基于小波降噪的船用行程传感器电磁干扰信号抑制研究

Research on reducing EMI of displacement sensor used in ships based on wavelet de-noising

针对船用行程传感器工作环境电磁干扰严重的特点,采用小波阈值法对船用行程传感器输出信号进行降噪。并通过软硬阈值折中法来克服单纯采用硬阈值或软阈值对低信噪比信号降噪效果较差的缺点。通过仿真分析,确定sym8小波对信噪比为2的含噪信号分解6层后可以较好地重构原信号。在此基础上,通过仿真对比,确定采用启发式阈值规则对信号进行降噪可以起到更好的降噪效果,误差在0.05%以内。最后,通过一个实验验证了结论,除个别点上的信号误差较大外,误差均值为0.3%。

Aiming at the serious electromagnetic interference （EMI） environment where the displacement sensor is used in ship, wavelet transform method is applied to reduce noise. And soft-hard thresholding denoising method with mean approximation is proposed in this paper to overcome the disadvantages of only using hard thresholding method or soft thresholding method. Through simulation and analysis, the signal with SNR of 2 is reconstructed well by disassembling to 6 levels using the sym8 wavelet function. On the basis of these, compared with other threshold methods, heuristic threshold is used to de-noise and better de-noising result can be obtained, and the error is less than 0.05%. Finally, an experiment was done to verify the conclusion, and the mean error is 0.3%.