利用精密星历验证ITRS与GCRS不同转换方法的差异

Verification of Coordinate Transformation Between ITRS and GCRS by Using Precise Ephemeris

在不同领域经常涉及到国际地球参考系(international terrestrial reference system,ITRS)和地心天球参考系(geocentric celestial reference system,GCRS)这两种不同坐标系之间的相互转换,其中ITRS用来描述地面点或近地卫星在地球上的位置,而GCRS用来描述自然天体或人造天体在空间的位置与方向。目前,基础天文标准库(standards of fundamental astronomy,SOFA)基于天球中间原点(celestial intermediate origin,CIO),提供两种坐标转换方法——经典角度法和X、Y序列转换方法。基于这两种转换方法,利用国际GNSS服务(IGS)提供的精密星历SP3,在不同历元对不同转换方法的差异进行了验证。实验表明,在任意历元,X轴和Z轴的差异均小于0.08mm,而Y轴差异小于0.03mm。

In different fields,it is often related to the transformation between International Terrestrial Reference System（ITRS）and Geocentric Celestial Reference System（GCRS）.ITRS is used to describe the position of the ground point or satellites near earth,while GCRS is used to describe the position and direction of the natural or artificial objects in space.Currently,Standards of Fundamental Astronomy（SOFA）based on Celestial Intermediate Origin（CIO）,provides two coordinate transformation methods—classical angle and X,Yseries methods.On the basis of these two conversion methods,we use precise ephemeris SP3,provided by IGS,to verify the difference between these two methods at different time.Experimental results show that at any time,the difference of the Xaxis and Zaxis is less than 0.08 mm,while the Yaxis is less than 0.03 mm.