Geomagnetic Compensation for the Rotating of Magnetometer Array During Magnetic Tracking

Based on a permanent magnet and a magnetometer array, magnetic tracking approach has some advantages such as wireless, real-time, and no line-of-sight problem. However, its tracking accuracy will be greatly deteriorated by the magnetometer array's rotating during the tracking process. The reason lies in the relative variation of triaxial geomagnetic components, which should be calibrated before the tracking process. In this paper, we proposed an inertial sensor-based geomagnetic compensation method to reduce the intervention of the triaxial geomagnetic components for the magnetic tracking performance. An inertial measurement unit, which is situated on the magnetometer array, can capture the triaxial rotation of the magnetometer array in real time. As the vector sum of the triaxial geomagnetic components is constant, the rotation vector of the magnetometer array can be converted to the variation of the triaxial geomagnetic components. Thus, the triaxial geomagnetic components, which are included in the magnetometer outputs, can be separated from the sensing signals of permanent magnet even if the magnetometer array is rotating. The experimental results indicate that the magnetic tracking accuracy has been significantly improved. This method extends the application scope of the magnetic tracking approach because it enables both the magnetometer array and magnet to rotate during the tracking process.