利用小波包系数信息熵去除GNSS站坐标时间序列有色噪声

Elimination of Colored Noise in GNSS Station Coordinate Time Series by Using Wavelet Packet Coefficient Information Entropy

  • 摘要: 针对全球卫星导航系统(global navigation satellite system, GNSS)基准站坐标时间序列中有色噪声影响测站运动参数估计精度的问题, 提出了一种以小波包变换为基础、利用信息熵理论剔除有色噪声的方法。首先, 以有色噪声中的闪烁噪声为例, 对包含闪烁噪声的仿真时间序列进行噪声估计, 检验闪烁噪声的估计精度。然后, 对仿真时间序列的残差序列分别进行离散小波变换和小波包变换, 利用信息熵理论剔除闪烁噪声, 并比较两种方法的去噪效果。最后, 采用KMIN站的坐标时间序列作为实测数据, 进一步验证小波包系数信息熵的去噪效果。实验结果表明, 利用小波包系数信息熵剔除的有色噪声与原有色噪声在频域以及时域均具有较好的一致性, 所提方法能够有效地剔除残差序列中的有色噪声, 仅余白噪声。

     

    Abstract:
      Objectives  The global navigation satellite system(GNSS) coordinate time series can be used to analyze the motion of GNSS station, and the colored noise in coordinate time series affects the estimation accuracy of the motion parameters. Therefore, in order to improve the reliability of the motion analysis, it is necessary to take effective measures to eliminate the colored noise.
      Methods  This paper proposes a method to eliminate colored noise by combining wavelet packet transform and information entropy theory. First, the simulation time series containing flicker noise is estimated to verify the estimation accuracy of the flicker noise. Then, discrete wavelet transform and wavelet packet transform are respectively carried out on the residual series of the simulation time series, and the flicker noise is eliminated by using information entropy.On this basis, the denoising effects of these two methods are compared. Finally, the coordinate time series at KMIN station is used as the measured data to further verify the denoising effect of wavelet packet coefficient information entropy.
      Results  The experimental results show that the power spectrum and the time series of colored noise eliminated by using wavelet packet coefficient information entropy are in good agreement with the original colored noise.
      Conclusions  The proposed method can effectively eliminate colored noise in the residual series and only retain white noise.

     

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