The Doris Satellite Radio Tracking System: Status and Plans

The goal of this paper is to present the status of the French DORIS system, the on-going developments and the plans for the future. The DORIS system is being developped by the combined efforts of three French groups: the CNES (Centre National d’Etudes Spatiales), the GRGS (Groupe de Recherche en Geodesie Spatiale) and the IGN (Institut Geographique National). DORIS is an acronym for Doppler Orbitography and Radiopositioning Integrated by satellite. Its main purpose is the precise orbit determination. Nevertheless, this system will also have significant positioning applications for geodesy and geophysics. This system is being built to be the nominal French system for orbit determination on the joint US-French oceanographic project TOPEX/POSEIDON planned for 1992.