We report a system for remote control and automatic management of a fleet of earth-moving and construction machines with assisted guidance in earthworks and road construction. The system can be divided into three segments: control segment, positioning segment, data transmission segment. The positioning segment is based on WAAS or classical DGPS techniques. The transmission segment consists of GSM and fixed telephone network modems. The 3D positions of the machines, calculated in real time, are sensed at the control segment, at the same time as the differential corrections, by a single device built for this application. The control segment is based on a computer and a skilled operator running GIS-CAD software which controls the working accuracy of the earth-moving or operating processes with respect to the planned profile of the works. Laboratory and field tests were carried out to simulate the working performance of the system: during the tests, the 3D positions were considered with differential corrections from the WAAS/EGNOS system and with DGPS RTCM differential corrections via Internet. In this paper, we describe the system architecture and the preliminary experimental results.