Distortion Magnetic Field Compensation of Geomagnetic Vector Measurement System Using a 3-D Helmholtz Coil

The magnetic interferential fields, such as soft-iron and hard-iron interferences, will seriously affect the accuracy of geomagnetic vector measurement system, and thus should be compensated. In this letter, a new compensation method using a 3-D Helmholtz coil is proposed. As a first step, the geomagnetic vector measurement system is exposed to different directions and the magnitudes of magnetic field generated by a 3-D Helmholtz coil to construct the equations of error model, and soft-iron parameters can be estimated by solving linear equations. Then, hard-iron parameters are estimated by changing the fixation direction of the three-axis magnetometer. Finally, all the estimated parameters are used for compensating distortion magnetic fields. In order to verify the effectiveness of the proposed method, the experiment is conducted, and the results demonstrate that the proposed method contributes to the accuracy improvement of geomagnetic vector measurement system.