Calibration of three-axis fluxgate magnetometers with nonlinear least square method

• Published in: Measurement : journal of the International Measurement Confederation Vol. 46; no. 4; pp. 1600 - 1606
• Main Authors: Pang, Hongfeng, Li, Ji, Chen, Dixiang, Pan, Mengchun, Luo, Shitu, Zhang, Qi, Luo, Feilu
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.05.2013
• Subjects: Nonlinear least square; Nonmagnetic rotation equipment; Three-axis magnetometers; Two-step algorithm; Unscented Kalman filter; Three-axis magnetometers; Nonmagnetic rotation equipment; Nonlinear least square; Two-step algorithm; Unscented Kalman filter
• ISSN: 0263-2241; 1873-412X
• DOI: 10.1016/j.measurement.2012.11.001

► Nonlinear least square was proposed for three-axis magnetometers calibration. ► The 36 points measurement strategy using nonmagnetic rotation equipment was designed. ► The proposed method is more effective than UKF and two-step algorithm. ► The proposed method is more convenient compared with UKF and two-step algorithm. ► The accuracy of a DM magnetometer and MAG3300 magnetometer are improved. The accuracy of three-axis magnetometers is limited by different scales, bias of each axis and nonorthogonality between axes, which is usually lower than that of scalar magnetometers. In this paper, the nonlinear least square method is proposed to calibrate three-axis magnetometers. The validity of this method was proved by simulation, in which the estimated parameters of the error model are close to prearranged parameters. In experiment, a three-axis fluxgate magnetometer (DM-050), a two dimensional nonmagnetic rotation equipment and a proton magnetometer (GSM-19T) were used. The scalar value of magnetic field was obtained by proton magnetometer and considered to be the true value. The calibration performance of unscented Kalman filter (UKF), two-step algorithm and nonlinear least square were compared. Experimental results show that the error average and standard deviation of nonlinear least square are the least among the three methods. After calibration, the average of scalar error is reduced from −76.2nT to −0.00093nT and the standard deviation is reduced from 10.832nT to 4.298nT. The results suggest an effective way for the calibration of three-axis fluxgate magnetometers.