本文選題：SAR　切入點：FPGA　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

【摘要】：合成孔徑雷達(dá)(SAR)成像技術(shù)是雷達(dá)技術(shù)中一個十分重要的應(yīng)用。而以無人機作為運動載體,高分辨微型SAR實時成像技術(shù)也日益成為研究熱點。與傳統(tǒng)的機載雷達(dá)相比,無人機上微型SAR實時成像系統(tǒng)對雷達(dá)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(dá)實時成像系統(tǒng)。本文首先介紹了合成孔徑雷達(dá)實時成像處理技術(shù)的發(fā)展?fàn)顩r和應(yīng)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(dá)的成像原理進(jìn)行分析以及對主處理芯片進(jìn)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(shè)計中處理芯片選擇了Z7系列芯片。Zynq-7000系列產(chǎn)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(fù)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(jìn)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(yù)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(zhuǎn)變?yōu)榛鶐盘�。�?jīng)數(shù)字下變頻處理后的數(shù)據(jù)進(jìn)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(yù)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(yù)濾波前的數(shù)據(jù)10KHz,而方位預(yù)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(yù)處理之后進(jìn)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(jìn)行成像處理,本文提出了模塊復(fù)用的思想。根據(jù)一次補償、距離徙動校正、方位脈壓的結(jié)構(gòu)特點,將三個模塊用一個模塊復(fù)用處理,實現(xiàn)資源高利用率。最后對系統(tǒng)進(jìn)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(nèi)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(dá)到了實時成像的要求,完成了任務(wù)指標(biāo)。最后是對本文工作的總結(jié)與展望。用本文論述的方法能達(dá)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(xué)位授予單位】：西安電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TN957.52

【參考文獻(xiàn)】

相關(guān)期刊論文 前2條

1 王吉濱,孟憲德,冀振元;直接中頻采樣實現(xiàn)正交相干檢波的研究[J];哈爾濱工業(yè)大學(xué)學(xué)報;2001年01期

2 張冠杰;張濤;張歡陽;王貞松;張守宏;;實時合成孔徑雷達(dá)成像中的專用快速CTM算法[J];西安電子科技大學(xué)學(xué)報;2006年01期

相關(guān)碩士學(xué)位論文 前1條

1 姚鑫東;基于多核DSP的實時雷達(dá)信號處理平臺設(shè)計[D];西安電子科技大學(xué);2014年

，

本文編號：1633584