非相干散射雷达波形设计与探测性能分析

发布时间：2018-02-03 21:59

本文关键词： 非相干散射雷达波形设计模糊函数混合编码 OFDM　出处：《西安电子科技大学》2016年硕士论文　论文类型：学位论文

【摘要】：电离层是地球大气层的重要组成部分,它对电磁传播的影响与人类的各项活动息息相关。非相干散射雷达是探测电离层最有效的手段之一,能够得到关于电离层特性的多种参数。由于电离层目标的特殊性,非相干散射雷达需要采用复杂的信号编码方式和信号处理方法进行电离层探测。本文结合我国第一部非相干散射雷达的自主研制和试验测试,开展非相干散射雷达的信号波形设计和探测性能分析,为进一步改善非相干散射雷达的探测性能以及推进我国电离层特性方面的研究提供相应的实验技术支撑。首先,研究了非相干散射雷达探测性能评价方法。给出了评价非相干散射雷达探测性能的几个重要的分辨率,分析了模糊函数,并且结合时延剖面矩阵,给出了计算回波信号自相关函数和功率谱的算法。研究了长脉冲,巴克码和二相交替码等传统的非相干散射雷达信号编码,利用实测数据对其信号处理算法和结果进行了分析和验证,对比了各种编码的优缺点。其次,重点研究了非相干散射雷达的混合编码及相应的探测性能分析。对巴克码调制多脉冲、巴克码调制二相交替码以及二相交替码调制多脉冲等三种编码调制方式进行了详细的讨论,给出了三种编码相应的信号处理方法,并仿真分析了各自的距离模糊函数和探测性能。最后,研究了一种新的编码方式,即正交频分复用(OFDM)调制多相交替码编码。针对二相交替码的不足引入了多相交替码,研究了多相交替码的特点,并仿真分析了其距离模糊函数。针对交替码的不足,提出采用OFDM调制多相交替码,将多相交替码的多组编码调制到OFDM的多组正交子载波上,根据子载波的正交性解码,可以得到每组子载波携带的散射信号。
[Abstract]:The ionosphere is an important part of the earth's atmosphere, and its influence on electromagnetic propagation is closely related to human activities. Incoherent scattering radar is one of the most effective means to detect the ionosphere. A variety of parameters can be obtained on the characteristics of the ionosphere, due to the particularity of the ionospheric target. Incoherent scattering radar needs to use complex signal coding and signal processing methods for ionospheric detection. In this paper, the first incoherent scattering radar is developed and tested independently. The signal waveform design and detection performance analysis of incoherent scattering radar are carried out. In order to further improve the detection performance of incoherent scattering radar and promote the study of ionospheric characteristics in China the corresponding experimental technical support is provided. First of all. In this paper, the detection performance evaluation method of incoherent scattering radar is studied, and several important resolutions are given to evaluate the detection performance of incoherent scattering radar. The ambiguity function is analyzed, and the delay profile matrix is combined. The algorithms for calculating the autocorrelation function and power spectrum of echo signal are given. The traditional incoherent scattering radar signal coding such as long pulse Barker code and two-phase alternating code are studied. The signal processing algorithms and results are analyzed and verified using the measured data, and the advantages and disadvantages of various codes are compared. Secondly. The hybrid coding of incoherent scattering radar and the analysis of its detection performance are emphasized. The Barker code is used to modulate the multi-pulse. Three kinds of coded modulation methods, such as Barker code modulation of two-phase alternating code and two-phase alternating code modulation of multi-pulse, are discussed in detail, and three corresponding signal processing methods are given. The range ambiguity function and detection performance are analyzed by simulation. Finally, a new coding method is studied. That is, orthogonal Frequency Division Multiplexing (OFDM) modulation polyphase alternating code coding. To overcome the shortcomings of two-phase alternating code, this paper introduces multi-phase alternating code, and studies the characteristics of multi-phase alternating code. The range ambiguity function is simulated and analyzed. Aiming at the deficiency of the alternating code, the OFDM modulation polyphase alternating code is proposed to modulate the multi-group code of the polyphase alternating code onto the multi-group orthogonal subcarrier of the OFDM. According to the orthogonality decoding of subcarriers, the scattering signals carried by each group of subcarriers can be obtained.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN958

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