Adaptive terminal guidance with control saturation under multiple constraints

The seeker's field-of-view, attack angle, and impact angle are constrained in terminal guidance against a ground target. A guidance method is presented in the consideration of the above constraints. The guidance problem is transformed to a stabilization problem of a linear system subject to control saturation. A longitudinal guidance law with a low-gain parameter is derived by using the parametric Lyapunov equation-based low-gain feedback design. The relationship between the low-gain parameter and the convergence of the closed-loop system is investigated by using the Lambert W function. An adaptive tuning method is proposed to adjust the low-gain parameter. All the constraints can be observed by tuning the parameter online. The proposed guidance method is demonstrated by numerical simulation. Simulation results suggest that the proposed method satisfies all the constraints and achieves high guidance accuracy.