顾及共模误差影响的澳大利亚GPS站长时间序列分析

Analysis of long time series of Australian GPS stations considering the influence of common mode errors

为探究澳大利亚板块GPS站时间序列的噪声特性与板块构造运动,选取IGS14框架下澳大利亚板块内19个GPS站2010—2020年坐标时间序列数据进行分析。采用主成分分析方法剔除坐标时间序列的共模误差,利用谱指数估计和最大似然估计法对滤波前后的时间序列进行噪声分析。结果表明:空间滤波能有效降低N、E向的白噪声、闪烁噪声,同时还原出3个方向中被掩盖的随机游走噪声,因而应考虑对该区域进行空间滤波;该区域GPS站坐标时间序列最优噪声模型为WN+FN+RWN,如仅考虑白噪声影响所计算得到的速度估值,其不确定性将会被低估;澳大利亚板块现今水平运动优势方向为北北东方向,平均速率约为65.1 mm/a,水平速率由北西向东南方向逐渐减小;垂直运动处于缓慢下沉趋势,平均速率约为-0.95 mm/a,且东、南方向相对西、北方向下沉更快。

In order to investigate the noise characteristics of the time series of GPS stations and the tectonic movement in the Australian plate,the coordinate time series data of 19 GPS stations from 2010 to 2020 in the Australian plate based on the IGS14 frame were selected for analysis.The principal component analysis method was used to remove the common mode errors in the coordinate time series,and the noise of the time series before and after filtering was analyzed with the method of the spectral index estimation and the maximum likelihood estimation.The research results show that:spatial filtering can effectively reduce white noise and flicker noise in the N and E directions,and can restore the random walk noise in the three directions that is covered,so spatial filtering of this area should be considered.The optimal noise model for coordinate time series of GPS stations in this area is WN+FN+RWN,as calculated only by considering white noise influence the uncertainty of speed estimate will be underestimated.The preponderant direction of the Australian plates horizontal movement is North-North-East,with an average velocity of about 65.1 mm/a,and the horizontal velocity gradually decreases from northwest to southeast.The vertical movement is in a slow sinking trend,with an average velocity of about-0.95 mm/a,and the East and South directions sink faster than the West and North directions.