无线电监测与测向中相关算法的研究与实现

发布时间：2018-03-12 22:27

本文选题：软件无线电　切入点：电磁环境监测/测向　出处：《电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：软件无线电技术的迅速发展带动了无线电监测测向技术的不断变革。目前基于软件无线电架构的监测系统正朝着数字化、网络化的方向发展。但随着通信技术的不断更新进步,无线环境变得越来越复杂,例如多种不同的调制方式并存和固定带宽内可能存在很多形式复杂且分布密集的信号等,这些都对现有监测系统中识别算法识别种类的多样性,以及测向算法的精度和实时性带来了极大的挑战。本文正是以电磁环境监测/测向系统为背景,主要研究内容为监测任务中多载波和单载波信号的类间识别和正交幅度调制(QAM)信号的类内识别,以及测向任务中的相关干涉测向算法:1.针对多载波和单载波信号的识别的问题,提出基于带宽和功率归一化的功率谱的Kurtosis系数的正交频分复用(OFDM)和单载波信号识别的方法,并仿真验证了该特征参数在多种条件下鲁棒性和识别性能。仿真表明,在SNR=0dB时,OFDM和单载波的正确识别率可达95%以上。2.针对定时误差和频偏会引起QAM信号识别率下降的问题,提出一种改善识别性能的方案:首先对接收到的MQAM信号采用OM定时同步和非线性差分处理,最后对信号进行幅度对数似然识别。仿真结果表明本文提出的方案对定时误差和频偏有很强的适应性,当SNR?12d B,QAM信号平均识别率可以达到98%。3.针对传统相关干涉测向算法中测向精度不高和实时性差等问题,提出采用插值拟合的方法来提高测向精度;另外提出对相关测向的结构进行改进,引入空间角,用一维信息来代替二维空域信息,单就计算量而言,减小了73%的计算量,从而提高了算法的实时性。4.基于FPGA+DSP硬件平台对双通道相关干涉测向处理模块的工作模式和样本数据库的存储,测向处理程序设计等几个方面进行了详细说明。最后对单频点测向实现结果进行了测向时间和准确度的分析,结果表明两者均达到测向指标。
[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.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN98

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