Abstract
For low Earth orbit (LEO) satellites, activities such as precise orbit determination, gravity field retrieval, and thermospheric density estimation from accelerometry require modeled accelerations due to radiation pressure. To overcome inconsistencies and better understand the propagation of modeling errors into estimates, we here suggest to extend the standard analytical LEO radiation pressure model with emphasis on removing systematic errors in time-dependent radiation data products for the Sun and the Earth. Our extended unified model of Earth radiation pressure accelerations is based on hourly CERES SYN1deg data of the Earth’s outgoing radiation combined with angular distribution models. We apply this approach to the GRACE (Gravity Recovery and Climate Experiment) data. Validations with 1 year of calibrated accelerometer measurements suggest that the proposed model extension reduces RMS fits between 5 and 27%, depending on how measurements were calibrated. In contrast, we find little changes when implementing, e.g., thermal reradiation or anisotropic reflection at the satellite’s surface. The refined model can be adopted to any satellite, but insufficient knowledge of geometry and in particular surface properties remains a limitation. In an inverse approach, we therefore parametrize various combinations of possible systematic errors to investigate estimability and understand correlations of remaining inconsistencies. Using GRACE-A accelerometry data, we solve for corrections of material coefficients and CERES fluxes separately over ocean and land. These results are encouraging and suggest that certain physical radiation pressure model parameters could indeed be determined from satellite accelerometry data.
Highlights
Interactions of photons and gas molecules with the surface of satellites lead to forces, which in turn cause orbit perturbations
For Gravity Recovery and Climate Experiment (GRACE), we found an average acceleration of about 3.7 × 10−8 m/s2 for solar radiation pressure (SRP) and 1.4 × 10−8 m/s2 for Earth radiation pressure (ERP) during January 2010
These models could aid in improving precise orbit determination (POD), gravity, and thermosphere recovery, but they could provide clues on systematic errors in radiation data products that we use in SRP and ERP modeling
Summary
Interactions of photons and gas molecules with the surface of satellites lead to forces, which in turn cause orbit perturbations. With increasing distance from the Earth’s surface, the acceleration due to Earth radiation pressure (ERP) becomes less relevant, whereas the effect of solar radiation pressure (SRP) becomes prevalent. Accurate modeling of these forces is required for precise orbit determination of GNSS satellites (Fliegel et al 1992; Rodríguez-Solano et al 2012; Arnold et al 2015; Steigenberger et al 2015; Darugna et al 2018; Bury et al 2019),. The accelerometer measurements onboard GRACE-D, which is the trailing satellite of the GRACE Follow-On mission launched in May 2018, are of lower quality as
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