A new explanation on Carrier Phase DGPS being used in GPS survey is given in this paper. In order to easily understand the essentials of the technique, Carrier Phase DGPS in two-dimensional space is firstly described concretely, and then actual case (three-dimensional space) is introduced briefly. The explanation is begun with an ideal case such as achievement of synchronization among receivers, and then real conditions are added. It is also proven that the new explanation is very effective for undrestanding on new applications of GPS, including RTK-GPS and VRS.
