ERS-1 and ERS-2 tandem mission: Orbit determination, prediction and maintenance

After a short summary of the successful orbit operations during the ERS-2 Launch and Early Orbit Phase, the transition to and implementation of the tandem mission for the two satellites is described, including a comparison of the required and achieved ground track spacing. The new implementation of the routine operational and precise orbit determination and prediction systems is presented briefly, and an estimate of the current orbit prediction and determination accuracy is given. These statistics include tracking data residuals, comparison between routine and precise orbits, comparisons with the D-PAF preliminary orbit solutions, and routine orbit prediction accuracy. Some geophysical results from the altimeter data, obtained in the precise orbit determination, are presented, with special attention to the calibration of the ERS-2 instrument. This paper also introduces the information presented on the Near-Earth Navigation and Geodesy Section's WWW pages on the Internet, where information about the routine and precise orbit determination for ERS-1 and ERS-2 is updated on a daily to weekly basis. Finally, some first results of the ERS-2 PRARE data processing at ESOC are presented. (C) 1997 COSPAR. Published by Elsevier Science Ltd.