Robust Terminal Guidance Law for Air-to-Air Missile of Adjustable Velocity

According to adjustable character of the velocity of air-to-air missile with variable-flow ducted rockets,a nonlinear terminal guidance law with robustness was proposed.The relative velocity of the missile and the target was taken as controlled state as well as the line-of-sight angular-velocity.Based on the principle of quasi constant bearing navigation,a proper Lyapunov function was chosen.The global asymptotic stability of the guidance system was ensured,and the expression of the robust terminal guidance law was obtained by means of the nonlinear H∞ robust control theory.Simulation results show that,for the missile intercepting a target with high maneuverability,the proposed terminal guidance law not only has strong robustness and excellent guidance precision,but also can shorten the interception time compared with the traditional one.