【摘要】：合成孔徑雷達(dá)(Synthetic Aperture Radar,SAR)常用的成像模式有聚束模式,條帶模式和掃描模式。相對(duì)于聚束模式,條帶模式有能夠進(jìn)行連續(xù)大面積成像的優(yōu)點(diǎn)。通常情況下,條帶SAR工作于正側(cè)視模式。但許多應(yīng)用場(chǎng)合,需將波束向前或向后斜視,從而獲得雷達(dá)平臺(tái)前方或后方的場(chǎng)景圖像,即采用斜視模式進(jìn)行雷達(dá)成像。斜視模式是重要的條帶SAR成像模式之一,具有很高的軍事應(yīng)用價(jià)值。然而,大斜視情況下的條帶合成孔徑雷達(dá)成像信號(hào)處理研究還不是很成熟,目前主要面臨兩個(gè)顯著的困難。一是大斜視角導(dǎo)致嚴(yán)重的距離方位耦合,二是對(duì)于全孔徑條帶SAR數(shù)據(jù)的處理,實(shí)時(shí)實(shí)現(xiàn)困難。極坐標(biāo)格式算法(Polar Format Algorithm,PFA)采用極坐標(biāo)格式存儲(chǔ)數(shù)據(jù),其成像精度與斜視角無(wú)關(guān),能夠有效解決大斜視條件下的高精度成像問(wèn)題。而且,PFA與其他成像算法相比,算法簡(jiǎn)潔高效,且適用于復(fù)雜雷達(dá)航跡,因此在大機(jī)動(dòng)/大斜視條件下具有很好的應(yīng)用前景。但是,PFA算法為經(jīng)典的聚束模式SAR成像算法,不能直接用于對(duì)條帶SAR數(shù)據(jù)進(jìn)行處理。本文通過(guò)將全孔徑條帶SAR數(shù)據(jù)進(jìn)行子孔徑劃分,在子孔徑內(nèi)采用改進(jìn)的極坐標(biāo)格式算法進(jìn)行聚焦成像處理,然后對(duì)各子孔徑成像結(jié)果進(jìn)行無(wú)縫拼接實(shí)現(xiàn)大斜視條帶SAR高精度實(shí)時(shí)成像處理。論文的主要工作如下:論文第一章緒論,從研究背景和意義出發(fā),回顧了SAR技術(shù)及起源,分析了國(guó)內(nèi)外SAR成像技術(shù)研究現(xiàn)狀,并介紹了本文的主要工作和結(jié)構(gòu)。論文第二章對(duì)PFA算法展開(kāi)研究。首先介紹PFA成像原理,然后介紹了PFA幾何模型,并從距離徙動(dòng)校正角度分析了極坐標(biāo)格式轉(zhuǎn)換過(guò)程,對(duì)PFA成像算法進(jìn)行了點(diǎn)目標(biāo)仿真驗(yàn)證。從分析波前彎曲效應(yīng)出發(fā),對(duì)幾何失真校正進(jìn)行研究并對(duì)幾何失真校正效果進(jìn)行了點(diǎn)目標(biāo)仿真驗(yàn)證。論文第三章研究條帶SAR數(shù)據(jù)的子孔徑聚束處理。首先,對(duì)條帶模式SAR與聚束模式SAR進(jìn)行比較,分別對(duì)條帶SAR信號(hào)模型和聚束SAR信號(hào)模型進(jìn)行分析研究。然后對(duì)條帶模式-聚束模式數(shù)據(jù)的轉(zhuǎn)換原理進(jìn)行闡述。隨后采用經(jīng)典的PFA算法對(duì)條帶SAR進(jìn)行子孔徑聚束成像,并經(jīng)過(guò)子孔徑圖像的空變后濾波處理及幾何失真校正處理,得到子孔徑PFA圖像。最后通過(guò)仿真結(jié)果驗(yàn)證了子孔徑條帶數(shù)據(jù)的PFA成像算法的有效性。論文第四章研究條帶SAR數(shù)據(jù)的拼接成像處理。提出了一種基于PFA的大斜視條帶SAR子孔徑拼接成像處理算法,利用改進(jìn)的PFA成像算法,解決了子孔徑內(nèi)大斜視高精度成像困難的問(wèn)題,通過(guò)子孔徑圖像的拼接成像原理,來(lái)實(shí)現(xiàn)全孔徑的實(shí)時(shí)成像。通過(guò)點(diǎn)目標(biāo)仿真及實(shí)測(cè)數(shù)據(jù)處理驗(yàn)證了提出算法的有效性。最后,結(jié)束語(yǔ)對(duì)全文的工作進(jìn)行了總結(jié),并對(duì)下一步需要繼續(xù)研究的問(wèn)題做出了展望。
[Abstract]:The usual imaging modes of synthetic Aperture Radar (Synthetic Aperture) are bunching mode, stripe mode and scanning mode. Compared with the bunching mode, the strip mode has the advantage of continuous large area imaging. In general, the strip SAR works in positive side-looking mode. However, in many applications, the beam should be strayed forward or backward to obtain the scene image in front or rear of the radar platform, that is, the squint mode is used for radar imaging. Strabismus is one of the most important SAR imaging modes, which has high military application value. However, the imaging signal processing of striped synthetic aperture radar (SAR) with large squint is not very mature, and it faces two significant difficulties. One is that the large oblique angle results in serious azimuth coupling and the other is the difficulty of processing the full aperture strip SAR data in real time. Polar coordinate format algorithm (Polar Format algorithm) uses polar coordinate format to store data, and its imaging accuracy is independent of oblique angle of view, which can effectively solve the problem of high-precision imaging under the condition of large squint. Compared with other imaging algorithms, PFA is simple and efficient, and suitable for complex radar tracks, so it has a good prospect in large maneuvering / large squint. However, the SAR algorithm is a classical bunch-mode SAR imaging algorithm, which can not be directly used to process strip SAR data. In this paper, by dividing the full aperture strip SAR data into sub-aperture, the improved polar format algorithm is used for focusing imaging in the sub-aperture. Then the subaperture imaging results are jointed seamlessly to realize the high precision real-time imaging processing of large squint strip SAR. The main work of the thesis is as follows: the first chapter introduces the background and significance of the research, reviews the SAR technology and its origin, analyzes the current research situation of SAR imaging technology at home and abroad, and introduces the main work and structure of this paper. In the second chapter, the PFA algorithm is studied. Firstly, the principle of PFA imaging is introduced, then the geometric model of PFA is introduced. The polar coordinate format conversion process is analyzed from the angle of range migration correction, and the point target simulation of PFA imaging algorithm is carried out. Based on the analysis of wavefront bending effect, the geometric distortion correction is studied and the point target simulation is carried out to verify the effect of geometric distortion correction. In chapter 3, the subaperture bunching processing of strip SAR data is studied. Firstly, the paper compares strip mode SAR with spotlight mode SAR, and analyzes the signal model of strip SAR and spotlight SAR respectively. Then, the conversion principle of strip pattern-spotlight mode data is expounded. Then the classical PFA algorithm is used to perform the sub-aperture bunching imaging of the strip SAR, and the subaperture PFA image is obtained by the space-variant filtering and geometric distortion correction of the sub-aperture image. Finally, the effectiveness of the PFA imaging algorithm based on sub-aperture strip data is verified by simulation results. In chapter 4, the stitching imaging of strip SAR data is studied. A large squint strip SAR subaperture stitching algorithm based on PFA is proposed. By using the improved PFA imaging algorithm, the problem of high precision imaging with large squint in the subaperture is solved, and the principle of subaperture image stitching is adopted. To achieve full aperture real-time imaging. The effectiveness of the proposed algorithm is verified by point target simulation and data processing. Finally, the conclusion summarizes the work of this paper, and makes a prospect for the further research.
【學(xué)位授予單位】：南京航空航天大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：TN957.52

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 梁媚蓉;王晨沁;毛新華;;基于極坐標(biāo)格式算法的大斜視條帶SAR子孔徑拼接成像算法[J];南京航空航天大學(xué)學(xué)報(bào);2016年05期

2 柴建忠;高旭;劉學(xué)強(qiáng);艾俊強(qiáng);;幾種載體表面縫隙對(duì)雷達(dá)目標(biāo)特性的影響[J];南京航空航天大學(xué)學(xué)報(bào);2014年04期

3 孟大地;胡玉新;石濤;孫蕊;李曉波;;基于NVIDIA GPU的機(jī)載SAR實(shí)時(shí)成像處理算法CUDA設(shè)計(jì)與實(shí)現(xiàn)[J];雷達(dá)學(xué)報(bào);2013年04期

4 劉寒艷;宋紅軍;程增菊;;條帶模式、聚束模式和滑動(dòng)聚束模式的比較[J];中國(guó)科學(xué)院研究生院學(xué)報(bào);2011年03期

5 毛新華;丁嵐;朱岱寅;朱兆達(dá);;勻速運(yùn)動(dòng)目標(biāo)的聚束SAR成像特征分析[J];數(shù)據(jù)采集與處理;2010年03期

6 魏青;楊紹全;羅明;饒鮮;;基于條帶式SAR與聚束式SAR內(nèi)在聯(lián)系的SAR成像研究[J];電路與系統(tǒng)學(xué)報(bào);2006年03期

7 魏青,楊紹全,饒鮮,羅明;條帶式合成孔徑雷達(dá)成像方法研究[J];西安電子科技大學(xué)學(xué)報(bào);2005年02期

8 朱岱寅,朱兆達(dá);方位掃描SAR區(qū)域成像研究[J];航空學(xué)報(bào);2005年02期

9 武昕偉,朱兆達(dá);基于聚束照射SAR成像算法的條帶SAR數(shù)據(jù)處理[J];南京航空航天大學(xué)學(xué)報(bào);2002年05期

10 孫進(jìn)平,洪文,柳重堪,毛士藝;條帶模式合成孔徑雷達(dá)回波數(shù)據(jù)的聚束成像算法處理[J];航空學(xué)報(bào);2001年S1期

相關(guān)博士學(xué)位論文 前1條

1 毛新華;PFA在SAR超高分辨率成像和SAR/GMTI中的應(yīng)用研究[D];南京航空航天大學(xué);2009年

相關(guān)碩士學(xué)位論文 前6條

1 鄧科;大斜視機(jī)載SAR成像算法[D];南京郵電大學(xué);2013年

2 仇志華;基于子孔徑處理的SAR高分辨率成像算法研究[D];南京航空航天大學(xué);2009年

3 張瑋;基于方位向尺度變換的聚束SAR成像算法研究[D];南京航空航天大學(xué);2006年

4 李琛;聚束模式SAR大場(chǎng)景成像算法研究[D];南京航空航天大學(xué);2005年

5 張強(qiáng);彈載條帶式SAR成像算法研究[D];國(guó)防科學(xué)技術(shù)大學(xué);2005年

6 張洪立;SAR原始信號(hào)仿真研究[D];西北工業(yè)大學(xué);2003年

，

本文編號(hào)：2143040