本文選題：軟件無(wú)線電　切入點(diǎn)：電磁環(huán)境監(jiān)測(cè)/測(cè)向　出處：《電子科技大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：軟件無(wú)線電技術(shù)的迅速發(fā)展帶動(dòng)了無(wú)線電監(jiān)測(cè)測(cè)向技術(shù)的不斷變革。目前基于軟件無(wú)線電架構(gòu)的監(jiān)測(cè)系統(tǒng)正朝著數(shù)字化、網(wǎng)絡(luò)化的方向發(fā)展。但隨著通信技術(shù)的不斷更新進(jìn)步,無(wú)線環(huán)境變得越來(lái)越復(fù)雜,例如多種不同的調(diào)制方式并存和固定帶寬內(nèi)可能存在很多形式復(fù)雜且分布密集的信號(hào)等,這些都對(duì)現(xiàn)有監(jiān)測(cè)系統(tǒng)中識(shí)別算法識(shí)別種類的多樣性,以及測(cè)向算法的精度和實(shí)時(shí)性帶來(lái)了極大的挑戰(zhàn)。本文正是以電磁環(huán)境監(jiān)測(cè)/測(cè)向系統(tǒng)為背景,主要研究?jī)?nèi)容為監(jiān)測(cè)任務(wù)中多載波和單載波信號(hào)的類間識(shí)別和正交幅度調(diào)制(QAM)信號(hào)的類內(nèi)識(shí)別,以及測(cè)向任務(wù)中的相關(guān)干涉測(cè)向算法:1.針對(duì)多載波和單載波信號(hào)的識(shí)別的問(wèn)題,提出基于帶寬和功率歸一化的功率譜的Kurtosis系數(shù)的正交頻分復(fù)用(OFDM)和單載波信號(hào)識(shí)別的方法,并仿真驗(yàn)證了該特征參數(shù)在多種條件下魯棒性和識(shí)別性能。仿真表明,在SNR=0dB時(shí),OFDM和單載波的正確識(shí)別率可達(dá)95%以上。2.針對(duì)定時(shí)誤差和頻偏會(huì)引起QAM信號(hào)識(shí)別率下降的問(wèn)題,提出一種改善識(shí)別性能的方案:首先對(duì)接收到的MQAM信號(hào)采用OM定時(shí)同步和非線性差分處理,最后對(duì)信號(hào)進(jìn)行幅度對(duì)數(shù)似然識(shí)別。仿真結(jié)果表明本文提出的方案對(duì)定時(shí)誤差和頻偏有很強(qiáng)的適應(yīng)性,當(dāng)SNR?12d B,QAM信號(hào)平均識(shí)別率可以達(dá)到98%。3.針對(duì)傳統(tǒng)相關(guān)干涉測(cè)向算法中測(cè)向精度不高和實(shí)時(shí)性差等問(wèn)題,提出采用插值擬合的方法來(lái)提高測(cè)向精度;另外提出對(duì)相關(guān)測(cè)向的結(jié)構(gòu)進(jìn)行改進(jìn),引入空間角,用一維信息來(lái)代替二維空域信息,單就計(jì)算量而言,減小了73%的計(jì)算量,從而提高了算法的實(shí)時(shí)性。4.基于FPGA+DSP硬件平臺(tái)對(duì)雙通道相關(guān)干涉測(cè)向處理模塊的工作模式和樣本數(shù)據(jù)庫(kù)的存儲(chǔ),測(cè)向處理程序設(shè)計(jì)等幾個(gè)方面進(jìn)行了詳細(xì)說(shuō)明。最后對(duì)單頻點(diǎn)測(cè)向?qū)崿F(xiàn)結(jié)果進(jìn)行了測(cè)向時(shí)間和準(zhǔn)確度的分析,結(jié)果表明兩者均達(dá)到測(cè)向指標(biāo)。
[Abstract]:The rapid development of software radio technology has led to the continuous change of radio monitoring and direction finding technology. At present, the monitoring system based on software radio architecture is developing towards the direction of digitization and networking. But with the development of communication technology, Wireless environment is becoming more and more complex, such as the coexistence of different modulation modes and the existence of many complex and distributed signals in fixed bandwidth. These are the diversity of recognition algorithms in existing monitoring systems. The precision and real time of the direction finding algorithm bring great challenge. This paper is based on the electromagnetic environment monitoring / direction finding system. The main contents of this paper are the inter-class recognition of multi-carrier and single-carrier signals and the intra-class recognition of quadrature amplitude modulation (QAM) signals, as well as the related interference direction finding algorithm: 1. Aiming at the problems of multi-carrier and single-carrier signals, A method of orthogonal frequency division multiplexing (OFDM) and single carrier signal recognition for Kurtosis coefficients of power spectrum based on bandwidth and power normalization is proposed. The robustness and recognition performance of the characteristic parameters are verified by simulation. The correct recognition rate of SNR=0dB and single carrier can be more than 95%. In view of the problem that timing error and frequency offset will cause the reduction of QAM signal recognition rate, A scheme to improve the recognition performance is proposed. Firstly, the received MQAM signal is processed with OM timing synchronization and nonlinear differential processing. Finally, the amplitude logarithmic likelihood recognition of the signal is carried out. The simulation results show that the proposed scheme has a strong adaptability to timing error and frequency offset, when SNR? The average recognition rate of 12d BU QAM signal can reach 98.3. aiming at the problems of low precision and poor real time in the traditional correlation interference direction finding algorithm, the interpolation fitting method is proposed to improve the direction finding accuracy. In addition, the structure of correlation direction finding is improved, the space angle is introduced, and one dimensional information is used to replace the two dimensional spatial information. In terms of calculation amount, the calculation amount of 73% is reduced. Therefore, the real-time performance of the algorithm is improved. 4. Based on the FPGA DSP hardware platform, the working mode and sample database storage of the dual-channel correlation interference direction finding processing module are presented. At last, the time and accuracy of direction finding at single frequency point are analyzed, and the results show that both of them reach the target of direction finding.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TN98

【參考文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前1條

1 劉思沉;短波寬帶測(cè)向算法研究及其實(shí)現(xiàn)[D];西安電子科技大學(xué);2010年

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本文編號(hào)：1603556