联合LMD与EMD的GNSS站坐标时间序列去噪方法

针对GNSS站坐标时间序列信噪不易分离的问题，在传统EMD去噪方法的基础上，本文提出了一种联合LMD与EMD的坐标时间序列去噪方法。该方法首先采用LMD分解原始坐标时间序列，基于连续均方误差（CMSE）原则分离高频噪声与低频信号，保持低频分量不变；然后对高频分量进行EMD去噪；最后以2次分解所得低频信号之和作为去噪后时间序列。以仿真数据与8个GNSS基准站实测数据进行试验，通过多种评价指标进行精度评估。结果表明，与传统EMD方法相比，联合LMD与EMD的方法能够更加精确地去除坐标时间序列中的噪声。

Denoising method of GNSS station coordinate time series based on LMD and EMD

Aiming at the problem that the signal and noise of GNSS station coordinate time series is hard to separate, based on the traditional EMD denoising method, a new method of coordinate time series denoising combining LMD and EMD is proposed. This method first uses LMD to decompose the original coordinate time series, separates high-frequency noise and low-frequency signals based on the principle of consecutive mean square error(CMSE), keeps the low-frequency components unchanged, and then performs EMD denoising on the high-frequency components. Finally, the sum of the low-frequency signals obtained by the two decompositions is the time series after denoising. Experiments are carried out with simulation data and measured data from 8 GNSS reference stations, and the accuracy is evaluated through a variety of evaluation indicators. The results show that the combined LMD and EMD method can remove the noise in coordinate time series more accurately than the traditional EMD method.