大型双反射面天线指向误差评估算法

Algorithm for Estimating Pointing Error of Large Dual-reflector Antenna

针对天线变形耦合影响指向误差评估精度的问题,提出基于几何光学的大型双反射面天线指向误差评估算法。通过建立变形反射面天线的最佳吻合抛物面、偏移副反射面以及馈源在基坐标下的数学模型,计算反射面辐射区间并确定指向误差权重因子,最终建立天线的指向误差评估模型。为验证算法的正确性,应用该模型对一座在建70 m天线的多组虚拟变形工况进行指向误差评估,其结果与现有波束偏移因子算法以及电磁仿真算法的评估结果进行对比,结果表明,该模型评估的指向误差结果与电磁仿真算法以及波束偏移因子算法的评估结果吻合,所提算法正确。该算法为分析天线变形耦合对指向误差评估精度的影响提供了理论依据,在一定程度上提高了天线的指向误差评估精度。

Considering the impact of antenna′s deformation coupling on the accuracy of pointing error estimation,an algorithm for estimating pointing error of large dual-reflector antenna is proposed based on geometric optics.A model for estimating pointing error of deformed dual-reflector antenna is deduced by establishing mathematical models for the best-fit paraboloid,the offset sub-reflector,and the feed based on the original coordinate system,calculating the radiation areas of reflector,and determining the weighting factor of pointing error.In order to verify this algorithm,the pointing errors for multiple virtual deformation conditions of a 70 m antenna under construction are estimated by this model,the results of which are compared with the results estimated by Beam Deviation Factor(BDF)algorithm and electromagnetic simulation algorithm.The final results show that the pointing errors estimated by the model are coincident well with the results of electromagnetic simulation algorithm and BDF algorithm,and the proposed algorithm is correct.The algorithm provides a theoretical basis for analyzing the effect of antenna′s deformation coupling on the accuracy of pointing error estimation,and improves the accuracy of pointing error estimation for antenna to some degree.