掩星状态下的太阳形状及强度的理论及数值分析

提出了一种掩星状态下获得太阳形状及强度的方法，并进行了理论推导，建立了数值仿真模型。建立了无大气折射效应下的太阳形状及强度矩阵，并以此作为参考，通过阿贝尔积分公式及折射率垂直剖面反演得到经大气折射后的太阳像面任意位置处的大气弯曲角，根据弯曲角计算得到掩星后太阳像面各个点位置相对于不发生掩星时的位移，根据参考像面即可得到掩星后的太阳像面形状及强度矩阵。 仿真结果表明，采用此模型能实现掩星状态下，不同轨道位置，任意切点下的太阳形状及强度分布。 同时，以卫星轨道高度600 km作为仿真算例，模拟获得了从5~60 km不同正切点高度位置处相应的太阳形状及强度分布，并且仿真得到了云层遮挡下的太阳强度分布图。此模型对应用于卫星姿态部件的测试标定、遥感技术及材料测量等领域，实现能够较为真实地反映太阳形状及强度的太阳模拟器，具有较高的参考价值。

Theoretical and Numerical Analysis of Solar Shape and Intensity in State of Solar Occultation

A method for capturing the solar shape and intensity on occurrence of solar occultation is proposed, and a numerical simulation model is established. The solar shape and intensity matrix without atmospheric refraction effects is taken as a reference; the atmospheric bending angle at any position of solar image surface produced by atmospheric refraction is inversely calculated through the Abel integral formula and the vertical distribution data of refractive index. Then the displacement occurred by the occultation state is obtained. Based on the reference image surface, the shape and intensity matrix of the solar image surface after the occultation state can be obtained by geometric calculation. The numerical results indicate that the model can simulate the solar shape and intensity in different orbital positions and any tangent point. Solar shape and intensity at the tangent points from 5 km to 60 km are simulated when the height of the satellite orbit is 600 km, and the distribution map of solar intensity is obtained. This model is of higher reference value for realizing the solar simulator which can comparatively truly reflect solar shape and intensity in application in such fields like measuring and calibration of posture parts of satellite, remote sensing technology, material measurement and so on.