本文關(guān)鍵詞： 導航抗干擾 采樣矩陣求逆 空時結(jié)構(gòu) FPGA實現(xiàn)　出處：《電子科技大學》2014年碩士論文　論文類型：學位論文

【摘要】：全球衛(wèi)星導航系統(tǒng)在民用領(lǐng)域的普及程度越來越高,在軍事領(lǐng)域的重要性更是日益凸顯,但同時由自身脆弱性所導致的極易受到人為干擾破壞的問題也很嚴重。改善衛(wèi)星性能和排布方式雖然是最有效的抗干擾手段,但成本過高而且耗時很長,因此利用軟件無線電技術(shù)在接收終端進行干擾抑制是目前的主流方向。本文在這樣的背景下對基于陣列信號處理的接收終端抗干擾技術(shù)及其硬件實現(xiàn)進行了研究和分析。功率倒置是基于陣列的導航抗干擾中最常用的方法之一,基于功率倒置的權(quán)值更新算法較多,其中LMS(最小均方誤差)算法因其在實現(xiàn)時運算量較小而成為工程首選,但是LMS也存在著自身無法回避的缺陷。本文在此基礎(chǔ)上詳細介紹了另外一種計算權(quán)值的方法即SMI(采樣矩陣求逆)算法,最后通過仿真將它與LMS算法在純空域和空時結(jié)構(gòu)下的性能進行了對比。仿真結(jié)果說明,LMS算法的收斂性能對自相關(guān)矩陣特征值的分布十分敏感,而SMI算法則可以有效地克服這個問題;SMI的空時結(jié)構(gòu)能夠在一定程度上改善衛(wèi)星信號和干擾信號來向靠近時的信號損失問題。在算法分析的基礎(chǔ)上,本文基于一個集成Stratix II系列FPGA芯片的導航接收機前端首先介紹了AD變換以后的數(shù)字域處理流程,然后給出了純空域SMI算法的FPGA實現(xiàn)方案,并利用實測數(shù)據(jù)進行了設(shè)計中各模塊功能的仿真驗證。最后進行外場實驗,通過信號源遠場發(fā)射干擾信號,有規(guī)律地改變干擾發(fā)射類型和發(fā)射功率,通過采集片上實時數(shù)據(jù)進行頻譜分析的方法驗證空域SMI算法的干擾抑制性能。在空域算法實現(xiàn)的基礎(chǔ)上,本文通過接收機內(nèi)嵌的型號為OMAP_L138的DSP芯片制定了空時二維SMI算法的FPGA和DSP聯(lián)合實現(xiàn)方案,并著重介紹了該方案中FPGA定點運算部分各模塊的實現(xiàn)流程,通過實測數(shù)據(jù)進行了ModelSim仿真驗證。最后采取與空域相同的外場實驗手段,通過采集實時數(shù)據(jù)進行空時二維SMI算法的干擾抑制性能的分析,并與純空域進行了對比。
[Abstract]:The global satellite navigation system is becoming more and more popular in the civilian field, and the importance of the global satellite navigation system in the military field is becoming more and more prominent. But at the same time, the vulnerability caused by human interference caused by the problem is also very serious. Improving satellite performance and layout is the most effective anti-jamming means, but the cost is too high and time-consuming. So it is the mainstream direction to use the software radio technology to suppress the interference at the receiving terminal. In this paper, the anti-jamming technology and its hardware implementation of the receiving terminal based on array signal processing are studied in this paper. Power inversion is one of the most common methods in array based navigation anti-jamming. There are many weight updating algorithms based on power inversion, among which LMS (least mean Square error) algorithm is the first choice because of its small operation time. However, LMS also has its own defects. On this basis, this paper introduces another method to calculate the weight of the SMI (sampling matrix inverse) algorithm in detail. Finally, the simulation results show that the convergence performance of LMS algorithm is sensitive to the distribution of eigenvalues of autocorrelation matrix. The SMI algorithm can overcome this problem effectively. The space-time structure of SMI can improve the loss problem of satellite signal and interference signal when approaching to a certain extent. This paper introduces the digital domain processing flow after AD transform based on the front end of navigation receiver based on an integrated Stratix II series FPGA chip. Then, the FPGA implementation scheme of pure spatial SMI algorithm is given, and the function of each module is simulated with the measured data. Finally, the external field experiment is carried out, and the interference signal is transmitted by the signal source in the far field. The interference emission type and power are changed regularly, and the interference suppression performance of the spatial SMI algorithm is verified by collecting the real-time data on the chip for spectrum analysis, based on the implementation of the spatial algorithm. In this paper, the FPGA and DSP implementation scheme of space-time two-dimensional SMI algorithm is developed based on the DSP chip with OMAP_L138 embedded in the receiver. The realization flow of each module of FPGA fixed-point operation in this scheme is introduced emphatically, and the ModelSim simulation verification is carried out through the measured data. Finally, the same external field experimental means as in airspace is adopted. The interference suppression performance of space-time two-dimensional SMI algorithm is analyzed by collecting real time data and compared with pure spatial domain.
【學位授予單位】：電子科技大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN967.1

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本文編號：1478676