中文摘要：

采用HY2A卫星2013年2月的实测数据，研究了GPS、星载多谱勒无线电定轨定位系统（DORIS）及卫星激光测距（SLR）三种观测数据的单独和联合定轨问题。通过与法国CNES的精密轨道数据比较发现：分别采用GPS、DORIS和SLR数据进行单独定轨，GPS数据确定轨道的径向平均精度为1．3cm，三维位置约为6．2cm；DORIS定轨的径向平均精度为1．6cm，比GPS结果略差；SLR确定轨道的径向平均精度为2．3cm。用GPS、DORIS和SLR三种数据联合定轨，确定轨道的径向平均精度为1．2cm，三维位置约为6．5cm。与星载GPS定轨结果比较，三种观测数据的联合定轨在提高卫星轨道确定精度上不明显，但联合定轨有利于保持计算轨道精度相对稳定。用站星间高度角大于60。的SI。R数据检验GPS／DORIS联合确定的轨道，两者在测距方向的均方差为2．5cm，可见基于HY2A的观测数据可以实现cm级的定轨需求。

英文摘要：

The problem of precise orbit determination was studied using three kinds of HY2A observa- tional data of GPS,DORIS and SLR separately and together in February 2013. Comparing the derived orbits with CNES precise orbits, the results show. （1） Using GPS, DORIS and SLR data separately,the GPS data to determine the radial orbit of average accuracy was 1.3 cm, the three-dimensional posi- tion was about 6.2 cm~ the radial average accuracy of the DORIS solution was 1.6 em, and slightly worse than the results of GPS~ and SLR to determine the radial orbit of the average accuracy was 2.3 em. （2） Comparing the CNES orbits with the orbits derived from GPS, DORIS and SLR data togeth- er, the difference of RMS was 1.2 cm in the radial direction, and the three-dimensional position was 6.5 cm. Compared to GPS solution, the combined three kinds of data cannot improve the accuracy of the derived orbit, but it is helpful to keep the calculated orbit in relative stability. （3） Using SLR data with high elevation passes （above 60 degrees） to validate the accuracy of the GPS/DORIS orbit, we found the RMS of the estimated biases to be about 2.5 cm, showing that HY2A data can determine the centimeter-level orbit.