[1] Men H T, Li G Y, Chen J Y et al. Research on the refined simulation method of laser altimetry satellite echo waveform[J]. Chinese Journal of Lasers, 46, 0110004(2019).

[2] Yang J X, Zhu Y D, Wang Q et al. Influence of surface reflectance and aerosol optical depth on performance of spaceborne integral path differential absorption lidar[J]. Chinese Journal of Lasers, 46, 0910001(2019).

[3] Jiang D, Qin Y C, Wang X P. Sensitivity analysis of atmospheric delay corrections for satellite-borne laser altimeter[J]. Laser & Optoelectronics Progress, 56, 230101(2019).

[4] Hu G J, Fang Y, Zhang L. Development of spaceborne lidar and analysis of its application prospect in surveying and mapping[J]. Geomatics Technology and Equipment, 17, 34-37(2015).

[5] Yu Z Z, Hou X, Zhou C Y. Progress and current state of space-borne laser altimetry[J]. Laser & Optoelectronics Progress, 50, 020006(2013).

[6] Wang C H, Li X, Peng H. Research on simulation and analysis of spaceborne full waveform laser altimeter[J]. Laser & Optoelectronics Progress, 52, 102801(2015).

[7] Liang M, Ma K. Study on the method of echo signal denoising based on gauss filter[J]. Geomatics & Spatial Information Technology, 40, 40-42(2017).

[8] Zuo Z Q, Tang X M, Li G Y et al. Adaptive Gaussian filtering of the full waveform of GF-7 satellite laser altimeter[J]. Infrared and Laser Engineering, 49, 20200251(2020).

[9] Li J H, Hu D Y, Cen J et al. Estimating forest canopy height using lidar data based on wavelet denoising[J]. Science of Surveying and Mapping, 40, 10-15(2015).

[10] Ma P G, Liu Y, Qi L et al. Wavelet filter algorithm for echo signal of pulsed lidar at low SNR[J]. Electronics Optics & Control, 18, 26-29, 45(2011).

[11] Qiu S, Xing Y Q, Li L C et al. ICESAT-GLAS data processing based on wavelet transform[J]. Forest Engineering, 28, 33-35, 59(2012).

[12] Wu H B, Xing Y Q, Xing T et al. Method of extracting ICESat/GLAS complete waveform data based on wavelet transform[C], 420-425(2010).

[13] Zhao W L. Threshold speech signal denoising based on wavelet transform[J]. Journal of Chongqing University of Science and Technology (Natural Sciences Edition), 7, 73-75(2005).

[14] Long S H, Zhou G Q, Wang H Y et al. Denoising of lidar echo signal based on wavelet adaptive threshold method[J]. The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, XLⅡ-3/W10, 215-220(2020).

[15] Li Z X, Xu H Z. A wavelet threshold de-noising algorithm based on empirical mode decomposition[J]. Computer Simulation, 26, 325-328, 337(2009).

[16] Boudraa A O, Cexus J C. EMD-based signal filtering[J]. IEEE Transactions on Instrumentation and Measurement, 56, 2196-2202(2007).

[17] Chang J H, Zhu L Y, Li H X et al. Noise reduction in lidar signal using correlation-based EMD combined with soft thresholding and roughness penalty[J]. Optics Communications, 407, 290-295(2018).

[18] Zhang Z J, Liu X F, Shu R et al. A novel noise reduction method for space-borne full waveforms based on empirical mode decomposition[J]. Optik, 202, 163581(2020).

[19] Qu C S, Lu T Z, Tan Y. A modified empirical mode decomposition method with applications to signal de-noising[J]. Acta Automatica Sinica, 36, 67-73(2010).

[20] Ma Y, Li S, Zhou H et al. Noise suppression method for received waveform of satellite laser altimeter based on adaptive filter[J]. Infrared and Laser Engineering, 41, 3263-3268(2012).

[21] Hofton M A, Minster J B, Blair J B. Decomposition of laser altimeter waveforms[J]. IEEE Transactions on Geoscience and Remote Sensing, 38, 1989-1996(2000).

[22] Donoho D L. De-noising by soft-thresholding[J]. IEEE Transactions on Information Theory, 41, 613-627(1995).

[23] Zhang Y K, Ma X C, Hua D X et al. An EMD-based denoising method for lidar signal[C], 4016-4019(2010).

[24] Sun G D, Qin L A, Cheng Z et al. Application of wavelet noise reduction for simulated signals of imaging lidar[J]. Laser & Optoelectronics Progress, 54, 090102(2017).

[25] Li H D, Li Q. Wavelet denoising based on technique of threshold[J]. Computer Technology and Development, 19, 56-58(2009).

[26] Wu G W, Wang C M, Bao J D et al. A wavelet threshold de-noising algorithm based on adaptive threshold function[J]. Journal of Electronics & Information Technology, 36, 1340-1347(2014).

[27] Du H F, Cong S. The study on wavelet de-noising under the environment of Matlab[J]. Computer Simulation, 20, 119-122(2003).

[28] Li K F, Wang Z. Application of improved wavelet threshold denoising in speech recognition[J]. Computer Technology and Development, 23, 231-234(2013).

[29] Huang N E, Shen Z, Long S R et al. The empirical mode decomposition and the Hilbert spectrum for nonlinear and non-stationary time series analysis[J]. Proceedings of the Royal Society of London Series A: Mathematical, Physical and Engineering Sciences, 454, 903-995(1998).

[30] Chen W P, Pan Z W. Denoising of wavelet threshold filtering based on empirical mode decomposition[J]. Journal of Anhui University of Technology (Natural Science), 27, 397-400(2010).

[31] Zhang Z J, Xie H, Tong X H et al. Denoising for satellite laser altimetry full-waveform data based on EMD-Hurst analysis[J]. International Journal of Digital Earth, 13, 1212-1229(2020).

[32] Kantelhardt J W, Zschiegner S A, Koscielny-Bunde E et al. Multifractal detrended fluctuation analysis of nonstationary time series[J]. Physica A: Statistical Mechanics and Its Applications, 316, 87-114(2002).