本项目致力于提高射电天球参考架的精度，从原始VLBI观测出发，深入剖析天测与测地VLBI数据处理的全过程。针对ICRF2存在的不足，逐个研究影响天球参考架精度的各关键模型和影响因素。综合应用模型改进、天体物理成图分析、时间序列分析、资料解算方法研究等多种手段和方法减弱各种误差的影响。本项目拟对VLBI时延观测模型是对流层时延、相对论效应、长期光行差等影响进行深入研究，建立基于广义相对论框架下皮秒级的时延观测模型。应用多种方法对射电源的结构指数进行分析和研究，给出一套最优的选择定义源的方法。对VLBI数据处理方法进行改进，并且改进相应的数据处理软件系统，对全球积累的30余年的VLBI海量数据进行综合处理，最终实现微角秒级的射电天球参考架。这一研究可为天体测量、地球科学、航天科学与深空探测等领域提供高精度的基准，也为现代天体测量中的Gaia及VLBI2010等项目提供重要技术支持。

On the basis of the original VLBI observation data analysis, this project aims to improve the accuracy of radio celestial reference frame and analyze deeply the whole process of VLBI data handling in astrometry and geodesy. In view of the insufficiency of ICRF2, this research discusses the key models and influencing factors respectively which may affect the accuracy of celestial reference frame. A wide variety of means and methods, such as the integrated application of model improvement, astrophysics mapping analysis, time series analysis and data decoding method research, will contribute to reduce various errors on the accuracy of the reference frame. In order to establish picosecond level time delay measurement model based on the framework of general relativity, the project is planning to have a deep research on the influencing factors relating to VLBI time delay measurement model, such as the troposphere delay effect, relativistic effects, apparent displacement etc. We also provide a set of optimal ways to choose the definition source with the application of a variety of methods, which are used to have the related analysis and research on the structure index of radio source. With the improvement of VLBI data processing method and the corresponding data processing software system, and with the accumulation over 30 years of VLBI data comprehensive processing in the global scope as well, the micro angle of second class radio celestial reference frame has been set up finally. This research can provide high-precision datum for astrometry, earth science, aerospace science, deep space explorations etc. and also provide important technical support for the modern astrometry in Gaia and VLBI2010 projects etc.