CoAuthors

Nikita Zelensky (SGT Inc., U.S.A.); Brian Beckley (SGT Inc., USA); Pierre Exertier (Observatoire de la Côte d’Azur, France); Douglas Chinn (SGT Inc., U.S.A.); Despina Pavlis (SGT Inc., U.S.A.); Jean-Paul Boy (EOST/IPGS, Université de Strasbourg, France)

Orbit error remains a major component in the overall error budget of all altimeter satellite missions. Error sources include terrestrial reference frame and station positions, systematic and unaccounted-for errors in the satellite tracking measurements, mismodeling of nonconservative forces, and incomplete modeling of time-variable gravity. This paper presents our choice of ITRF2014-based complements from among the other 2014 ITRS realizations, resulting in a complete and consistent time series of improved orbits from TOPEX/Poseidon to Jason-3. The altimeter measurement calibration with tide gauges is shown, and the GSFC orbits are compared with orbits from other analysis centers, including the CNES, JPL, ESA and the GFZ. We also characterize the errors due to epoch time corrections in SLR data derived from Jason-2/T2L2, orbit mis-centering and atmospheric pressure loading, the current IERS pole tide model, and incomplete application of time-varying gravity. Plans for updating our POD standards are discussed.