Theoretical study on power spectrum of atmospheric scintillation of aperture receiving for satellite-to-ground downlink

Based on the temporal covariance of logarithmic amplitude, analytical expression was obtained for aperture receiving power spectrum of atmospheric scintillation of satellite-to-ground downlink. The effect of the receiving aperture and outer scale of turbulence on the power spectrum of atmospheric scintillation was analyzed. The results indicate that the power spectrum of atmospheric scintillation includes low-frequency spectrum and high-frequency spectrum. The amplitude of low-frequency spectrum is constant. The high-frequency spectrum obeys the power law and the absolute value of power-law is 11/3. When the aperture scale increases, the power spectrum gradually increases its amplitude while keeping its shape. With the outer scale of turbulence increasing, the amplitude of low-frequency spectrum increases and the high-frequency is invariable.