Sliding-mode-control based robust guidance algorithm using only line-of-sight rate measurement

Robust guidance algorithm using only line-of-sight rate measurement is proposed for the interceptor with passive seeker. The initial relative distance, initial closing velocity and their error boundaries are employed to obtain their estimations according to the interceptor-target relative kinematics. A robust guidance law based on sliding mode control is formulated, in which the boundary of target maneuver is needed and the chattering phenomenon inevitably exists. In order to address the defects above, an estimation to the boundary of the target acceleration is proposed to improve the robust guidance law and the Lyapunov stability analysis is included. The main feature of the robust guidance algorithm is that it reduces the influence of the relative distance, the closing velocity and the target maneuver on the interception and enhances the effect of line-of-sight rate. With two worst conditions of initial measured distance and initial measured closing velocity, performances of the proposed guidance laws are verified via numerical simulations against different target maneuvers.