CoAuthors

Anton Reinhold (GFZ German Research Centre for Geosciences, Germany); Susanne Glaser (GFZ German Research Centre for Geosciences, Germany); Karl Hans Neumayer (GFZ German Research Centre for Geosciences, Germany)

Aside of GGOS-SIM, a German project aiming at simulating all space-geodetic techniques for the next generation of global Terrestrial Reference Frames (TRFs) in view of the objectives of the Global Geodetic Observing System (GGOS), we evaluate real Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) observations from the satellites JASON-1, JASON-2, and ENVISAT for the period 2008 to 2014. These missions are part of the ensemble of missions that was used for the contribution of the International DORIS Service (IDS) of the International Association of Geodesy (IAG) to the recent International TRF, the ITRF2014. As initially Precise Orbit Determination (POD) is performed with view on the use of the orbits in altimetry, in this study the objective is to generate weekly normal equations containing ground station positions and Earth Rotation Parameters (ERPs). Therefore it is necessary to change the arc length, the standards, and the parameter space. Eventually the weekly normal equations are accumulated and a DORIS-only TRF is determined. The estimates are evaluated with respect to solvability and accuracy. Finally the contribution of each mission, and the effect of estimating UT1 or not, can be quantified.