A modified ellipsoid calibration method for three-axis magnetometer based on anisotropic magnetoresistive sensors

Calibration is essential to three-axis magnetometers in most applications. Typically, ellipsoid calibration method considers a sensor’s positive sensitive directions along its geometric axes as default, which may lead to inaccurate in sensitivities and misalignments. In this work, we propose a modified ellipsoid calibration algorithm to eliminate such indeterminacy. A three-axis magnetometer comprised of anisotropic magnetoresistive sensors and 3D printed structure was calibrated to prove the effectiveness of proposed method. And it realized 1.68° and 3.94° average errors of azimuth and elevation, respectively, for spatial DC magnetic field angle detection. Also, we demonstrate a two-step method for angle resolving, and a Monte Carlo simulation method for calibration performance prediction based on uncertainties. The proposed method reveals significant potential for calibration and evaluation of three-axis magnetometers.