VLF Atmospheric Noise Suppression Using Median Filter and Wavelet Threshold Denoising

Very low-frequency (VLF) atmospheric noise is nonGaussian, consisting of the sum of a Gaussian background and narrow pulses caused by lighting strokes, and conventional denoising method fails on it. In this paper, a new strategy to suppress the VLF atmospheric noise is proposed. First, the corrupt signal is passed through a median filter and the impulses in the atmospheric noise are suppressed. Then the disposed signal is shrunk with wavelet threshold to suppress the residual Gaussian noise. Finally, ultimate reconstructed signal is attained. The results are compared to the conventional method in the VLF communication system.