为解决地气光对星敏感器星提取精度影响问题，采用微元法建立了地气光对星敏感器的辐照度影响模型，并对影响辐照度大小的各变量进行了分析。阐释了地气光的影响机理，通过不同方差的高斯白噪声来对不同辐射照度的地气光进行散焦模拟，并对不同时刻不同位置地气光影响条件下的星提取精度进行仿真对比。仿真结果表明：地气光会导致星提取过程中星提取精度降低。该结果可用来对星敏感器遮光罩的抗地球反照干扰性能进行评估。

Aiming at solving the problem of the impact of earth and atmosphere radiation on star extraction accuracy of the star sensor，the model about the irradiance effect on the star sensor was proposed by adopting infinitesimal method and analysis of the variables affecting the magnitude of the irradiance were made. The mechanism of the influence of earth and atmosphere radiation was explained，and defocusing simulation of earth and atmosphere radiation with different magnitude was achieved by White Gaussian Noise (WGN) with different variance and simulation comparison of the accuracy of star extraction was made under the condition of the earth and atmosphere radiation with different position and time. The simulation results indicate that earth and atmosphere radiation can lead to the decrease of the accuracy of star extraction, which can be adopted to evaluate the anti-earth albedo performance of the lens hood of star sensor.