太阳子午线是大气偏振模式中重要的特征，可以将其作为导航的参考基准，从而获取其中所蕴含的重要导航信息；因此通过检测大气偏振模式中太阳子午线的位置，可以得到运动载体的二维航向信息。仿真实验结果表明，在不同太阳高度角时，太阳子午线的提取精度和航向解算精度都会受到影响。太阳高度角小于30°时，航向角误差维持在0．02°以内，在解算时可忽略；当太阳高度角在30°～60°时，航向角误差从0．02°开始缓慢增大为0．05°；当太阳高度角大于60°时，航向角误差急剧增大，最大可达0．1°以上；而当太阳高度角达到90°时，则完全不能进行航向测量。经过理论分析得出，当太阳高度角增大时，太阳子午线附近特征点分布区域会发散，在利用最小二乘法进行拟合时造成了误差。依据该分析可以在今后的航向解算时进行相应的误差补偿、优化算法以提高航向解算精度。%The solar meridian is the significant feature of the atmospheric polarization pattern.It can be used as an important reference benchmark to obtain the important of navigation information.Therefore, by detecting the po-sition of the solar meridian in the atmospheric polarization pattern, a two-dimensional heading information of moving object can be got.However, the simulation results show that at different angle of the sun, the extraction accuracy of sun's meridian and heading calculating precision will be affected.When the solar elevation angle is less than 30 °, heading angle error is maintained at less than 0.02 °, which can be ignored; when the solar elevation angle changed from 30 °to 60 °, heading error is increased slowly from 0.02 °to 0.05 °;When the solar elevation angle greater than 60 °, heading angle error increases sharply, up to 0.1 °or more;and when the solar elevation angle reaches 90 °,heading measurement can not be done completely.Through theoretical analysising, the distribution of the feature points near the solar meridian would diverge as the solar elevation angle becoming large.So there will be some errors when fitting using least square method.And based on this analysis a appropriate error compensation during calculating the heading angle in the future can be made.And more optimization algorithm will be proposed to improve the calculating precision in the future.
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