测绘地理信息

地心天球参考系（geocentric celestial reference system,GCRS）和国际地球参考系（international terrestrial reference system,ITRS）之间的坐标转换对天体动力学研究具有重要意义。目前实现坐标转换的两种方法分别为基于春分点的经典方法和基于天球中间原点（celestial intermediate origin,CIO）的无旋转原点方法，IERS(International Earth Rotation and Reference Systems Service)规范先后推荐了不同的岁差章动模型用于转换。以国际GNSS服务提供的精密星历数据为例，通过对比ITRS和GCRS坐标转换前后三轴坐标序列的差异，计算并分析了两种坐标转换方法之间的差异，同时还分析了两个岁差章动模型和地球定向参数对坐标转换的影响。结果表明，基于春分点和基于CIO的方法一致性较好，IAU2000与IAU2006/2000A两种岁差章动模型间的差异对卫星坐标转换的影响在1 cm以内，极移、天极偏差、时间系统的使用也会影响转换精度。

The coordinate transformation between geocentric celestial reference system(GCRS) and the international terrestrial reference system(ITRS) is very important for many applications in astrodynamics. Two coordinate transformation models are the classical method based on vernal equinox point and the non-rotation origin method based on celestial intermediate origin(CIO). Taking the precise ephemeris data provided by international GNSS service(IGS) as an example, this paper compares the differences of three-axis coordinate sequences after coordinate transformation, the differences between the two coordinate transformation methods, the precession and nutation models, and the influence of the Earth Orientation Parameters on the coordinate transformation are calculated and analyzed. The results show that there is good consistency between the equinox-based and CIO-based methods, and the difference between IAU2000 and IAU2006/2000A precession nutation model is less than 1 cm; polar shift, celestial deviation and the use of time system will also affect the conversion accuracy.