调制偏振光可以作为方位信息的载体，实现方位角度信息的传递，在**、航天和生物医药等领域有广泛的应用前景。阐述了基于磁光调制偏振光的方位失调角测量原理，分析了现有测量原理中的误差来源。为了从理论方法上提高测量精度，提出了直接计算的方法，将磁光调制后的光强信号直接进行取极值点处理，建立了失调角与极值点之间的方程，详细分析了方程解的取舍情况，最终得出了失调角的计算公式。同时引入二倍角公式，扩大了失调角的测量范围。将仿真计算的方式与现有的测量方法进行对比，结果表明，提出的方法测量精度高、测量范围广，为实现空间方位失调角高精度测量提供了一种新方案。

As the medium of azimuthal information, modulated polarized light can be used to transmit azimuthal information, and this technique can be widely applied in military, aerospace and biomedicine. The principle of measuring azimuth with magnetooptic modulation polarized light is expatiated on, and the error sources by existing methods are analyzed. In order to improve the measurement precision theoretically, the method of calculating azimuth directly is brought forward. The extremum of modulated light signal is extracted, and the equation between the extremum and azimuth is established. The equation′s solutions are analyzed, and the formula of calculating azimuth is acquired. At the same time, the measuring range of azimuth is wider because the double angle formula is introduced. The precision of the new method is compared with those of the existing methods. The results show that the theoretic measurement precision of the new one is higher and measuring range is wider. It provides a new way to measure spatial azimuth with high precision.