Long-Term Analysis of Possible Remaining Sources of Orbit Error II

Alexandre Couhert (CNES, France)

CoAuthors

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

Event: 2014 Ocean Surface Topography Science Team Meeting

Session: Precision Orbit Determination

Presentation type: Type Poster

The error budget of the Jason GDR-D orbit solutions identified four main contributors to the long-term (seasonal to decadal time scales) radial orbit errors: non-tidal geocenter motion, atmospheric/hydrological loading, reference frame, and time-variable gravity. The first two contributions are not introduced in the current orbit standards, since there is no consensus model recommended in the IERS Conventions. Despite this, available models will be tested to provide a tentative explanation of degradations of residuals observed on well performing SLR stations, and differences in North/South centering between orbit solutions using different tracking techniques and/or parameterization. We will also compare orbits based on different GRACE monthly gravity field solutions (from the processing centers CSR, GFZ, JPL and CNES/GRGS) to better gauge their "internal" error, especially for the low degree and order terms. Additionally, estimating well-chosen spherical harmonics and station positions, making the most of the available tracking data on-board the satellites, and monitoring the differences between dynamic and reduced dynamic orbit solutions could help inferring an approximate "external" error budget of the previous models.
 
Alexandre Couhert
CNES
France
alexandre.couhert@cnes.fr