国际天文联合会（IAU）2000年决议定义了广义相对论框架下的天文参考系。但是该参考系是建立在渐近平坦的时空背景中的，太阳系为唯一的引力源。IAU2000天文参考系完全忽略了太阳系所在的银河系以及宇宙中的其他可视物质的引力作用；该参考系没有考虑占宇宙构成96%的暗物质和暗能量的影响：标准宇宙学模型给出的背景引力场并非是渐近平坦的；IAU2000的度规也没有给出参数化后牛顿表达式。因此IAU现有的天文参考系已经开始不能适应更高精度天体测量计划的要求。本项目拟在IAU2000决议的基础上，建立包含银河系引力影响、暗物质和暗能量在内的高精度相对论天文参考系，并将其从太阳系扩展到银河系乃至宇宙学尺度上。此外，本项目还将把结果推广为包含多种引力理论的参数化后牛顿形式。本课题研究结果可用于未来高精度天体测量计划的资料处理、相对论天体力学计算、基本引力理论的验证、暗物质暗能量的测量以及宇宙学模型的检验。

The International Astronomical Union (IAU) defined the astrometric reference systems in relativistic frame in the IAU 2000 resolutions.But such astrometric reference systems adopted by the IAU resolutions postulate that spacetime is asymptotically-flat and the only gravitational field source is the matter of the solar system. The IAU 2000 astrometric reference systems completely ignore the presence of the huge distribution of mass in our Galaxy and the other visible matter of the entire universe; The IAU 2000 Astometric reference systems do not take into account the presence of the dark matter and dark energy which make up to 96% of the totally observed universe. Therefore, the background spacetime given by the standard cosmological model including the dark matter and dark energy is not asymptotically-flat at all；And the IAU 2000 reference systems do not give out parametrized post-Newtonian formalisms. Because of the above mentioned reasons, the present astrometric reference systems by IAU have already started can not meet the requests of more accurately astrometric projects. Based on the IAU 2000 resoltions, in the present proposal, we plan to build a set of highly precise-relativistic astrometric reference systems which include the influence of the Galactic gravitation, dark matter and dark energy. Furthermore, we extend the astrometric reference systems to globle ones for our Galaxy even for cosmology. In addition, we will extend them to parametrized post-Newtionian formalisms for including alternative gravitation theories . The results of this research can be uesed for data precess of highly precise astrometric projects in future, calculations in relativistic celestial mechanics, experiments of the element gravitational theory, measurements of the dark matter and dark energy, and tests of cosmological models.