QQ客服 官方微博 反馈留言

题名	机载逆合成孔径雷达（ISAR）信号处理算法研究
作者	于化林
学位类别	博士
答辩日期	2007-08-08
授予单位	中国科学院电子学研究所
授予地点	电子学研究所
导师	朱敏慧
关键词	机载ISAR 平动补偿 越分辨单元走动 三维转动 距离瞬时多普勒成像算法
其他题名	Studies on signal processing algorithms for airborne ISAR imaging
中文摘要	本论文以机载ISAR成像信号处理算法为研究对象，对海面目标ISAR成像中的平动补偿、散射点越分辨单元走动校正、目标三维转动对ISAR成像的影响以及适合于目标三维转动情况下的距离瞬时多普勒成像算法展开了深入的研究。在此基础上，提出了一些新的思想和方法并进行了初步的探索。 结合投影平面概念和回波多普勒的表达式，详细分析了目标三维转动对ISAR成像的影响。指出在目标三维转动情况下回波多普勒会产生额外的线性频移和调频率的变化以及两部分影响和投影平面变化的对应关系，给出各部分影响的处理原则。 对现有的包络对齐算法和相位校正算法进行了理论分析、仿真及实测数据验证。分析了各种方法的使用条件和可能存在的问题，在此基础上，提出了利用通信系统中早迟门比特同步电路中寻找时间同步点的思想改进平动补偿的方法。验证了各种平动补偿算法在机载ISAR成像模式下的适用性。 详细地分析了产生散射点越分辨单元走动的原因以及在目标存在三维转动情况下进行越分辨单元走动校正可能存在的困难。对现有的 算法和 变换算法校正走动的原理进行了分析和仿真验证，指出了这两种算法的局限性。为了解决三维转动情况下MTRC校正问题，提出了一种结合子孔径和子回波包络校正的算法。 针对三维转动目标ISAR成像问题，引入距离瞬时多普勒成像方法。讨论了基于Radon-Wigner变换的成像算法以及chirplet分解成像算法。在此基础上给出了一种结合参数估计和局部搜索的chirplet分解快速成像算法。 分析了基于时频分析的距离瞬时多普勒算法所提供信息的冗余性，在此基础上提出了一种结合分数阶傅立叶变换和dechirp技术直接获取成像时刻瞬时多普勒分布的距离瞬时多普勒ISAR成像算法。 This thesis is focused on the signal processing algorithms for airborne ISAR imaging, especially on the translational motion compensation, the correction algorithms of scatters migration through resolution cell, the influences of the target multi-dimensional rotations on ISAR imaging, and range instantaneous Doppler imaging algorithms. Several novel ideas and algorithms are presented and verified by simulation data and real data. The effects of target multi-dimensional rotations on ISAR imaging are analyzed using Doppler frequency history and projection of imaging. We draw a simple conclusion that additional Doppler shift and chirp rate change will be introduced into the echo frequency due to target multi-dimensional rotations. We also analyzed the relationship of the change of Doppler and the change of imaging projection. Finally, the principle to deal with the two parts of the effects is presented. Several range alignment and phase correction algorithms are theoretically analyzed and verified by simulation and real data. After analyzing the problems of these algorithms, a new method with the same idea with early-late gate is proposed to improve the performance of existing algorithms. The applicability of several motion compensation algorithms is verified by real data. The scatters migration through resolution cell and the special problems generated by multi-dimensional rotations are studied comprehensively. The principle to correct migration through resolution cell of the PFA algorithm and keystone transform algorithm is analyzed. The two algorithms are not suitable for multi-dimensional rotations target. To deal with these special problems generated by multi-dimensional rotations, a new MTRC correction method based on sub-echo envelope correction and sub-aperture is presented. With respect to the ISAR imaging of multi-dimensional rotations target, the idea of range instantaneous Doppler algorithm is introduced. Two imaging algorithms based on Radon-Wigner transform and on chirplet decomposition respectively are discussed. A new method is proposed to make the decomposition much faster through parameters estimating and local matching pursuit. After analyzing the redundancy of information provided by range instantaneous Doppler algorithms based on time frequency analysis, a novel imaging algorithm is presented which obtains the instantaneous Doppler distribution directly by dechirp technique combined with fractional Fourier transform.
语种	中文
公开日期	2011-07-19
页码	142
内容类型	学位论文
源URL	[http://159.226.65.12/handle/80137/8401]
专题	电子学研究所_电子所博硕士学位论文_电子所博硕士学位论文_学位论文
推荐引用方式 GB/T 7714	于化林. 机载逆合成孔径雷达（ISAR）信号处理算法研究[D]. 电子学研究所. 中国科学院电子学研究所. 2007.

个性服务

查看访问统计

相关权益政策

暂无数据

收藏/分享

除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。