Design Of Swing Mirror Control System Of Spaceborne Atmospheric Composition Detector

As the world’s requirements for air pollution monitoring technology become higher and higher,satellite-borne remote sensing instruments have the advantages of large-scale,continuous,dynamic,and all-weather comprehensive monitoring,which are used in the ecological environment,natural resources,agriculture,forestry and grass,meteorology,etc.The field of application is becoming more and more extensive.Using the satellite-borne atmospheric pollution component limb detector can observe the distribution of polluted gas above the earth.Obtain a variety of hyperspectral absorption lines through a spectrometer,which can monitor a variety of different atmospheric pollutants.The detector uses the swing sweep of the swing mirror to expand the range of the observation field of view,obtains hyperspectral remote sensing products in the ultraviolet to visible band,and realizes the quantitative monitoring of the global atmospheric trace component distribution and changes.Provide assistance for my country’s pollution reduction,environmental quality supervision,atmospheric composition and climate change monitoring.Therefore,it is necessary to develop an air pollution monitoring spectrometer to monitor the origin and spread of air pollution.It is conducive to the improvement of hyperspectral observation ability in enviro nmental aspects（such as atmosphere,water resources,land,etc.）,Obtain domestic hyperspectral data to provide technical support for domestic air pollution monitoring,water resources monitoring,soil monitoring,ecological environment monitoring,environmental supervision and law enforcement and other environm ental protection aspects,and provide help for China’s agricultural and forestry,meteorological observation,land use management,defense and mitigation of ear thquake disasters.The spectrometer atmospheric pollution monitoring spectrometer can be used to directly observe the ground,and the spectrometer can obtain a variety of absorption lines in the hyperspectral,and can monitor a variety of different at mospheric pollutants.When the spectrometer air pollution monitoring spectrometer scans the ground,it scans along the moving direction of the aircraft.Generally,only the optical information in the direction of motion can be obtained,but the optical information perpendicular to the motion direction of the aircraft cannot be obtained,but the spectral information perpendicular to the moving direction of the aircraft cannot be obtained.At this time,it is necessary to use a radiation mirror to reflect the light information perpendicular to the movement direction of the aircraft to the main optical path to obtain regional light information.On various remote sensing satellites,it is a common method to obtain ground optical information through mirrors.The performance of the swing mirror system determines the quality of the imaging performance of the spectrometer.The index of the swing mirror control system includes optical performance requirements,mechanical performance requirements and motion performance requirements.In the design,the step angle,pointing accuracy and stability of the swing mirror are required.Keep it within the margin of error.Based on the research of"Space Scanning Mechanism Control Technology"as the background,this paper designs a DC torque motor control system based on STM32 finite rotation angle combined with actual engineering needs.In this paper,the closed-loop control technology of position,speed and current of limited angle DC torque motor,SSI communication protocol between photoele ctric encoder and STM32 microcontroller,PID control program of position loop,speed loop and current loop of system motor regulation,interrupt service function.Investigate the development and research status of the swing mirror scanning control system at home and abroad,and its application prospects.Combine the research topics of the thesis to carry out research on the swing mirror control systemThe working mode of finite angle motor is studied.The working principle of the control system is studied by analyzing the detection scheme of the position.System hardware circuit design,chip interface and its peripheral circuit,motor drive circuit,level conversion circuit design.Through the internal resource configuration of STM32 chip（clock circuit,power circuit,timer function,A/D conversion function,etc.）.The main program first initializes the system function,and then the subroutine includes position subroutine,speed subroutine,current loop subroutine,interrupt service function subroutine to control the motor.The modularization design of the system software has good advantages in read ability and maintainability.The positioning accuracy reached 1.03",and the value of rotation accuracy±was 11.9%and-14.3%,respectively.Then the imaging spectrometer was performed using a horizontal turntable.Field experiment to test its imaging quality.After that,the experimental data is processed,and the two-dimensional imaging analysis of NO₂gas using DOAS is used to realize the observation of pollution in the area near the power plant.Finally,through experimental verification,the designed control system meets the requirements of the control system.In addition,field experiments were conducted to simulate the working process of the spectrometer in a stationary orbit,and to observe the air pollution around the power plant.Through the photoelectric autocollimator test system’s angle positioning accuracy and small angle rotation accuracy,the result data surface,the designed control system accuracy initially meets the system design requirements.