3D Stealthy Trajectory Planning Scheme for Multi-UAVs Based on Improved A-Star Algorithm

To address the survivability challenge of multi-UAVs in hostile environments, a three-dimensional (3D) stealth trajectory planning scheme based on an improved A-star algorithm is proposed for threat avoidance. First, a 3D environment model incorporating radar detection and no-fly zones is established. Subsequently, four evaluation metrics are constructed to assess UAV mission fault tolerance, flight stability, trajectory smoothness, and stealth performance. The weighted sum of these evaluation metrics is defined as the multi-UAV 3D trajectory planning efficiency function. Building upon this framework, an optimization model for multi-UAV stealth trajectory planning in 3D dynamic environments is formulated, with the objective of maximizing the efficiency function while incorporating constraints such as no-fly zones and UAV maneuverability parameters. Finally, a two-step solution method based on the improved 3D A-star algorithm is employed to solve the optimization model. Simulation results demonstrate that, compared to the benchmark, the proposed scheme generates feasible 3D stealth paths for multiple UAVs that satisfy maneuverability constraints and exhibit the low probability of being detected by the radar network.