【作者】 余恒；

【导师】 马洪；

【作者基本信息】 华中科技大学 ， 通信与信息系统， 2009， 硕士

【摘要】 随着人类在气象、航空、航天及微电子领域的研究和长足发展,雷电灾害的影响面越来越广,其破坏力及造成的经济损失越来越大,从而研究更先进、更有效的闪电探测定位系统,特别是针对云闪的探测系统,就成了当务之急。云闪信号主要集中在VHF频带,因此本文首先将基于LABVIEW软件平台,就VHF频段内的雷电信号展开时域、频域及空域方面的研究,主要包括以下内容:关于VHF频段的雷电信号的时域和频域特性研究:介绍了VHF频段的雷电信号的接收和采集存储方法、雷电信号的时域特征提取方法、频域特征分析方法及概率分布特征分析方法的算法设计、软件实现、所得结论及应用分析。基于LABVIEW及MATLAB的算法仿真详细论述了雷电信号概率分布特征的统计结果,即验证了原始雷电信号的幅度服从高斯分布的特性;雷电信号的时域特征提取分别得到未滤波及两种标准滤波情况下的四种分类的雷电信号的时域波形图、功率及标准偏差的数值,并且总结出雷电信号时域特征的一个变化规律,即:采集的雷电信号辐射越强,时域波形图的幅度越大,功率及标准偏差的数值也越大,且滤波后的雷电信号的脉冲相比滤波前更尖锐;雷电信号的频域特征分析分别得到未滤波及两种标准滤波情况下的四种分类的雷电信号的功率谱图,并且总结出雷电信号频域特征的一个变化规律,即:采集的雷电信号辐射越强,功率谱越大,且典型有雷电情况下的功率谱比典型无雷电情况下的功率谱高出20dBm以上。关于VHF频段的雷电信号的空域特性研究:介绍了基于均匀圆阵的多重信号分类算法(MUSIC, Multiple Signal Classification)的LABVIEW软件实现方法。按照流程图的设计思想将整个二维测向算法分为四个模块,依次对各个模块进行软件实现,最后组合成一个完整的测向系统,并利用两个性能测试实验对其性能进行分析,从而初步实现了对雷电信号的二维空间谱估计。更多还原

【Abstract】 With the research and rapid development of human in the field of meteorology, aviation, aerospace and microelectronics, the impact of lightning disaster has become increasingly widespread, and the damage and economic losses caused by it have been growing and growing. As the reasons above, the study of more advanced and more effective detection and positioning system of lightning comes to be an urgent affair.Inter-cloud lightning signal mainly concentrates in the VHF band. So in this thesis, we focus on the VHF frequency band when doing the research of lightning in time domain、frequency domain and space domain. The main contents of this research are as follows:1) The research of characteristics of VHF-Band lightning Signal in time-frequency domain.With the help of LABVIEW software platform, we establish the software system includes the data collection, the analysis of signal in time domain and frequency domain and the analysis of the probability distribution of lightning signal. LABVIEW and MATLAB based simulation of the algorithm discusses in detail the characteristics of the probability distribution of lightning signal, which validates the conclusion that the amplitude of original lightning signal fits the Gaussian distribution. The extraction of Four-classified lightning characteristics in time domain gains the wave graphs、the power and the standard deviation both with and without filters, which summarizes that the stronger the lightning is, the greater the amplitude of waveforms、signal power and standard deviation are. Moreover, the signal pulse of lightning is more intense pre-filter. The extraction of Four-classified lightning characteristics in frequency domain gains the power spectrum graphs both with and without filters, which summarizes that the stronger the lightning is, the greater the power spectrum is. Further more, the power spectrum of typical lightning signal is 20dBm higher than the power spectrum of typical non-lightning signal. 2) The research of characteristics of VHF-Band lightning Signal in space domain.Based on the LABVIEW software platform, we investigate the estimation system of the MUSIC (Multiple Signal Classification) algorithm in the case of uniform circle array, which is divided into four modules. Furthermore, with the help of two experiments, we test the performance of this system, in order to achieve the initial simulation result of two-dimension spatial spectral estimation on lightning signal.更多还原