A current location updating display for indicating the current location of moving members such as an automobile while updating from time to time based on output from a magnetic azimuth sensor adapted to detect the azimuth of terrestrial magnetism. Output signals from the magnetic azimuth sensor are stored...http://www.google.de/patents/US4673878?utm_source=gb-gplus-sharePatent US4673878 - Vehicle location display device with averaging means for correcting location information
