CoAuthors

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

As recommended by the 2014 OSTST meeting at Lake Constance, Germany,
the orbit-centering discrepancies between the different POD analysis centers
remain to be elucidated. Since the satellite orbit defines the reference frame
for the altimetric measurements, care must be taken to better understand
the nature and origin of the miscentering of the orbit.

While geocenter motion estimates from the DORIS stations network or the
GPS constellation agree reasonably well for their X and Y components with
those from SLR, they differ significantly in the Z direction. Also, the transfer
function to DORIS/GPS-based orbits of the current state-of-the-art seasonal
SLR CoM correction model is rather complex, especially as the actual variations
of the non-tidal geocenter motion may not only be limited to annual terms.

Thus, we will examine strategies to mitigate sensitivity to miscentering effects
on the orbit coming from the DORIS tracking measurements. Test orbits will be
calculated on different altimeter satellites to illustrate and validate this approach.