Study On Ground Testing And Calibration Of Atmospheric Ultraviolet Imaging Spectrograph

The prototype of the Atmospheric Ultraviolet Imaging Spectrograph (AUVIS) is developed by CSSAR CAS, which employs hyperspectral imaging in a push-broom mode. The AUVIS instrument has been equipped with a two-dimensional CCD detector to record both the spectrum and the swath perpendicular to the flight direction. The aim of this dissertation is to study the ground testing and calibration of the AUVIS instrument, attempting to lay the foundation for its quantitative measurement and accumulate experience for development of the follow-up ultraviolet imaging spectrograph.In chapter 1, the main application domains of atmospheric ultraviolet remote sensing are introduced, the developments and the calibration methods of atmospheric ultraviolet spectrometer are described, and examples of groud calibration at home and abroad are given. In chapter 2, the AUVIS instrument is introduced, including the detection targets, the principle, the working modes, the main performance, the design of the systems components, and the calibration contents to be studied in the next three chapters.In chapter 3, 4&5, the ground testing and calibration of the AUVIS instrument are studied, including spectral calibration, radiance calibration, viewing calibration, linearity test and stray light test. The main studies are as follows:In chapter 3, spectral calibration technology of the AUVIS instrument is studied. Firstly, the calibration theory is discussed. Secondly, the wavelength calibration technology is studied. A Pt-Ne gas discharge lamp is chosen as the source, and the calibration setup is established. After the experimental data preprocessing, peak finding, peak location-wavelength pairing, subpixel location and regression analysis, a function of―column number-wavelength‖is established. The uncertainty of the wavelength calibration is analyzed. Secondly, considering the characteristics of the AUVIS, the spectral response function is estimated using the gas discharge lamp method. The Pt-Ne lamp used in the wavelength calibration is also used, and the spectral response function and spectral resolution are estimated. Thirdly, the results of the spectral calibration are verified by two methods.In chapter 4, radiance calibration technology of the AUVIS instrument is studied. Firstly, the calibration theory is discussed, including the principle and two methods-the diffuser method and the integrating sphere method. Secondly, the AUVIS radiance calibration is performed by the two methods. A 1000 W FEL lamp is chosen as the source, and two calibration setups are established. After the experimental data processing, the radiance calibration results are calculated and compared. The uncertainty of the radiance calibration of the two methods are analyzed and compared.In chapter 5, viewing calibration, linearity testing and stray light testing technology are studied. Firstly, the viewing calibration is studied, including the FOV calibration and the spatial response function measurement. The calibration principle and method of the FOV calibration are discussed, the calibration setup is established, and the FOV of the AUVIS is calibrated. The spatial response function and the spatial resolution are measured. Secondly, the linearity of the AUVIS is tested by two methods-the polarizer method and the exposure time method. Thirdly, the stray light of the AUVIS is measured.In chapter 6, diffuser calibration and testing in the UV are studied. Firstly, the descriptions of the diffuse properties are introduced, and the BRDF measurement principle and method are discussed. Secondly, the three diffusers of FY-3 TOU are calibrated, and the error is analyzed. Thirdly, the absolute BRDF testing technology is studied employing a Spectro-Gonio-Reflectometer. Finally, the hemispherical reflectance of the two diffusers is measured, which have the same technology and the same class with the three diffusers of FY-3 TOU, and their long-term changes are monitored.In chapter 7, all of the studies in the dissertation are summarized, and the next-step research idea is briefly described.