Effect of exposure time on atmospheric scintillation of uplink beams

Extending the exposure time of photoelectric detectors based on time-averaging effects is one of the effective ways to mitigate the extension of an atmospheric scintillation and to reduce the effect of the atmospheric scintillation of uplink optical beams on the reliability of satellite-ground laser links.In consideration of the time-averaging effects of exposure time,the expressions for time-averaging factors for large zenith angles and small zenith angles are derived,respectively.Based on the above,the effects of zenith angles and the heights from ground to an optical transmitter on the time-averaging are analyzed.Analyzed results show that extending the exposure time can mitigate the extension of the atmospheric scintillation of uplink optical beams and can improve the stabilities of the Pointing,Acquisition and Tracking(PAT) links.The results also show that the extension of the time-averaging effects decreases with the increases of the zenith angles and the heights from ground to the optical transmitter.