Research on relative navigation method based on INS/Vision using sigma-point Kalman filter

According to the leader-follower flight mode of unmanned aerial vehicle, the relative navigation method based on INS/Vision is presented considering the measurement of vision navigation equipment with time delay. The relative inertial equation and line of sight between leader and follower is derived. Because of the strong nonlinearity of INS/Vision relative navigation system, the unscented kalman filter is used to estimate the relative position, relative velocity and relative attitude by fusing the relative inertial information and line of sight. For the quaternion normalization, an unconstrained three-component vector is used to presented an attitude error quaternion. For the time delay problem of vision navigation equipment, the method of fusing the inertial navigation information and the measurement with time delay is provided.