SAR高分辨成像及抗干扰技术研究

【作者】 张焱；

【导师】 王建国；

【作者基本信息】 电子科技大学 ， 信号与信息处理， 2007， 硕士

【摘要】 合成孔径雷达是主动式微波成像雷达,能全天候、全天时、实时获取大地域的地面图像,具有良好的植被和地面穿透能力,对资源探测和军事侦察等有重大意义。随着技术的发展,现代合成孔径雷达正朝着高分辨和提高自身抗干扰能力方向发展,因此,对高分辨合成孔径雷达宽带信号产生技术和对合成孔径雷达的抗干扰技术的研究已经成为该领域中的重要课题。在这个课题背景下,本文全面分析了一种新的高分辨合成孔径雷达宽带信号产生技术,即利用Chirp子脉冲频率步进信号合成宽带LFM信号的方法,并进行了详细的误差分析和性能评估。在抗干扰方面,本文研究了一种采用相位扰动LFM信号的针对数字储频干扰方式的抗干扰方法,并进行了抗干扰性能分析,取得了较好的抑制干扰效果。针对高分辨合成孔径雷达宽带信号产生技术的研究包括以下几个方面:1.研究了利用Chirp子脉冲频率步进技术产生宽带信号方法,并分析了距离向高分辨原理;2.定量分析了信号发射过程中载频跳变误差和子脉冲发射时间误差对宽带信号产生的影响,给出了载频跳变误差和子脉冲发射时间误差的理论允许范围;定量分析了目标径向运动对宽带信号产生的影响,推导了运动补偿因子;3.针对Chirp子脉冲频率步进产生的宽带LFM信号,研究了该信号RD(range-doppler)SAR成像算法,通过仿真试验0得到了高分辨成像结果。针对SAR数字储频干扰模式进行抗干扰技术的研究主要包括以下几个方面:1.研究了SAR数字储频干扰原理,并对压制式储频干扰和欺骗式储频干扰进行了分析推导;2.研究了两种相位扰动信号SV(slope-varying)LFM和MT-PM(Multi-tone Phase-modulated)LFM的自相关性、互相关性、功率谱等特性,理论分析和仿真试验验证了采用相位扰动信号抑制数字储频干扰的可行性;3.详细分析了SV LFM信号的抗干扰性能,研究了直接匹配压缩和先干扰消减后匹配压缩两种抗干扰方法及实现结构,并比较两种方法的抑制干扰效果。更多还原

【Abstract】 Synthetic Aperture Radar (SAR) is a kind of active microwave imaging radar. It can all-weather, all-day and timely get ground images of wide region and has fine penetrability to vegetation and ground. SAR is pretty important to resources exploitation and military reconnaissance. Today with the development of technology, SAR is paid more attention to due to its great capabilities in high range resolution and robust anti-jamming, so the technology of high resolution SAR waveform design and the technology of anti-jamming have become the hot field in the radar world. The dissertation is focused on ultra wide band (UWB) waveforms, which achieve UWB return without increasing the instantaneous bandwidth, and new anti-jamming method.The research on UWB waveform includes the following aspects:1. Analyses the chirp stepped-frequency waveform synthesizing the wideband signal and the range resolution of chirp stepped-frequency waveform2. Analyses the effect of the carrier frequency error, transmitting time error and the velocity on the synthetic range profile, discusses the radial velocity compensation3. Discusses the method to design waveform and the steps of SAR imagingThe research about anti-jamming method against digital radio frequency memory (DRFM) jamming are as follow:1. Analyses the principle of DRFM repeat jamming, finds the weakness of the jamming system2. Analyses the performance of multi-tone phase-modulated (MT-PM) LFM signal and slope-varying (SV) LFM signal including the autocorrelation, cross-correlation and power spectrum3. Analyses a signal processing method for penalizing a DRFM repeat jamming, gives the target simulation.更多还原