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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。
In order to deeply understand the time-frequency characteristics of atmospheric flickering, this paper provides references for the engineering design and performance evaluation of optical systems operating in the atmosphere. The general analytical expression of the power spectrum of the flicker in the atmosphere is theoretically deduced. The numerical simulation of the atmospheric flicker under different transmission conditions Time-frequency characteristics. Under the aperture reception, for the horizontal uniform path, the high-frequency region of the plane wave flicker appears approximately -17 / 3th power, and the spherical wave approximately exhibits -11 / 3th power. For the full-layer descending path, the high-frequency region is approximately -17 / 3 power rate, there is a slow change between the low frequency area and the high frequency area, the larger the aperture, the wider the change area. The spectral width of the low frequency region plus the creep region under typical atmospheric conditions is about 150 Hz.