赫尔默特方差分量估计方法在嫦娥一号卫星测角计算中的应用

在我国探月工程嫦娥一号卫星测轨中,需要对测距观测和VLBI时延观测进行综合解算,以确定卫星的角位置时间序列,因而需要考虑不同类型观测资料之间的权重分配问题。本文通过仿真计算,具体比较了不同情况下最小二乘平差方法与赫尔默特(Helmert)方差分量估计方法下测角计算的精度。虽然通常情况下观测资料都提供误差估计,但此估计却不一定能够准确反映实际的观测精度。仿真计算表明,此时应用Helmert求解方法,能够显著提高解算的精度。相比于最小二乘平差方式,Helmert求解方式在计算量上略有增加,但这对于现代计算设备几乎可以忽略。

On the application of the Helmert variance component estimation to the angular position determination of the Chang'E-1 satellite

The observations of range and time delay will be synthetically analyzed for determining time series of angular positions in the orbit measurement of Chang'E-1 satellite of Chinese lunar exploration project,and so it is necessary to discuss the relative weights between different kinds of observation data.Through data simulation the precisions of angular position determined by least squares adjustment and by Helmert method for Variance Component Estimation(VCE) are compared under various circumstances of observations.The estimated uncertainty is usually provided along with the observations and used to determine the relative weights in data processing,but it may not reflect the real precision of observation.Simulation results show that the application of Helmert method of VCE could obviously improve the solution precision.Compared with the least squares adjustment,the Helmert method is relatively complicated in calculations,however,this is almost negligible to modern computer.