多通道SAR高分辨率成像及動目標(biāo)檢測技術(shù)研究
發(fā)布時間:2018-06-07 22:47
本文選題:SAR + 高分辨率; 參考:《電子科技大學(xué)》2014年碩士論文
【摘要】:相比于單通道合成孔徑雷達(SAR)系統(tǒng),多通道系統(tǒng)因增加了接收通道而使回波數(shù)據(jù)有了冗余,系統(tǒng)自由度增加,能夠獲取目標(biāo)豐富的細節(jié)信息,更精準(zhǔn)地從背景雜波和噪聲中區(qū)分出目標(biāo),適用于高分辨率成像和目標(biāo)檢測技術(shù)研究。多通道系統(tǒng)具有數(shù)據(jù)利用率高、系統(tǒng)成本低、靈活性強等優(yōu)勢,本文以此為背景,將寬帶合成技術(shù)和動目標(biāo)檢測方法同時應(yīng)用到多通道SAR系統(tǒng)中,研究了基于寬帶合成的距離向高分辨率成像技術(shù)和中心頻率步進的多通道SAR動目標(biāo)檢測方法,所做的具體工作及創(chuàng)新如下:1、首先介紹了寬帶合成技術(shù),說明了距離向分辨率的原理和通道數(shù)與距離向分辨率的關(guān)系;然后結(jié)合兩種經(jīng)典的多通道SAR動目標(biāo)檢測技術(shù)分析了多通道SAR系統(tǒng)用于動目標(biāo)檢測中的優(yōu)勢和存在的問題。2、研究了基于誤差補償?shù)念l域?qū)拵Ш铣煞椒āJ紫?建立了多通道SAR回波信號模型。然后,介紹了一種典型的頻域?qū)拵Ш铣煞椒?針對該方法中同等效相位中心合成帶來的傳輸路徑誤差,結(jié)合仿真實驗分析了其對寬帶合成的影響,并給出誤差補償方法;針對該方法中通道不一致帶來的幅相誤差,結(jié)合仿真實驗分析了其對寬帶合成的影響,并給出誤差補償方法;尤其針對該方法中的子帶重疊誤差提出一種頻域滾降濾波法,詳細給出了算法原理及處理步驟,并結(jié)合仿真實驗論證了該誤差補償方法的有效性。最后,針對這種典型的頻域?qū)拵Ш铣煞椒ù嬖诘倪@三種誤差,采用上述補償方法,獲得了距離向高分辨率的SAR圖像,驗證了基于誤差補償?shù)念l域?qū)拵Ш铣煞椒ǖ挠行浴?、提出了圖像域的寬帶合成方法。針對傳統(tǒng)的寬帶合成技術(shù)存在的運算量大、實時性差的問題,本文提出基于圖像域的寬帶合成方法:首先,介紹了圖像域?qū)拵Ш铣伤惴ǖ幕舅悸?推導(dǎo)并建立了算法模型;然后,給出了算法步驟和框圖;最后,從理論上說明了在SAR圖像分辨率相當(dāng)?shù)那闆r下,所提的圖像域?qū)拵Ш铣煞椒ㄝ^傳統(tǒng)的寬帶合成方法在運算量和實時性方面有明顯的優(yōu)勢。4、研究了中心頻率步進的三通道ATI動目標(biāo)檢測及重定位技術(shù)。首先研究了偏置相位中心天線(DPCA)和沿跡干涉(ATI)兩種SAR動目標(biāo)檢測方法,對比說明了ATI在動目標(biāo)檢測方面有更好的檢測性能和抗干擾特性;然后,針對傳統(tǒng)的兩通道ATI無法提取動目標(biāo)參數(shù)的問題,重點研究了中心頻率步進的三通道ATI動目標(biāo)檢測技術(shù),并通過提取動目標(biāo)的相位信息,進而估計目標(biāo)的多普勒參數(shù)和運動參數(shù),實現(xiàn)對動目標(biāo)的檢測和重定位。
[Abstract]:Compared with single channel synthetic Aperture Radar (SAR) system, the multi-channel system increases the echo data redundancy, increases the degree of freedom of the system, and can obtain the rich detailed information of the target. It is more accurate to distinguish targets from background clutter and noise, and is suitable for high resolution imaging and target detection. Multi-channel system has the advantages of high data utilization, low system cost and strong flexibility. In this paper, wideband synthesis technology and moving target detection method are applied to multi-channel SAR system at the same time. The range high resolution imaging technology based on wideband synthesis and the multi-channel SAR moving target detection method based on step by step of center frequency are studied. The specific work and innovation are as follows: 1. Firstly, broadband synthesis technology is introduced. The principle of the range resolution and the relationship between the number of channels and the range resolution are explained. Then, the advantages and problems of moving target detection in multi-channel SAR system are analyzed with two classical multi-channel SAR moving target detection techniques, and the wideband synthesis method in frequency domain based on error compensation is studied. Firstly, the multi-channel SAR echo signal model is established. Then, a typical broadband synthesis method in frequency domain is introduced. Aiming at the transmission path error caused by the same equivalent phase center synthesis in this method, the influence of the method on broadband synthesis is analyzed in combination with the simulation experiment, and the error compensation method is given. Aiming at the amplitude-phase error caused by channel inconsistency in this method, this paper analyzes its influence on wideband synthesis and gives an error compensation method combined with simulation experiments, especially, a frequency-domain rolling filtering method is proposed for the overlapping error of sub-band in this method. The principle and processing steps of the algorithm are given in detail, and the effectiveness of the error compensation method is demonstrated by simulation experiments. Finally, aiming at the three errors of this typical broadband synthesis method in frequency domain, the range high-resolution SAR images are obtained by using the compensation method mentioned above. The effectiveness of the frequency domain wideband synthesis method based on error compensation is verified. 3. A wideband synthesis method in image domain is proposed. Aiming at the problems of large computation and poor real-time performance in traditional wideband synthesis technology, a wideband synthesis method based on image domain is proposed in this paper. Firstly, the basic idea of wideband synthesis algorithm in image domain is introduced, and the algorithm model is derived and established. Then, the algorithm steps and block diagrams are given. Finally, it is theoretically explained that the resolution of SAR images is the same as that of SAR images. Compared with the traditional wideband synthesis method, the proposed wideband synthesis method has obvious advantages in computation and real time performance. A three-channel ATI moving target detection and relocating technique with center frequency step is studied in this paper. In this paper, two kinds of SAR moving target detection methods, DPCA (offset phase center antenna) and ATI (interference along track), are studied. The comparison shows that ATI has better detection performance and anti-jamming performance in moving target detection. In order to solve the problem that traditional two-channel ATI can not extract moving target parameters, a three-channel ATI moving target detection technique with center frequency stepping is studied, and the phase information of moving target is extracted. Then the Doppler parameters and motion parameters of the target are estimated to detect and relocate the moving target.
【學(xué)位授予單位】:電子科技大學(xué)
【學(xué)位級別】:碩士
【學(xué)位授予年份】:2014
【分類號】:TN957.52
【參考文獻】
相關(guān)碩士學(xué)位論文 前1條
1 劉齊發(fā);基于現(xiàn)代數(shù)字信號處理理論提高SAR圖像分辨率[D];武漢理工大學(xué);2008年
,本文編號:1993127
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