Robust guidance law considering two-order dynamics of autopilot

For the case of a three-dimensional interception, a new continuous nonlinear H∞ guidance law with robustness is proposed. The mathematic model was built according to relationship between missile and target whose acceleration as disturbance was introduced and considering two-order autopilot dynamic. Based on the method of zeroing the rate of line-of-sight angle, a global nonlinear H∞ control strategy was contrived to obtain the continuous nonlinear guidance law. The asymptotic stability of guidance system was strictly proven by Lyapunov stability theory instead of solving the Hamilton-Jacobi-Isaacs(HJI) partial differential equation, at the same time the relative velocity was not controlled applying the method. Finally an illustrative example is given to show that new guidance law is more robust and suitable to the missile for intercepting the target with high velocity and high maneuver than proportional navigation law, and the better precision of guidance law is obtained.