【作者】 句赫；

【导师】 宋红军；

【作者基本信息】 中国科学院研究生院（电子学研究所） ， 通信与信息系统， 2006， 硕士

【摘要】 高分辨率成像是机载合成孔径雷达(SAR)的一个重要发展方向。目前，各发达国家正在争先研制具有高分辨率的机载SAR系统。SAR的模式和相应的成像算法是实现高分辨率机载SAR成像的主要方面，但是随着分辨率要求的提高，运动补偿方面几乎成为了制约机载SAR分辨率提高的决定因素。运动补偿技术是实现高分辨率机载SAR成像的关键。研究高分辨率机载SAR成像必须展开对运动补偿方面的深入研究。 本文主要做了以下几部分工作。第一，在分析了SAR的基本理论和信号模型的基础上，对机载SAR的几何关系作了描述并推导了运动补偿的基本方法，分析了载机飞行过程中的非理想因素引起的运动误差所导致的回波信号相位误差的主要形式及其对SAR成像结果的影响；第二，由于经过运动传感器补偿后的数据仍然存在残留误差，基于雷达数据本身的运动补偿算法有助于消除此项误差，所以本文接下来主要研究了基于雷达回波数据的运动补偿算法，重点是对MD、PD、最大对比度和PGA算法等几种自聚焦算法进行了理论分析和仿真证明，并着重探讨了适合于高分辨率机载SAR成像要求的、对任意阶相位误差都有较好的自聚焦性能的相位梯度自聚焦算法(PGA)的有关问题及其实现方法；第三，使用一种将自聚焦算法与chirp-scaling算法(CSA)相结合的方法，以发挥CSA在大前视角和大范围成像时的优越性能，提出将基于雷达数据的自聚焦算法与CSA相结合的方法，使CSA更具有实用性；第四，讨论了在实时处理中运动补偿自聚焦算法选取的问题以及实时处理中运动补偿计算量的估计方法的问题。更多还原

【Abstract】 High resolution airborne synthetic aperture radar (SAR) is an important direction for SAR. Currently, the advanced countries are trying their best to develop high resolution SAR systems. SAR mode and its corresponding image formation algorithms are the main problems for high resolution airborne SAR. But as the resolution requirement increased, motion compensation becomes the critical factor to impact the improvement of resolution for airborne SAR. Motion compensation technique is a key to realization of high resolution airborne SAR. To research high resolution airborne SAR, it is necessary to carry on deep researching on motion compensation problems.My thesis work is organized as follows. First, I review the fundamental principles of SAR imaging, the model of SAR system, and echo signals, the geometry of airborne SAR and the basic compensation methods are briefly introduced, then through mathematical derivation I analyze how SAR image quality is degraded by phase errors and quantitatively derive motion errors that are induced by undesired flight during the disarrange of the synthetic time. Second, the phase error still exits after the real-time compensation by motion sensors, the compensation algorithms based on the echo data are helpful to eliminate the remained error, so the next I do my research based on the echo signals mostly, In particular, I compare four practical auto-focus techniques, such as map-drift (MD), phase difference(PD), contrast optimization, and phase gradient auto-focus(PGA). This paper especially researches on PGA and its implementation in discrete domain, analyses and summarizes some relevant problems which have well-deserved reputation for airborne high order auto-focus. Third, this paper presents an approach to intergrate the auto-focus algorithm with chirp-scaling algorithm(CSA), by this way, the advantage of CSA can be given a full play. This paper also suggests a method to combine motion compensation based on auto-focus algorithm with radar data in CSA, this method is very suitable for high-resolution airborne SAR. Forth, this paper discusses the special problems on motion compensation in real-time processing of high resolution airborne SAR.更多还原