基于MIMU测量系统的两步校准法

Two-Step Calibration Method Based on the MIMU Measurement System

三轴加速度计是微惯性测试单元(MIMU)测量组合的重要组成器件,其测量准确度直接影响系统姿态解算的准确度。因此需要对三轴加速度计的零偏误差、标度因素误差、各轴之间的不正交误差以及传感器与测试单元的安装误差进行分析和补偿。提出了一种两步校准法,即首先利用椭球假设的MIMU现场快速标定方法分析微惯性测量组合的误差模型,得到加速度计的零偏、标度因素和不正交角;之后利用四位置法校准出加速度计的安装误差。该方法实际操作简单,不需要高精度辅助设备。测试平台实验表明:该方法能够有效提高三分量测量数据的准确性,可应用于MIMU姿态测量系统中加速度计的校准。

The three-axis accelerometer is an important component of the micro inertial measure- ment unit （MIMU） measurement combination, and its measurement accuracy directly affects the attitude algorithm accuracy of the system. Therefore, it is necessary to analyze and compensate for the zero-bias error, scale factor error, non-orthogonal error of the three-axis accelerometer and the installation error between the sensor and test unit of the three-axis accelerometer. A two- step calibration method was proposed, the error model of the micro inertial measurement combi- nation was analyzed by using the MIMU on-the-spot rapid calibration method of the ellipsoid hy- pothesis to obtain the zero bias, scale factor and non-orthogonal angle of the accelerometer first- ly. Then the installation error of the accelerometer was calibrated by the four-position method. The method is simple in the actual operation with no need for high-precision auxiliary equipment. The experimental results of the test platform show that the method can effectively improve the measurement data accuracy of three components, and can be applied to the calibration of the ac- celerometer in MIMU attitude measurement systems.