High precision altimetry from the Envisat mission

The paper will outline the orbit determination and associated activities planned at ESOC in the scope of flight dynamics support of the ESA Envisat mission. As a result of nearly a decade of experience with POD of ERS and TOPEX/Poseidon, Envisat will be able to build on a base of very accurate models. Of particular interest is the processing of altimetry to determine more accurate mean and dynamic sea surface topography models. The nearly complete coverage by precise DORIS tracking in zones of major interest like the Pacific Ocean will make it possible to compute more precise orbits where simultaneous tracking and altimetry were not available for the ERS spacecraft. To support the orbital operations (determination and control) of this satellite, ESOC is developing the NAvigation Package for Earth Observation Satellites (NAPEOS). The paper will conclude with a description of some salient aspects of this software package. (C) 1999 COSPAR. Published by Elsevier Science Ltd.