Robust Autocalibration of Triaxial Magnetometers

• Published in: IEEE transactions on instrumentation and measurement Vol. 70; pp. 1 - 12
• Main Authors: Hong, Je Hyeong, Kang, Donghoon, Kim, Ig-Jae
• Format: Journal Article
• Language: English
• Published: New York IEEE 2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Accelerometer; Accelerometers; Anomalies; Calibration; Convexity; Ellipsoids; Elliptic fitting; Estimation error; Magnetic disturbances; magnetometer; Magnetometers; Mathematical model; nonlinear least squares; Optimization; Outliers (statistics); robust optimization; Robustness; Self calibration; Three axis; Time measurement
• ISSN: 0018-9456; 1557-9662
• DOI: 10.1109/TIM.2020.3035184

Self-calibration of a magnetometer usually requires controlled magnetic environment as the calibration output can be affected by field distortions from nearby magnetic objects. In this article, we develop a two-stage method that can accurately self-calibrate magnetometer from measurements containing anomalous readings due to local magnetic disturbances. The method proceeds by robustly fitting an ellipsoid to measurement data via L 1 -norm convex optimization, yielding initial model variables that are less prone to magnetic disruptions. These are then served as a starting point for robust nonlinear least-squares optimization, which refines the magnetometer model to minimize sensor estimation errors while suppressing heavy anomalies. Synthetic and real experimental results are provided to demonstrate improved accuracy of the proposed method in the presence of outliers. We additionally show empirically that the method is directly applicable to self-calibration of three-axis accelerometers.