湍流大气中激光传输对傅里叶望远镜成像质量的影响

针对傅里叶望远镜系统激光在湍流大气中传输造成的成像质量下降，分析了湍流对光束传输特性的影响，指出成像质量的下降主要来自于上行传输链路中湍流造成的光束漂移与光束扩展，从而产生光束指向误差。分析了指向误差影响成像的机理。通过数值计算得出了不同强度湍流造成整条上行链路光束指向误差，并通过系统仿真，得到了不同强度大气湍流条件下的成像结果。结果显示:在弱湍流与中湍流条件下（大气折射率结构常数小于10-14 m-2/3），随机指向误差较小(偏移比小于0.06)，复原图像有较好的识别性；在强湍流条件下，成像质量下降严重。因此系统应选择避开强湍流地理位置与时段进行工作。

Effects of laser propagation through atmospheric turbulence on imaging quality in Fourier telescopy

In order to determine the imaging quality degradation caused by the laser propagation through atmospheric turbulence in the Fourier telescopy system, the effects of turbulence on beam propagation characteristics are analyzed. We pointed out that the degradation in the quality of imaging is mainly from the beam wander and beam spreading induced by atmospheric turbulence that arises the pointing error. The mechanism of the pointing error affecting imaging process is analyzed. The pointing errors caused by turbulence of the entire uplink are calculated and imaging results are simulated under different atmospheric conditions. It is concluded that in weak and moderate turbulence (the refractive index structure constant of atmospheric turbulence is less than 10-14 m-2/3), the random pointing error is small (the random pointing offset proportion is less than 0.06) while the reconstructed image has good recognizability. However, in strong turbulence, imaging quality suffers severe decline. Thus the Fourier telescopy should be selected to avoid the strong turbulence location and time.