Command filtered integrated estimation guidance and control for strapdown missiles with circular field of view

In this paper, an integrated estimation guidance and control (IEGC) system is designed based on the command filtered backstepping approach for circular field-of-view (FOV) strapdown missiles. The three-dimensional integrated estimation guidance and control nonlinear model with limited actuator deflection angle is established considering the seeker's FOV constraint. The boundary time-varying integral barrier Lyapunov function (IBLF) is employed in backstepping design to constrain the body line-of-sight (BLOS) in IEGC system to fit a circular FOV. Then, the nonlinear adaptive controller is designed to estimate the changing aerodynamic parameters. The generalized extended state observer (GESO) is designed to estimate the acceleration of the maneuvering targets and the unmatched time-varying disturbances for improving tracking accuracy. Furthermore, the command filters are used to solve the “differential expansion” problem during the backstepping design. The Lyapunov theory is used to prove the stability of the overall closed-loop IEGC system. Finally, the simulation results validate the integrated system's effectiveness, achieving high accuracy strikes against maneuvering targets.