基于改进CEEMDAN的应答器上行链路信号降噪研究

针对在高速铁路复杂电磁环境中应答器上行链路(balise uplink, BU)信号传输受扰的问题，提出了一种基于自适应白噪声完备经验模态分解(complete ensemble empirical mode decomposition with adaptive noise, CEEMDAN)与小波包自适应阈值的联合降噪方法。首先，采用CEEMDAN算法将模拟BU信号分解为12个模态分量，根据相关系数判断分量为相关分量或无关分量；然后，相关分量经小波包降噪处理后重构为降噪后的BU信号；最后，选用信噪比(signal-noise ratio, SNR)和均方根误差(root mean square error, RMSE)作为评价指标，将该方法与目前广泛采用的6种降噪方法进行对比，信噪比提高了0.486 1～6.144 dB,均方根误差降低了0.054 9～11.091。为检验该方法的实际应用效果，采用联合降噪方法对实测BU信号进行降噪处理。仿真验证和实验验证的结果表明，采用联合降噪方法降噪后的BU信号不仅噪声分量得到了有效去除，而且信号特征保存完好，证明该方法能够应用于解决实际BU信...

De-noising of balise uplink signal based on improved CEEMDAN

For the problem that the balise uplink (BU) signal transmission was interfered in the complex electromagnetic environment of high-speed railway, a denoising method based on the complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) combined with wavelet packet adaptive threshold was proposed. Firstly, the CEEMDAN algorithm was used to decompose the simulated BU signal into 12 modal components, and the components were determined to be correlated or irrelevant based on the correlation coefficients; Then, the relevant components were reconstructed into the denoised BU signal after wavelet packet denoising processing; Finally, signal noise ratio (SNR) and root mean square error (RMSE) were selected as evaluation metrics to compare this method with six widely used denoising methods. The SNR increased by 0.486 1~6.144 dB and the RMSE decreased by 0.054 9~11.091. To verify the practical application effect of this method, this joint denoising method was adopted to denoise the measured BU signal. The results of simulation and experimental verification showed that the BU signal denoised by the joint denoising method not only effectively removed the noise component, but also preserved the signal features well, proving that this method can be applied to solve the problem of actual BU signal interference.