本文選題：SAR　切入點：FPGA　出處：《西安電子科技大學》2014年碩士論文　論文類型：學位論文

【摘要】：合成孔徑雷達(SAR)成像技術是雷達技術中一個十分重要的應用。而以無人機作為運動載體,高分辨微型SAR實時成像技術也日益成為研究熱點。與傳統(tǒng)的機載雷達相比,無人機上微型SAR實時成像系統(tǒng)對雷達的體積、重量、功耗都有苛刻的要求。本文主要論述了一種基于單片F(xiàn)PGA的雷達實時成像系統(tǒng)。本文首先介紹了合成孔徑雷達實時成像處理技術的發(fā)展狀況和應用,對基于FPGA的成像系統(tǒng)做了總體介紹。隨后,本文對合成孔徑雷達的成像原理進行分析以及對主處理芯片進行選型。文中確定了成像算法,采用距離多普勒算法。系統(tǒng)設計中處理芯片選擇了Z7系列芯片。Zynq-7000系列產品是首款在一塊芯片上同時集成了雙核ARM和FPGA的芯片。ARM處理器的主要優(yōu)勢在于能夠高效地控制系統(tǒng)流程。同時對于復雜的高精度算法(如運動參數(shù)估計、多普勒中心估計)也可以由ARM處理器進行處理。而芯片中集成的FPGA可以完成成像的主要算法流程,來實現(xiàn)實時成像處理。數(shù)據(jù)預處理是實現(xiàn)實時成像的重要環(huán)節(jié)。數(shù)字下變頻將中頻直接采集的數(shù)字信號轉變?yōu)榛鶐盘�。�?jīng)數(shù)字下變頻處理后的數(shù)據(jù)進行濾波抽取,濾波抽取在保證距離向信號不失真的同時減少了數(shù)據(jù)量,節(jié)省資源。方位向預濾波在保證方位向信號不失真的同時減少數(shù)據(jù)量,增加處理時間間隔。方位向預濾波前的數(shù)據(jù)10KHz,而方位預濾波后,數(shù)據(jù)的重頻為500Hz。距離脈壓完成了距離向的一維脈沖壓縮處理。成像算法處理是在數(shù)據(jù)預處理之后進行的,主要包括一次補償、距離徙動校正和方位壓縮。一次補償、距離徙動校正操作使成像更加清晰,分辨率更高。經(jīng)方位脈壓后,最終實現(xiàn)系統(tǒng)成像處理。為了節(jié)省資源,更高效地進行成像處理,本文提出了模塊復用的思想。根據(jù)一次補償、距離徙動校正、方位脈壓的結構特點,將三個模塊用一個模塊復用處理,實現(xiàn)資源高利用率。最后對系統(tǒng)進行測試,一幅SAR圖像方位向數(shù)據(jù)位8192,而數(shù)據(jù)重頻為500Hz,則要求在16s內必須完成一幅圖的處理,在本系統(tǒng)中,10s就可以完成圖像處理,所以達到了實時成像的要求,完成了任務指標。最后是對本文工作的總結與展望。用本文論述的方法能達到更高的成像分辨率。
[Abstract]:Synthetic Aperture Radar (SAR) imaging technology is a very important application in radar technology, and with UAV as motion carrier, high-resolution micro-#en0# real-time imaging technology has become a hot spot. The volume and weight of the micro SAR real-time imaging system on the UAV, This paper mainly discusses a kind of radar real-time imaging system based on monolithic FPGA. Firstly, this paper introduces the development and application of SAR real-time imaging processing technology. The imaging system based on FPGA is introduced. Then, the imaging principle of synthetic Aperture Radar (SAR) is analyzed and the main processing chip is selected. In the system design, the processing chip selected Z7 series chip. Zynq-7000 series product is the first chip to integrate dual core ARM and FPGA on a single chip. The main advantage of the chip. Arm processor is that it can efficiently. Control system flow. For complex high-precision algorithms, such as motion parameter estimation, Doppler center estimation) can also be processed by the ARM processor. And the integrated FPGA in the chip can complete the main algorithm flow of imaging. Data preprocessing is an important link to realize real-time imaging. Digital downconversion converts the digital signal directly collected by if into baseband signal. The data processed by digital down-conversion is filtered and extracted. Filtering decimation reduces the amount of data while ensuring that the distance signal is not distorted and saves resources.; the azimuth prefiltering ensures that the azimuth signal is not distorted and the amount of data is reduced at the same time. Increase the processing time interval. The data before azimuth pre-filtering is 10kHz, and after azimuth pre-filtering, the data repetition frequency is 500Hz. It mainly includes primary compensation, range migration correction and azimuth compression. First compensation, range migration correction operation makes the imaging clearer and higher resolution. After azimuth pulse compression, the system image processing is finally realized. For more efficient imaging processing, this paper presents the idea of module multiplexing. According to the structural characteristics of primary compensation, range migration correction and azimuth pulse compression, the three modules are multiplexed with one module. Finally, a SAR image with a azimuth data bit 81922 and a data repetition frequency of 500Hz is required to complete the processing of a picture in 16s. In this system, the image processing can be completed in 10s. Therefore, the requirements of real-time imaging are achieved, and the task targets are fulfilled. Finally, the work of this paper is summarized and prospected. The method discussed in this paper can achieve higher imaging resolution.
【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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本文編號：1633584