本文選題：無源雷達　切入點：機會照射源　出處：《南京航空航天大學》2014年碩士論文　論文類型：學位論文

【摘要】：無源雷達是一種自身不發(fā)射電磁信號的雷達,它利用各種外部輻射源實現(xiàn)對目標的無源檢測與成像,因此具有良好的電子對抗特性。隨著科技的不斷發(fā)展,近些年可用外部機會照射源的數(shù)量日益增多,分布更加廣泛,由于不僅可獲得良好的電子對抗特性,還可節(jié)省系統(tǒng)成本和節(jié)約頻帶資源,基于機會照射源的無源雷達再次成為研究熱點。另一方面,動目標是一類非常重要的雷達目標,針對動目標的探測與成像技術一直以來是雷達領域的重要研究內容�；谏鲜鰞煞矫�,論文開展利用WiMAX、WiFi等外部機會照射源的無源雷達動目標成像方法研究。首先簡要介紹無源雷達的概念及其成像技術,回顧國內外相關研究現(xiàn)狀,并給出本文的研究背景、意義及主要內容。然后開展利用機會照射源的無源逆合成孔徑雷達(ISAR)成像技術研究。ISAR是一種用于非合作運動目標成像的雷達,可獲得動目標的高分辨圖像,用于雷達目標識別�；跈C會照射源的ISAR成像屬于雙基ISAR成像,論文首先闡述雙基ISAR成像原理,以及必需的ISAR運動補償和成像方法,然后以復雜海情下艦船目標成像為例,采用WiMAX信號,給出具體的無源艦船成像方法和成像處理流程,最后利用WiMAX信號對無源ISAR成像性能進行驗證。目前大部分已有無源成像方法假定發(fā)射源信息已知或是通過輔助手段獲取,然后經過最佳匹配接收處理,然而發(fā)射信號的信息通常很難獲得,且會增加系統(tǒng)的硬件成本。論文給出一種無需發(fā)射源信息的無源成像方法。該方法基于廣義似然比檢驗理論,且適用于合作與非合作運動目標成像。通過分析該成像方法的點目標擴展函數(shù),對動目標成像分辨率進行分析,并在此基礎上研究不同接收機和發(fā)射源配置對成像的影響。在自由空間的基礎上,進一步研究多徑環(huán)境下的無源動目標成像。以往處理中,大多數(shù)算法均是直接將多徑信號抑制,未將其考慮到成像中。通過建立符合多徑環(huán)境下的回波模型,將多徑分量引入到成像中,研究其對成像可能存在的積極與消極作用。由于大部分機會照射源帶寬窄,導致成像距離向分辨較差,針對這一現(xiàn)狀,論文研究利用多通道合成技術以改善系統(tǒng)的距離向分辨。首先建立多通道信號模型,推導多通道帶寬合成處理方法,然后以多通道DVB-T信號為例,給出模糊函數(shù)特性分析并進行仿真實驗。結果表明成像的距離分辨率得到提高,驗證了該處理技術的有效性。論文最后對全文所做工作進行總結,指出仍需進一步研究的問題。
[Abstract]:Passive radar is a kind of radar which does not transmit electromagnetic signal by itself. It uses various external emitter sources to realize passive detection and imaging of target, so it has good characteristics of electronic countermeasure. With the development of science and technology, In recent years, the number and distribution of sources of exposure to external opportunities available are increasing and more widely distributed, as a result of which good electronic countermeasures characteristics can be obtained, as well as system cost savings and frequency band resources savings, Passive radar based on opportunistic irradiating source has become a research hotspot again. On the other hand, moving target is a kind of very important radar target. Detection and imaging technology for moving targets has been an important research content in radar field. Based on the above two aspects, In this paper, the imaging method of passive radar moving target using external opportunity sources such as WiMAXY WiFi is studied. Firstly, the concept and imaging technology of passive radar are briefly introduced, and the research status at home and abroad is reviewed, and the research background of this paper is given. Research on passive inverse synthetic Aperture Radar (ISAR) Imaging using opportunistic irradiating sources. ISAR is a kind of radar used for imaging non-cooperative moving targets, which can obtain high resolution images of moving targets. For radar target recognition, ISAR imaging based on opportunity source is bistatic ISAR imaging. The principle of bistatic ISAR imaging, the necessary ISAR motion compensation and imaging methods are described in this paper, and then the ship target imaging under complex sea conditions is taken as an example. Using WiMAX signal, the specific imaging method and processing flow of passive ship are given. At last, the passive ISAR imaging performance is verified by WiMAX signal. At present, most of the existing passive imaging methods assume that the source information is known or obtained by auxiliary means, and then receive the best matching processing. However, the information of transmitted signals is usually difficult to obtain and increases the hardware cost of the system. In this paper, a passive imaging method without transmitting source information is presented. The method is based on the generalized likelihood ratio test theory. And it is suitable for cooperative and non-cooperative moving target imaging. The resolution of moving target imaging is analyzed by analyzing the point target expansion function of the imaging method. On this basis, the influence of different receiver and source configuration on imaging is studied. On the basis of free space, the passive target imaging in multipath environment is further studied. Most of the algorithms directly suppress the multipath signal and do not take it into account. By establishing the echo model in a multipath environment, the multipath component is introduced into the imaging system. To study its possible positive and negative effects on imaging. Because of the narrow width of the source band due to most opportunities, the range resolution of the imaging is poor, and in view of this situation, In this paper, the multi-channel synthesis technology is used to improve the range resolution of the system. Firstly, the multi-channel signal model is established, and the processing method of multi-channel bandwidth synthesis is derived, and then the multi-channel DVB-T signal is taken as an example. The characteristics of the ambiguity function are analyzed and simulated. The results show that the range resolution of the imaging is improved, and the effectiveness of the processing technique is verified. Finally, the paper summarizes the work done in this paper, and points out the problems that need further study.
【學位授予單位】：南京航空航天大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN958.97
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本文編號：1596912