Tensor coaxial calibration of magnetic sensor array

In order to effectively solve the influence of the magnetic sensor array error caused by axial inconsistency on the measurement accuracy, an array composed of four fluxgate sensors is built by using the Euler rotation matrix, and the consistency correction is carried out. Firstly, aiming at the non orthogonal, scale factor, zero bias and other error factors of the sensor itself, a 9-PARAMETER correction coefficient matrix is constructed to compensate the non orthogonal magnetic field measurement of the sensor, and the ideal orthogonal three component magnetic field measurement value is obtained. On the above-mentioned basis, the reference sensor in the magnetometry array is selected, and the roll, pitch and azimuth of the sensor to be calibrated are transformed to establish the Euler rotation matrix, and the model for 9-PARAMETER consistency correction is constructed. The reference sensor and the sensor to be calibrated are placed on the magnetic gradiometer for experimental verification. The experimental results show that the root mean square error of magnetic field measurement is within 10 nT after the sensor measurement error compensation correction, and the angle error of each axis measurement is within 0.01åfter the consistency correction (4.22 nT). It shows that the magnetic field measurement values of different measuring points in the sensor array can be well projected on the coordinate axis of the reference sensor after correction, and the magnetic field information of the measuring points can be correctly projected, which has high reliability. 为了有效解决磁强计阵列由于轴向不一致引起的误差对测量精度造成的影响，搭建由4个磁通门磁强计构成的阵列，利用欧拉旋转矩阵对其进行一致性校正。针对磁强计自身存在的非正交、刻度因子、零偏等误差影响因素，构建九参数校正系数矩阵对磁强计的磁场测量进行非正交补偿校正，得到理想正交的三分量磁场测量值。在此基础上选定测磁阵列中的参考磁强计，对待校正磁强计进行横倾、俯仰、方位3种姿态变换建立欧拉旋转矩阵，构建九参数一致性校正模型。并把参考磁强计与待校正磁强计置于无磁转台上进行实验验证。实验结果表明，经过磁强计测量误差补偿校正后，磁场测量均方根误差在10 nT以内，经过一致性校正后，各轴测量角度误差在0.01°(4.22 nT)以下。说明经过校正后磁强计阵列中不同测量点的磁强计磁场测量值可以很好地投影到基准磁强计的坐标轴上，并且可以正确放映测量点的磁场信息，具有很高的可靠性。