The SLR observations to GNSS satellites: Preliminary results and open questions

In the present study, we show the results of the multi-year processing of SLR observations to GNSS satellites (both for GPS and GLONASS satellites), using the Bernese GNSS Software. The aim of the study is to investigate the associated SLR range residuals, defined as the differences between: (a) the observed SLR ranges and (b) the computed spatial distances between the ground stations and the GNSS (precise) orbits, respectively. The residuals are estimated on daily basis, taking into account inter alia, the Non Tidal Atmospheric Loading (NTAL) and the Atmospheric Ocean De-aliasing (AOD) effect. The results indicate different biases for the GPS and GLONASS satellites and show remarkable variability among the ground stations