An on-line compensation method for the disturbance rejection rate of seekers

An on-line estimation and compensation method of disturbance rejection rate (DRR) without the disturbance torque model is proposed to solve DRR problems caused by the disturbance torque of a gyro platform seeker. Subsequently, the DRR model and the seeker dynamic model of the platform seeker are established. On the basis of the guidance signal from the command of the stable loop or the output of the angular rate gyro, the transfer functions of line-of-sight (LOS) rate and DRR under a damping moment and spring torque are derived, respectively. Then, the stability domain of the parasitic loop caused by DRR are analyzed. The Kalman filter is used to estimate the angular acceleration caused by disturbance torque. According to the seeker dynamics, the LOS rate caused by additional angular acceleration can be calculated to compensate the seeker output. Thus, the effect of DRR can be eliminated to improve the output accuracy of LOS rate. Simulation results showed that the compensation method effectively improved the isolation level of the disturbance torque. Moreover, the impact of disturbance on LOS rate is reduced under different guidance signal extraction points and disturbance torques. In the miss distance simulation of the guidance and control system with seeker dynamics, the on-line DRR compensation scheme significantly reduced the DRR effect of the seeker on the guidance system. Consequently, the stability of the guidance system and the miss distance are significantly improved.