射电天球参考架指向维持方法讨论

依据河外射电源天球参考架的现状与建立射电天球参考架的最终目的，本文提出了以共同基本源维持参考架指向的观点。对实际资料的归算结果表明，在确保参考架指向长期稳定性方面，共同基本源指向维持模型优于ＩＥＲＳ维持模型。依据验算结果，文中同时讨论了选源标准与参考架指向稳定性的关系，指出基本源一次性变更的比例不能过高。一方面应完善选源标准；另一方面，一旦此标准发生性？上的改变时，应对在旧标准下选出的基本源进行复核，并作相应的指向调整，否则将可能造成参考架指向的跳变。

A Discussion on the Maintenance of the Orientation of Radio Celestial Reference Frames

According to the present status and the ultimate aim of the establishment of the Celestial Reference Frames based on the extragalactic objects, the orientation maintenance method based on common primary sources is recommended. Calculations show that this maintenance model is more desirable than the IERS one, which was on the hase of all primary sources of a version of the frame, in the consideration of orientation stability for a long time span. The relationship between the selection standards of primary sources and the orientation maintenance process is also discussed. It is shown that the ratio of the substituted objects to the whole must not be too high in order to keep the orientation continuity. On the one hand, the selection standards must be perfect. On the other hand,when ever changes occurred in the standards, the selected obJects based on old standards must be tested by the new one, and the orientation must be adjusted correspondingly.Otherwise, orientation gapes may be resulted in.