Abstract: An apparatus and a method are described for determining with a high degree of accuracy the location of an object, based upon signals transmitted from a plurality of satellites rotating about the earth in known orbits. First, the latitude and longitude of a fixed point is determined with accuracy. The object is capable of moving with respect to the fixed point. Second, the satellite signals are received at the fixed point and processed to determine the approximate latitude and longitude of the fixed point. A first difference between the accurate and approximate latitudes is taken to provide a differential latitude correction of a magnitude corresponding to the first difference and of a direction to the north or south. A second difference between the accurate and approximate longitudes is also taken to provide a differential longitude correction of a magnitude corresponding to the second difference and of a direction to the west or east.