【摘要】 该文简要回顾了ICRF的发展历史和现状。介绍了天球参考架之间的连接和综合。根据目前ICRF的特点及研究现状和进展,以ICRF的精度、数据采集的精度、源结构的分析及ICRF定义源的选取标准等方面深入分析了当前ICRF存在的缺陷,并结合当前的各种软硬件条件分析了ICRF的改进趋势,对未来的ICRF建立和维持作了展望。更多还原

【Abstract】 ICRF(International Celestial Reference Frame)is the geometric kinematics reference frame,its newly version is ICRF-Ext.2 realized by a total of 717 extragalactic radio sources which have an average of one source per 8 square degrees on the sky,include 212 defining sources 294 candidate sources and 102 other sources.Orientation of ICRF axes is specified through 212 defining sources.The accuracy of the individual source positions is as small as 250μas while the orientation of the ICRF axes is good to the 20μas.At present,ICRF is the best realization of CRS,but years practice and researches show that the current ICRF have some flaws.Selection criterions of defining sources are not reasonable,density and distribution of sources are not ideal,these all affect the precision of ICRF.Researches of source structure show that structure index of many defining sources are not with a value of 1 or 2,indicating they are not compact sources.Researches of source stability show that some defining sources do not accord with stability criterions.Furthermore density of sources is sparse and distribution of sources is largely nonuniform on the sky.All these faults made current ICRF cannot fit the requirements of researches on some domains.In this paper,the histories and present status of ICRF are presented briefly first.Then the relationship about connection and integration of CRF(Celestial Reference Frame)are introduced.Based on the characteristics and evolvements of researches on ICRF,the faults of ICRF are analyzed through the aspects of ICRF precision,data acquisition precision, source structures analysis and the criterions of selecting defining sources.At last,the improvement trends of ICRF by instruments and programs are analyzed.The prospect of establishment and maintaining on ICRF in future is discussed.With the progress of new technology and data acquisition precision,more and more weaker sources can be detected in future.These all help to improve the exist ICRF,a high precision of ideal ICRF will be realized in the future.更多还原