【摘要】：空間微動(dòng)目標(biāo)是一類重要的空間目標(biāo),隨著人類空間活動(dòng)愈加頻繁,微動(dòng)目標(biāo)成像由于能夠?yàn)槟繕?biāo)識(shí)別和空間安全提供重要信息,已逐漸成為研究熱點(diǎn)。然而這些目標(biāo)由于大多不滿足小角度近似,現(xiàn)有的成像手段難以達(dá)到較為理想的成像效果,所以還需作更深入的研究。本文針對(duì)微動(dòng)目標(biāo)成像的特殊性,在分析微多普勒和距離-慢時(shí)間回波的基礎(chǔ)上對(duì)成像難點(diǎn)和成像方法進(jìn)行了概述。優(yōu)化了基于非微動(dòng)參量估計(jì)的時(shí)頻分析瞬時(shí)成像法。從提高微動(dòng)參數(shù)誤差容限的角度改進(jìn)了后向投影變換成像法,并將其推廣到了進(jìn)動(dòng)旋轉(zhuǎn)對(duì)稱目標(biāo)上去。從在固有微動(dòng)參數(shù)誤差容限下提高成像效果的角度改進(jìn)了基于重采樣和壓縮感知的自旋目標(biāo)成像法。本文主要工作如下:1.研究了自旋和進(jìn)動(dòng)目標(biāo)的微多普勒和距離-慢時(shí)間回波的時(shí)變特性,分析了其成像的難點(diǎn)在于難以直接在方位向采用傅立葉變換壓縮成像。根據(jù)是否需要事先估計(jì)自旋角速度等微動(dòng)參數(shù),將微動(dòng)目標(biāo)成像方法分為了基于非微動(dòng)參量估計(jì)的成像法和基于微動(dòng)參量估計(jì)的成像法,并簡(jiǎn)要介紹了其處理過(guò)程。2.研究了基于非微動(dòng)參量估計(jì)的自旋目標(biāo)時(shí)頻分析瞬時(shí)成像法,針對(duì)目標(biāo)轉(zhuǎn)速較大時(shí)隨機(jī)選取瞬時(shí)像可能選取到成像質(zhì)量較差的圖像來(lái)這一不足,提出了一種分段優(yōu)選策略。采用圖像對(duì)比度最優(yōu)準(zhǔn)則,最終得到一組不同時(shí)間段下的較好目標(biāo)圖像,并進(jìn)行了仿真驗(yàn)證。3.分析了在有角速度估計(jì)誤差時(shí)的自旋目標(biāo)成像,基于微動(dòng)參量估計(jì)的后向投影變換法(BPT)主要表現(xiàn)為能量發(fā)散并出現(xiàn)虛假點(diǎn),此外當(dāng)存在網(wǎng)格誤差也會(huì)出現(xiàn)虛假點(diǎn)。針對(duì)這些不足,在分析包絡(luò)檢測(cè)的基礎(chǔ)上提出了一種結(jié)合廣義Radon變換(GRT)的聯(lián)合成像法(GRT-BPT)。該方法利用加權(quán)互篩在成像效果和誤差容限間取得了一個(gè)平衡,推廣到進(jìn)動(dòng)旋轉(zhuǎn)對(duì)稱目標(biāo)成像中也取得了較好效果。4.從在固有微動(dòng)參數(shù)誤差容限下提高成像效果的角度研究了角速度存在估計(jì)誤差時(shí)的快速自旋目標(biāo)成像法,在目標(biāo)回波傳統(tǒng)周期重采樣消除自旋效應(yīng)的基礎(chǔ)上提出了自旋對(duì)稱目標(biāo)半周期重采樣法以及遮擋目標(biāo)間隔半周期重采樣法。并對(duì)重采樣所需自旋角速度估計(jì)精度進(jìn)行了分析,指出了其誤差容限。由于重采樣后得到的回波數(shù)據(jù)較少,文中改進(jìn)了標(biāo)準(zhǔn)傅立葉基,并利用壓縮感知手段成像。仿真實(shí)驗(yàn)表明其避免了重采樣后直接進(jìn)行RD成像的圖像模糊問(wèn)題。
[Abstract]:Space fretting target is an important kind of space target. With the increasing of human space activities, fretting target imaging has become a research hotspot because it can provide important information for target recognition and space security. However, because most of these targets do not satisfy the small angle approximation, the existing imaging methods are difficult to achieve a more ideal imaging effect, so more in-depth research is needed. Aiming at the particularity of fretting target imaging, this paper summarizes the imaging difficulties and imaging methods based on the analysis of micro-Doppler and range-slow time echo. The time-frequency analysis instantaneous imaging method based on non-fretting parameter estimation is optimized. In this paper, the backward projection transform imaging method is improved from the angle of increasing error tolerance of fretting parameters, and it is extended to precession rotating symmetric target. The spin target imaging method based on resampling and compression sensing is improved from the point of view of improving the imaging effect under the error tolerance of inherent fretting parameters. The main work of this paper is as follows: 1. The time-varying characteristics of micro-Doppler and range-slow time echo of spin and precession targets are studied. The difficulty of imaging is that it is difficult to use Fourier transform compression imaging directly in azimuth direction. According to whether it is necessary to estimate the spin angular velocity and other fretting parameters in advance, the fretting target imaging method is divided into two methods: the imaging method based on the non-fretting parameter estimation and the imaging method based on the fretting parameter estimation, and the processing process is introduced briefly. 2. In this paper, the time-frequency analysis instantaneous imaging method of spin target based on non-fretting parameter estimation is studied. In order to solve the problem of random selection of instantaneous image to the image with poor imaging quality when the speed of target is high, a piecewise optimal selection strategy is proposed. Finally, a group of better target images in different time periods are obtained by using the optimal contrast criterion, and the simulation results are verified. In this paper, the spin target imaging with angular velocity estimation error is analyzed. The backward projection transformation method based on fretting parameter estimation (BPT) is mainly characterized by energy divergence and false points, in addition, there are false points in the presence of mesh errors. Based on the analysis of envelope detection, a combined imaging method (GRT-BPT) combined with generalized Radon transform (GRT) is proposed. A balance between the imaging effect and the error tolerance is obtained by using the weighted mutual sieve, and the method is extended to the imaging of the precession rotating symmetric target. 4. In this paper, the fast spin target imaging method with angular velocity estimation error is studied from the angle of improving the imaging effect under the tolerance of inherent fretting parameter error. Based on the traditional periodic resampling of target echo to eliminate the spin effect, a semi-periodic resampling method and a half-period resampling method for blocking the target are proposed. The accuracy of spin angular velocity estimation for resampling is analyzed and the error tolerance is pointed out. Because the echo data after resampling is less, the standard Fu Li leaf base is improved, and the compression sensing method is used to image it. The simulation results show that it avoids the image blur problem of RD imaging directly after resampling.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TN957.52

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 邵長(zhǎng)宇;杜蘭;韓勛;劉宏偉;;基于雙視角距離像序列的空間錐體目標(biāo)參數(shù)估計(jì)方法[J];電子與信息學(xué)報(bào);2015年11期

2 張豪;李松;羅迎;岳韶華;;彈道目標(biāo)進(jìn)動(dòng)頻率精確提取方法研究[J];計(jì)算機(jī)仿真;2015年08期

3 曹文杰;張磊;杜蘭;劉宏偉;;基于瞬時(shí)頻率估計(jì)的進(jìn)動(dòng)錐體目標(biāo)微多普勒頻率提取方法[J];電子與信息學(xué)報(bào);2015年05期

4 胡杰民;占榮輝;牛威;歐建平;;基于后向投影變換的進(jìn)動(dòng)旋轉(zhuǎn)對(duì)稱目標(biāo)成像新方法[J];電子與信息學(xué)報(bào);2012年08期

5 王虹現(xiàn);梁毅;邢孟道;張守宏;;基于稀疏信號(hào)表示的空間碎片成像[J];宇航學(xué)報(bào);2011年10期

6 ;Narrow-band radar imaging of spinning targets[J];Science China(Information Sciences);2011年04期

7 吳亮;魏璽章;黎湘;凌永順;;基于距離-慢時(shí)間匹配濾波和復(fù)值反投影的快速旋轉(zhuǎn)目標(biāo)三維成像算法[J];信號(hào)處理;2010年12期

8 張磊;李亞超;劉燕;邢孟道;保錚;;基于時(shí)頻特性的窄帶高速自旋目標(biāo)運(yùn)動(dòng)估計(jì)及成像算法[J];中國(guó)科學(xué):信息科學(xué);2010年06期

9 ;Narrowband imaging method for spatial precession cone-shaped targets[J];Science China(Technological Sciences);2010年04期

10 劉進(jìn);王雪松;李文臣;王濤;;基于進(jìn)動(dòng)的旋轉(zhuǎn)對(duì)稱彈頭雷達(dá)成像方法[J];信號(hào)處理;2009年09期

相關(guān)博士學(xué)位論文 前3條

1 黃雅靜;大轉(zhuǎn)角目標(biāo)ISAR成像技術(shù)研究[D];國(guó)防科學(xué)技術(shù)大學(xué);2013年

2 劉記紅;基于壓縮感知的ISAR成像技術(shù)研究[D];國(guó)防科學(xué)技術(shù)大學(xué);2012年

3 吳亮;復(fù)雜運(yùn)動(dòng)目標(biāo)ISAR成像技術(shù)研究[D];國(guó)防科學(xué)技術(shù)大學(xué);2012年

相關(guān)碩士學(xué)位論文 前1條

1 曹攀;高分辨ISAR成像中運(yùn)動(dòng)補(bǔ)償技術(shù)研究[D];西安電子科技大學(xué);2011年

，

本文編號(hào)：2407722