AbstractAsystemhas been developed, utilizing the Navy Navigation Satellites, which can provide azimuth information on a world wide basis. Two antennas, separated by 50 to 100 meters, are used in an interferometer configuration to make measurements of the received phase difference from the satellite as it passes overhead. From the data received during a single satellite pass it is possible to determine the azimuth of the baseline connecting the two antennas and their separation.This system, although useable world wide, is particularly useful in the polar regions for heading determination, where gyro compasses experience difficulties in alignment.