Analysis And Research On Stray Light Of Optical System Payload Of Sun Synchronization Satellite "Terminator-orbit Satellite"

With the detecting precision unceasing enhancement,inhibition level of stray light gradually becomes the key indicator factor that restricts the detection performance of space optical system.The modeling and simulation analysis of the stray source and propagation mode of stray light of satellite optical system and effect evaluation could provide reliable evidence for integrated system design,and shorten the development period.This research could provide effective guidance for the space research activities,which has become the necessary steps of space optical system research and development of high precision.According to the need of the payload development mission of space satellites,this research completes the modeling analysis of comprehensive influence of terminator-orbit satellite payload stray light.Firstly,the simulation modeling of stray light caused by the strong radiation source from the off-axis has been done.Utilizing STK software,the orbit modeling of the satellite for all year round has been established,and the change rule of the incident angle which between the Radiative Vector relative to the optical axis of satellite optical system all year round has been analyzed,when the radiation comes from sun and moon is used as stray light source.The impact of stray light on image detector after the transmission of the interior structure of satellite payload is analyzed,and measuring the interference of stray light on the detector by the concept of Extinction Ratio.Through comprehensive modeling and analysis,the shielding system can fully suppress the influence of off-axis strong noise sources on the imaging quality of the system during satellite load operation.The extinction ratio is greater than 10E-9.Subsequently,the stray light in the field of view of the optical load due to atmospheric radiation and ground scattering is analyzed and evaluated.Based on the atmospheric parameter database of MODTRAN software,the modeling calculation of the ground radiance received by the satellite load is completed.An improved signal-to-noise ratio model is proposed based on the requirements of the Earth observation mission for space-borne loads.This model is used to evaluate the effect of atmospheric scattered stray light on the quality of satellite payload imaging.The signal-to-noise ratio analysis at different solar zenith angles and visible distances is completed.The analysis results show that the signal-to-noise ratio of the improved model is shorter in the visible wavelength than the traditional SNR model which does not consider the atmospheric effects.The difference is larger than 105.The calculation of the signal-to-noise ratio of the satellite load at different solar zenith angles and visible distances shows that the signal-to-noise ratio of the satellite load is negatively correlated with the solar zenith angle.The average signal-to-noise ratio is 197(the solar zenith angle is 0°).)drops to 113(the sun zenith angle is 60°).In contrast,the signal-to-noise ratio of the satellite load is positively correlated with the visible distance,and the average signal-to-noise ratio is increased from 43(visible distance 5Km)to 116(visible distance 23Km).