Chinese Academy of Sciences Key Laboratory of Quantitative Remote Sensing Information Technology,Chinese Academy of Sciences,Aerospace Information Research Institute
In recent years, nighttime remote sensing has become a new hotspot in remote sensing field that can make up for the limitation of thermal infrared remote sensing at night. And nighttime remote sensing can provide nighttime radiation products with daytime resolution. However, at present, the uncertainty of on-orbit nighttime remote sensing radiometric calibration is relatively high, the main reason is that it is difficult to use the site for high-precision calibration due to the particularity of load. At present, the traditional spectrometer has high requirements for optical signal intensity, which can only be used during the day and cannot be used at night. Therefore, it is necessary to obtain accurate information of weak signal targets for accurate site calibration. To solve the above problems, a technical proposal that (the charge-coupled device (CCD) detector and image intensifier direct coupling) is proposed. A low-level light spectrometer that can measure weak signal targets information has been designed, and its gain is 5000 times that of the traditional spectrometer. The low-level light spectrometer can solve the problem that the traditional spectrometer cannot measure the radiation and reflectance of the surface target under the condition of low-level light, and it can improve the accuracy of nighttime remote sensing sites vicarious calibration. To solve these problems, a technical proposal that the charge-coupled device (CCD) detector and image intensifier direct coupling is proposed. In this paper, the technical scheme of directly coupling the CCD (charge coupled device) detector of the traditional spectrometer with the image intensifier is proposed to improve the information acquisition ability of the spectrometer under low illumination conditions. A low-level light spectrometer that can be applied to the weak signal targets information is designed, and it is 5000 times the gain of the traditional spectrometer. The problem that the traditional spectrometer cannot measure the radiation and reflectance of the surface target under the condition of low-level light is solved in the design of the low-level light spectrometer. In addition, the accuracy of nighttime remote sensing sites vicarious calibration is also improved. In this paper, the experiment environment for the low-level light spectrometer is selected in Great Chaidan area in Golmud, Qinghai province where is flat, high altitude, good atmospheric conditions, single type of land cover and far away from city lights. The experimental results show that the low-level light spectrometer can effectively measure the spectral information of the ground target with good and stable performance under the condition of moonlight and starlight.