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International Celestial Reference Frame (ICRF-3)

国际天体参考系（ICRF-3）

基本信息

批准号：
270124295
负责人：
Privatdozent Dr.-Ing. Axel Nothnagel
金额：
--
依托单位：
Lehrstuhl für Geodäsie
依托单位国家：
德国
项目类别：
Research Units
财政年份：
2015
资助国家：
德国
起止时间：
2014-12-31 至 2018-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/270124295?language=en
关键词：
International Celestial Reference Frame ICRF

项目摘要

Astrometric radio source catalogs in general and the International Celestial Reference Frame (ICRF) in particular represent the most accurate and most stable realizations of a quasi-inertial celestial reference system. While previous ICRFs were composed of a single VLBI solution of all available global S/X-band observations, the new (third) frame, ICRF-3, to be compiled in the next few years on request of the International Astronomical Union (IAU), will be a combined multi-frequency catalog. The reason is that by now a competitive solution of X/Ka-band observations from NASA/JPL is available, which will be combined with multiple solutions of S/X-band observations. The project, which is applied for in the framework of the Research Unit 1503 "Space-Time Reference Systems for Monitoring Global Change and for Precise Navigation in Space", will develop the necessary methods and procedures for the combination of multiple catalogs. New is the approach of using intermediate results of the least squares solutions of the observations namely normal equation systems instead of the source positions themselves. This method permits for the first time the transfer of the full variance-covariance information to the final catalog. Furthermore, the parameterization of unstable sources may be refined introducing linear splines where deemed appropriate following critical investigations. For the combination to work properly, i.e., without introducing frame constraints and other distortions, the input normal equation systems have to be free of datum constraints or have to be made datum-free. In the project, the final ICRF-3 catalog will be compiled in close collaboration with the IAU Working Group on the Third Realization of the International Celestial Reference Frame.

天体测量射电源表，特别是国际天球参考架（ICRF）代表了准惯性天球参考系最精确和最稳定的实现。虽然以前的ICRF是由一个单一的VLBI解决方案的所有可用的全球S/X波段观测，新的（第三）框架，ICRF-3，将在未来几年内应国际天文学联合会（IAU）的要求编制，将是一个合并的多频目录。原因是到目前为止，NASA/JPL的X/Ka波段观测的竞争性解决方案是可用的，它将与S/X波段观测的多个解决方案相结合。该项目是在1503研究股“监测全球变化和精确空间导航的时空参照系统”的框架内申请的，它将为合并多个目录制定必要的方法和程序。新的方法是使用观测值的最小二乘解的中间结果，即正规方程组，而不是源位置本身。这种方法首次允许将全部方差-协方差信息转移到最终星表中。此外，不稳定源的参数化可以在关键调查之后适当地引入线性样条来改进。为了组合正常工作，即，在不引入框架约束和其它失真的情况下，输入法方程系统必须不受基准约束或必须不受基准约束。在该项目中，最终的ICRF-3目录将与IAU第三次实现国际天球参考架工作组密切合作编制。