Research For Aircraft Attitude Determination Algorithm Of High-Degree CKF Based On Quaternion

Nonlinear filtering is a key technology in spacecraft attitude estimation.The performance of attitude estimation is determined directly by nonlinear filtering.At present,quaternion unscented Kalman filter(QUKF)has become a effective method of attitude estimation due to its advantages including implement with ease,moderate filtering accuracy,and good convergence.However,existing QUKF has bad numerical accuracy and numerical stability because of its negative weights,which deteriorates the accuracy of attitude estimation and degrades its practical engineering value.In order to solve these problems,the main works done in this paper are as follows:To improve the numerical performance of QUKF,a new quaternion cubature Kalman filter(QCKF)is first proposed based on the third-degree spherical-radial cubature rule in the paper.The proposed QCKF has better numerical accuracy and numerical stability as compared with existing QUKF because its weights are all positive,which improves the accuracy of attitude estimation.Moreover,the proposed QCKF has lower computation burden than existing QUKF because it has fewer sigma points than QUKF.To further improve the estimation accuracy of QCKF,a new quaternion high-degree cubature Kalman filter(QHCKF)is proposed based on the high-degree spherical-radial cubature rule.QHCKF has higher estimation accuracy than QCKF because it can capture higher degree Taylor expansion term of nonlinear process and measurement functions.In order to solve the problem that the accuracies of QCKF and QHCKF degrade when noise is involed in the nonlinear propagation,quaternion augmented CKF(QACKF)and quaternion augmented HCKF(QACKF)are proposed.Although QACKF and QAHCKF can improve estimation accuracy of attitude to some extent,their computation complexity are much higher than QCKF and QAHCKF.To reduce the computation burden of QACKF and QAHCKF,quaternion state switching CKF(QSSCKF)and quaternion state switching high-degree CKF(QSSHCKF)are proposed respectively.QSSCKF and QSSHCKF have higher lower computation burden and almost consistent estimation accuracy as compared with QACKF and QAHCKF.The platform of Gyro/CCD integrated attitude estimation is used to illustrate the superiority of the proposed methods.Simulation results show that both the proposed QCKF and the proposed QHCKF have higher estimation accuracy of attitude than existing QUKF,and QHCKF has higher estimation accuracy than QCKF.Moreover,both QACKF andQSSCKF proposed in the paper outperform QCKF,and both QAHCKF and QSSHCKF outperform QHCKF.It is worth noting that QSSHCKF have not only high estimation accuracy but also suitable computation burden,which shows its good practical engineering value.