CHAMP is a German geoscience satellite. It was launched on July 15, 2000 from the Russian COSMODROME Plesetsk, Russia (62.50 N, 40.30 E) into an almost circular, near polar orbit with an initial altitude of 454 km (eccentricity=0.004, inclination=87.2�). The scientific project is under lead from GFZ. The main goals are the determination Earth's gravity and magnetic field and the application of the GPS Radio Occultation (RO) technique for precise atmospheric sounding on a global scale.
GPS RO measurements aboard CHAMP were activated for the first time on February 11, 2001, and indicated already the potential of CHAMP RO data to significantly improve the GPS occultation technique. Numerous scientific studies related to data processing and the scientific application of CHAMP's data have demonstrated this during the following years. Currently CHAMP data are in use by a large number of research groups throughout the world. The data were and are also used to prepare several satellite missions with GPS RO capability, as, e.g., COSMIC, Metop and others. CHAMP is generating the first and unique long-term set of GPS RO data, which is already used for climatological studies. Since 2006 the CHAMP data is also used to improve global weather forecasts. The base for this application is the near-real time provision of RO data from CHAMP by GFZ.