基于通信信号结构化特点的组阵信号合成关键技术研究与实现

发布时间：2018-01-08 00:16

本文关键词：基于通信信号结构化特点的组阵信号合成关键技术研究与实现　出处：《解放军信息工程大学》2014年硕士论文　论文类型：学位论文

【摘要】：深空通信鉴于其特殊的应用背景,其信号到达地面时经历了巨大的路径损耗而十分微弱,利用多天线组阵对信号进行接收并合成是深空通信低信噪比下实现信号可靠接收的有效途径,并已成为深空通信的重要发展方向。组阵接收中对信号间时延、相位等参数差异的估计与补偿是保证信号有效合成的前提和关键,因此研究低信噪比下的信号间参数差异估计方法具有重要意义。本文以充分利用数字通信信号所具有的逐符号信息传输特性、循环平稳特性等在内的结构化特点为思路,以提升组阵接收中低信噪比下的参数差异估计性能为目标,主要针对低信噪比下信号间时延、相位差异的估计问题展开研究,并基于以FPGA为核心的数字化中频处理平台设计并实现了组阵信号合成系统。论文主要工作和创新点如下:1.针对双天线组阵接收下的时差估计问题,利用数字通信信号逐符号信息传输特性所包含的定时信息,提出了一种基于定时信息加权的时差估计算法。算法通过对定时信息的获取建立时差估计量,将其与广义互相关法的时差估计量构建关于真实时差的观测模型,基于该模型和对观测误差的相关性分析,分别给出了时差的最小二乘估计和加权最小二乘估计,并对上述估计的物理概念进行了分析,表明利用观测误差的协方差矩阵对时差进行加权最小二乘估计即是其最佳线性无偏估计。仿真结果表明,充分利用了数字通信信号逐符号信息传输所包含定时信息的时差估计算法,较经典的广义互相关法可以有效提升低信噪比下的时差估计性能。2.针对双天线组阵接收下的相位差估计问题,利用数字通信信号逐符号信息传输特性所包含的定时信息,给出了一种基于定时信息辅助的相位差估计算法。从信噪比越大越有利于参数估计的角度分析了非最佳采样点对相位差估计的影响,算法基于获取定时信息并利用插值恢复得到的最佳采样点序列进行相关得到相位差估计。仿真结果表明,基于定时信息辅助的相位差估计算法较传统利用所有采样点直接进行相关的方法可以有效提升低信噪比下的相位差估计性能。3.针对多天线组阵接收下的参数差异问题,基于通信信号的循环平稳性提出了一种基于循环相关的多天线信号时延/相位联合对准算法。算法通过迭代处理实现对信号间时差和相位差的估计和补偿,使各路信号的时延/相位在迭代调整的过程中逐步实现“对齐”。在迭代求解参数差异的过程中给出了如何利用二阶循环统计量构造单路信号估计的合成参考,在求解时差时,构造单路信号与其它每路信号的循环互相关函数包络和作为循环相关合成参考,在求解相位差时,构造单路信号与其他路信号和的循环互相关函数与单路信号的循环自相关函数作为相位差估计的观测向量和观测矩阵。仿真结果表明,由于算法在迭代求解的过程中充分利用到了通信信号的循环平稳性,较经典SUMPLE的合成对准算法能够有效提升各路信号时延/相位的对准性能。4.结合理论研究,设计并实现了支持最大36MHz带宽信号的八天线组阵信号合成系统。针对于深空通信的实际需求,在基于以FPGA为核心的数字化中频处理板上完成了系统的总体设计、基于Qsys的软硬件协同方案设计及自动增益控制模块、Nios II系统调度模块等主要功能模块的设计与实现,最后对整个系统进行了测试,结果表明,在单天线接收信号归一化信噪比0/bE N为-6dB条件下的八天线组阵增益能达到平均8.4dB,验证了整套系统实现方案的可行性。
[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.

【学位授予单位】：解放军信息工程大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN911.23

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