Abstract
Abstract. In the framework of the COmbination Service for Time-variable Gravity fields (COST-G) gravity field solutions from different analysis centres are combined to provide a consolidated solution of improved quality and robustness to the user. As in many other satellite-related sciences, the correct application of background models plays a crucial role in gravity field determination. Therefore, we publish a set of data of various commonly used forces in orbit and gravity field modelling (Earth's gravity field, tides etc.) evaluated along a one day orbit arc of GRACE, together with auxiliary data to enable easy comparisons. The benchmark data is compiled with the GROOPS software by the Institute of Geodesy (IfG) at Graz University of Technology. It is intended to be used as a reference data set and provides the opportunity to test the implementation of these models at various institutions involved in orbit and gravity field determination from satellite tracking data. In view of the COST-G GRACE and GRACE Follow-On gravity field combinations, we document the outcome of the comparison of the background force models for the Bernese GNSS software from AIUB (Astronomical Institute, University of Bern), the EPOS software of the German Research Centre for Geosciences (GFZ), the GINS software, developed and maintained by the Groupe de Recherche de Géodésie Spatiale (GRGS), the GRACE-SIGMA software of the Leibniz University of Hannover (LUH) and the GRASP software also developed at LUH. We consider differences in the force modelling for GRACE (-FO) which are one order of magnitude smaller than the accelerometer noise of about 10−10 m s−2 to be negligible and formulate this as a benchmark for new analysis centres, which are interested to contribute to the COST-G initiative.
Highlights
The correct application of background models plays a crucial role in many satellite-related sciences, such as orbit and gravity field determination
To show the results of the software comparison for all provided force models, we evaluate all force models with the Bernese GNSS software and compute the norm of the difference vector between the benchmark accelerations and the accelerations from Bernese
The limit for the difference in evaluating the models along the reference orbit was set to 10−11 m s−2, at least one order of magnitude lower than the accelerometer noise in the high-precision axes of GRACE (Touboul et al, 1999)
Summary
The correct application of background models plays a crucial role in many satellite-related sciences, such as orbit and gravity field determination. We took the opportunity to test several software packages available within the COST-G consortium, which are the Bernese GNSS software (Dach et al, 2015) from AIUB (Astronomical Institute, University of Bern), EPOS (Zhu et al, 2004) of the German Research Centre for Geosciences (GFZ), the GINS software, developed and maintained by the Groupe de Recherche de Géodésie Spatiale (GRGS), the GRACE-SIGMA (Koch et al, 2020) software of the Leibniz University of Hannover (LUH) and the GRASP software (Weigelt et al, 2013) from LUH We use this reference data to set a benchmark for new analysis centres, which are interested to contribute to the COST-G initiative.
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