中文摘要：

VLBI技术及USB技术成功应用于中国的探月工程，极大地提高了月球探测器的定轨精度。随着中国深空探测向更远目标的推进，对VLBI测量精度提出了更高的要求。选取合适的射电源可以有效地提高探测器的定轨精度。本文综合考虑射电源的流量、信噪比、与探测器的角距等信息，探讨了从最新国际天球参考架中选取校准射电源的方法。本文以月球探测卫星的差分VLBI观测为例，结合中国VLBI网的现状，筛选出了可用的候选校准源表。

英文摘要：

The successful use of VLBI technique in China＇s lunar exploration project, greatly improves the positioning accuracy of the lunar spacecraft. As the development of China＇s deep space exploration, higher accuracy for VLBI measurements is required. Choosing the appropriate radio sources can improve the positioning accuracy effectively. We introduced the method of choosing radio sources from the latest international celestial reference frame in this paper, which is under the consideration of the flux density of radio sources, SNR, and the angular between the radio source and the spacecraft. This method is used to select the candidate calibration radio sources for the differential VLBI observation of China＇s lunar spacecraft. It＇s proves that this method is helpful for improving the accuracy of Chinese VLBI network,