华北地区GPS基准站坐标时间序列噪声特征研究

Noise in GPS Coordinate Time Series for North China Fiducial Stations

利用华北地区GPS连续运行基准站网络2008-08~2013-04观测数据,分析36个基准站坐标时间序列的噪声特征。利用区域堆栈滤波方法对GPS单日解坐标时间序列进行共性误差剔除,使用极大似然估计准则定量估计坐标时间序列的噪声特性,并分析有色噪声对测站计算速度的影响。结果表明,华北地区GPS基准站坐标时间序列的共性误差在N、E和U方向分别约为1mm、1mm和3mm,且共性误差具有类似闪烁噪声的特性;共性误差剔除前,坐标时间序列的噪声特性可以用可变白噪声加闪烁噪声模型或可变白噪声加幂律噪声模型来描述;共性误差剔除后降低了坐标时间序列噪声中闪烁噪声的成分,突出了本地效应部分噪声,坐标时间序列的噪声特性可以用可变白噪声加闪烁噪声和随机漫步噪声模型或可变白噪声加幂律噪声模型来描述;最优噪声模型计算的速度误差比仅考虑可变白噪声所计算的速度误差增大5~8倍;剔除共性误差,可使测站速度的精度获得40%左右的提高。

We assess the characteristics of noise in the coordinate time series of daily position from August 2008 to April 2013 at 36north China GPS fiducial stations.Regional stacking filtering is employed to remove the common mode errors from the daily position time series.The noise characteristics of time series and the station velocities are assessed using maximum likelihood estimation.The results indicate that the common mode errors are attributed to the flicker noise and that their variations are 1mm for the NS component,1mm for the EW component and 3mm for the vertical component.The noise in the unfiltered position time series can be described as a combination of variable white noise plus flicker noise or variable white noise plus power-law noise,while the filtered position time series can be described as a combination of variable noise plus flicker noise plus random walker noise or variable white noise plus power-law noise.The removal of the common mode errors decreases the flicker noise component and highlights the corresponding noise component related to site effects.The velocity uncertainties are about 5-8times greater than if only variable white noise is considered.The velocity uncertainties decrease by about 40%if the common mode errors are removed.