CoAuthors

Flavien Mercier (CNES, France); Sabine Houry (CNES, France); John Moyard (CNES, France); Eva Jalabert (CNES, France); Silvia Rios-Bergantinos (CS SI, France)

The SARAL satellite (CNES/ISRO) extends the time series of centimeter-level ocean topography observations, being complementary to the reference Ocean Surface Topography Mission/Jason-2 satellite, and flying on the same ground-track as the former ERS-1/2 and ENVISAT satellites.
This talk will review the status of the Precision Orbit Determination (POD) activities for SARAL GDR (version D) orbits. As the satellite has been in orbit for more than 1.5 years (since February 2013), it provides an opportunity to focus on the long-term stability of the orbit solutions. In particular long-term variations of the geopotential are still one of the largest remaining sources of orbit error. Thus we will focus on the impact of the time-varying gravity field on the geographically correlated errors that are of interest for the altimeter analyst. We will also give an overview of the performance of the tracking systems (DORIS and SLR), and discuss prospects for improvements including improved force modeling that could be used in the next GDR orbit standards.