Optimized Design Of Lidar Visibility Meter

Atmospheric visibility is a very important parameter in the meteorological field of civil aviation.The research of visibility detection is of great significance for ensuring the timely operation of airport flights and the safety of aircraft.Among them,the mass concentration of particulate matter is the main factor affecting the visibility of haze weather.Atmospheric visibility detection mainly includes three kinds of measuring methods:atmospheric transmission instrument,forward scattering visibility instrument and lidar visibility instrument.The lidar visibility meter uses the principle of lidar echo signals to detect visibility.It is popular for its large sampling area,flexibility,light weight,easy operation,and more suitable for detecting slope visibility.There are some problems with the lidar visibility instrument developed in the laboratory,including the large blind area and insufficient consideration of geometric overlap factors,which need to be optimized.At the same time,in order to solve the problem that it is difficult to measure the distribution of PM_2.5 mass concentration at different heights in space,iterative algorithms need to be optimized,and joint detection is performed with lidar,atmospheric transmission instrument,and particle size spectrometer.First,according to the basic principles of the Galileo telescope and the Cassegrain telescope,the Zemax simulation software is used to redesign the optical structure of the system,and the geometric overlap factor of the system is solved according to the parameters of the designed part.The geometric overlap factor is solved experimentally,and the two are compared to achieve the purpose of optimizing the optical structure.Then,taking the embedded motherboard as the control core,selecting a photon counting card and other suitable devices,rebuilding the lidar visibility meter system,and writing software for the control and interaction interface.Finally,an iterative algorithm for selecting boundary values is optimized,and the lidar visibility instrument,atmospheric transmission instrument,and particle size spectrometer are used to perform PM_2.5 mass concentration profile inversion research at vertical height.The results show that the optimized lidar visibility instrument reduces the blind area and improves the accuracy.At the same time,the PM_2.5 mass concentration profile obtained from the joint detection inversion reflects the microphysical changes of the vertical distribution of atmospheric aerosols.