星地下行孔径接收闪烁频谱的理论研究

 基于孔径接收的对数振幅时间相关函数，结合星地激光下行链路的实际情况，推导了适用于星地下行孔径接收的闪烁频谱表达式。进而分析了孔径尺度和湍流外尺度对闪烁频谱的影响。结果表明，下行孔径接收闪烁频谱分为低频段和高频段两个区间，低频段为常数，高频段呈幂指数规律变化，且幂律的绝对值为11/3。当接收孔径增加时，频谱的幅值和宽度逐渐减小，其形状保持不变。随着等效湍流外尺度的增加，低频谱的幅值逐渐增大，高频谱保持不变。

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.