北斗接收机的空时二维抗干扰算法的研究与实现

发布时间：2018-03-20 13:32

本文选题：北斗　切入点：BOC　出处：《电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：在全球导航系统蓬勃发展的今天,各国相继发展属于自己国家的,具有独立知识产权的导航系统,我国的北斗导航系统应运而生。而如何在众多导航系统保持自身系统的不可干扰性,并尽可能的对他国导航系统形成干扰,是在导航战背景下的关键命题。我国北斗导航系统采用BOC类调制方式,其信号特征与相关峰特征与GPS信号存在诸多不同,因此其抗干扰算法与GPS抗干扰算法研究存在很多不同,所以研究针对北斗导航信号的抗干扰算法,并将其进行实现是非常有必要的。这也是本文最大的创新之处。本论文的目标是为我国自主研发的北斗导航接收机设计相应的抗干扰算法模块,以在压制性干扰源存在的条件下,能对干扰源所在方向形成波束零陷,从而对干扰信号形成压制,提高接收机输入端的信噪比。本论文选择空时二维自适应结构作为本文的核心抗干扰结构。首先,给出了空时二维自适应结构的整体框架构造图,该结构的重点以及难点是如何快速且准确的确定各级滤波系数的权值系数。而对于权值系数如何确定的问题可以归结为最优系数的求解问题。其次,采用最优化求解方法对其进行求解,最优目标函数采用功率倒置准则进行确定,而最优化方法方法采用约束LMS算法与拉格朗日算子法进行求解。在仿真结果部分,论文中分别给出了采用约束LMS算法与拉格朗日算子法得到的仿真结果。在本文中利用拉格朗日算子法,分别对线形天线阵和圆形天线阵性能,输入干扰源角度对抗干扰算法性能的影响,以及双干扰源条件下的仿真性能进行了分析和比对。同时,在本文中给出了空时二维自适应滤波算法对导航信号质量指标的影响,这也是首次将空时二维抗干扰算法应用与BOC调制信号。最后值得一提的是,在本论文中引入了归一化奇异值法对延迟深度进行求解从而避免了复杂的运算,这也属于本文一个创新之处。最后,在硬件实现上,采用Xilinx公司生产的VC707板卡实现相关功能,其在实现上可以分为自适应滤波模块、协方差矩阵计算模块以及权系数计算模块。其中涉及的矩阵求逆运算采用LU分解实现。通过将结果导入上位机进行分析,可以得出结论,该算法是可行并有效的。本文的研究成果对北斗二代二期信号的抗干扰接收机研制都有重要的参考价值。
[Abstract]:With the vigorous development of global navigation system (GNSS), every country has developed its own navigation system with independent intellectual property right. The Beidou navigation system of our country arises at the historic moment. However, how to maintain the non-interference of its own system in many navigation systems and to interfere with the navigation system of other countries as far as possible, Beidou navigation system in China adopts BOC modulation mode, its signal characteristics and correlation peak characteristics are different from GPS signals, so there are many differences between its anti-jamming algorithm and GPS anti-jamming algorithm. So the anti-jamming algorithm for Beidou navigation signal is studied. And it is very necessary to implement it. This is also the biggest innovation of this paper. The goal of this paper is to design the corresponding anti-jamming algorithm module for Beidou navigation receiver, which is independently developed in our country. Under the condition of the existence of the suppressed interference source, the beam can be trapped in the direction in which the interference source is located, and thus the interference signal can be suppressed. In this paper, space-time adaptive structure is chosen as the core anti-jamming structure. Firstly, the whole frame diagram of space-time adaptive structure is given. The emphasis and difficulty of the structure is how to determine the weight coefficients of filter coefficients at all levels quickly and accurately. However, the problem of how to determine the weight coefficients can be reduced to the problem of solving the optimal coefficients. The optimal objective function is determined by power inversion criterion, while the optimization method is solved by constrained LMS algorithm and Lagrange operator method. The simulation results obtained by using constrained LMS algorithm and Lagrange operator method are given in this paper. In this paper, the performance of linear and circular antenna arrays is obtained by using Lagrange operator method, respectively. The influence of the angle of input interference source on the performance of anti-jamming algorithm and the simulation performance under the condition of dual interference source are analyzed and compared. At the same time, the effect of space-time adaptive filtering algorithm on navigation signal quality index is given in this paper. It is also the first time that space-time two-dimensional anti-jamming algorithm is applied to BOC modulation signal. Finally, it is worth mentioning that the normalized singular value method is introduced to solve the delay depth in this paper. This also belongs to the innovation of this paper. Finally, in the hardware implementation, the VC707 card produced by Xilinx Company is used to realize the related functions, which can be divided into adaptive filtering module. Covariance matrix calculation module and weight coefficient calculation module. The matrix inversion is realized by LU decomposition. By introducing the results into the upper computer for analysis, we can draw a conclusion. This algorithm is feasible and effective. The research results in this paper have important reference value for the development of anti-jamming receiver for Beidou second generation signal.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN967.1

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