本文選題：雷達關聯(lián)成像 + 低信噪比��； 參考：《國防科學技術大學》2014年碩士論文

【摘要】：雷達關聯(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難點問題,具有重要的理論意義和工程實踐價值。本文圍繞正在組建的雷達關聯(lián)成像實驗系統(tǒng),建立了噪聲條件下的雷達關聯(lián)成像模型,分析了成像誤差影響因素和實驗系統(tǒng)噪聲環(huán)境,研究了低信噪比下對靜止目標和運動目標的脈沖積累方法,為實驗系統(tǒng)在低信噪比條件下實現(xiàn)對目標準確重構提供了理論參考和方法指導。第一章系統(tǒng)介紹了雷達關聯(lián)成像的課題背景和研究意義,闡述了雷達關聯(lián)成像的產生和發(fā)展歷程,介紹了本文的工作和結構安排。第二章闡述了雷達關聯(lián)成像的基本理論。首先介紹了雷達關聯(lián)成像的基本原理,分析了雷達陣列發(fā)射的隨機調制信號的時間相關性和空間相關性,然后推演了目標所在平面的空時二維隨機輻射場,最后分析了理想條件下通過參數(shù)化關聯(lián)成像方法獲得目標圖像的可行性。第三章分析了噪聲條件下的雷達關聯(lián)成像誤差。首先建立了噪聲條件下雷達關聯(lián)成像的參數(shù)化模型,通過理論推導得出參數(shù)估計誤差與接收信號的信噪比、發(fā)射信號帶寬、目標散射點個數(shù)以及回波時延等因素有關,通過仿真實驗驗證了以上觀點的正確性。最后結合系統(tǒng)參數(shù)分析了發(fā)射通道和接收通道的噪聲水平,為稀疏重構算法提供了噪聲先驗。第四章研究了低信噪比下的雷達關聯(lián)成像算法。首先分析了稀疏重構算法對低信噪比下雷達關聯(lián)成像的適用性,然后針對靜止目標分析了相參積累的效果,仿真結果和理論推導結果吻合,最后提出了對運動目標的非相參積累方法,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重構質量。最后對全文進行了總結,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.
【學位授予單位】：國防科學技術大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN957.52

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本文編號：1968262