Andel Ján, Šimák Vojtech, Kanálikova Alžbeta, Pirník Rastislav
Department of Control and Information Systems, Faculty of Electrical Engineering and Information Technology, University of Žilina, 010 26 Žilina, Slovakia.
Sensors (Basel). 2022 Nov 3;22(21):8447. doi: 10.3390/s22218447.
With the development of MEMS sensors, the magnetometer has increasingly become a part of various wearable devices. The magnetometer measures the intensity of the magnetic field in all three axes, resulting in a 3D vector-direction and power. Calibration must be done before using a magnetometer, especially in wearable electronics, due to the low quality of the sensor and high proximity to other electromagnetic emission sources. Several magnetometer calibration algorithms exist in the literature, with most of them requiring multi-sided rotation. However, such calibration is highly impractical when the sensor is mounted on larger objects, e.g., vehicles, which cannot easily be rotated. Vehicles contain a large amount of ferromagnetic soft and hard material that affects the measured magnetic field. A magnetometer can be useful for an INS system in a car as long as it does not drift over time. This article describes how to calibrate a magnetometer using the GNSS motion vector. The calibration is performed using data from the initial section of the vehicle's trajectory. The quality of the calibration is then validated using the remaining section of the trajectory, comparing the deviation between the azimuth obtained by GNSS and by the calibrated magnetometer. Based on the azimuth and speed of the vehicle, we predicted the position of the vehicle and plotted the prediction on the map. The experiment showed that such calibration is functional. The uncalibrated data were unusable due to the strong effect of ferromagnetic soft and hard materials in the vehicle.
随着微机电系统（MEMS）传感器的发展，磁力计越来越成为各种可穿戴设备的一部分。磁力计测量所有三个轴上的磁场强度，从而得到一个三维矢量方向和强度。由于传感器质量较低且靠近其他电磁辐射源，在使用磁力计之前，尤其是在可穿戴电子产品中，必须进行校准。文献中存在几种磁力计校准算法，其中大多数需要多面旋转。然而，当传感器安装在较大物体（如车辆）上时，这种校准非常不切实际，因为车辆不容易旋转。车辆包含大量影响测量磁场的铁磁软质和硬质材料。只要磁力计不会随时间漂移，它对汽车中的惯性导航系统（INS）就会很有用。本文描述了如何使用全球导航卫星系统（GNSS）运动矢量来校准磁力计。校准使用车辆轨迹初始段的数据进行。然后使用轨迹的其余部分验证校准质量，比较GNSS获得的方位角与校准后的磁力计获得的方位角之间的偏差。基于车辆的方位角和速度，我们预测了车辆的位置并将预测结果绘制在地图上。实验表明这种校准是有效的。由于车辆中铁磁软质和硬质材料的强烈影响，未校准的数据无法使用。
