地层传播弹性波接收端的多径分离与分集接收方法的研究

发布时间：2019-04-19 23:10

【摘要】：本文主要针对弹性波在大地信道中的多径传播特性,在固有源信号和变异源信号的情况下,分别采用RAKE接收和盲源分离对弹性波信号进行了多径分离与分集接收,提高了弹性波接收端的信噪比,改善了通信质量。(1)分析了弹性波在大地信道中的多径传播特性。首先研究了弹性波传播的基础理论,然后对弹性波在地层中的传播特性进行了分析,最后建立了地层传播弹性波的多径传播模型,并利用Matlab及Comsol对弹性波的多径传播进行了仿真,验证了所建模型的正确性,得到了随着煤层厚度的增加,弹性波的各反射波相对于直达波的时延越长;随着时间的增加,弹性波的能量接近于指数规律衰减。(2)研究了固有源特性的弹性波多径分离与分集接收。分析且比较了现有的分集与合并方式,选取了路径分集来获得独立多径信号,最大比合并对多径信号进行接收;设计了弹性波多径信号的RAKE接收方案,建立了弹性波RAKE接收模型并利用Matlab软件进行了仿真,结果表明RAKE接收能有效解决弹性波多径问题,提高接收端的信噪比。(3)研究了变异源特性的弹性波多径分离与分集接收。首先建立了弹性波多径信号的盲源分离模型,对基于全局最优算法的盲源分离算法及基于最大信噪比的盲源分离算法进行了研究,利用Matlab软件对两种算法进行了仿真,结果表明两种算法都可对多径信号进行分离,但基于最大信噪比的盲源分离算法的分离效果优于基于全局最优的盲源分离算法。
[Abstract]:In this paper, according to the multipath propagation characteristics of elastic wave in geodetic channel, the multipath separation and diversity reception of elastic wave signal are carried out by using RAKE receiver and blind source separation under the condition of inherent source signal and mutation source signal, respectively. The signal-to-noise ratio of the elastic wave receiver is improved and the communication quality is improved. (1) the multipath propagation characteristics of the elastic wave in the geodetic channel are analyzed. Firstly, the basic theory of elastic wave propagation is studied, and then the propagation characteristics of elastic wave in strata are analyzed. Finally, the multipath propagation model of elastic wave propagation in strata is established. The multi-path propagation of elastic wave is simulated by Matlab and Comsol, and the correctness of the model is verified. The results show that with the increase of coal seam thickness, the time delay of each reflection wave of elastic wave is longer than that of direct wave. With the increase of time, the energy of elastic wave decays close to exponential law. (2) multipath separation and diversity reception of elastic wave with inherent source characteristics are studied. The existing diversity and merging methods are analyzed and compared. The path diversity is selected to obtain the independent multipath signal, and the maximum ratio combination is used to receive the multipath signal. The RAKE receiving scheme of elastic wave multipath signal is designed. The elastic wave RAKE receiving model is established and simulated by Matlab software. The results show that the elastic wave multipath problem can be effectively solved by RAKE receiver. The signal-to-noise ratio (SNR) of the receiver is improved. (3) the multipath separation and diversity reception of elastic waves with variable source characteristics are studied. Firstly, the blind source separation model of elastic multi-path signal is established. The blind source separation algorithm based on the global optimal algorithm and the blind source separation algorithm based on the maximum signal-to-noise ratio are studied. The two algorithms are simulated by Matlab software. The results show that both algorithms can separate multipath signals, but the blind source separation algorithm based on the maximum signal-to-noise ratio is better than the blind source separation algorithm based on global optimization.
【学位授予单位】：山东科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD65

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