大气闪烁的时间频域特性研究

为了深入认识大气闪烁的时间频域特性,给在大气中工作的光学系统的工程设计和性能评估提供参考,理论推导了大气闪烁功率谱的通用解析表达式,数值研究了不同传输条件下大气闪烁的时间频域特性.孔径接收下,对于水平均匀路径,平面波闪烁功率谱高频区近似呈现-17/3幂率,球面波近似呈现-11/3幂率;对于整层下行路径,高频区均近似呈现-17/3幂率,低频区与高频区之间存在一缓变区,孔径越大,缓变区越宽.典型大气条件下低频区加上缓变区的频谱宽度约为150 Hz.

Characteristics of the temporal spectrum of atmospheric scintillation

In order to thoroughly understand the characteristics of the temporal spectrum of atmospheric scintillation and provide references for engineering design and performance evaluation of the optics system employed in the atmosphere, the generally analytic expression of the atmosphere scintillation power spectrum was theoretically deduced and the frequency domain characteristics of atmospheric scintillation under different propagation conditions was numerically investigated. For horizontal path with an aperture receiver, in the high frequency area, the scintillation power spectrum of the plane wave obeys the power law with an exponent of -17/3, while the scintillation power spectrum of the spherical wave obeys the power law with an exponent of -11/3; for the whole layer downlink path, the scintillation power spectra obey the power law with an exponent of -17/3 in the high frequency area, and there is a slow transformation area between the low frequency area and the high frequency area. The larger the aperture becomes, the wider the slow transformation area grows; besides the frequency spectrum width of the low frequency area and the slow transformation area is about 150 Hz under typical atmosphere conditions for plane wave.