极化雷达具有全天时全天候对目标和场景进行观测的优势,在诸多领域得到广泛应用。极化雷达作为一种多通道系统,不同极化通道间的交叉耦合和通道不平衡等非理想因素会使目标极化散射矩阵存在测量误差,进而影响对目标散射的解译性能。文中以人造目标为研究对象,利用极化测量误差模型和相干极化目标分解开展了极化测量误差对散射解译性能的影响研究。以Krogager分解为例,推导了三面角、二面角、偶极子和螺旋体等基本散射体的极化目标分解分量与测量误差源的解析表达式,给出了分解特征参数的变化曲线图,揭示了极化测量误差对散射解译性能的影响机理。在此基础上,基于“开拓者”无人机暗室实测数据开展定量分析。当Krogager分解误差小于10%时,要求极化隔离度小于-23dB,极化通道幅度不平衡和极化通道相位不平衡分别小于3dB 和8.4°。研究工作为极化雷达系统参数设计等提供了指导。

The polarimetric radar has the advantage of observing the target scene all-weather and day-night. It is widely used in many fields. As a multi-channel system, non-ideal factors such as crosstalk and channel imbalance between polarization channels can lead to the measurement error of the target polarimetric scattering matrix, which can further affect the scattering interpretation performance of the target. In this paper, man-made target as the research object, the influence of polarization measurement error on scattering interpretation performance is studied by using polarization measurement error model and coherent polarimetric target decomposition. Taking Krogager decomposition as an example, the analytical expressions of the decomposition components and measurement error sources of typical scatterers such as trihedral, dihedral, dipole and helix are derived, and the variation curves of decomposition feature parameters are given, revealing the influence mechanism of polarization measurement error on scattering interpretation performance. On this basis, the darkroom measured data of “pioneer” UAV are quantitatively analyzed. When Krogager decomposition error is less than 10%, polarization isolation is required to be less than -23 dB, polarization channel amplitude imbalance and polarization channel phase imbalance are less than 3 dB and 8.4°, respectively. The research work provides guidance for the parameter design of polarimetric radar system.

TN958

国家自然科学基金资助项目(61771480);湖南省杰青基金资助项目(2020JJ2034);湖湘青年英才资助项目(2019RS2025)