Key Technology Research And Design Of Semiconductor Laser Ceilometer Transmitter/Receiver System

Clouds is the converge consequence of water droplets and ice crystals which are floating in the air.It can reflect the state of motion and stability of water vapor in the air,and can also be used to forecast the weather,which is closely related to our daily life.An important parameter of cloud is cloud height.Getting the accurate information of cloud altitude can provide technical support for mastering the laws of weather changes,and provide action guidance for daily life and production activities,and ensure the safety of the transportation,the take-off and landing and the flight safety of the aircraft and the spacecraft.In order to meet the demand of the Meteorological Bureau and the Airport about acquisition the accurate and real-time cloud altitude information in the range of 150m～7500m,this paper has conducted the research and design the key technology of semiconductor laser ceilometer system.Firstly,according to the characteristics of the laser power and the backscattering signal,a biaxial system for transmitter and receiver is designed.Then,the transmitter system is designed by the combination of a long focal length single lens with a small aperture,which is used to complete the collimated and expansion beam of the laser beam,and the beam divergence angle is about 0.667mrad;the receiver system is designed by the Galileo telephoto filter structure and the secondary focusing lens,which is used to receive the backscattering signal.and the receiving field of view is about 2.5mrad.The optical of designed is simulated by Zemax software,and the simulation results are in good agreement with the design results,which proves the feasibility of the design system.At the same time,the mechanical structure of transmitter/receiver system is design completely.It avoids the optical interference and reduces the complexity of the optical system and improves the ability of detecting the near and the far.Secondly,the overlap factor is studied,and the influence of optical axis offset on the overlap factor is simulated by Matlab.And a method of adjust the optical axis parallel based on CCD imaging is proposal,which is suitable for non-visible light system and can effectively reduce the offset.Finally,the experimental results show that the system can acquisition the real-time and accurate information of cloud altitude within the demand.