Many applications in Wireless Sensor Networks (WSN) require some knowledge of the node locations, such as data stamping, data routing and mobile tracking. In a small deployment, it is possible to configure nodes with their locations, but in a large-scale deployment or when the nodes are mobile, the use of GPS becomes very interesting. The standard civil GPS is used for different applications but its current accuracy is not sufficient for all these applications because its measurements suffer from many errors especially in city. To improve its accuracy the differential (DGPS) mode has been introduced. In this paper we present a new DGPS solution based on using a set of low cost standard civil GPS communicating receivers. We present the design, implementation and some experimental results of this solution.