基于改进小波阈值的激光陀螺漂移信号降噪

Ring laser gyro drift signal denoising based on improved wavelet threshold

针对固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阈值,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阈值,采用该阈值消除噪声信噪比更高。

In ring laser gyro drift signal denoising,universal threshold ＂kills＂ the significant wavelet coefficients because 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 level.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 signal characteristics and eliminate noise effectively.Simulation results reveal that the proposed threshold method outperforms universal threshold,heursure threshold and Minimax threshold methods.