双轴旋转式SINS非线性初始对准方法

Nonlinear initial alignment method of dual-axis rotary SINS

双轴旋转调制技术可以实现全部惯性元件常值误差的自补偿,从而提高惯性导航系统的导航精度。以双轴旋转调制式SINS初始对准方法为研究对象,建立了双轴旋转式SINS大方位失准角非线性误差模型,利用简化Unscented卡尔曼滤波(UKF)算法,设计了双轴旋转式SINS大方位失准角初始对准算法。利用提出的UKF算法进行了方位失准角为任意大小的数字仿真试验,并进行了同样条件下的EKF算法对比仿真试验。最后进行了UKF算法的系统对准验证试验,验证试验的1σ统计结果为水平误差小于3″,方位误差小于1′。试验结果表明建立的双轴旋转SINS大方位失准角非线性误差模型是正确的,提出的UKF对准算法在工程应用中是有效、可行的。

The drift errors of various inertial elements in SINS can all be auto-compensated by the dual-axis rotation modulation technique.First,the dual-axis rotary SINS initial alignment algorithm is studied,and the nonlinear error model of large azimuth misalignment（LAM） is established.Then the LAM initial alignment algorithm based on the unscented Kalman filter（UKF） is designed.The UKF initial alignment simulation for any heading misalignment angle of the dual-rotary SINS is implemented.To make a comparative study,the EKF initial alignment simulation is performed under the same conditions.The experiments are made to verify the UKF initial alignment algorithm performance.The alignment results of 1s are as below： the level error is less than 3″ and the heading error is smaller than 1′.The results show that the LAM for dual-axis rotary SINS is correct,and the UKF initial alignment algorithm is effective and feasible in engineering application.