Estimating surface optical properties and thermal thrust for Galileo satellite body and solar panels

Abstract Precise orbit determination of GNSS (Global Navigation Satellite System) satellites requires accurate models perturbing forces acting on the spacecraft, i.e., solar radiation pressure (SRP) and thermal forces. With officially published satellite metadata, analytical box-wing model is usually used to describe most SRP accelerations rest assumed be compensated by estimating ECOM/ECOM2 (Empirical CODE Orbit Model) parameters. However, we find that precision Galileo orbits shows notable degradation inside eclipse seasons for 3-day-arc solutions 24-h predictions. For instance, RMS (root-mean-square) misclosures increases about a factor two in season when using as priori 5-parameter ECOM top. The reason proven mostly due ignoring imbalanced (i.e., radiator emission panels) properties are unknown. These effects cannot fully absorbed parameters because earth’s shadowing causes periodic changes environment. To cope with this problem, first estimate optical part based tracking data covering 1 year. Then, add physical radiators panels evaluate performance different determination. As shown misclosures, predictions SLR (Satellite Laser Ranging) residuals, 7-parameter ECOM2 performs better than 9-parameter satellites. When top, impact 2 cm, respectively, solutions.