利用区域网GPS/BDS数据确定地球自转参数

Earth Rotation Parameters Determination Using Local GPS/BDS Network Data

地球自转参数是卫星轨道确定、深空探测器导航等的重要基础数据,是联系天球坐标系和地固坐标系不可缺少的物理参数。本文针对我国自主确定地球自转参数时,需要回答其精度和可靠性问题,提出利用区域网GPS/BDS数据确定极移、日长变化等地球自转参数估计方法,详细推导了地球自转参数偏导数的计算公式。利用2013年6月我国陆态网27个分布均匀的GPS基准站数据获得了地球自转参数的估计结果,并利用MGEX网BDS数据进行了地球自转参数确定的初步试验。计算表明:由我国陆态网数据可获得极移X、Y分量的精度约0.294mas和0.398 mas,日长变化精度约0.112 ms/d。由MGEX网BDS数据自主确定的极移X、Y分量精度约0.923 mas和1.017 mas,低于陆态网GPS数据的解算结果,日长变化精度约0.055 ms,优于陆态网GPS数据的解算结果。利用区域网GPS/BDS确定的极移参数存在明显的系统性偏差,而日长变化的系统性偏差较小。研究成果为我国自主确定地球自转参数提供了有益的参考和借鉴。

Earth rotation parameters (ERPs)are necessary parameters to achieve mutual transformation of the celestial ref-erence frame and earth-fix reference frame.They are very important for satellite precise orbit determination (POD),high-preci-sion space navigation and positioning.In this paper,the determination of ERPs including polar motion (PM)and length of day (LOD)are presented using Local GPS or BDS network data.The formula of partial derivative with ERPs is derived in de-tails.GPS data of 27 stations from Crustal Movement Observation Network of China (CMONOC)are used to estimate the ERPs.BDS data of IGS Muti-GNSS Experiment (MGEX)network are the first time used to estimate the ERPs.The results show that the RMS of x and y component errors of PM are about 0.294mas and 0.398mas respectively,and the RMS of LOD is about 0.112 ms/d by CMONOC GPS data.The RMS of x and y component errors of PM by MGEX BDS data are about 0.923 mas and 1.017mas respectively which is obviously worse than those from CMONOC GPS data.The mean RMS of LOD is about 0.055 ms/d is better than those from CMONOC GPS data.The research results from this paper will benefit to Chinese ERP determination independently.