A Stable Adaptive Observer for Hard-Iron and Soft-Iron Bias Calibration and Compensation for Two-Axis Magnetometers: Theory and Experimental Evaluation
A Stable Adaptive Observer for Hard-Iron and Soft-Iron Bias Calibration and Compensation for Two-Axis Magnetometers: Theory and Experimental Evaluation
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DOI：
10.1109/lra.2020.2967308
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发表时间：
2020-04
影响因子：
5.2
通讯作者：
Andrew R. Spielvogel;L. Whitcomb
中科院分区：
文献类型：
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作者：
Andrew R. Spielvogel;L. Whitcomb
这封信解决的问题，在线估计和补偿的硬铁和软铁偏置下的动态运动的2轴磁力计，仅利用偏置测量从2轴磁力计。所提出的自适应观测器将真实磁场矢量和磁强计测量值之间的关系表示为一个代数系统，其中未知偏差线性进入。观测器是全局稳定的。当磁强计测量持续激励（PE），系统被证明是全局渐近稳定的，和偏差收敛到它们的真实值。估计的偏差被用来提供一个校准的磁场方向矢量，该矢量被用来估计磁大地航向。自适应观测器进行了评估，在数值模拟和全尺寸的车辆试验。提议的观察员：$（i）$的仪器姿态的知识是不需要传感器偏差估计，$（ii）$零的先验知识的本地磁场矢量大小或矢量方向是必要的，$（iii）$的系统被证明是全局稳定的，$（iv）$的误差系统被证明是全局渐近稳定时，所测量的磁强计信号是PE。$（v）$磁力计硬铁和软铁偏差补偿被证明可以显著提高动态航向估计精度。
This letter addresses the problem of on-line estimation and compensation of the hard-iron and soft-iron biases of a 2-axis magnetometer under dynamic motion, utilizing only biased measurements from a 2-axis magnetometer. The proposed adaptive observer formulates the relation between the true magnetic field vector and the magnetometer measurements as an algebraic system where the unknown biases enter linearly. The observer is shown to be globally stable. When the magnetometer measurements are persistently exciting (PE), the system is shown to be globally asymptotically stable, and the biases are shown to converge to their true values. The estimated biases are used to provide a calibrated magnetic field direction vector which is utilized to estimate magnetic geodetic heading. The adaptive observer is evaluated in a numerical simulation and a full-scale vehicle trial. For the proposed observer: $(i)$ knowledge of the instrument attitude is not required for sensor bias estimation, $(ii)$ zero a priori knowledge of the local magnetic field vector magnitude or vector direction is needed, $(iii)$ the system is shown to be globally stable, $(iv)$ the error system is shown to be globally asymptotically stable when the measured magnetometer signal is PE. $(v)$ magnetometer hard-iron and soft-iron bias compensation is shown to dramatically improve dynamic heading estimation accuracy.