Line of Sight Stabilization Technology Based on Visual Attitude Estimation

Referring to the possible problem of gyro random drift effect on the Line of Sight (LOS) stabilization accuracy, a method for the LOS stabilization based on visual attitude estimation is proposed. A monocular vision system is established by four coplanar reference points on the ground and a double-focus CCD camera in the carrier. The quaternion is used to represent the transform relation between geodetic coordinate system and carrier coordinate system, and the square-root unscented Kalman filter in which the current statistical model is applied to obtain the system state equations is used to estimate the attitude parameters. On this basis, the velocity interference model of the LOS is derived according to coordinate transformation and rigid body kinematics, and the method of feedforward control is adapted to isolate the influence of the LOS velocity disturbance. The simulation results indicate that the proposed method is effective in stabilizing the LOS without changing the structure of the tracking units.