联合区域叠加滤波法与小波变换去除GPS站坐标时间序列噪声

Combine Region Stack Filtering and Wavelet Transformation to Reduce Noise in GPS Coordinate Time Series

GPS站坐标时间序列中存在的周期性与非周期性误差严重影响了对测站运动特征的分析及其非线性变化的物理机制解释。因此,为削弱噪声的影响,本文首先利用区域叠加滤波法去除了南加利福尼亚地区16个测站时间序列的共模误差,以此削弱时间序列中存在的包括周年和半周年误差在内的周期性误差。为去除滤波后残留的噪声,对滤波后的信号进行静态离散小波变换,提取了周期为半周年以上的信号。结果表明,联合区域叠加滤波法与小波变换对GPS站坐标时间序列进行处理,既能够削弱周期性误差对信号的影响,又能较好地提取测站的非线性运动信号。

The periodic and nonperiodic errors in coordinate time series of GPS stations have seriously affected the analysis of the characteristics of the stations and the explanation of the physical mechanism of the nonlinear motion. Therefore, in order to weaken the influence of noise, the region stack filtering method is used to remove the common mode error of the time series of 16 stations in Southern California, which weakens the periodic errors including annual and semi-annual errors in time series. In order to remove the residual noise after filtering, the filtered signals are subjected to static discrete wavelet transform processing, and the signals with the periods of more than half a year are extracted. The results show that the combined region superposition filtering method and wavelet transform can deal with the time series of GPS station coordinate time series, which can weaken the influence of periodic errors of the signal and extract the nonlinear motion signals of the station as well.