New method for magnetometers based orientation estimation

Low cost magnetometers can be used for estimating the orientation with respect to the magnetic North. Although magnetometers work very well in clean magnetic environments like in the outdoors, they are strongly influenced by magnetic perturbations produced by manmade infrastructure in the indoors. Calibration techniques exist that can be used to compensate for these perturbations only if they are constant and associated with the navigation platform itself. But in the indoors, these perturbations vary spatially and render the previously available calibration techniques useless. In this paper, we present a new calibration technique that can be used to compensate for the varying magnetic perturbations on the host platform with better accuracy. Based on this new calibration algorithm, magnetic heading is estimated using multiple magnetometers mounted in a special geometric arrangement. Results show that the new calibration technique and heading computation successfully estimate the cumulative effects of perturbations and gives a better orientation estimate as compared with previous work.