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Precise Orbit Determination

The Envisat Precise Orbit Determination (POD) is performed by the Navigation Support Office (OPS-GN) at the European Space Operations Centre (ESOC). The Navigation Support Office generates two different precise orbits for Envisat. The first is a fast delivery orbit (FD) and is based on SLR and Altimeter data and has a delay of 36 hours. This orbit is used for the comparison with the operational orbit, the CNES MOE orbit and the near real time monitoring of the Envisat Altimeter (RA-2). The second precise orbit (POD) is based on SLR and Doris and has a delay of 6-9 weeks (depending on when the Doris data becomes available). This orbit is used in the comparison with the CNES precise orbit (POE) and to generate the Doris and SLR statistics available on this page.