Research On Performance Simulation Of Laser Coherent Wind Measurement Technology

In the remote sensing detection,the laser coherent detection technology is one of the most important ways to study the atmospheric wind field,and it has many applications in the fields of environment,military,aerospace and meteorology,due to its high spatial and temporal resolution in real time under clear sky.Because of the difficulty of debugging and the high cost of the wind measurement system based on laser coherence detection technology,it is necessary to carry out system parameter optimization analysis and numerical simulation analysis before the system is built,which lays a foundation for the development of the system.In this paper,the significance of the measurement of atmospheric wind field is briefly introduced,and its application in different fields is analyzed and summarized based on the current development of coherent laser wind measurement system.In view of the rapid development of numerical simulation technology and its important role in engineering development,this paper analyses the system parameter selection based on the principle of laser coherent wind measurement technology,and the optimization design scheme of system key parameters with performance index as reference was put forward to determine the diameter of the system telescope and the size of the laser beam.Based on Feuillete Model,the end-to-end coherent laser wind measurement system model was established by using the numerical simulation tool Simulink.The detection performance of typical accumulation high pulse energy-low repetition frequency(HPE-LPRF)and low pulse energy-high repetition frequency(LPE-HPRF)systems in different wind speed models at 1.5?m bands was compared and analyzed,and the result shows the former one has better overall detection performance than the latter one under the same average power and detection conditions,when the wind speed measurement error and noise-carrying ratio are taken as the evaluation basis.If data is processed by the way of multi-pulse accumulation,the detection performance of LPE-HPRF system will be obviously improved.In this research project,an all-fiber laser coherent wind measurement system was used to measure the static hard target and noise.By measuring the building about 170m away from the experimental system,the corresponding frequency information of 150m-180m distance gate we got is 80.47MHz,which means,the estimated value of corresponding wind speed is 0.36m/s.The analysis of the spectrum distribution of the measured echo signal shows that the variation of the power spectrum component of noise in the detection frequency range is the same as the trend of the low-frequency response of the balance photodetector.The noise power spectrum distribution curve of each range gate was fitted by polynomial least square method.The fitting result is taken as the base noise and deducted from the spectrum of echo signal,as a result,the maintenance of wind speed continuity in the range of 0?3km detection has been significantly improved.