Characterization of Galileo yaw attitude on tidal loading and range bias in SLR-based orbit validation

Abstract

Satellite laser ranging (SLR) has been widely used for satellite orbit validation. SLR residual is defined as the difference between the satellite-station distance and the SLR ranging measurement. The SLR residual not only indicates the satellite orbit accuracy but also implies the force mis-modeling left from satellite orbit determination. We characterize satellite yaw attitude on the SLR residual of the Galileo orbit in terms of the tidal loading effect and the range bias estimated in the procedure of orbit validation. The attitude characterization is defined as the slope of the SLR residual as a function of the elongation angle, which is formed by the sun elevation with respect to the orbital plane and the difference in the argument of latitude of the satellite with respect to the sun. We find that the yaw attitude is insensitive to the surface deformation caused by the tidal loading due to the slight change in slope from − 0.0106 to − 0.0117 cm/°. However, this is not the case for the range bias estimated in the orbit validation procedure. The slope of the SLR residual is changed from − 0.0106 to − 0.0014 cm/° when the range bias is estimated. This indicates that the range bias is specific to the satellite yaw attitude, in particular for the beta angle less than 20°. In addition, the range bias has a relatively high dependency on the force mis-modeling, as compared to the tidal loading. This suggests that the yaw-related force mis-modeling shall be considered in the estimation of the range bias for the Galileo satellites. This work can serve as a reference for assessing the characterization of satellite yaw attitude on the tidal loading effect and the range bias estimated in the satellite orbit validation using SLR.