Abstract: Systems and methods for correcting experienced EM fields measured at each of one or more EM trackers of an EM tracking system as such measurements are influenced by a known distorter are disclosed herein. An EM emitter may transmit an EM field such that it contains the one or more EM trackers. The system then determines a pose of a distorter within the EM field. The system receives, from each EM tracker, data representing experienced EM fields as distorted by a distortion field caused by the distorter. The system proceeds to determine the distortion field using the pose and a model comprising one or more characteristics of the distorter. The system may first optimize the model. The system calculates data representing corresponding corrected experienced EM fields based on each respective experienced EM field and the determined distortion field at the same location.