The thermal distortion of an optical reflector surface due to the changing sunlight in a space environment will cause shift and spreading of its reflected focus and thereby influence the performance of space-to-ground...The thermal distortion of an optical reflector surface due to the changing sunlight in a space environment will cause shift and spreading of its reflected focus and thereby influence the performance of space-to-ground laser communication links. Based on the characteristics of a low orbit satellite, the normal shift of a plan mirror caused by thermal distortion is analyzed with the software of the ANSYS of finite element analysis. A general expression of the transmitted beam from a distorted reflector surface and a counting formula for the shifts of the focus center before and after thermal distortion are deduced. The result of simulation shews that the magnitude order of the normal shift of the antenna mirror surface can be as high as tens of urad. The worse the mirror thermal distortion is, the larger the shift of the received focus center is. And the change of the shifts does not obey a linear rule.展开更多
The profiling method is the first method to select in measuring the remote-sensing reflectance. In the light of the characteristics of China’s coastal waters, we develop a new method to compensate the environment’s ...The profiling method is the first method to select in measuring the remote-sensing reflectance. In the light of the characteristics of China’s coastal waters, we develop a new method to compensate the environment’s effects with the downwelling (λ)rsi r radiance’s profile and to estimate the underwater remote-sensing reflectance r. (λ)rsT he result indicates that the relative deviation of repetitious r in one station is around 10 %.展开更多
基金Funded by 863 project (NO:2002AA107493)youthfounda-tion project of UESTC(NO:JX03018)
文摘The thermal distortion of an optical reflector surface due to the changing sunlight in a space environment will cause shift and spreading of its reflected focus and thereby influence the performance of space-to-ground laser communication links. Based on the characteristics of a low orbit satellite, the normal shift of a plan mirror caused by thermal distortion is analyzed with the software of the ANSYS of finite element analysis. A general expression of the transmitted beam from a distorted reflector surface and a counting formula for the shifts of the focus center before and after thermal distortion are deduced. The result of simulation shews that the magnitude order of the normal shift of the antenna mirror surface can be as high as tens of urad. The worse the mirror thermal distortion is, the larger the shift of the received focus center is. And the change of the shifts does not obey a linear rule.
文摘The profiling method is the first method to select in measuring the remote-sensing reflectance. In the light of the characteristics of China’s coastal waters, we develop a new method to compensate the environment’s effects with the downwelling (λ)rsi r radiance’s profile and to estimate the underwater remote-sensing reflectance r. (λ)rsT he result indicates that the relative deviation of repetitious r in one station is around 10 %.
