aiden-wei / magnetometer_calibration

This repository contains a platformio library and an explanatory jupyter notebook for calculating the hard and soft iron offsets of an magnetometer.

Magnetometer_Calibration

This repository contains a platformio library and an explanatory jupyter notebook for calculating the hard and soft iron offsets of an magnetometer as descriped in Calibrating an eCompass in the Presence of Hard- and Soft-Iron Interference by NXP.

Jupyter notebook

Simply run jupyter notebook int his folder to start jupyter. Then open the mag_calibration notebook. There you find all informations needed.

C++ implementation

This implementation depends on Eigen. For platform.io projects you can use Eigen_Platformio_Header.

Usage:

#define NO_CALIBRATION_MEASUREMENTS 5000
Eigen::Array<float, NO_CALIBRATION_MEASUREMENTS, 1> mxs;
Eigen::Array<float, NO_CALIBRATION_MEASUREMENTS, 1> mys;
Eigen::Array<float, NO_CALIBRATION_MEASUREMENTS, 1> mzs;
Eigen::Array<float, NO_CALIBRATION_MEASUREMENTS, 1> rolls;
Eigen::Array<float, NO_CALIBRATION_MEASUREMENTS, 1> pitchs;

// Fill measurement arrays

Magnetometer_Calibration mag_cal;
mag_cal.calibrate(mxs, mys, mzs, rolls, pitchs);
Winv = mag_cal.getWinv();
W = mag_cal.getW();
V = mag_cal.getV();
B = mag_cal.getB();
incl = mag_cal.getInclination();