The Doppler frequency and pseudorange model are important information for open-loop tracking of GPS/LEO signal.The Doppler frequency model can be predicted through iteration,with the use of a bending angle/refractivity climatology and satellite orbits.The pseudorange model can be obtained by multi-epoch or single-epoch algorithm.About 7279 COSMIC radio occultation soundings,from DOY (day of year) 71 to DOY 73 in 2007,recorded in open-loop mode are processed by above-mentioned algorithms,the calculated Doppler frequency and pseudorange model are compared with corresponding COSMIC observations.The statistical comparisons of the difference between COSMIC Doppler frequency observation and Doppler frequency model show: above 2 km impact height,the mean Doppler frequency shift caused by the Earth’s neutral atmospheric condition is less than 3 Hz,the corresponding standard deviation is less than 6 Hz.The mean and standard deviation of the difference between COSMIC phase observation and pseudorange model calculated by multi-epoch algorithm are less than 15 m and 23 m,respectively,above 2 km.Similar results can be found in the single-epoch algorithm.The accuracy of the pseudorange model calculated by single-epoch algorithm is better than that of multi-epoch algorithm.Therefore,the atmospheric Doppler and pseudorange model predicted by the single-epoch algorithm can be used to track the GPS radio occultation signals recorded in the open-loop mode.