Research On Signal Processing Technique Of Incoherent Laser Wind Lidar

Incoherent laser wind lidar can probe wind quickly. Echo signals are very weakat far distance, containing random noise and rayleigh scattering signals，which isthus non-stationary and nonlinear. Whether the signal processing system couldincrease signal SNR, improve smoothness of signal, and accurately calculateDoppler frequency shift, affects the quality of signal and accuracy of wind velocityseriously. Different signal processing algorithms are used when echo is detecteduntil wind retrieval, which could increase the accuracy of the whole lidar system.SPCM and data acquisition card are used to make up the hardware of detectionand acquisition module while LabVIEW as control software. The SPCM is alsostandarded by experiment. Pulse discriminator, based on LabVIEW, is used to countthe electrical pulse of SPCM related to the number incident photo.Median filter, moving average, EMD techniques are used to process the lidarecho signal. Results of experiments prove that all three methods can eliminate noise,increase SNR and increase smoothness of original signals.Wind velocity detecting experiments are put forward, and all three signalprocessing methods are used on wind velocity. The results show that all threealgorithms can improve the accuracy of wind detecting. Based on radial directionwind speed of wind detecting experiments, wind field is retrieved by VAP method.