本文選題：太赫茲 + 雜波特性　； 參考：《電子科技大學(xué)》2016年博士論文

【摘要】：太赫茲(Terahertz,THz)波在電磁波譜中位于微波頻段向光學(xué)頻段之間的過渡區(qū)域。相比于微波頻段,太赫茲波具有較短的波長,易實現(xiàn)大時寬帶寬積信號和極窄的天線波束;同時,多普勒效應(yīng)在太赫茲頻段更加明顯,有利于對運動目標(biāo)的檢測與跟蹤。與光學(xué)頻段相比,太赫茲波對非極性材料具有良好的穿透能力,可以應(yīng)用于隱蔽目標(biāo)的探測與成像。以上這些優(yōu)勢使得太赫茲技術(shù)在目標(biāo)探測領(lǐng)域成為研究熱點之一,具有重要的研究意義與廣闊的應(yīng)用前景。由于太赫茲波在電磁波譜中的特殊位置,傳統(tǒng)的電磁波理論和光學(xué)理論都無法準(zhǔn)確描述該頻段的電磁散射特性,這為利用太赫茲技術(shù)進行雷達(dá)目標(biāo)探測帶來了困難。相比于微波與光學(xué)雷達(dá),關(guān)于太赫茲雷達(dá)的研究剛剛興起,特別是由于太赫茲雷達(dá)系統(tǒng)關(guān)鍵器件的研制水平相對滯后,直至近幾年來才有較為穩(wěn)定的太赫茲雷達(dá)系統(tǒng)樣機問世。正是由于上述原因,對太赫茲頻段雜波和目標(biāo)特性的研究一直缺乏實測數(shù)據(jù)進行分析與驗證,這也使得利用太赫茲雷達(dá)進行目標(biāo)檢測遇到了一定的困難。本文針對上述問題,在對傳統(tǒng)頻段雷達(dá)雜波與目標(biāo)特性、檢測算法進行總結(jié)和分析的基礎(chǔ)上,以太赫茲雷達(dá)實驗為基礎(chǔ),對太赫茲頻段目標(biāo)探測的關(guān)鍵技術(shù)進行了一系列的研究。論文的主要工作和貢獻(xiàn)包括以下幾個方面:1.在總結(jié)太赫茲雷達(dá)系統(tǒng)進展、傳統(tǒng)雷達(dá)雜波與目標(biāo)特性、檢測理論和方法的基礎(chǔ)上,結(jié)合太赫茲雷達(dá)的特點,分析了利用太赫茲技術(shù)進行雷達(dá)目標(biāo)探測時存在的問題。2.針對太赫茲雷達(dá)系統(tǒng)噪聲與地雜波統(tǒng)計建模的問題,提出了基于MoLC的太赫茲雷達(dá)系統(tǒng)噪聲與雜波統(tǒng)計建模方法。該方法結(jié)合傳統(tǒng)雷達(dá)噪聲與雜波分布模型,利用MoLC對太赫茲雷達(dá)系統(tǒng)噪聲與地雜波的統(tǒng)計特性進行參數(shù)估計,并通過模型與實測結(jié)果之間的KL距離確定噪聲與地雜波的統(tǒng)計模型。針對太赫茲頻段非均勻地雜波的特點,對其時域與空域特性分別進行了統(tǒng)計建模,驗證了太赫茲頻段地雜波的統(tǒng)計模型,為太赫茲雷達(dá)的應(yīng)用奠定了基礎(chǔ)。3.針對太赫茲頻段目標(biāo)散射波動劇烈的問題,提出了一種基于小角度ISAR成像的太赫茲雷達(dá)目標(biāo)散射特性測量方法。該方法利用太赫茲波長短、ISAR成像所需積累角度小的特點,利用小角度ISAR成像重建目標(biāo)散射分布圖,并從中提取目標(biāo)各角度的散射特性。實驗結(jié)果表明,該方法的測量結(jié)果可以準(zhǔn)確的描述太赫茲頻段復(fù)雜目標(biāo)散射的起伏特性與統(tǒng)計特性,解決了傳統(tǒng)方法中由于目標(biāo)回波波動劇烈而導(dǎo)致的測量不準(zhǔn)確的問題。4.根據(jù)太赫茲寬帶雷達(dá)目標(biāo)HRRP特性,提出了使用單一分布模型和混合分布模型對太赫茲寬帶雷達(dá)目標(biāo)回波中不同類型距離單元進行統(tǒng)計建模的方法。該方法根據(jù)太赫茲雷達(dá)目標(biāo)回波距離單元中散射中心數(shù)量與強弱分布的不同對距離單元進行分類,并結(jié)合單一分布模型和混合分布模型對不同類型的距離單元回波統(tǒng)計特性進行建模,分別使用MoLC和DSEM對單一分布模型和混合分布模型進行參數(shù)估計。實驗結(jié)果表明,該方法可以對不同分辨率下太赫茲寬帶雷達(dá)目標(biāo)的各類距離單元進行統(tǒng)計建模,并取得良好的結(jié)果。5.根據(jù)太赫茲雷達(dá)回波特性,提出了一種基于融合中心的分布式太赫茲雷達(dá)CFAR檢測算法。該算法利用太赫茲易實現(xiàn)極窄天線波束的特點,設(shè)計了均勻分布于圓周上的分布式CFAR檢測器,每個局部檢測器通過具有極窄波束的天線對觀測區(qū)域進行掃描,并形成局部二維檢測結(jié)果,最終,通過融合中心將局部二維檢測結(jié)果進行融合,得到全局二維檢測結(jié)果。相比于單一傳感器的CFAR檢測算法,該算法不僅提高了檢測性能,并且能夠得到觀測場景內(nèi)各點目標(biāo)的二維坐標(biāo)。針對太赫茲高分辨率雷達(dá)目標(biāo)檢測的問題,結(jié)合太赫茲寬帶雷達(dá)回波特性,提出了使用基于確定散射中心模型的廣義似然比算法對太赫茲雷達(dá)距離擴展目標(biāo)進行檢測的思路,并利用實測數(shù)據(jù)對不同帶寬下的檢測性能進行了驗證與分析,為太赫茲雷達(dá)的實際應(yīng)用提供了技術(shù)支持。綜上所述,本文圍繞太赫茲雷達(dá)目標(biāo)探測關(guān)鍵技術(shù)展開了一系列研究,為太赫茲技術(shù)的實際應(yīng)用提供了一定的理論和技術(shù)支持。
[Abstract]:Terahertz (Terahertz, THz) wave in the electromagnetic spectrum in the microwave frequency band between the optical transition zone. Compared to the microwave frequency band, THz wave has shorter wavelength, easy implementation of large time bandwidth product signal and antenna beam is very narrow; at the same time, the Doppler effect is more obvious in the terahertz band, is conducive to the detection and the tracking of the moving object. Compared with the optical band, THz wave for non-polar material has good penetrating ability, can be applied to the detection and imaging of concealed targets. These advantages make the target detection in the field of terahertz technology has become a research hotspot, has important research significance and application prospect broad. Because of the special position THz wave in the electromagnetic spectrum, the traditional electromagnetic wave theory and optical theory cannot accurately describe the electromagnetic scattering characteristics of the band, this is for the use of Terahertz Technology Radar target detection difficult. Compared with microwave and optical radar, research on terahertz radar have emerged, especially due to the level of the development of key devices in terahertz radar system is lagging behind, until recent years before the advent of a terahertz radar system like machine more stable. It is because of these reasons, the research on clutter and the target of terahertz has been the lack of measured data was analyzed and verified, which also makes the target detection has encountered certain difficulties using terahertz radar. Aiming at the above problem, in the traditional band radar clutter and target characteristics, based on the analysis and summary of detection algorithm, THz radar experiment based on the key. Terahertz technology of target detection are studied. The main contributions of this thesis include the following aspects: 1. on the basis of Terahertz This progress in radar system, traditional radar clutter and target characteristics, detection theories and methods, combined with the characteristics of terahertz radar, analyzed by using terahertz technology of radar target detection problem when.2. noise in radar system and terahertz clutter statistical modeling, the terahertz radar system and noise MoLC clutter modeling method based on statistics. This method combines traditional radar noise and clutter distribution model, the statistical characteristics of the noise and clutter of the terahertz radar system by using the MoLC parameter estimation, and between the model and the measured results of the KL distance to determine noise and clutter statistical model for terahertz wave. Non uniform ground clutter the characteristics of waves on the temporal and spatial characteristics of statistical modeling, verified the clutter statistical model of THz wave, THz radar should be used for The foundation of.3. to solve the problem of terahertz scattering fluctuations, proposes a measurement method of radar target scattering characteristics of terahertz small angle based on ISAR imaging. The method using terahertz wave length, ISAR imaging features of accumulation of small angle, using small angle ISAR imaging reconstruction of target scattering distribution and extract scattering from the angle of the characteristics of the target. The experimental results show that the measurement results of this method can accurately describe the complex fluctuation characteristics of terahertz frequency and statistical characteristics of target scattering, solve the target to measure wave caused by the severe problem of inaccurate.4. based on terahertz broadband radar target HRRP characteristics due to the traditional method, is put forward methods using a single distribution model and mixed distribution model and statistical modeling of different types of terahertz range unit of wideband radar target echo in the. Method of scattering center based on terahertz radar target echo distance unit number and intensity distribution on different distance unit classification, combined with a single distribution model and mixed distribution model to model the statistical characteristics of different types of echo distance units, respectively using MoLC and DSEM on a single distribution model and mixed distribution model to estimate the parameters. The experimental results show that the this method can, various distance unit of radar target terahertz broadband different resolution for statistical modeling, and achieved good results of.5. according to the echo characteristics of terahertz radar, puts forward a kind of distributed radar CFAR detection algorithm based on terahertz fusion center. The algorithm is easy to realize by using terahertz narrow antenna beam, uniformly distributed CFAR detector distributed in the circumference of the design, each local detector has a very narrow beam through the day Line scanning of the observation area, and the formation of the 2D test results, finally, through the fusion center of local two-dimensional detection results are fused to obtain global two-dimensional detection. CFAR detection algorithm is compared to the single sensor, the algorithm not only improves the detection performance, and can obtain the two-dimensional coordinates of each point in the scene observation target. According to the high resolution radar target terahertz detection problem, combined with the characteristics of terahertz radar echo, and proposes to use the generalized likelihood to determine the scattering center model than the algorithm to detect the terahertz radar range extended target detection based on the idea of the performance of different bandwidth and the measured data were validated and analyzed, which provides technical support for the practical application terahertz radar. In summary, this paper focuses on the key technology of terahertz radar target detection has launched a series of research, It provides some theoretical and technical support for the practical application of terahertz technology.

【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2016
【分類號】：TN957.51
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本文編號：1752444