本文選題：雷達(dá)關(guān)聯(lián)成像 + 低信噪比��； 參考：《國防科學(xué)技術(shù)大學(xué)》2014年碩士論文

【摘要】：雷達(dá)關(guān)聯(lián)成像是一種新穎的凝視高分辨成像方法,其在低信噪比條件下的成像算法是一個(gè)難點(diǎn)問題,具有重要的理論意義和工程實(shí)踐價(jià)值。本文圍繞正在組建的雷達(dá)關(guān)聯(lián)成像實(shí)驗(yàn)系統(tǒng),建立了噪聲條件下的雷達(dá)關(guān)聯(lián)成像模型,分析了成像誤差影響因素和實(shí)驗(yàn)系統(tǒng)噪聲環(huán)境,研究了低信噪比下對靜止目標(biāo)和運(yùn)動(dòng)目標(biāo)的脈沖積累方法,為實(shí)驗(yàn)系統(tǒng)在低信噪比條件下實(shí)現(xiàn)對目標(biāo)準(zhǔn)確重構(gòu)提供了理論參考和方法指導(dǎo)。第一章系統(tǒng)介紹了雷達(dá)關(guān)聯(lián)成像的課題背景和研究意義,闡述了雷達(dá)關(guān)聯(lián)成像的產(chǎn)生和發(fā)展歷程,介紹了本文的工作和結(jié)構(gòu)安排。第二章闡述了雷達(dá)關(guān)聯(lián)成像的基本理論。首先介紹了雷達(dá)關(guān)聯(lián)成像的基本原理,分析了雷達(dá)陣列發(fā)射的隨機(jī)調(diào)制信號的時(shí)間相關(guān)性和空間相關(guān)性,然后推演了目標(biāo)所在平面的空時(shí)二維隨機(jī)輻射場,最后分析了理想條件下通過參數(shù)化關(guān)聯(lián)成像方法獲得目標(biāo)圖像的可行性。第三章分析了噪聲條件下的雷達(dá)關(guān)聯(lián)成像誤差。首先建立了噪聲條件下雷達(dá)關(guān)聯(lián)成像的參數(shù)化模型,通過理論推導(dǎo)得出參數(shù)估計(jì)誤差與接收信號的信噪比、發(fā)射信號帶寬、目標(biāo)散射點(diǎn)個(gè)數(shù)以及回波時(shí)延等因素有關(guān),通過仿真實(shí)驗(yàn)驗(yàn)證了以上觀點(diǎn)的正確性。最后結(jié)合系統(tǒng)參數(shù)分析了發(fā)射通道和接收通道的噪聲水平,為稀疏重構(gòu)算法提供了噪聲先驗(yàn)。第四章研究了低信噪比下的雷達(dá)關(guān)聯(lián)成像算法。首先分析了稀疏重構(gòu)算法對低信噪比下雷達(dá)關(guān)聯(lián)成像的適用性,然后針對靜止目標(biāo)分析了相參積累的效果,仿真結(jié)果和理論推導(dǎo)結(jié)果吻合,最后提出了對運(yùn)動(dòng)目標(biāo)的非相參積累方法,解釋了脈沖積累沒有獲得信噪比增益的原因,一定數(shù)量的脈沖積累可以提高目標(biāo)重構(gòu)質(zhì)量。最后對全文進(jìn)行了總結(jié),并提出了下一步的研究方向。
[Abstract]:Radar correlation imaging is a novel staring high-resolution imaging method. Its imaging algorithm under low signal-to-noise ratio (SNR) is a difficult problem and has important theoretical significance and practical value. In this paper, the radar correlation imaging model under the noise condition is established around the radar correlation imaging experimental system, and the influence factors of the imaging error and the noise environment of the experimental system are analyzed. The method of pulse accumulation for stationary and moving targets at low SNR is studied, which provides a theoretical reference and method guidance for the experimental system to realize accurate target reconstruction under low SNR. In the first chapter, the background and significance of radar correlation imaging are introduced systematically, the generation and development of radar correlation imaging are described, and the work and structure of this paper are introduced. The second chapter describes the basic theory of radar correlation imaging. Firstly, the basic principle of radar correlation imaging is introduced, and the temporal and spatial correlation of random modulated signals transmitted by radar array is analyzed, and then the space-time two-dimensional random radiation field of the target plane is deduced. Finally, the feasibility of obtaining target images by parameterized correlation imaging under ideal conditions is analyzed. In chapter 3, the radar correlation imaging error under noise condition is analyzed. Firstly, the parameterized model of radar correlation imaging under noise condition is established. By theoretical derivation, it is concluded that the parameter estimation error is related to the SNR of received signal, the bandwidth of transmitted signal, the number of scattering points of target, and the time delay of echo, etc. The correctness of the above views is verified by simulation experiments. Finally, the noise level of the transmission channel and the receiving channel is analyzed with the system parameters, which provides a noise priori for the sparse reconstruction algorithm. In chapter 4, the algorithm of radar correlation imaging under low signal-to-noise ratio (SNR) is studied. Firstly, the applicability of sparse reconstruction algorithm to radar correlation imaging under low SNR is analyzed, and then the effect of coherent accumulation is analyzed for stationary targets. The simulation results are consistent with the theoretical results. Finally, a non-coherent accumulation method for moving targets is proposed, which explains why the signal to noise ratio gain is not obtained by pulse accumulation, and a certain number of pulse accumulations can improve the quality of target reconstruction. Finally, the paper summarizes the full text and puts forward the next research direction.
【學(xué)位授予單位】：國防科學(xué)技術(shù)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TN957.52

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