捷联惯导连续旋转方位轴式初始对准研究

针对捷联惯导系统初始对准时可观测性差的缺点,提出了一种提高系统状态变量可观测度的新方法。该方法通过连续旋转方位轴来等效地变换捷联惯导系统误差模型中的系统矩阵,从而提高了初始对准过程中的可观测度,满足了初始对准过程中对精度和速度的要求。分析了连续旋转方位轴式对准时系统的可观测性,并对不同方式下的捷联惯导初始对准过程中系统状态的可观测度进行了对比研究,指出采用连续旋转方式时系统状态的可观测度最高。仿真验证结果表明,连续旋转方位轴式初始对准对姿态误差角的估计精度较二、三位置方法提高了一倍。

Initial alignment of SINS based on the continuous rotation of the azimuth axis

In order to improve the observability of strapdown inertial navigation system(SINS)in the process of initial alignment,a new initial alignment method is presented by changing the transform matrix of the SINS’modeling error when the azimuth axis rotated continuously.The new method improves the observability of SINS in the process of initial alignment,and meets the requirements of accuracy and time.The SINS’observability in this new method has been compared with the alignment based on the stationary and the traditional multiposition,and it deduced that the observability of the continuous rotation manner is highest.The simulation results show that the estimation accuracy of azimuth misalignment angle in the presented method is approximately 2 times higher than that of the two-position and three-position alignment,therefore the accuracy of initial attitude is improved.