为了消除大气内观星时蒙的影响，提高载体定姿精度，提出了一种蒙气差补偿算法。首先给出了补偿过程涉及的姿态转移矩阵，并完成了相关矢量坐标映射变换；接着在星敏感器坐标系内，用两矢量内积法求得视天顶距；最后利用几何公式列出了以真星光矢量投影点估计位置为未知量的方程组，作为星敏感器任意姿态下蒙气差补偿算法模型。在没有任何误差的条件下对模型有效性进行了仿真，10-6 pixel量级的位置估计精度表明了算法的有效性。加入不同量级的陀螺漂移误差进行了仿真，给定的漂移误差对于蒙气差补偿模型的估计精度影响甚微，仿真结果表明在捷联载体存在一定姿态误差的前提下，蒙气差补偿模型也是适用的，补偿后的星像坐标用以实现星光姿态确定，并进一步对陀螺漂移完成补偿。

In order to eliminate the influence of atmospheric refraction when observing starlight in the atmosphere and enhance the accuracy of carrier attitude fixing, a compensation algorithm of the refraction is proposed. Firstly, the attitude transfer matrices involved in the whole process and complete the corresponding vector coordinate mapping transform are given. Then in the star sensor coordinate system, the visual zenith angle according to the interior product of two vectors is calculated. Lastly, with geometric formula, the system of equation taking the estimated position of the real starlight vector projection point to be the unknown variables is listed, which can be used as the refraction compensation algorithm model when the star sensor is in any attitude. Under the condition of no error, the simulation to model validity is carried out, and the magnitude of position estimation precision is 10-6 pixel, showing the validity of the proposed algorithm. The simulation is done again with different orders of magnitude gyroscope drift errors, and the effect on the estimation precision of refraction compensation model from the given gyroscope drift error is little. The simulation results show that under the premise that there are certain attitude errors of the strapdown carrier, the refraction compensation model is also applicable. The compensated star coordinates are used for starlight attitude determination, and further to compensate the gyroscope drift error.