【摘要】：近年來,以多極化/多天線為代表的多通道SAR成為了SAR發(fā)展的一大趨勢。多極化信息的獲取使SAR對(duì)目標(biāo)散射特性的描述更加完整;多天線使SAR可以從多個(gè)不同的角度對(duì)場景進(jìn)行觀測,擴(kuò)大了SAR的信息來源,拓展了SAR的應(yīng)用范圍。論文立足于多通道SAR體制,以提高SAR的戰(zhàn)場情報(bào)獲取能力和處理能力為目標(biāo),深入開展了多通道SAR成像理論與方法研究,其研究成果有助于拓展SAR在超分辨成像、前視成像、動(dòng)目標(biāo)成像等領(lǐng)域的應(yīng)用。第一章闡述了課題研究的背景和意義,歸納了極化SAR相干斑濾波、極化SAR超分辨成像、前視SAR成像、多通道SAR-GMTI理論和系統(tǒng)的研究現(xiàn)狀,并分析了當(dāng)前研究所存在的問題,最后概括了論文的主要工作。第二章研究了基于均值移動(dòng)的極化SAR相干斑抑制方法。首先回顧了相干斑的形成機(jī)理、統(tǒng)計(jì)特性和幾種經(jīng)典的極化SAR相干斑濾波算法。接下來,針對(duì)當(dāng)前極化SAR相干斑濾波算法不能很好的保護(hù)圖像細(xì)節(jié)信息和極化散射特性的不足,提出了一種基于均值移動(dòng)的極化SAR相干斑濾波算法——PDAN算法。該算法采用了空間域和值域的聯(lián)合濾波,充分利用了極化信息和幅度信息,滿足了極化SAR相干斑濾波的基本原則�；诘聡鳧LR的L波段E-SAR數(shù)據(jù)和中國電子科技集團(tuán)38所的X波段機(jī)載極化SAR數(shù)據(jù)的實(shí)驗(yàn)結(jié)果表明:PDAN算法比當(dāng)前廣泛使用的精致Lee極化濾波算法和IDAN濾波算法具有更平滑的相干斑濾波效果以及更好的圖像細(xì)節(jié)、邊界信息、極化散射特性保持能力。第三章圍繞著“改善抗噪性能”和“超分辨成像”兩個(gè)問題開展了基于稀疏重建的極化SAR超分辨成像方法研究。首先,提出了一種新的SAR成像處理框架,該處理框架可以有效克服雜波和噪聲的影響。在此基礎(chǔ)之上,基于壓縮感知理論和非二次最優(yōu)化技術(shù)提出了一種迭代超分辨成像算法——IFCS算法�；诜抡鏀�(shù)據(jù)的成像結(jié)果表明,IFCS算法在抗噪性能和超分辨性能方面都優(yōu)于現(xiàn)有算法。設(shè)計(jì)并構(gòu)建了X波段步進(jìn)頻軌道SAR實(shí)驗(yàn)系統(tǒng),開展了成像實(shí)驗(yàn),實(shí)驗(yàn)場景中包含有角反射器和車輛目標(biāo)。實(shí)驗(yàn)結(jié)果表明,對(duì)于結(jié)構(gòu)簡單的角反射器目標(biāo),IFCS算法能夠得到背景干凈,旁瓣很低的成像結(jié)果。對(duì)于具有復(fù)雜結(jié)構(gòu)的車輛目標(biāo),IFCS算法在克服旁瓣影響的同時(shí)獲得了更多的目標(biāo)細(xì)節(jié)信息。第四章深入開展了高速多通道前視SAR成像算法研究。首先,針對(duì)當(dāng)前多通道前視SAR成像算法只適用于低速平臺(tái)的問題,建立了高速多通道前視SAR信號(hào)模型,并以此為依據(jù),提出了適用于高速多通道前視SAR的DBS和RD成像算法,解決了高速運(yùn)動(dòng)平臺(tái)的運(yùn)動(dòng)補(bǔ)償問題。接下來,為了解決多通道前視SAR方位向分辨率受到平臺(tái)物理尺寸制約的問題,將壓縮感知理論創(chuàng)新的應(yīng)用在多通道前視SAR成像領(lǐng)域,提出了兩種適用于高速多通道前視SAR的超分辨成像算法。其中,二維壓縮感知超分辨成像算法具有不低于5倍的超分辨能力,但是需要對(duì)場景做二維剖分,計(jì)算量較大。方位向壓縮感知超分辨成像算法雖然成像精度和分辨率略有降低,但大大降低了運(yùn)算量,適合于較大場景的成像。基于Mini SAR實(shí)測數(shù)據(jù)的分布式目標(biāo)成像仿真表明:本算法對(duì)建筑物目標(biāo)和飛機(jī)目標(biāo)均具有很好的重構(gòu)性能。第五章結(jié)合國內(nèi)首部7通道SAR-GMTI系統(tǒng)的數(shù)據(jù)處理工作,深入開展了多通道SAR-GMTI處理方法研究。首先建立了運(yùn)動(dòng)目標(biāo)在SAR系統(tǒng)中的回波模型,并利用理論推導(dǎo)和計(jì)算機(jī)仿真的手段對(duì)運(yùn)動(dòng)目標(biāo)的成像效果進(jìn)行了分析。在此基礎(chǔ)上,進(jìn)一步分析了運(yùn)動(dòng)目標(biāo)在不同通道中的成像差異,建立了多通道SAR-GMTI信號(hào)模型。接下來,在回顧DPCA、ATI、STAP這3種典型的多通道SAR-GMTI處理算法的基礎(chǔ)上,開展了7通道SAR-GMTI系統(tǒng)實(shí)測數(shù)據(jù)的處理,重點(diǎn)研究了慣導(dǎo)信息缺失情況下的自聚焦、通道均衡以及降維STAP處理方法。提出了一種實(shí)用的通道均衡方法——線性均衡方法,取得了不錯(cuò)的通道均衡效果。最終,完成了國內(nèi)首部7通道SAR-GMTI系統(tǒng)的數(shù)據(jù)處理工作,得到了很好的處理結(jié)果。第六章總結(jié)了全文的主要工作和創(chuàng)新點(diǎn),并對(duì)需要進(jìn)一步研究的問題進(jìn)行了展望。
[Abstract]:In recent years, the multi-channel SAR represented by multi-polarization/ multi-antenna has become a major trend of the development of SAR. The acquisition of multi-polarization information makes the description of the SAR to the target scattering characteristic more complete; the multi-antenna enables the SAR to observe the scene from a plurality of different angles, enlarges the information source of the SAR, and expands the application range of the SAR. In this paper, based on the multi-channel SAR system, the research on the multi-channel SAR imaging theory and method is carried out in order to improve the information acquisition ability and processing ability of the battlefield information of the SAR, and the research results can help to expand the application of the SAR in the fields of super-resolution imaging, front-view imaging, moving target imaging and the like. In the first chapter, the background and significance of the subject research are described, and the research status of the polarization SAR coherent spot filter, the polarization SAR super-resolution imaging, the front-view SAR imaging, the multi-channel SAR-GMTI theory and the system are summarized, and the problems existing in the current research institute are analyzed, and the main work of the paper is finally summarized. In the second chapter, the method of polarization SAR coherent spot suppression based on mean-shift is studied. First, the formation mechanism, statistical property and several classical polarization SAR coherent spot filtering algorithms of coherent spot are reviewed. Next, aiming at the insufficient protection of the image detail information and the polarization scattering property of the current polarized SAR coherent spot filtering algorithm, a polarized SAR coherent speckle filtering algorithm based on the mean movement is proposed. In this paper, the combined filtering of the spatial domain and the range is used, the polarization information and the amplitude information are fully utilized, and the basic principle of the coherent speckle filtering of the polarized SAR is met. The experimental results of the L-band E-SAR data based on DLR and the X-band on-board polarized SAR data of China E & T Group 38 show that: The PDAN algorithm has a smoother coherence-spot filtering effect and better image detail, boundary information, and polarization-scattering property retention capability than the sophisticated Lee-polarized filter algorithm and the IDAN filtering algorithm which are widely used in the present invention. In the third chapter, based on the two problems of 鈥渋mprove anti-noise performance鈥，

本文編號(hào)：2341865