An electronic compass (10) having at least two sense windings (11, 12) is mounted in a vehicle. The outputs (x(h), y(h)) of the windings are measured for a number of compass directions (headings). From this data an error difference angle (.phi.), from a nominal angle, which actually exists between the...http://www.google.com.tw/patents/US5287295?utm_source=gb-gplus-share專利 US5287295 - Method and apparatus for calibrating an electronic compass to account for alignment errors in the compass windings
