中文摘要：

基于非差观测值和无一阶电离层误差、无几何距离的组合准则导出2个UGIF组合,进而提出GNSS非差伪距随机模型估计的UGIF非差组合方法。该方法仅需单站、单颗卫星的UGIF组合,适用于高低频情况下的非差伪距随机模型的实时或事后估计。利用中国矿业大学单基站连续运行站双模双频数据,验证方法的正确性与有效性。

英文摘要：

Probability histograms of three quadruple difference series are extracted from 24 hours GPS observations of two IGS stations with 5Hz sampling rate based on this,it is pointed out that quadruple difference series are not nearly applicable for stochastic modeling due to requirements of high sampling rate,baseline length and probability distribution assumptions on different stations and satellites.Undifferenced combination observation using both geometry-free and ionospheric-free criteria（short for UGIF）is derived from dual-frequency observations,and then a stochastic modeling method for GNSS undifferenced pseudo-range observations is presented based on UGIF.The proposed method can estimate the stochastic model of a single station and satellite pseudo-range observations with high or low sampling rate in real-time or post-processing modes.Finally a case is implemented to test the validity and rationality of the UGIF method using dual-frequency GPS and GLONASS observations collected at CUMT＇s single reference station.