This review paper explores the most common technologies of vector magnetic field sensors. Specifically, the AMR, GMR, TMR, GMI, Hall, Fluxgate, Search Coil and SQUID sensors are considered. The physical phenomena that permit their operation as well as the structure and operating principles of each sensor are presented. In addition, the basic linear, time-invariant error sources of magnetic sensors are described along with some popular calibration techniques. Finally, some representative application examples of each sensor are described.

This work introduces the MAGnetometer - Inertial sensors Calibration and ALignment (MAG.I.C.AL.) methodology for unified calibration and joint axes alignment of 3-axis magnetometer, 3-axis accelerometer and 3-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 application of the algorithm.

The calibration of three-axis magnetic field sensors is reviewed. Seven representative algorithms for in-situ calibration of magnetic field sensors without requiring any special piece of equipment are reviewed. The algorithms are presented in a user friendly, directly applicable step-by-step form, and are compared in terms of accuracy, computational efficiency and robustness using both real sensors’ data and artificial data with known sensor’s measurement distortion.

In this work, we propose an algorithm for joint calibration and axes alignment of a 3-axis accelerometer and a 3-axis magnetometer. The proposed algorithm applies when the two sensors are fixed on the same rigid platform. It achieves accurate calibration without requiring any external piece of equipment like a turntable for the accelerometer or Gauss magnetic chamber and Maxwell coils setup for the magnetometer. The efficiency and accuracy of the proposed algorithm are evaluated using experimental data.

In this work we introduce a computationally efficient algorithm for simultaneous joint calibration and axes alignment of multiple 3-axis accelerometers or 3-axis magnetometers. The proposed algorithm applies to ensembles of multiple sensors of the same type, fixed to the same rigid platform. It 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 can be implemented in a simple 12-step sequence and provides fast and accurate calibration without requiring any special piece of equipment.

A computationally efficient algorithm for axes alignment of a 3-axis accelerometer and a 3-axis magnetometer is introduced. The proposed algorithm applies when the two sensors are fixed on the same rigid platform and individually calibrated. It exploits the magnetic inclination phenomenon to derive both the inclination angle, and, the axes alignment rotation matrix. It is more than 50 times faster than the existing algorithms based on the same principle and using the Newton-Raphson or the gradient descent methods. The algorithm’s accuracy and computational efficiency are demonstrated using multiple measurement sets as well as simulated data sets.