“…However, the target information is usually hard to be estimated if the target maneuver changes rapidly, and more sensors and estimators required may increase the complexity and the cost of guidance law system. With the development of modern control methods, some effective approaches have been employed to design robust guidance laws, including optimal control [5][6][7][8][9], nonlinear geometric method [12], Lyapunov approach [13], adaptive control [14], first-order slidingmode control [15], nonlinear H 1 [16], and finite time control [17,18]. Besides that, to improve the control precision, impact time and impact angle constraints have been taken into account in the design process of a three-dimensional guidance law [8][9][10][11]19,20].…”