Differential GPS positioning

The GPS satellite navigation system is capable of providing civil users with a horizontal positioning accuracy of 100 metres. As this is often inadequate for surveying or navigation, the differential GPS technique is used to improve positioning accuracy in a growing number of applications. The paper explains the differential GPS technique, outlines a typical differential GPS system and describes the procedure for computing position. In the latter part of the paper, the potential for the further development of differential GPS is reviewed and the applications described