The guidance system design of the semi-strapdown homing guided missile

The present paper focuses mainly on the semi-strapdown homing guided system design, which includes control system design of the two-degree-of-freedom semi-strapdown homing seeker and estimation of the guidance information. According to Euler dynamics theory and momentum moment theorem, the two-degree-of-freedom nonlinear dynamic model of the semi-strapdown homing seeker is built in common coordinate frames. Then the control-oriented state-space model of the semi-strapdown homing seeker system is proposed innovatively, and a nonlinear controller is designed by integrating the feedback linearization and linear lead controller. Next, the estimation and construction method of the guidance information based on the unscented Kalman filter is presented for the semi-strapdown homing guided missile. Finally, a three-dimensional interception flight simulation is made using the six-degree-of-freedom axial-symmetry nonlinear aerodynamic model of the semi-strapdown homing guided missile. Simulation results show that guidance information of the semi-strapdown homing guided missile can be estimated via the unscented Kalman filter, and can be used in shaping seeker control command. The seeker nonlinear controller based on feedback linearization can improve the disturbance rejection effect of the semi-strapdown homing seeker effectively with good target tracking ability.