Correcting Distortions

A system comprising: a magnetic transmitter configured to generate magnetic fields; a magnetic sensor configured to generate signals based on characteristics of the magnetic fields; and one or more computer systems configured to: cause the magnetic transmitter to generate a first plurality of magnetic fields at a first frequency; receive a first plurality of signals from the magnetic sensor; determine data indicative of a position and orientation of the magnetic sensor at a first position of the magnetic sensor; determine a distortion term that corresponds to a first position of the magnetic sensor; cause the magnetic transmitter to generate a third plurality of magnetic fields at the first frequency; receive a third plurality of signals from the magnetic sensor; and determine a second position and orientation of the magnetic sensor relative to the magnetic transmitter, wherein the first frequency is greater than the second frequency. 一种系统，包括：磁发射器，其被配置为生成磁场；磁传感器，其被配置为基于所述磁场的特性来生成信号；以及一个或多个计算机系统，其被配置为：使所述磁发射器在