LAUSR

Abstract To improve the denoising performance of echo signal in a receiver of frequency modulated system, an adaptive modulation interval threshold denoising algorithm on the basis of empirical mode decomposition is proposed. By means of measuring the energy variation in each intrinsic mode function of noise interference and different background clutter, the optimal decomposition stopping time of empirical mode decomposition and the order of intrinsic mode functions needed to be filtered are determined. Combined with the soft interval threshold, an adjustment factor is added into the soft interval threshold formula to process the intrinsic mode function adaptively. The simulation and practical measurement results show that the proposed method improves signal-to-noise ratio by 1–3 dB and reduces the root mean square error by 10–25% compared with the direct empirical mode decomposition denoising method and traditional threshold denoising method.