Precise tracking and orbit determination of ERS-1.

The application of the ERS-1 altimeter for investigating the global ocean circulation requires that the satellite's orbit, and in particular the radial position component, are known very accurately. Results are presented of orbit determination error analyses for 15 min, 2 revolution and 3 day data arcs, applying laser, Tranet and Prare tracking systems. For the center part of the short arc radial orbit errors of less than 10 cm are achievable. For the multirevolution arcs the global rms radial error is found to be about 0.6 m and is dominated by the gravity field model error contribution. Finally, the feasibility of applying the altimeter as a tracking device is discussed and orbit determination results are presented from the processing of actual Seasat altimeter data.