本文關(guān)鍵詞：基于通信信號結(jié)構(gòu)化特點的組陣信號合成關(guān)鍵技術(shù)研究與實現(xiàn)　出處：《解放軍信息工程大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 深空通信 組陣信號合成 結(jié)構(gòu)化特點 參數(shù)估計 Qsys

【摘要】：深空通信鑒于其特殊的應(yīng)用背景,其信號到達地面時經(jīng)歷了巨大的路徑損耗而十分微弱,利用多天線組陣對信號進行接收并合成是深空通信低信噪比下實現(xiàn)信號可靠接收的有效途徑,并已成為深空通信的重要發(fā)展方向。組陣接收中對信號間時延、相位等參數(shù)差異的估計與補償是保證信號有效合成的前提和關(guān)鍵,因此研究低信噪比下的信號間參數(shù)差異估計方法具有重要意義。本文以充分利用數(shù)字通信信號所具有的逐符號信息傳輸特性、循環(huán)平穩(wěn)特性等在內(nèi)的結(jié)構(gòu)化特點為思路,以提升組陣接收中低信噪比下的參數(shù)差異估計性能為目標(biāo),主要針對低信噪比下信號間時延、相位差異的估計問題展開研究,并基于以FPGA為核心的數(shù)字化中頻處理平臺設(shè)計并實現(xiàn)了組陣信號合成系統(tǒng)。論文主要工作和創(chuàng)新點如下:1.針對雙天線組陣接收下的時差估計問題,利用數(shù)字通信信號逐符號信息傳輸特性所包含的定時信息,提出了一種基于定時信息加權(quán)的時差估計算法。算法通過對定時信息的獲取建立時差估計量,將其與廣義互相關(guān)法的時差估計量構(gòu)建關(guān)于真實時差的觀測模型,基于該模型和對觀測誤差的相關(guān)性分析,分別給出了時差的最小二乘估計和加權(quán)最小二乘估計,并對上述估計的物理概念進行了分析,表明利用觀測誤差的協(xié)方差矩陣對時差進行加權(quán)最小二乘估計即是其最佳線性無偏估計。仿真結(jié)果表明,充分利用了數(shù)字通信信號逐符號信息傳輸所包含定時信息的時差估計算法,較經(jīng)典的廣義互相關(guān)法可以有效提升低信噪比下的時差估計性能。2.針對雙天線組陣接收下的相位差估計問題,利用數(shù)字通信信號逐符號信息傳輸特性所包含的定時信息,給出了一種基于定時信息輔助的相位差估計算法。從信噪比越大越有利于參數(shù)估計的角度分析了非最佳采樣點對相位差估計的影響,算法基于獲取定時信息并利用插值恢復(fù)得到的最佳采樣點序列進行相關(guān)得到相位差估計。仿真結(jié)果表明,基于定時信息輔助的相位差估計算法較傳統(tǒng)利用所有采樣點直接進行相關(guān)的方法可以有效提升低信噪比下的相位差估計性能。3.針對多天線組陣接收下的參數(shù)差異問題,基于通信信號的循環(huán)平穩(wěn)性提出了一種基于循環(huán)相關(guān)的多天線信號時延/相位聯(lián)合對準(zhǔn)算法。算法通過迭代處理實現(xiàn)對信號間時差和相位差的估計和補償,使各路信號的時延/相位在迭代調(diào)整的過程中逐步實現(xiàn)“對齊”。在迭代求解參數(shù)差異的過程中給出了如何利用二階循環(huán)統(tǒng)計量構(gòu)造單路信號估計的合成參考,在求解時差時,構(gòu)造單路信號與其它每路信號的循環(huán)互相關(guān)函數(shù)包絡(luò)和作為循環(huán)相關(guān)合成參考,在求解相位差時,構(gòu)造單路信號與其他路信號和的循環(huán)互相關(guān)函數(shù)與單路信號的循環(huán)自相關(guān)函數(shù)作為相位差估計的觀測向量和觀測矩陣。仿真結(jié)果表明,由于算法在迭代求解的過程中充分利用到了通信信號的循環(huán)平穩(wěn)性,較經(jīng)典SUMPLE的合成對準(zhǔn)算法能夠有效提升各路信號時延/相位的對準(zhǔn)性能。4.結(jié)合理論研究,設(shè)計并實現(xiàn)了支持最大36MHz帶寬信號的八天線組陣信號合成系統(tǒng)。針對于深空通信的實際需求,在基于以FPGA為核心的數(shù)字化中頻處理板上完成了系統(tǒng)的總體設(shè)計、基于Qsys的軟硬件協(xié)同方案設(shè)計及自動增益控制模塊、Nios II系統(tǒng)調(diào)度模塊等主要功能模塊的設(shè)計與實現(xiàn),最后對整個系統(tǒng)進行了測試,結(jié)果表明,在單天線接收信號歸一化信噪比0/bE N為-6dB條件下的八天線組陣增益能達到平均8.4dB,驗證了整套系統(tǒng)實現(xiàn)方案的可行性。
[Abstract]:Deep space communication because of its special application background, the signal reaches the ground through the path loss of huge and very weak, the use of multi antenna array for signal receiving and synthesis is the deep space communication under low SNR is effective way to realize the reliable receiving signal, and has become an important direction of development of deep space communication. Group array receiving signal on the time delay estimation and compensation, phase difference and other parameters of the signal is to ensure the efficient synthesis of the premise and the key, so the study of low SNR signal parameter estimation method. The difference is of great significance to make full use of symbolic information transmission characteristics by the digital communication signals, cyclostationary the characteristics, structural characteristics of ideas, to enhance the array receiving low SNR under different parameter estimation performance as the goal, according to the low SNR signal delay, phase difference Research on estimation problem, and based on FPGA as the core of the digital intermediate frequency processing platform design and implementation of array signal synthesis system. The main work and innovation are as follows: 1. for the dual antenna array receiving group difference under estimation of timing information by the transmission characteristics of symbolic information contained in digital communication signals using the proposed a time based on timing information weighted estimation algorithm is presented. Through the establishment of the access time estimates of timing information, and the generalized correlation method of TDOA estimation construction observation model about real time difference correlation analysis, the model and the observation error are given based on the least squares and weighted least squares estimation of TDOA estimation that and the estimation of the physical concept of the analysis, show that the observation error covariance matrix using the weighted least squares estimate of time difference is Is the best linear unbiased estimation. The simulation results show that the time difference estimation algorithm makes full use of digital communication signal symbol information transmission contains timing information, other than the classical generalized correlation method can effectively improve the low signal-to-noise performance estimation of.2. based on the double antenna array receiving the phase difference estimation problem than time. The transmission characteristics of symbol timing information by information contained by digital communication signals, a phase difference estimation algorithm based on auxiliary timing information is given. From the angle of signal-to-noise for parameter estimation of non optimal sampling point difference estimation of phase ratio is bigger, and recovery algorithm to obtain timing information obtained by interpolation the best sampling point sequence were obtained based on phase difference estimation. The simulation results show that the estimation algorithm is better than the traditional use of all sampling points of phase difference based on timing information assistant Direct correlation method can effectively improve the low SNR performance of.3. phase difference estimation for multiple antenna array receiving the set of parameters difference problem, cyclostationary signal presents a circular multi antenna signal delay / related phase combined alignment algorithm based on the algorithm. Based on the estimation and compensation of time and the phase difference between the signals through iterative processing, the delay / signal phase in the process of iterative adjustment in the progressive realization of "alignment". In the process of difference iterative parameter in the proposed how to use the two order cyclic statistics to construct reference single signal estimation is made, in solving the time difference, the single channel signal and structure every other signal envelope and the cyclic cross-correlation function as circulating synthesis related reference in solving phase difference, structure of single channel signal and other signals and the cyclic cross-correlation function With the single signal of the cyclic autocorrelation function as the phase difference estimation of the observation vector and observation matrix. The simulation results show that the algorithm in the process of iterative methods to make full use of cyclostationarity of communication signals, compared with the classical SUMPLE algorithm can effectively enhance the synthesis of alignment signal delay / phase alignment performance with.4. theoretical research, design and implementation of array signal synthesis system of eight antenna support maximum 36MHz bandwidth signal. According to the actual needs of deep space communication, the overall design of the system in the digital intermediate frequency based on FPGA as the core processing board, collaborative design and automatic gain control module hardware and software based on Qsys, and design and implementation of the main function of Nios II scheduling module, finally the system was tested. The results show that the single antenna signal normalized SNR 0/b E N can reach an average of 8.4dB for the eight antenna array gain under the condition of -6dB, which verifies the feasibility of the whole system implementation scheme.

【學(xué)位授予單位】：解放軍信息工程大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TN911.23

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