Impact of tidal loading and range bias on Galileo orbit using satellite laser ranging system

Satellite laser ranging (SLR) is one of the main space geodetic techniques and provides an independent ranging measurement at millimeter-accuracy level as compared to Global Navigation Satellite System (GNSS). The SLR can be used to assess a long-term time series of the satellite orbit accuracy and other geophysical parameters, e.g., realization of International Terrestrial Reference Frame. This study utilizes the SLR measurements, called normal points, to validate the Galileo satellite orbit and assesses the impact of tide loading effect, including ocean tide loading (OTL) and atmospheric tidal loading (ATL), on SLR residuals. Here the SLR residual is defined as difference between the satellite-station distance and the SLR measurement. Furthermore, we also assess the impact of range bias (RGB) estimation on the SLR residuals. The SLR normal points from Galileo satellite were collected from September 2019 to May 2022, together with the precise ephemeris, earth rotation parameters, OTL, ATL and RGB. The Bernese software is used to process the SLR normal points in this work. We design three different solutions, termed Solution A, Solution B and Solution C, where the existence and non-existence of the tide loading correction and the RGB estimation are dominated.