BDS载波相位时频传递性能分析

Performance Analysis of BDS Carrier Phase Time and Frequency Transfer at KARR and PTVL

采用GFZ精密卫星轨道、钟差和MGEX测站观测数据,分析BDS载波相位时频传递性能。在KARR站BDS可视卫星数较多(平均为10.1颗)时,BDS时间传递精度为0.2ns,与GPS、GLONASS相当;在PTVL站BDS可视卫星较少(平均为6.9颗)时,平均TDOP为3.5,大于GPS和GLONASS,其时间传递精度较低,仅为0.68ns,差于GPS和GLONASS。目前,由于BDS全球跟踪站有限,MEO卫星较少,BDS收敛时间长于GPS和GLONASS。两测站三系统频率传递结果和频率稳定度结果基本相当,变化趋势一致。因测站KARR、PTVL未配备高稳定度的原子钟作为外接频标,得到的频率传递精度和频率稳定度较差。

Adopting precise satellite orbits and clocks provided by GFZ, data from MGEX are pro- cessed to analyze the performance of BDS carrier phase time and frequency transfer. The results show that the accuracy of BDS time transfer is 0.2 ns when the average number of visible satellites is 10.1 at KARR, which is equivalent to GLONASS and GPS. When the average number of visible satellites is 6.9 at PTVL, the average TDOP is obviously bigger than GLONASS and GPS, and the accuracy of time transfer is only 0.68 ns, which is significantly worse than GLONASS and GPS. At present, BDS convergence time is significantly longer than GLONASS and GPS, due to the lack of global tracking stations and fewer MEO satellites. The frequency transfer result and frequency stability of the three systems are basically equivalent and have the same change trend. As the station KARR, PTVL is not equipped with atomic clocks, the frequency transfer results and frequency stability are relatively poor.