本文選題：合成孔徑雷達 + 運動目標檢測�。� 參考：《西安電子科技大學》2014年碩士論文

【摘要】：合成孔徑雷達地面運動目標檢測(SAR-GMTI)系統(tǒng)在對觀測場景進行二維高分辨率成像的同時還能檢測場景中的運動目標,目前已經(jīng)廣泛應用于軍用和民用領域。本文主要對SAR-GMTI系統(tǒng)的檢測性能進行了研究,分析了影響檢測性能的各個因素,并針對運動目標的散焦效應對系統(tǒng)檢測性能造成的不利影響提出了改進的方法。SAR-GMTI系統(tǒng)的自由度比較低,系統(tǒng)的檢測性能和參數(shù)估計性能不高,而MIMO雷達通過多天線同時發(fā)射和接收相互正交的信號,可以獲得遠多于天線個數(shù)的系統(tǒng)自由度。利用MIMO-SAR GMTI系統(tǒng)的高自由度特性可以顯著提高SAR-GMTI系統(tǒng)的成像分辨率、目標檢測能力等性能。本文的主要研究內(nèi)容有以下幾點:1.研究了SAR-GMTI系統(tǒng)檢測概率的計算流程,對不同計算環(huán)節(jié)中涉及到的各個因素分別進行了分析,并說明了其對系統(tǒng)檢測性能的影響。2.研究了運動目標的散焦效應。由于運動目標存在方位向速度,其成像結(jié)果會出現(xiàn)散焦,這會造成目標的能量分散,信雜噪比下降,因而不利于運動目標的檢測。針對散焦造成的不利影響,本文利用傳統(tǒng)的相位梯度自聚焦方法和最小熵法對運動目標進行重聚焦,可以使運動目標的能量分布更加集中,增加了信雜噪比,從而提高了系統(tǒng)的檢測性能。并針對兩種算法的優(yōu)缺點進行了分析。3.研究了MIMO-SAR GMTI系統(tǒng)信號處理技術(shù)。將MIMO技術(shù)和SAR相結(jié)合,不僅可以解決SAR系統(tǒng)固有的高分辨率和寬觀測條帶之間的矛盾,而且還能獲得更好的系統(tǒng)檢測性能。MIMO-SAR系統(tǒng)在距離向發(fā)射載頻不同的窄帶信號,然后經(jīng)頻譜疊加合成大帶寬信號,可以提高系統(tǒng)在距離向上的分辨率。由于MIMO-SAR GMTI系統(tǒng)自由度高于SAR-GMTI系統(tǒng)自由度,因而可以檢測到更慢速或更弱小的目標。本文提出了一套完整的MIMO-SAR GMTI系統(tǒng)的數(shù)據(jù)處理方案,并且根據(jù)不同載頻對應的可檢測速度范圍不同,解決了速度模糊和盲速問題,使得運動目標的參數(shù)估計更加準確。
[Abstract]:The synthetic Aperture Radar (SAR) ground moving target detection system (SAR-GMTI) can detect the moving targets in the scene as well as 2D high-resolution imaging, which has been widely used in military and civil fields. In this paper, the detection performance of SAR-GMTI system is studied, and the factors that affect the detection performance are analyzed. Aiming at the adverse effect of defocusing effect of moving target on the detection performance of the system, an improved method. The degree of freedom of SAR-GMTI system is relatively low, and the detection performance and parameter estimation performance of the system are not high. MIMO radar transmits and receives orthogonal signals simultaneously by multiple antennas, which can obtain much more system degrees of freedom than the number of antennas. The high degree of freedom characteristic of MIMO-SAR GMTI system can significantly improve the imaging resolution and target detection ability of SAR-GMTI system. The main contents of this paper are as follows: 1. In this paper, the process of calculating the detection probability of SAR-GMTI system is studied, the factors involved in different calculation links are analyzed respectively, and the influence of it on the detection performance of the system is explained. The defocusing effect of moving target is studied. Because of the azimuth velocity of the moving target, the imaging result will appear defocusing, which will cause the energy dispersion of the target and the decrease of the signal-to-noise ratio, which is not conducive to the detection of the moving target. In view of the adverse effects caused by defocusing, the traditional phase gradient autofocus method and minimum entropy method are used to refocus moving targets, which can make the energy distribution of moving targets more concentrated and increase the signal-to-noise ratio. Thus, the detection performance of the system is improved. The advantages and disadvantages of the two algorithms are analyzed. The signal processing technology of MIMO-SAR GMTI system is studied. The combination of MIMO and SAR can not only solve the contradiction between high resolution and wide observation bands inherent in SAR system, but also obtain better detection performance. MIMO-SAR system can transmit different carrier frequency narrowband signals in range direction. Then a large bandwidth signal is synthesized by spectrum superposition, which can improve the resolution of the system in the range up. Because the degree of freedom of MIMO-SAR GMTI system is higher than that of SAR-GMTI system, slower or weaker targets can be detected. In this paper, a complete data processing scheme for MIMO-SAR GMTI system is proposed. According to the different range of detectable velocities corresponding to different carrier frequencies, the problem of velocity blur and blind velocity is solved, which makes the parameter estimation of moving targets more accurate.
【學位授予單位】：西安電子科技大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN957.52

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相關(guān)期刊論文 前1條

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本文編號：1961241