论文部分内容阅读
在机载合成孔径雷达(synthetic aperture radar,SAR)运动补偿中一般存在两个近似:波束中心近似和参考高程近似,这两种近似会在机载单天线SAR系统和机载干涉SAR系统成像过程中引入运动补偿残余误差。本文针对机载顺轨干涉SAR(airborne along-track interferometric SAR,ATI-SAR)系统,分析了上述两种近似导致的运动补偿残余误差对干涉性能的影响。首先针对机载双天线ATI-SAR系统,在不存在参考高程误差和存在参考高程误差两种情况下分别推导了其运动补偿残余误差,然后利用机载仿真参数证明了推导公式的正确性,并展示了运补残余误差对ATI-SAR干涉相位的影响程度。结果表明,当不存在参考高程误差时,由于运补残余误差导致的干涉相位误差可以忽略;而当存在参考高程误差且参考高程误差大于某个门限值时,对于相应的测速精度要求,由于波束中心近似导致的干涉相位误差不可忽略。本文的研究为机载ATI-SAR误差源分析和信号处理提供了理论基础。
There are generally two approximations in synthetic aperture radar (SAR) motion compensation: the beam center approximation and the reference elevation approximation, both of which can be used in the imaging of airborne single-antenna SAR systems and airborne interferometric SAR systems In motion compensation residual error. In this paper, the airborne along-track interferometric SAR (ATI-SAR) system is analyzed, and the influence of the above two kinds of approximations on the residual error of motion compensation on the interference performance is analyzed. First of all, for the airborne dual-antenna ATI-SAR system, the motion compensation residual errors are deduced in the absence of reference elevation error and existing reference elevation error respectively. Then the correctness of the derivation formula is proved by the on-board simulation parameters The effect of residual error in compensation on the interference phase of ATI-SAR is shown. The results show that when there is no reference elevation error, the interference phase error due to the residual error can be neglected. However, when there is a reference elevation error and the reference elevation error is greater than a certain threshold, The interference phase error caused by the approximate beam center can not be neglected. The research in this paper provides a theoretical basis for error source analysis and signal processing of airborne ATI-SAR.