| Lidar uses laser as the light source to remotely detect the characteristics of substances in the atmosphere,which utilizes the scattering echo signal generated by the interaction between laser and substances.Mie scattering lidar,Rayleigh scattering lidar,Raman scattering lidar,high spectral resolution lidar and Doppler lidar are the specific forms of lidar,which can measure atmospheric parameters such as aerosol,temperature,water vapor and wind field with the high spatial and temporal resolution,and provide the long-term and reliable data support for scientific research on the environment,meteo rology,and climate.The lidar for atmospheric detection puts forward higher requirements for the real-time monitoring of long-range,automatic,multi-station and multi-function areas.It is a trend of the development of lidar to establish a lidar network to realize the remote sensing measurement of a wide range of atmospheric parameters.Based on the in-depth study of the characteristics of atmospheric detection lidar,this thesis carried out the research on the automatic control technique of lidar system,to better realize the automatic control function of each subsystem of lidar and the sampling and storage function of lidar data,and to improve the operation performance of lidar system.Based on the full analysis of the influence parameters of the lidar equation,the key components to influence the lidar performance include the laser emission,telescope receiver,photoelectric detection and data acquisition and processing subsystems of atmospheric detection lidar,therefore the automatic control function design of laser,high-voltage power supply,laboratory skylight and data acquisition system are carried out.Among them,the laser is used as the excitation light source,and its automatic control is mainly realized by monitoring and regulating the laser state parameters.The high-voltage power supply is the feeding mode of the photoelectric converter(photomultiplier tube)of the lidar spectral output,which is controlled to obtain the optimal output gain.The laboratory dormant window is the protection unit of the lidar system,and the effective emission of outgoing laser can be realized by controlling the opening and closing of the dormant window.NI data acquisition system is a data acquisition and processing platform for lidar echo signal.The design of data acquisition and storage function modules to meet the sampling requirements can greatly improve the later data inversion ability of lidar data.This thesis makes full use of the advantages of Lab VIEW language,and designs the lidar automatic control subsystem based on serial communication and PCIe,which realizes the continuous light output of the laser in multi-mode,the automatic adjustment of the parameters of the high-voltage power supply of the photomultiplier tube,the automatic opening and closing of the laboratory dormant window,and the automatic acquisition and data storage of the NI data acquisition system.At the same time,in order to improve the efficiency of data storage and retrieval,a lidar data storage file based on HDF5 file storage format is designed to realize the unified storage of lidar system parameters and lidar detection channel data in a single file,and the automatic acquisition and storage of lidar data with the high efficiency.After completing the automatic control technology of atmospheric detection lidar and the software and hardware development of each subsystem,the automatic control,data acquisition and storage function test based on the Raman scattering lidar in Xi’an University of Technology are carried out.The test results show that laser,high voltage power supply,laboratory dormant window and NI data acquisition system can fully realize automatic control function,and the data of five-channel lidar based on HDF5 file format can be viewed clearly,the information is clear,and the reading and writing are convenient.The inversion results of measured data show that the HDF5 format data of atmospheric detection lidar is true,reliable and effective,which provides a reliable technical guarantee for the storage of atmospheric lidar data. |
