本文關(guān)鍵詞：海雜波中目標(biāo)檢測(cè)的時(shí)頻方法研究　出處：《西安電子科技大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 海雜波 功率譜密度 時(shí)頻特性 FRFT

【摘要】：隨著對(duì)地高分辨觀測(cè)技術(shù)的發(fā)展,海雜波的背景中目標(biāo)的識(shí)別和檢測(cè)越來(lái)越成為熱門(mén)研究話題。海面目標(biāo)的回波,主要是來(lái)自海面背景本身的雜波和目標(biāo)的散射回波。要實(shí)現(xiàn)雷達(dá)對(duì)海面目標(biāo)的檢測(cè),就要區(qū)分這兩種散射回波的特征。因此,論文基于加拿大McMaster大學(xué)IPIX雷達(dá)實(shí)測(cè)數(shù)據(jù),利用時(shí)頻分析方法,研究背景海雜波和目標(biāo)的散射回波的特性。論文的主要工作如下：1、介紹了兩種典型的雷達(dá)海雜波數(shù)據(jù)的產(chǎn)生方法,即無(wú)記憶非線性變換法(ZMNL)和球不變隨機(jī)過(guò)程法(SIRP)。重點(diǎn)用ZMNL法產(chǎn)生了符合瑞利分布、對(duì)數(shù)正態(tài)分布和韋伯兒分布的海雜波。用SIRP方法產(chǎn)生了符合相關(guān)K分布的海雜波,并分析了兩種雜波的產(chǎn)生方法的優(yōu)缺點(diǎn)。2、分析了海雜波的功率譜特性。研究海雜波功率譜的估計(jì)方法有經(jīng)典的周期圖法和現(xiàn)代譜估計(jì)法,用這兩種方法分析了實(shí)測(cè)海雜波數(shù)據(jù)的功率譜,結(jié)果表明不同極化和海情的雜波的功率譜存在差異,同時(shí)發(fā)現(xiàn)現(xiàn)代譜分析方法比經(jīng)典的周期圖法取得更加平滑和清晰的效果。然后用相關(guān)函數(shù)法分析了海雜波的時(shí)間相關(guān)性,研究表明海雜波的時(shí)間相關(guān)性都有一個(gè)共同的特點(diǎn)就是經(jīng)歷過(guò)一個(gè)去相關(guān)時(shí)間,然后是一個(gè)比較長(zhǎng)的衰減期直到相關(guān)函數(shù)值幾乎為O。然后對(duì)海雜波的空間相關(guān)性作了分析。3、研究了實(shí)測(cè)海雜波數(shù)據(jù)的統(tǒng)計(jì)特性。列舉了瑞利分布、對(duì)數(shù)正態(tài)分布、韋伯兒分布和K分布這四種統(tǒng)計(jì)分布模型。根據(jù)實(shí)測(cè)海雜波數(shù)據(jù),用理論分布模型和實(shí)際分布進(jìn)行了對(duì)比研究,結(jié)果表明相關(guān)K分布可以很好地?cái)M合實(shí)測(cè)海雜波數(shù)據(jù)。4、描述了背景海雜波和帶目標(biāo)的海雜波的時(shí)頻分析方法。包括短時(shí)傅里葉變換法(STFT),維格納分布法(Wigner-Ville)法,Wigner-Hough變換法,分?jǐn)?shù)階傅里葉變換法(FRFT)。然后用實(shí)測(cè)海雜波數(shù)據(jù)對(duì)以上方法的有效性進(jìn)行了驗(yàn)證和對(duì)比,發(fā)現(xiàn)短時(shí)傅里葉變換能夠得到清晰的時(shí)頻分布特性。然后用Matlab仿真實(shí)測(cè)海雜波數(shù)據(jù)的維格納分布、平滑維格納分布和平滑偽維格納分布,仿真結(jié)果表明平滑偽維格納分布能夠有效克服交叉干擾項(xiàng)對(duì)維格納分布帶來(lái)的影響,取得較好的時(shí)頻分析效果。同時(shí)通過(guò)研究背景海雜波數(shù)據(jù)和帶目標(biāo)的雜波數(shù)據(jù)可以發(fā)現(xiàn)維格納分布可以識(shí)別海面慢速運(yùn)動(dòng)的目標(biāo),并且在二維的時(shí)頻圖上得到直線帶狀結(jié)構(gòu),而Wigner-Hough變換可以識(shí)別這種直線帶狀結(jié)構(gòu),通過(guò)坐標(biāo)變換可以得到非常清晰的直線尖峰,從而進(jìn)一步驗(yàn)證了Wigner-Ville方法對(duì)海面目標(biāo)識(shí)別的應(yīng)用。另外,還確定了背景海雜波和帶目標(biāo)的雜波在經(jīng)過(guò)分?jǐn)?shù)階傅里葉變換后,在最佳變換區(qū)域內(nèi)得到不同的分形特征,為海面目標(biāo)識(shí)別提供了依據(jù)。
[Abstract]:With the development of high-resolution observation technology, target recognition and detection in sea clutter background has become a hot topic. It is mainly clutter from sea background and scattering echo from target. In order to detect sea surface target by radar, it is necessary to distinguish the characteristics of these two kinds of scattering echo. Based on the measured data of IPIX radar at McMaster University in Canada, the characteristics of background sea clutter and scattering echo of target are studied by using time-frequency analysis method. The main work of this paper is as follows: 1. Two typical methods for generating radar sea clutter data are introduced. That is, the memoryless nonlinear transformation method (ZMNL) and the spherical invariant stochastic process method (SIRP). The emphasis is on the ZMNL method, which is consistent with the Rayleigh distribution. The sea clutter with logarithmic normal distribution and Weber distribution is generated by SIRP method, and the advantages and disadvantages of the two methods are analyzed. The power spectrum characteristics of sea clutter are analyzed. The classical periodic chart method and modern spectrum estimation method are used to estimate the power spectrum of sea clutter data, and the power spectrum of measured sea clutter data is analyzed by these two methods. The results show that there are differences in the power spectrum of the clutter with different polarization and sea conditions. At the same time, it is found that the modern spectral analysis method is more smooth and clear than the classical periodic chart method, and then the correlation function method is used to analyze the temporal correlation of sea clutter. The research shows that the temporal correlation of sea clutter has a common characteristic, that is, it has experienced a de-correlation time. Then a long attenuation period until the correlation function value is almost O. then the spatial correlation of sea clutter is analyzed. 3. The statistical characteristics of the measured sea clutter data are studied and the Rayleigh distribution is listed. The four statistical distribution models of logarithmic normal distribution, Weber distribution and K distribution are compared and studied by using the theoretical distribution model and the actual distribution according to the measured sea clutter data. The results show that the correlation K distribution can fit the measured sea clutter data. 4. The time-frequency analysis method of background sea clutter and sea clutter with target is described, including STFT (short time Fourier transform). Wigner-Hough transform is a Wigner-Ville-based distribution method. The fractional Fourier transform method is used to verify and compare the effectiveness of the above method with the measured sea clutter data. It is found that the short-time Fourier transform can obtain a clear time-frequency distribution, and then the Wigner distribution, smooth Wigner distribution and smooth pseudo-Wigner distribution of sea clutter data measured by Matlab are simulated. Simulation results show that smooth pseudo-Wigner distribution can effectively overcome the influence of cross-interference on Wigner distribution. At the same time, by studying background sea clutter data and clutter with target data, we can find that Wigner distribution can identify slow moving target. And the linear band structure can be obtained on the two-dimensional time-frequency map, and the Wigner-Hough transform can identify the linear band structure, and can get a very clear straight line spike by coordinate transformation. The application of Wigner-Ville method to sea surface target recognition is further verified. In addition, the background sea clutter and the clutter with target are determined after fractional Fourier transform. Different fractal features are obtained in the optimal transform region, which provides a basis for the recognition of sea surface targets.
【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
【分類號(hào)】：P715

【參考文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前1條

1 鄧澤懷;基于實(shí)測(cè)數(shù)據(jù)的海雜波統(tǒng)計(jì)建模[D];西安電子科技大學(xué);2014年

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本文編號(hào)：1436148