本文關(guān)鍵詞： 非相干散射雷達 波形設(shè)計 模糊函數(shù) 混合編碼 OFDM　出處：《西安電子科技大學》2016年碩士論文　論文類型：學位論文

【摘要】：電離層是地球大氣層的重要組成部分,它對電磁傳播的影響與人類的各項活動息息相關(guān)。非相干散射雷達是探測電離層最有效的手段之一,能夠得到關(guān)于電離層特性的多種參數(shù)。由于電離層目標的特殊性,非相干散射雷達需要采用復雜的信號編碼方式和信號處理方法進行電離層探測。本文結(jié)合我國第一部非相干散射雷達的自主研制和試驗測試,開展非相干散射雷達的信號波形設(shè)計和探測性能分析,為進一步改善非相干散射雷達的探測性能以及推進我國電離層特性方面的研究提供相應的實驗技術(shù)支撐。首先,研究了非相干散射雷達探測性能評價方法。給出了評價非相干散射雷達探測性能的幾個重要的分辨率,分析了模糊函數(shù),并且結(jié)合時延剖面矩陣,給出了計算回波信號自相關(guān)函數(shù)和功率譜的算法。研究了長脈沖,巴克碼和二相交替碼等傳統(tǒng)的非相干散射雷達信號編碼,利用實測數(shù)據(jù)對其信號處理算法和結(jié)果進行了分析和驗證,對比了各種編碼的優(yōu)缺點。其次,重點研究了非相干散射雷達的混合編碼及相應的探測性能分析。對巴克碼調(diào)制多脈沖、巴克碼調(diào)制二相交替碼以及二相交替碼調(diào)制多脈沖等三種編碼調(diào)制方式進行了詳細的討論,給出了三種編碼相應的信號處理方法,并仿真分析了各自的距離模糊函數(shù)和探測性能。最后,研究了一種新的編碼方式,即正交頻分復用(OFDM)調(diào)制多相交替碼編碼。針對二相交替碼的不足引入了多相交替碼,研究了多相交替碼的特點,并仿真分析了其距離模糊函數(shù)。針對交替碼的不足,提出采用OFDM調(diào)制多相交替碼,將多相交替碼的多組編碼調(diào)制到OFDM的多組正交子載波上,根據(jù)子載波的正交性解碼,可以得到每組子載波攜帶的散射信號。
[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.
【學位授予單位】：西安電子科技大學
【學位級別】：碩士
【學位授予年份】：2016
【分類號】：TN958

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