An Impact Point Guidance for a Launch Vehicle With Aerodynamics Control

This paper presents an impact point (IP) guidance algorithm for launch vehicles reentering the atmosphere with limited aerodynamic maneuverability, aiming to correct the IP of the vehicle to a desired position. Given the structural limits of the launch vehicles that restrict aerodynamic maneuvers, the guidance algorithm is designed to generate minimal control commands. The proposed algorithm is derived from the principle of forming collision geometry toward a target point. The desired ballistic trajectory (DBT), where the IP aligns with the desired position, is determined using a rapid ballistic prediction technique. This involves partial closed-form solutions of the ballistic trajectory equations accounting for aerodynamic drag. Subsequently, the corresponding angular errors are calculated and nullified in a finite time, governed by the optimal error dynamics, thereby directing the vehicle's IP to the target position with regularized control effort. The algorithm's key strengths lie in its state- feedback form, and according resilience to uncertainties. Numerical simulations demonstrate the algorithm's effectiveness, validating its potential for practical applications.