Path Following of Optimal Trajectories Using Preview Control

This paper investigates the use of optimal preview control for tracking trajectories for air-to-surface missiles. A trajectory is generated off-line by solving a trajectory optimization problem, which incorporates the mission constraints and a model of the missile dynamics. A controller is then designed using optimal preview control to track the reference trajectory on-line and preserve the mission constraints. The control design process involves linearizing and discretizing the missile model and designing an outer guidance loop. By exploiting the structure of the problem, the preview gain sequence can be easily computed via the closed-loop transition matrix and the preview length can be tuned in accordance with the tracking requirements. The preview controller is used up to the radar acquisition range when a seeker is used to detect the target and a closed-loop guidance law is activated. A closed-loop guidance trajectory is presented using this approach and the results are discussed.