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以平流层飞行器用星光导航为背景,研究在平流层内星光传输过程受大气湍流的影响机理,揭示平流层中星光的衰减规律,为建立平流层星光导航星库以及电耦合器件(CCD)所摄取的星图补偿方法提供理论依据。研究提出将流场密度和流场密度脉动变化大的区域划分为宽度为L的特性截面,并基于几何光学法及统计光学理论分别计算星光穿过各特性截面后产生的光线偏折及平均光强衰减,进而推导整个平流层内星光传输过程中的能量衰减变化曲线。采用基于k-ε双方程湍流模型的雷诺平均法计算不同极端情况下的大气湍流场密度及密度脉动分布。通过计算机数值仿真表明:星光穿过具有湍流的平流层时将发生明显偏折,其偏折程度与流场密度值有关;同时星光光强衰减,衰减程度与流场密度脉动值有关。
Based on the star navigation of the stratospheric aircraft, the influence mechanism of atmospheric turbulence in the stratosphere during starlight transmission is studied. The attenuation of the starlight in the stratosphere is revealed. In order to establish a stratospheric starlight navigation satellite database and an electrical coupling device Ingestion of star map compensation method to provide a theoretical basis. It is proposed that the area with large fluctuation of the flow field density and the flow field density be divided into the characteristic cross section of width L and the light deflection and the average light generated after the starlight passes through each characteristic cross section are respectively calculated based on the geometrical optics method and the statistical optics theory Strong attenuation, and then deduces the energy attenuation curve of the entire light transmission in the stratosphere. The Reynolds-averaged method based on k-ε turbulence model was used to calculate the atmospheric turbulence field density and density pulsation distribution under different extreme conditions. Computer numerical simulation shows that the star will deflect obviously when it passes through the stratosphere with turbulence, and the degree of deflection is related to the density of flow field. At the same time, the attenuation of the light intensity of the star light is related to the fluctuation value of flow density.