Triple-frequency observations will introduce an inter-frequency clock bias (IFCB) between the new frequency and the original dual-frequency observations. It has been verified that satellite IFCB can reach dozens of centimeters and several centimeters for GPS Block IIF satellite and BDS satellite, respectively. The existence of satellite IFCB will significantly affect undifferenced triple-frequency data processing. Based on 4-year data collected from 80 globally distributed stations, the long-term characteristics of IFCB coefficients obtained by using harmonic analysis have been studied. The results demonstrate that the coefficients of IFCB periodic model cannot be well fitted only by using sun elevation angle. Also, coefficients have obvious periodic characteristics and their periods differ among different satellites. Thus, a new linear-plus-periodic model is proposed to fit the long-term coefficients. Then, IFCB empirical correction models for 12 GPS Block IIF satellites and BDS GEO and IGSO satellites are built. In order to validate the correction model, IFCB standard deviation (STD), triple-frequency precise point positioning (PPP) and undifferenced extra-wide-lane (EWL) ambiguity resolution are employed. The results based on more than 4-year observations show that, with correction model applied, the average IFCB STD decreases by about 65.5% and 45.5% for GPS and BDS satellites, respectively. Compared to triple-frequency PPP without IFCB correction, triple-frequency PPP results with IFCB correction show that Up, North and East components accuracy are improved by 12.3%, 16.0% and 13.2%, respectively. Besides, IFCB correction will greatly improve the consistence of EWL fractional cycle bias among different stations and improve the success rate of EWL ambiguity resolution.

中文翻译：

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GPS Block IIF与北斗卫星异频时钟偏差的经验修正模型研究

三频观测将在新频率和原始双频观测之间引入频率间时钟偏差 (IFCB)。经验证，GPS Block IIF卫星和BDS卫星IFCB分别可以达到几十厘米和几厘米。卫星IFCB的存在将显着影响无差三频数据处理。基于80个分布在全球的站点的4年数据，研究了通过谐波分析获得的IFCB系数的长期特征。结果表明，仅使用太阳高度角不能很好地拟合IFCB周期模型的系数。此外，系数具有明显的周期特征，不同卫星的周期不同。因此，提出了一种新的线性加周期模型来拟合长期系数。然后，建立了12颗GPS Block IIF卫星和BDS GEO和IGSO卫星的IFCB经验校正模型。为了验证校正模型，采用了IFCB标准偏差（STD）、三频精确点定位（PPP）和无差超宽车道（EWL）模糊度分辨率。超过4年的观测结果表明，应用修正模型后，GPS和北斗卫星的平均IFCB STD分别下降了约65.5%和45.5%。与没有 IFCB 校正的三频 PPP 相比，经过 IFCB 校正的三频 PPP 结果表明，Up、North 和 East 分量的精度分别提高了 12.3%、16.0% 和 13.2%。除了，