星载SAR解方位模糊技术及其对InSAR成像的影响研究

发布时间：2018-04-15 10:39

本文选题：星载SAR + 方位模糊　；参考：《电子科技大学》2014年硕士论文

【摘要】：星载SAR在实现高分辨成像、宽测绘带成像等方面具有广阔的前景,多个星载SAR组成的星座系统在地形数据获取、动目标检测等领域也有着深厚的潜力。因此,星载SAR受到了广泛关注,并成为当前雷达技术领域的一个研究热点。然而,在星载SAR设计中,存在着这样一个问题：系统在距离向上的宽测绘带导致系统需要采用低的脉冲重复频率(PRF)来避免出现距离模糊,但低的PRF带来了方位向上的欠采样,这样就导致得到的图像中出现方位模糊。本文着眼于星载SAR的方位模糊抑制,重点研究了基于一发多收(SIMO)SAR系统的方位模糊抑制方法以及它对InSAR处理的影响。本文的主要工作内容和创新如下：1.分析了在基于SIMO-SAR的方位模糊抑制方法中存在的三个主要问题：通道失衡、传输路径误差、方位向周期性非均匀采样对SAR图像质量的影响。针对通道失衡问题和方位向周期性非均匀采样问题,分别给出了它们造成的成像相位误差的表达式,为后续InSAR处理提供了帮助。2.建立了SIMO-SAR的等效相位中心模型,提出了一种基于BP算法的传输路径误差补偿方法,实现了对全部成像单元的传输路径补偿。通过仿真实验验证了该方法的有效性,并指出它相比于传统的传输路径误差补偿方法,具有更高的补偿精度。3.分析了地形存在起伏时,等效相位中心处理带来的传输路径误差,并提出了一种基于迭代的高度逼近方法,进一步提高了传输路径的补偿精度。然后通过面目标仿真实验,验证了该方法的有效性,同时也验证了基于SIMO-SAR的方位模糊抑制方法用于消除InSAR图像方位模糊的可行性。最后对比分析了传统的基于CS算法的处理方法和本文所使用的基于BP算法的处理方法的相位质量,指出本文所使用的方法具有更高的相位精度。
[Abstract]:Spaceborne SAR has a broad prospect in realizing high-resolution imaging and wide-band imaging. The constellation system composed of multiple space-borne SAR has great potential in topographic data acquisition, moving target detection and so on.Therefore, spaceborne SAR has received extensive attention and has become a hot spot in the field of radar technology.However, in the design of spaceborne SAR, there is such a problem: the system needs to use low pulse repetition frequency (PRF) to avoid range ambiguity, but low PRF brings up azimuth under-sampling.This results in a blur in the resulting image.This paper focuses on azimuth fuzzy suppression of spaceborne SAR, and focuses on the azimuth fuzzy suppression method based on single transmitter and multi-receiving Simo SAR system and its influence on InSAR processing.The main contents and innovations of this paper are as follows: 1.Three main problems in azimuth fuzzy suppression based on SIMO-SAR are analyzed: channel imbalance, transmission path error, and the influence of azimuth periodic non-uniform sampling on the quality of SAR images.Aiming at the problem of channel imbalance and azimuth periodic nonuniform sampling, the expressions of the imaging phase errors caused by them are given respectively, which can be helpful for the subsequent InSAR processing.The equivalent phase center model of SIMO-SAR is established, and a transmission path error compensation method based on BP algorithm is proposed, which can compensate the transmission path of all imaging units.The effectiveness of the proposed method is verified by simulation experiments, and it is pointed out that the proposed method has higher compensation accuracy than the traditional transmission path error compensation method.In this paper, the transmission path error caused by equivalent phase center processing is analyzed when terrain undulation exists, and an iterative height approximation method is proposed to further improve the compensation accuracy of the transmission path.Then the effectiveness of the method is verified by surface target simulation, and the feasibility of azimuth fuzzy suppression method based on SIMO-SAR is also verified for eliminating azimuth blur of InSAR image.Finally, the phase quality of the traditional processing method based on CS algorithm and that of BP algorithm used in this paper is compared and analyzed. It is pointed out that the method used in this paper has higher phase accuracy.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN957.52

【共引文献】