本文選題：合成孔徑雷達(dá) + 運(yùn)動(dòng)目標(biāo)檢測(cè)�。� 參考：《西安電子科技大學(xué)》2014年碩士論文

【摘要】：合成孔徑雷達(dá)地面運(yùn)動(dòng)目標(biāo)檢測(cè)(SAR-GMTI)系統(tǒng)在對(duì)觀測(cè)場(chǎng)景進(jìn)行二維高分辨率成像的同時(shí)還能檢測(cè)場(chǎng)景中的運(yùn)動(dòng)目標(biāo),目前已經(jīng)廣泛應(yīng)用于軍用和民用領(lǐng)域。本文主要對(duì)SAR-GMTI系統(tǒng)的檢測(cè)性能進(jìn)行了研究,分析了影響檢測(cè)性能的各個(gè)因素,并針對(duì)運(yùn)動(dòng)目標(biāo)的散焦效應(yīng)對(duì)系統(tǒng)檢測(cè)性能造成的不利影響提出了改進(jìn)的方法。SAR-GMTI系統(tǒng)的自由度比較低,系統(tǒng)的檢測(cè)性能和參數(shù)估計(jì)性能不高,而MIMO雷達(dá)通過(guò)多天線同時(shí)發(fā)射和接收相互正交的信號(hào),可以獲得遠(yuǎn)多于天線個(gè)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(biāo)檢測(cè)能力等性能。本文的主要研究?jī)?nèi)容有以下幾點(diǎn):1.研究了SAR-GMTI系統(tǒng)檢測(cè)概率的計(jì)算流程,對(duì)不同計(jì)算環(huán)節(jié)中涉及到的各個(gè)因素分別進(jìn)行了分析,并說(shuō)明了其對(duì)系統(tǒng)檢測(cè)性能的影響。2.研究了運(yùn)動(dòng)目標(biāo)的散焦效應(yīng)。由于運(yùn)動(dòng)目標(biāo)存在方位向速度,其成像結(jié)果會(huì)出現(xiàn)散焦,這會(huì)造成目標(biāo)的能量分散,信雜噪比下降,因而不利于運(yùn)動(dòng)目標(biāo)的檢測(cè)。針對(duì)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(duì)運(yùn)動(dòng)目標(biāo)進(jìn)行重聚焦,可以使運(yùn)動(dòng)目標(biāo)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(cè)性能。并針對(duì)兩種算法的優(yōu)缺點(diǎn)進(jìn)行了分析。3.研究了MIMO-SAR GMTI系統(tǒng)信號(hào)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(cè)條帶之間的矛盾,而且還能獲得更好的系統(tǒng)檢測(cè)性能。MIMO-SAR系統(tǒng)在距離向發(fā)射載頻不同的窄帶信號(hào),然后經(jīng)頻譜疊加合成大帶寬信號(hào),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(cè)到更慢速或更弱小的目標(biāo)。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(duì)應(yīng)的可檢測(cè)速度范圍不同,解決了速度模糊和盲速問(wèn)題,使得運(yùn)動(dòng)目標(biāo)的參數(shù)估計(jì)更加準(zhǔn)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(xué)位授予單位】：西安電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：TN957.52

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相關(guān)期刊論文 前1條

1 孫娜,周蔭清,李景文;一種新的雙孔徑天線干涉SAR動(dòng)目標(biāo)檢測(cè)方法[J];電子學(xué)報(bào);2003年12期

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本文編號(hào)：1961241