简化5级-CKF在SINS大失准角初始对准中的应用

Application of Simplified 5th-CKF in SINS Initial Alignment for Large Misalignment Angles

针对大失准角情况下,利用3级-CKF进行SINS初始对准性能不高的问题,提出5级-CKF算法。在系统模型噪声和量测噪声均为加性噪声且量测方程为线性方程时,推导了简化5级-CKF算法,步骤需要在Kalman滤波的基础上利用5级容积采样点对非线性状态方程的状态及其方差进行预测。采用SINS静基座初始对准仿真实验验证算法的有效性,结果表明:简化5级-CKF对任意失准角都是有效的,失准角较小时,3级-CKF和简化5级-CKF的对准精度和收敛速度性能相近,但简化5级-CKF的数值稳定性更高;失准角较大时,简化5级-CKF较3级-CKF具有更高的收敛速度和对准精度。

Against the performance of 3th-CKF is not high for SINS initial alignment with large misalignment angle, a simplified 5th-CKF was deduced under the situation that both process noise and measurement noise were additive noise with liner measurement equation. The simplified 5th-CKF is identical to that of classical Kalman filter except for the predicting of states and their covariance matrix by spherical-radial cubature rule. Simulation results show that the simplified 5th-CKF is useful under any misalignment angle, And under large misalignment angle, the per-formance of simplified 5th-CKF is superior to that of 3th-CKF in terms of accuracy and SINS alignment speed.