利用全天域大气偏振检测的航向角解算

Calculation of Heading Angle Using All-sky Atmosphere Polarization

针对偏振光导航航向获取需求,提出一种以全天域大气偏振模式作为信息来源实现载体航向解算的新方法。该方法利用"沿着太阳子午线方向的E矢量垂直于太阳子午线"这一偏振特性实现太阳子午线特征点提取,采用最小二乘法确定太阳子午线在载体坐标系下的方位角;并利用"太阳子午线附近的偏振度小于逆太阳子午线附近的偏振度"的特性,解决航向获取角度歧义性的问题;结合太阳在地理坐标系下的方位计算航向信息。实验表明,在设定的全天域偏振信息采样方式下,该方法在不同时刻、不同航向、不同采样点数下的航向获取精度为0.05°内;在偏振角测量误差8°以内,平均误差仍在0.2°内;证明了该方法解算精度高,适应性好,可以有效解算航向信息。

To improve the performance of polarization navigation, a new method to calculate the heading angle using all-sky polarization pattern is proposed. Through analyzing the distribution feature of atmospheric polarization pattern, we propose a method to identify the sample points of solar meridian area, from which we can decide the azimuth angle of solar meridian in carrier coordinate by least square algorithm. The DOP distribution feature along meridian is used to distinguish the solar meridian and anti-solar meridian, thus solving the problem of ambiguity in acquiring the heading angle. And then the heading angle is figured out since we can get the azimuth angle in geographic coordinate by astronomic theory. The simulated results show that under sampling mode that we set, the error of heading angle is below 0.05°; under different simulated conditions namely different time of a day, different input heading angle and different amount of sampling points. When there is an error within 8° with angle of polarization, the average error of heading angle stay within 0.2°, thus proving the high precision and well adaptation of the method.