Orthogonality Correction for Concentric Tri-axis Fluxgate Magnetometer

In this work, a compact tri-axis fluxgate magnetometer comprising a single magnetic core was implemented and the effectiveness of the orthogonality correction algorithm was demonstrated. The vector magnetometer consists of a tube-shaped soft magnetic flux chopper with a toroidal coil and three concentric pick-up coils. The tube-shaped flux chopper with magnet wires has the total dimension of 10 mm x 10 mm. The number of turns of the pick-up coils X-, Y-, and Z- are 110, 110 and 150, respectively. The center of flux chopper is also the geometric center of the three pick-up coils, of which the sensing directions are aligned along the Cartesian axes. The concentric design ensures a single field point for the three sensing axes. When using the tri-axis fluxgate magnetometer as an electronic compass, the geomagnetic field components converted from the demodulated outputs of the sensing coils shows high accuracy by using the voltage-to-field transfer matrix. The proposed fluxgate system is suitable for applications related to high-accuracy static magnetic field measurement, e.g. geomagnetic field monitoring, electronic compass, and magnetic field mapping.