Earth rotation parameters from GPS and BDS: Contributions from MEO and IGSO satellites

Abstract

The Earth Rotation Parameters (ERPs) are fundamental transformation parameters to link the celestial reference frame and Earth-fixed reference frame. Global Navigation Satellite System (GNSS) is one of the key technologies to determine the ERPs and BeiDou Navigation Satellite System (BDS) has been constructed completely in 2020. In this study, we present a 2.5-years (01/2020–06/2022) results of the ERPs determination based on the GPS, global BDS (BDS-3), the regional BDS (BDS-2) combined BDS-3 (as BDS solution), Medium Earth Orbit (MEO)-only BDS (BDS-M) and the GPS combined BDS (GC). We take the IERS 14C04 products as reference to evaluate the accuracy of the ERPs estimates. The results of 3-day arc solution show that (1) compared to the estimates based on GPS solution, the GC combined solution achieves an improvement of 1 %, 7 %, 12 %, 3 % and 5 % for X and Y pole coordinates, X and Y pole coordinate rates and LOD, respectively. In detail, for GC solution, the standard deviation (STD) is 62.9 and 57.4 μas for X and Y pole coordinates, 81.3 and 85.7 μas/d for X and Y pole coordinate rates, 7.8 μs/d for LOD. (2) the STD of BDS solution is 86.2 μas, 79.9 μas, 118.9 μas/d , 111.5 μas/d , and 11.8 μs/d for pole coordinates, their rates and LOD, which has an improvement of 10 %, 3 % for pole coordinates, 5 %, 5 % for pole coordinate rates than BDS-3 and BDS-M solutions, respectively. In terms of the STD for LOD, the BDS solution leads to a decrease about 5 % comparing with BDS-3 solution but has little difference with BDS-M solution. (3) From the point view of spectrum analysis, comparing with those from BDS-3 and BDS-M, the spurious signals in the ERPs estimates derived from BDS can be reduced, demonstrating the superior contribution of BDS-2 and IGSO satellites. The GC combination and 3-day arc solution are proved to further mitigate the artificial signals.