of UAVs in urban airspace.