CEEMDAN-WT 降噪提升 BOTDA 信噪比研究

针对布里渊光时域分析仪(BOTDA)存在的信号噪声问题,提出一种自适应噪声完备集合经验模态分解联合小波阈值 (CEEMDAN-WT)的降噪方法。 首先,分析了 CEEMDAN-WT 算法降噪原理,基于微波扫频测量原理建立了 BOTDA 信号解调模 型,通过仿真研究验证了 CEEMDAN-WT 方法可有效去除信号中的随机噪声。 其次,搭建了 BOTDA 测温系统,在不同传感距离 和不同空间分辨率下进行了降噪效果实验验证。 结果表明,在 30 km 的传感距离和 2 m 的空间分辨率下,CEEMDAN-WT 方法 将光纤末端的信噪比提升了 8. 89 dB。 研究证明,CEEMDAN-WT 方法可为 BOTDA 信噪比提升提供一种有效方案。

Signal-to-noise ratio improvement for BOTDA using CEEMDAN-WT method

To improve the Brillouin optical time domain analysis (BOTDA) system performance limited by signal noise, we proposed a noise reduction method based on complete ensemble empirical mode decomposition with adaptive noise combined wavelet threshold (CEEMDAN-WT). First, the noise reduction principle of CEEMDAN-WT algorithm is analyzed. Besides, the BOTDA signal demodulation model is set up based on the principle of microwave sweep frequency measurement. The simulation results show that CEEMDAN-WT method can remove the random noise in the signal effectively. Then, the BOTDA system is set up for temperature measurement. The CEEMDAN-WT method is adopted to suppress the noise of each measured power curve at different sensing distances and different spatial resolutions. Finally, the experimental results show that the signal-to-noise ratio ( SNR) at the end of the optical fiber is improved by 8. 89 dB utilizing the CEEMDAN-WT noise reduction method, under the sensing distance of 30 km and the spatial resolution of 2 m. Research show that the CEEMDAN-WT method provides an effective scheme for improving the SNR of BOTDA.