Abstract: Low-altitude path planning is a core link to ensure the safe and efficient development of the low-altitude economy.Traditional A^*algorithms face problems such as low search efficiency and insufficient path safety in three-dimensional low-altitude environments.To address these challenges,this paper proposes an improved A^*algorithm integrated with GeoSOT-3D grid modeling for low-altitude path planning.Based on the GeoSOT-3D grid,the algorithm constructs a three-dimensional low-altitude environmental model,introduces a 7-neighborhood extended search strategy,incorporates a safety obstacle avoidance mechanism,and adopts Catmull-Rom spline curves to smooth and optimize the result paths.Comparative results of three groups of simulation experiments show that,in the 19th,20th and 21st level GeoSOT-3D grid environments,the improved A^*algorithm reduces the average number of searched and expanded nodes by more than 83%.Moreover,the average time consumption of the improved A^* algorithm is reduced by approximately 17%～26% compared with the traditional A^*algorithm,and by approximately 1%～12% compared with the Theta^*algorithm.While maintaining both path safety and smoothness,the improved algorithm enhances the efficiency of path planning.

Key words: GeoSOT-3D grid, A^*algorithm, path planning, node expansion, safety obstacle avoidance