GNSS广播星历轨道空间基准性能评估OA

Currently,there is still a lack of long-term systematic monitoring of broadcast ephemeris or-bit frames for multi-GNSS systems.We systematically investigate the long-term performance of the spatial reference frame for broadcast ephemeris orbits of the four GNSS satellite navigation systems(BDS-3,GPS,GLONASS,and Galileo)based on Helmert seven-parameter transformations between broadcast ephemeris and precise orbits,and the derived root sum squares(RSS)comprehensive index,as well as BDS-3/GLONASS analysis results from the data exchanged with the TsNIIMash,Russia,covering the period from August 2020 to December 2024.The results show that Galileo orbit demonstrates the best overall stability in realizing the spatial frame,with a RSS 7-parameter value of approximately 4.7-5.2 cm,following by GPS and BDS-3(7.7-9.0/7.5-13.8 cm),while GLONASS has an uncertainty of 19.9-23.3 cm.Among the four systems,the Z-component of Helmert transla-tion parameters for GPS,Galileo,and BDS-3 all exhibit significant annual periodic variations,which are likely related to deficiencies in the solar radiation pressure models used during orbit determination.Since the optimization of the Earth orientation parameters(EOP)update strategy in 2023,the BDS-3 system has shown a significant improvement in orbit frame maintenance accuracy,with the fluctua-tions of rotation parametersRX/Ry/Rz components reduced from±6/±8/±8 mas to±2/±4/±3 mas,and the overall frame accuracy clearly improved,as RMS of RSS7 decreased from 12.2 cm to 7.5 cm.This finding is consistent with the analysis results from TsNIIMash.