Abstract
We have studied the simplified DGPS using two GPS receivers, and obtained from 1 to 10m accuracy of a point positioning. Applying the simplified DGPS to mobile positioning, it occurs that sufficient positioning accuracy couldn't be obtained because of the effect of surrounding obstacles. In this paper, we investigate and discuss few problems in the mobile positioning with simplified DGPS in city area. A strong relation between the changes of combination of satellites used for the positioning and its accuracy is comfirmed experimentally.
