Correlation Lidar Design And Simulation Study

Existing means of measuring the wind mainly contain radiosondes, Doppler radar and wind lidar, wind lidar includes coherent detecting and direct detecting.They are both based on Doppler effect, use aerosols'scattering of the laser beam, and Doppler shift extracted form further treatment of the echo signal to calculate the wind speed. The system structure is complex, large and high cost.As the disadvantage of traditional wind lidar, this paper introduced the correlation method wind lidar which is different from traditional doppler wind lidar. It has these advantages: only monitor the echo signal's strength ,low requirment of the device , achieve easier, and cheaper.This paper has deeply studied the correlation wind lidar.Contacting with the parameters of existing wind lidar., we construct the lidar system.The system choose Nd:YAG laser, emiting energy 10mJ,simulate the detecting of 3km height,s wind field.The system has 16 detecting positon and the distance of each point is 2m. The power of simulated echo is 8.7×10 ?6W.As the detector's sensitivity range is 10 ?7～10 ?8W,so the signal is able to be detected.The system can detect the maximum is 560m/s,minimum is 1m/s.In the department of signal processing we use Mente-Carlo method to generate wind lidar's echo signal.In order to get pure signal ,we use the method of distance correction and noise processing to revert the signal . In the interest of getting the wind field information that we need ,we use correlation method to process the signal which had been pretreated,through the way of calculating different time signal's correlation coefficient to ensure whether the signals come from the same target,then we can use the relationship between distance and time to retrieval the mean wind speed between two time intervals.In order to introduce the process of correlation method.This paper has analysed The process of position choosing by diagram.Using correlation calculation to find the max value position.Then contrast with the base poiont, retrieval the wind speed.Through calculation of the 16 point ,we compute the mean speed of the wind in detecting range,and use the values to reconstruct the wind field.