Ground based modeling and real time On-board calibration of a three axis magnetometer

This paper presents a dynamic and robust method to model and calibrate a three axis magnetometer. The STUDSAT-2 (STUDent SATellite-2) satellite uses a low cost three axis digital magneto resistive magnetometer. Low cost magnetometers can be used for estimating the orientation with respect to the magnetic North. Although magnetometers work very well in clean environment, they are strongly influenced by magnetic perturbations produced by the electronics around them. Modelling the biases and scale factors of the magnetic sensor is a viable solution to estimate the errors. The local geomagnetic field vector is measured with a magnetometer and by comparing it to a model of the earth´s magnetic field, an estimation of the attitude angles and angular rates can be made. A control torque to change the attitude of a satellite can be generated by a magnetic moment that interacts with the local geomagnetic field. On board calibration of the sensor helps in increasing the accuracy of spacecraft´s attitude.