GPS/BDS三频信号频间时钟偏差估计与定位验证

在三频GNSS应用中，受精密产品频率基准不一致的影响，会引入系统性偏差，即频间时钟偏差（IFCB）。本文首先通过对IFGF组合观测值进行历元差分，利用全球分布的80个MGEX观测站及中国区域内100个连续运行参考站，在2021年年积日（DOY）153—160 d的实测数据，进行了IFCB的估计并分析了其时变特性；然后将IFCB的估计结果运用到非差非组合PPP中。结果表明：GPS BLOCK Ⅱ-F的IFCB较大，幅值可达14 cm，GPS BLOCK Ⅲ与BDS的IFCB则较小，一般不超过5 cm。在定位验证中，经过IFCB改正后，GPS/BDS-2/BDS-3-IGSO在第3频点L5、B2I、B2a的相位残差分别减小了59.54%、26.31%、10.98%。其中，动态定位的GPS、BDS-2/BDS-3-IGSO、GPS/BDS-2/BDS-3-IGSO 3种方案的点位精度分别提升了56.55%、29.16%、20.72%，改善效果显著。

Estimation and validation of inter-frequency clock bias on GPS/BDS triple signals

In three-frequency GNSS data analysis, a systematic deviation named as inter-frequency clock bias (IFCB) arises due to the inconsistent frequency reference of clock products. Using data from 80 globally MGEX stations and 100 regionally CORS stations in China on day of year 153-160 in 2021, the epoch will be brought in differences of IFGF combinations are formed to realize a estimation of IFCB and analysis of the time-varying characteristics further. Finally, the estimated IFCB is applied to the undifferenced and uncombined PPP. The results show that the IFCB of GPS BLOCK Ⅱ-F with an amplitude up to 14 cm is larger than that of GPS BLOCK Ⅲ and BDS (generally less than 5 cm). For PPP validation, the GPS positioning accuracy has improved significantly with considering IFCB. The phase residuals of GPS/BDS-2/BDS-3-IGSO at the third frequency L5/B2I/B2a are reduced by 59.42%, 24.66%, and 16.00, respectively, and The point accuracy of GPS, BDS-2/BDS-3-IGSO, GPS/BDS-2/BDS-3-IGSO improve by 56.55%, 29.16%, and 20.72% in kinematic mode.