Line-of-Sight Stabilization and Reconstruction of Yaw-Pitch Seeker Installed on Rotating Platform

The technical of tracking a moving target and measuring the line-of-sight (LOS) angular velocity using a two-axes yaw-pitch gimbal seeker fixed on rotating missile is interesting and nontrivial. For the gimbal failing to reject roll motion, the image sensor fixed on optical axis will rotate with missile, and the measurement of the rate gyro fixed on the optical axis is no longer match the real LOS angular velocity. The dynamic model of two axes gimbal is using to provide detailed analysis of the mechanisms about how inertial disturbances coupled to the axes, proper inertial balancing design is also discussed to minimize the disturbances. Tracking principles and stabilization control law are presented with missile roll motion impacts on target tracking performance. An estimation strategy is proposed to obtain the LOS angular velocity from the gyro measurement using unscented Kalman filter (UKF) under considering of the influence of parametric uncertainties and channel coupling. The relationships between LOS gradient and relative acceleration is built for the estimation model. Numerical simulation results confirm the effectiveness of the proposed seeker LOS estimation method.