双基前视SAR快速时域成像算法研究

发布时间：2018-03-04 19:14

本文选题：双基前视SAR　切入点：BP算法　出处：《电子科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：雷达前视成像在自主着陆、物资空投及战场侦察等方面有着广阔的应用前景。双基合成孔径雷达Bistatic Synthetic Aperture Radar,B)(iSAR收发天线分置在两个平台,构型灵活,适当的几何布局条件下可以实现单基SAR不能完成的前视成像。以后向反投影(Back Projection,BP)算法为代表的SAR时域成像算法相对于频域算法具有适用于任何构型的优势,但BP算法运算量较大,所以研究双基前视SAR快速时域成像算法具有重要意义。本论文围绕着双基前视SAR快速时域成像算法的相关问题,主要开展了以下的研究工作:(1)研究了移不变双基前视聚束SAR构型下的回波性质和成像二维分辨率特性,为后续算法的分析和设计奠定了基础。(2)研究了双基前视SAR的BP成像算法和基于因式分解的快速后向反投影(Fast Factorized Back Projection,FFBP)算法,并实现了两种算法的精确成像。(3)提出了基于方位等间距坐标的FFBP算法。根据双基前视SAR等距-等多普勒线的分布,每级子图像的方位向由在局部椭圆极坐标系采样变为在地面直角坐标系采样。从而实现了对FFBP算法运算效率上的优化。(4)研究了基于FFBP算法的运动补偿方法。对SAR收发双站进行运动误差建模,通过对回波相位补偿,将弯曲的实际路径补偿到理想直线路径,使FFBP算法在航姿存在一定误差的情况下仍然可以成像。(5)提出了双基前视SAR扩展场景回波时域快速模拟方法。通过对扩展场景中像素点的合并,对回波的插值、近似以及叠加操作,完成回波的模拟。本算法相对于传统回波时域模拟算法在运算效率上提升显著。以上算法均通过仿真实验进行了验证。结果表明,本论文提出的算法能够很好的完成双基前视SAR成像和扩展场景的回波模拟。
[Abstract]:Radar forward imaging has a broad application prospect in the fields of autonomous landing, material airdrop and battlefield reconnaissance, etc. The antenna of Bistatic Synthetic Aperture Radaran / Bistatic is separated on two platforms, and the configuration is flexible. The forward imaging can be realized under the condition of proper geometric layout. The back projection back projection back projection (BP) algorithm represents the SAR time-domain imaging algorithm, which is suitable for any configuration compared with the frequency-domain algorithm. But the computation of BP algorithm is large, so it is very important to study bistatic forward SAR fast time domain imaging algorithm. This paper focuses on the related problems of bistatic forward looking SAR fast time domain imaging algorithm. In this paper, the following research work is carried out: (1) the echo properties and the two-dimensional resolution characteristics of the imaging in a bistatic forward focusing SAR configuration are studied. The BP imaging algorithm of bistatic forward looking SAR and fast backward Factorized Back projection algorithm based on factorization are studied. The FFBP algorithm based on azimuth and equidistant coordinates is proposed. According to the distribution of bistatic forward looking SAR isometric and equal Doppler lines, The azimuth direction of each sub-image is changed from sampling in the local elliptical polar coordinate system to sampling in the ground right-angle coordinate system. Thus, the optimization of the computational efficiency of the FFBP algorithm is realized.) the motion compensation method based on the FFBP algorithm is studied, and the motion compensation method based on the SAR algorithm is studied. The model of motion error is established by sending and receiving two stations. By compensating the phase of the echo, the actual curve path is compensated to the ideal straight line path. So that the FFBP algorithm can still be imaged even if there is a certain error in heading and attitude. (5) A fast simulation method for echo of bistatic forward looking SAR extended scene in time domain is proposed. By combining pixel points in extended scene, interpolation of echo is proposed. Compared with the traditional echo time domain simulation algorithm, the computational efficiency of this algorithm is significantly improved. The above algorithms are verified by simulation experiments. The results show that, The algorithm proposed in this paper can well perform bistatic forward SAR imaging and echo simulation of extended scenes.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN957.52

【参考文献】