MAG.I.C.AL.–A Unified Methodology for Magnetic and Inertial Sensors Calibration and Alignment

Abstract

This paper introduces the MAGnetometer-Inertial sensors Calibration and ALignment (MAG.I.C.AL.) methodology for unified calibration and joint axes alignment of three-axis magnetometer, three-axis accelerometer, and three-axis gyroscope. MAG.I.C.AL. compensates for all linear time-invariant distortions such as scale-factor, cross-coupling, and offset, including the soft-iron and hard-iron distortions of the magnetometer. It introduces a new, computationally efficient, least-squares-based iterative algorithm for the calibration of the magnetometer and the accelerometer. It aligns their axes and introduces a new way to calibrate the gyroscope based on their joint data. MAG.I.C.AL. is implemented in a 15-step sequence achieving fast convergence and high accuracy without using any external piece of equipment and without requiring external attitude references. Simulation and experimental results using low-cost sensors are presented to support the accuracy, efficiency, and the applications of the algorithm.