基于改进小波阈值的激光陀螺漂移信号降噪.pdfVIP

学兔兔 第32卷 第2期 仪 器 仪 表 学 报 Vo1．32 No．2 2011年2月 Chinese Journal of Scientific Instrument Feb．2011 基于改进小波阈值的激 光陀螺漂移信号降噪水 张 通，张 骏，张 怡 (西北_T业大学自动化学院 西安 710072) 摘 要：针对同定阈值法对激光陀螺漂移信号去除噪声会出现“过扼杀”小波系数的现象，提出一种称为E—median的小波阈 值。信号进行平稳小波变换，计算各尺度高频小波系数的E-median阂值，采用软阈值法修正高频小波系数，通过平稳小波逆变 换重构信号。对激光陀螺漂移仿真信号和实测信号去除噪声，该阈值均能保留原信号的特征并有效去除噪声。仿真结果表明 相对于固定阈值、混合阈值以及Minimax阂值，采用该阈值消除噪声信噪比更高。 关键词：激光陀螺；随机漂移；平稳小波变换；信号降噪；小波阈值 中图分类号：V249．3 U666．1 文献标识码：A 国家标准学科分类代码：510．40 Ring laser gyro drift signal denoising based on improved wavelet threshold Zhang Tong，Zhang Jun，Zhang Yi (College of Automation，Northwestern Polytechnic University，Xi’an ∞72，China) Abstract：In ring laser gyro drift signal denoising。universal threshold‘‘kills”the significant wavelet coefficients be— cause the threshold value is higher than what ought to be．This paper proposes a new wavelet threshold，called E—median threshold．The noisy signal is decomposed by stationary wavelet transform(SWT)for several levels．The E—median threshold is estimated by the detail at every leve1．The recovery signal is reconstructed based on inversed SWT．Simulations are carried out in MATLAB using ring laser gyro signal，the procedure could reserve original sig— nal characteristics and eliminate noise effectively．Simulation results reveal that the proposed threshold method out— performs universal threshold，heursure threshold and Minimax threshold methods． Key words：ring laser gyro；random drift；stationary wavelet transform；signal denoising；wavelet threshold