Research On Key Techniques Of Laser Radar Echo Signal Processing Based On Wavelet Transform

Laser radar as a product of integrated multidisciplinary field,has a very high application value and application range,but also destined to become the current high-tech field research hot spot.However,the broad range of applications forms a complex and varied use environment for laser radar,and,to the greatest extent,limits the ability to detect and process target signals.In this paper,the laser radar detection system in the signal processing system to study carefully,trying to echo detection signal noise reduction,to achieve the detection of target information extraction,to improve the sensitivity of the laser radar to complex environments,to overcome the environmental factors the measurement accuracy and the detection distance is insufficient.As an effective signal processing theory,wavelet transform has been widely used in the field of signal denoising in recent years because of its superior denoising performance,and gradually realized the transition from wavelet theory to application.In this paper,the wavelet transform as the basic theory,the threshold de-noising method,the correlation denoising method and improved method to achieve the laser echo detection signal denoising research.Firstly,the theory of wavelet transform is introduced,and the multi-resolution analysis of wavelet transform is introduced,and the deep understanding of multi-resolution is realized by MATLAB simulation.Then,the characteristics of the laser radar are analyzed synthetically and the noise model is established.When the laser beam is transported in the atmosphere,the influence of atmospheric absorption,scattering and turbulence often leads to attenuation of the laser signal energy.When the echo detection signal is received by the receiving system,the noise model composed of noise of background noise,detector noise and preamplifier noise is mainly formed.,Combining with the study of noise properties,the noise model of Gaussian white noise is proposed.Finally,the single-pulse and multi-pulse accumulation of laser echo detection signal denoising research.The single-pulse signals with different signal-to-noise ratios are analyzed by threshold method and correlation method.The wavelet function,the decomposed layer number,the threshold value and the threshold function are selected,and the denoising experiment is carried out.Based on the multi-pulse accumulation of the low signal-to-noise ratio(SNR)signal,the denoising experiment of the detection signal is realized by combining the adjacent scale hard threshold method and the adjacency scale method.The denoising method is verified by the simulation data.The simulation results show that the threshold method and the correlation method have good denoising performance for the laser echo detection signal with high signal-to-noise ratio,but the low signal to noise ratio detection signal denoising effect is not ideal.The denoising of the low signal-to-noise ratio signal is achieved by the multi-pulse accumulation with the adjacent scale and the threshold method,and the threshold method is better the adaptability.