Optical Design Of Ground Based Solar Spectroscopy Remote Sensing System

The sun plays an important role in human life.When the solar spectrum radiated by it reaches the ground,it will be absorbed by atmospheric components.Therefore,the ground-based equipment can be used to retrieve the content of pollutant gases in the atmosphere through remote measurement of the solar spectrum,which is also one of the current hot research topics in atmospheric science.Among them,the solar occultation Fourier infrared spectroscopy(SOF-FTIR)technology used to measure the solar spectrum has the characteristics of convenience and strong maneuverability.It can monitor real-time regional polluting gases and evaluate their emissions.Based on the technical principle of SOF-FTIR,this paper designs the optical part of a solar spectrum ground-based telemetry system.The working band of the system is the mid-infrared region of 600-5000cm-1.This band contains most of the characteristics of atmospheric pollutants.spectrum.Aiming at the sun tracking structure in the current system based on SOF-FTIR technology,there is a problem that the incident luminous flux is unstable due to the change of the solar altitude angle,and the tracking angle range is limited.A new type of high-speed solar tracking and tracking mechanism is designed.The mechanism is based on orthogonal mirrors and the principle of imaging using small holes,and uses a photoelectric tracking method to achieve sun tracking.In the modeling stage of the control method,the movement rule of the spot on the two-dimensional position sensitive detector(PSD)during tracking is analyzed,and the theoretical formula of the trajectory change is established,which provides a key model for the PSD measurement tracking control algorithm.According to the designed tracking optical path,a mobile automatic sun tracking device was developed to make it accurately receive and transmit direct sunlight into the FTIR spectrometer.The designed solar spectrum telemetry system includes solar tracking system,collimation system and interferometer system.In the design stage,according to the application scenario,the key technical indicators were demonstrated,and the appropriate optical structure was determined in turn.On the basis of the initial demonstration of the initial parameters of the optical structure,the system was modeled and simulated using point sequence diagrams,interferograms,etc.Evaluate the performance and further optimize the optical path design of the overall system.Finally,an experimental device was built,a preliminary field test to observe the solar spectrum was carried out,and the test results were analyzed.The results show that the solar spectra collected under fixed and moving conditions have good consistency and stable luminous flux;the sex-to-noise ratios are 116:1 and 122:1,respectively,and the difference between the two is small;the tracking measurements in the two cases are analyzed The accuracy is 0.00280 and 0.0225°respectively,which meets the performance index of the system.It has laid the foundation for regional pollution gas monitoring.