城市低空场景下无人机运行对地风险量化评估

A ground risk assessment model for unmanned aerial vehicle (UAV) operation was developed in order to guarantee the safe operation of UAVs in low-altitude urban areas. It was proposed that a ground risk map that considered multi-factors and multi-levels be used to define the ground risk associated with UAVs and quantify the degree of risk to the ground from flight operations over different areas. First, the typical characteristics of urban low-altitude and the causal chain of UAV crash-landing accidents were analyzed to establish a quantitative ground risk assessment model under the influence of multiple factors, and analyze in detail the mechanism of the influence of each factor on the ground risk. Second, to determine the chance of the danger happening at various locations, the probability density function of the impact region of a UAV crash-landing was computed while accounting for the UAV’s descending behavior and the uncertainty of the wind parameter. Then, the risk value of each geographic reference unit was calculated by combining multiple layers such as urban area map, population density, shelter effect, obstacles and no-fly zones; then the ground risk map of a large regional scale was generated, which can intuitively show the risk level of different areas of the city. Finally, the proposed method was validated and analyzed based on real examples. The findings demonstrate that there are clear differences in the risk distribution across different urban areas, and that the risk level is strongly correlated with the distribution of population density, the impact of surface shelter, the distribution of ground-level obstacle heights, the designation of the city’s no-fly zones, and the UAV’s flight height. The application of ground-based risk maps in the operation of UAVs will help to identify the level of danger of the areas flown over, avoid high-risk areas, and enhance operational safety in urban low-altitude.