带斜置元件的光纤陀螺捷联惯组标定方法

Calibration method of FOG strapdown IMU with skewed sensor axes

采用冗余传感器的捷联惯性测量组合能有效提高可靠性,并为降低测量误差和提高导航性能提供必要条件,但同时对标定提出了新问题。给出了一种具有斜置陀螺和加速度计的光纤陀螺捷联惯组标定方法。首先利用陀螺(加速度计)特性:只响应角速率(加速度)在其输入轴方向的投影分量,推导了该传感器输入轴方向的方向余弦与其安装方式的对应关系,建立了组合误差模型。用最优估计理论推导模型参数解算方法,同时考虑了地球转速及重力加速度对标定过程的影响;整个试验过程不增加标定工作量,无需北向基准。试验证明,该方法是一种高精度的工程实用标定方法,由交耦系数换算后的安装误差角符合实际情况,陀螺和加速度计的斜轴综合测量误差分别不大于0.140(°)/h和6.442E-5g。

The strapdown inertial measurement unit (SIMU) with redundant sensors can increase the reliability and provide necessary conditions for lowering the measurement errors and improving the navigation accuracy. But it also causes new calibration problems. Hence, a calibration method of fiber optic gyro SIMU with skewed sensor axes is presented. Based on the characteristics of gyro (accelerometer) which is only sensitive to the velocity (acceleration) projection along its input axis, the relation between the direction cosine and the fixing mode is deduced, and the SIMU error models are established. The model parameters are obtained based on optimal estimation theory by taking into account the earth rotation and gravity. The calibration test needs no additional workload and no north reference. Test results show that this method is effective and applicable to the high-accuracy SIMU. The installation angles computed from the cross-coupling coefficients are consistent with the practical situation. The synthetic measurement errors of the skewed gyro and accelerometer are no more than 0.140 (°)/h and 6.442E-5g, respectively. ©, 2015, Editorial Department of Journal of Chinese Inertial Technology. All right reserved.