Trajectory planning and guidance design for the automatic landing phase of reusable launch vehicle

Abstract Reusable Launch Vehicles are crucial for reducing space mission costs and improving efficiency through multiple flights. The unpowered return and automatic landing phase pose challenges due to aerodynamic uncertainties, the absence of propulsion, and strict landing constraints. This research integrates the Gauss pseudospectral method with a three-degree-of-freedom simulation model to plan the landing trajectory. The model includes Earth’s curvature, ground effects, and landing gear deployment. A Linear Active Disturbance Rejection Controller manages vertical speed, while the L1 guidance method handles lateral control. Key findings show precise trajectory handling during landing gear deployment and robustness to aerodynamic disturbances. Monte Carlo simulations confirm the system’s resilience to deviations.