时间频率学报

卫星差分码偏差产品能有效提升GNSS PPP授时性能。研究PPP-B2b播发的码间偏差(DCB)改正数、状态空间表述(SSR)产品中播发的绝对信号偏差(OSB)改正数对北斗三号B1C+B2a双频消电离层组合下的实时精密单点定位(PPP)单向授时以及时间比对的影响，实验结果表明，使用DCB/OSB改正后，PPP-B2b、CAS0和WHU0的单向授时标准差(STD)分别从1.94 ns、0.90 ns和0.91 ns提升至0.41 ns、0.56 ns和0.41 ns,峰峰值从6.36 ns、4.11 ns和3.41 ns提升至1.87 ns、3.17 ns和1.83 ns,万秒稳定度从9.54×10^-14、7.55×10^-14和6.35×10^-14提升至2.21×10^-14、3.75×10^-14和2.38×10^-14。短基线条件下，不修正DCB/OSB的单向授时结果呈现周期性波动，经过两台并址运行设备的站间差分之后可以消除周期性波动，所以DCB/OSB修正与否对时间比对的影响不明显，此时的STD均小于0.3 ns。

Satellite differential code bias products can effectively improve GNSS PPP timing performance.In this paper, we analyzed the effects of the differential code bias(DCB) corrections broadcast by PPP-B2b and the observable-specific bias(OSB) corrections in the state-space representation(SSR) products on the real-time precision point positioning(PPP) one-way timing and time transfer under the dual-frequency ionosphere-free combination model of the BDS-3 B1C+B2a.The experimental results showed that the standard deviation(STD) of one-way timing in PPP-B2b, CAS0,and WHU0 were increased from 1.94 ns, 0.90 ns, and 0.91 ns to 0.41 ns, 0.56 ns and 0.41 ns, the peak-to-peak values improved from 6.36 ns, 4.11 ns and 3.41 ns to 1.87 ns, 3.17 ns and 1.83 ns, and the 10 000 s ADEV of the one-way timing were improved from 9.54×10^-14,7.55×10^-14 and 6.35×10^-14 to 2.21×10^-14,3.57×10^-14 and 2.38×10^-14.Under the short baseline condition, the one-way timing of the two concurrent receivers without the DCB/OSB correction showed periodic fluctuations, which could be eliminated after the inter-station differencing, so the effect of DCB/OSB correction on the time transfer results was not obvious, and the STDs at this time were all less than 0.3 ns.