DORIS: From orbit determination for altimeter missions to geodesy

In the late 1980s, the French ‘Centre national d’études spatiales' (CNES), in conjunction with the ‘Institut géographique national’ (IGN) and the ‘Groupe de recherche en géodésie spatiale’ (GRGS) developed a new geodetic tracking system called DORIS for precise orbit determination of low Earth orbiting satellites for oceanographic missions. Since then, the number of applications has increased, leading recently to the creation of an International DORIS Service (IDS), making it a part of the Global Geodetic Observation System (GGOS) currently under development within the International Association of Geodesy (IAG). The goal of this paper is to present the current applications of the DORIS system for precise orbit determination as well as for geodesy, geophysics, Earth rotation or atmospheric sciences. Current accuracies are discussed as well as already planned improvements. In particular, recent improvements in on-board real time orbit showing 5-cm radial agreement with post-processed orbits are discussed. In addition, when using a 5-satellite constellation, 1-cm precision is achievable for station position as well as sub milli-arcsecond precision for polar motion.