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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。
A fixed thresholding method is proposed to remove the noise of the laser gyro drifting signal and the phenomenon of “strangulation ” wavelet coefficient is proposed. A wavelet threshold called E-median is proposed. The signal is subjected to a stationary wavelet transform to calculate the E-median threshold of the high-frequency wavelet coefficients at each scale. The soft-threshold method is used to correct the high-frequency wavelet coefficients and the signals are reconstructed by the stationary wavelet inverse transform. The laser gyro drift simulation signal and the measured signal to remove noise, the threshold can retain the characteristics of the original signal and effectively remove the noise. Simulation results show that this threshold is used to eliminate noise with higher signal-to-noise ratio with respect to fixed thresholds, mixed thresholds, and Minimax thresholds.