GPS辅助MIMU静止条件下的初始对准方法

Initial Alignment Method of MIMU Aided by GPS under Static Condition

当载体处于静止状态时,针对微惯组测量噪声大,尤其是陀螺仪误差较大,不能辨别地球自转角速度,造成捷联惯性导航系统不能实现自对准的问题,采用GPS辅助微惯组进行初始对准。在粗对准过程中,通过加速度计输出信息解算水平姿态角,GPS解算航向角实现。在精对准过程中,建立四元数的状态空间模型,采用改进的自适应卡尔曼滤波算法估计四元数。仿真实验表明,采用滤波的方法,可以有效降低初始姿态角的估计误差,且载体的初始水平姿态角小于5°时,水平姿态角误差估计在5'之内,航向角误差估计在15'之内。

In view of the large measurement noise of the Miniature Inertial Measurement Units（ MIMU）,especially the gyroscope can not distinguish the self-rotation speed of the earth,which causes the failure of self-alignment with only the MIMU when the vehicle is in a static state. Therefore,the global positioning system（ GPS） is used to assist the MIMU in the process of alignment. In the process of coarse alignment,the horizontal attitude angle is solved by accelerometer output information,and the yaw angle is calculated by GPS. In the process of precise alignment,the state space model of quaternion is established,and the improved adaptive Kalman filtering algorithm is used to estimate the state of quaternion. The simulation experiment shows that the estimation error of the initial attitude angle can be effectively reduced by using the filtering method. When the vehicle＇s initial horizontal attitude angle is less than 5 degrees,the estimation of the horizontal attitude angle error is within 5＇,and the yaw angle error is estimated to be within 15＇.