Abstract:

For the problem of measuring heading and attitude of small tail sitter aircraft, a measurement system is designed. The quaternion method is used to update heading and attitude, then the quaternion is transformed into Euler angle for output. Due to large change range of attitude, for the surge problem of attitude under disturbance from quaternion to Euler angles, an improved all attitude conversation algorithm is proposed. By analyzing the symbol of elements in attitude matrix, two groups of Euler angles are obtained from the quaternion. The right group is chosen in the interests of attitude control. For the precision decreasing of unscented Kalman filter (UKF) in the interference of outside noise, the adaptive algorithm is introduced to make the statistical feature of measurement noise adjust adaptively along with the change of noise. The anti-interference ability of the system is improved. For the problem of attitude mutation of small tailsitter aircraft, a strong tracking filter is designed. The role of historical information is reduced and the share of current information is increased by multiple fading factors. The precision of tracking rapidly changing state is improved. Finally, experiments verify the feasibility of the all attitude solution algorithm, adaptive UKF and strong tracking filter. The result shows the applicability of the designed heading and attitude measurement system in small tail sitter aircraft.