Abstract: Aiming at the current stage of BeiDou system in BDS-3+BDS-2 hybrid service and BDS-3 broadcasts B1C and B2a new frequency signals, a position datum coordinate transfer model based on BeiDou systemis proposed and a BDS position datum long-baseline coordinate transfer network based on B1I+B3I and B1C+B2a data is established for the application testing. Four IGS tracking stations in China and its surrounding areas that simultaneously support BDS-3+BDS-2 and GPS data as well as a fixed station are selected to lay a BDS position datum long-baseline coordinate transfer network.7 sessions of data based on 24 hour continuous observation from 096～102 in 2024 are selected and 4 experimental schemes are designed for data processing, and comparative analysis and evaluation are carried out in terms of the accuracy of phase observation values, post standardized root-mean-square error, quality of baseline vectors,and point results of datum transfer network adjustment.The experimental results show that different from L1+L2 dual-frequency data of GPS, the differences of datum transfer in point direction are both of only millimeter level using B1I+B3I dual-frequency data of BDS-3 and BDS-3+BDS-2, and millimeter to centimeter level using B1C+B2a dual-frequency data of BDS-3, which is effective to be applied to the long-baseline coordinates transfer for BeiDou high-precise position datum.

Key words: BeiDou system, position datum, baseline solving, network adjustment, dual-frequency data, long-baseline coordinate transfer network