随机模型对解算西安流动SLR站坐标的影响

Influence of Stochastic Model on the Coordinate of Xi’an Mobile SLR Station Determination

合理的参数估计及精度评定不仅需要可靠的函数模型,而且需要正确的随机模型。从权函数和粗差编辑两方面,研究了不同随机模型对西安流动卫星激光测距(satellite laser ranging,SLR)站坐标解算的影响,采用全球Lageos-1卫星观测数据计算了西安流动SLR站坐标。计算结果表明:①西安流动SLR站的观测精度和坐标解算精度均达到厘米级。②随机模型直接影响SLR站坐标的解算结果及可靠性;对于相同的计算弧段,抗差方差分量估计得到的站坐标精度最高、结果最稳定,残差加权均方差最小,观测资料利用率也最高;对于相同的计算方案,采用的SLR数据越多,坐标估计精度越高。

Reasonable parameter estimation and precision evaluation not only need reliable function model but also need right stochastic model.The influence of stochastic model on the coordinate of Xi’an mobile satellite laser ranging(SLR)station determination is researched in the ways of weight function and outlying observations edit.The coordinate of Xi’an mobile SLR station is determined by using the data of Lageos-1 of all SLR observation stations in the world,which observed from May 1 to June 29,2016.When the coordinates of Xi’an mobile SLR station are computed,SLRF2014 station positions and velocities are employed.The coordinates of Xi’an mobile SLR station are computed with the orbit of satellite Lageos-1 determination.Three thirty-day orbital arcs and four computation plans are used to compute the coordinates of Xi’an mobile SLR station.There are sufficient numbers of SLR observations to compute reliable orbits,and the values of post-fit range residual root mean square(RMS)is about 2 cm.The difference of the results of the three thirty-day orbital arcs and the four computation plans are compared.By comparison and analysis,we find that the precision of Xi’an mobile SLR observation and the precision of the coordinate computed both reached the level of centimeter.Furthermore,the stochastic model has direct effects on the coordinate of SLR station determination result and reliability.The plan of robust variance component estimation can provide the most precision coordinate,the most stable result,the smallest weighted root mean square(WRMS)and the largest number of SLR data used,when using same computation arc.The more SLR data is used,the higher precision of coordinate is gotten,when using same computation plan.