星载AIS接收机的多用户分离算法研究
发布时间：2018-08-24 19:48
【摘要】：星载船舶自动识别系统（Automatic Identification System，AIS）是各国竞相发展的船舶动态监控系统，在军事、经济和政治等领域均具有重要的意义。多用户分离是星载AIS中的一个核心技术，直接影响到信号的接收效果和检测性能，该课题的研究对其它卫星通信系统同样具有重要的价值。本文以星载AIS为应用背景，对时隙碰撞概率、信号分离算法和接收机的多用户分离等方面进行研究。 建立了星载AIS接收信号时隙碰撞概率分析模型。该模型以泊松分布为基础，为了使概率分析更加贴近实际情况，模型建立的过程中考虑到了：A、B类船台的消息发送间隔是不同的；不同航行状态的船舶消息发射间隔是不同的；信号混叠程度对信息完整性的影响是不同的。 提出了变步长的复值快速独立分量分析（Fast Independent Component Analysis,FastICA）分离算法。以非高斯性为基础建立了表示混合信号独立性的目标函数，并采用具有较高收敛速度的牛顿迭代法对目标函数进行优化。为使目标函数始终朝着最优解的方向收敛，，迭代过程采用可变步长的牛顿迭代法，同时，为了保持算法收敛速度，基于Wolfe-Powell准则确定迭代步长的搜索范围。仿真实验对混合的信号进行了提取，并对不同的FastICA算法进行对比，证明基于Wolfe-Powell准则的FastICA，仅增加很少的计算量就解决了收敛性的问题。 针对AIS信号的空间传输特点，提出了一种卫星接收机的多用户分离方法。首先采用三交叉的二元线阵对不同极化方向的信号进行接收，基于极化分集减小时隙碰撞的概率；然后利用数字波束形成，将卫星的视场划分为多个带状区域，基于空间分集减小时隙碰撞的概率；最后结合变步长的复值FastICA分离算法对时隙碰撞的AIS信号进行逐个提取。仿真实验模拟了接收机接收前端的主要信号处理流程，证明该方法是切实可行的。
[Abstract]:Spaceborne ship automatic Identification system (Automatic Identification System,AIS) is a dynamic ship monitoring system developed by many countries. It is of great significance in military, economic and political fields. Multi-user separation is a core technology in spaceborne AIS, which directly affects the signal receiving effect and detection performance. The research of this topic is also of great value to other satellite communication systems. Taking spaceborne AIS as the application background, this paper studies the slot collision probability, signal separation algorithm and multi-user separation of receiver. A time-slot collision probability analysis model for spaceborne AIS received signals is established. The model is based on Poisson distribution. In order to make the probability analysis more close to the actual situation, it is considered that the message sending interval of class B ship is different in the process of establishing the model. The effect of signal aliasing on information integrity is different. A variable step fast independent component analysis (Fast Independent Component Analysis,FastICA) separation algorithm is proposed. On the basis of non-Gao Si, the objective function representing the independence of mixed signals is established, and the Newton iteration method with high convergence rate is used to optimize the objective function. In order to keep the objective function converging towards the optimal solution, the variable step size Newton iteration method is used in the iterative process. Meanwhile, in order to maintain the convergence speed of the algorithm, the search range of the iteration step size is determined based on the Wolfe-Powell criterion. Simulation results show that FastICA, based on Wolfe-Powell criterion can solve the problem of convergence with only a small amount of computation. According to the spatial transmission characteristics of AIS signal, a multi-user separation method for satellite receiver is proposed. In order to reduce the probability of slot collision based on polarization diversity, a binary linear array with three intersections is used to receive signals in different polarization directions, and then the satellite's field of view is divided into several zonal regions by digital beamforming. The probability of slot collision is reduced based on spatial diversity. Finally, the AIS signal of slot collision is extracted one by one with the variable step size complex value FastICA separation algorithm. The simulation results show that the method is feasible and feasible.
【学位授予单位】：天津理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U675.7
本文编号：2201846
[Abstract]:Spaceborne ship automatic Identification system (Automatic Identification System,AIS) is a dynamic ship monitoring system developed by many countries. It is of great significance in military, economic and political fields. Multi-user separation is a core technology in spaceborne AIS, which directly affects the signal receiving effect and detection performance. The research of this topic is also of great value to other satellite communication systems. Taking spaceborne AIS as the application background, this paper studies the slot collision probability, signal separation algorithm and multi-user separation of receiver. A time-slot collision probability analysis model for spaceborne AIS received signals is established. The model is based on Poisson distribution. In order to make the probability analysis more close to the actual situation, it is considered that the message sending interval of class B ship is different in the process of establishing the model. The effect of signal aliasing on information integrity is different. A variable step fast independent component analysis (Fast Independent Component Analysis,FastICA) separation algorithm is proposed. On the basis of non-Gao Si, the objective function representing the independence of mixed signals is established, and the Newton iteration method with high convergence rate is used to optimize the objective function. In order to keep the objective function converging towards the optimal solution, the variable step size Newton iteration method is used in the iterative process. Meanwhile, in order to maintain the convergence speed of the algorithm, the search range of the iteration step size is determined based on the Wolfe-Powell criterion. Simulation results show that FastICA, based on Wolfe-Powell criterion can solve the problem of convergence with only a small amount of computation. According to the spatial transmission characteristics of AIS signal, a multi-user separation method for satellite receiver is proposed. In order to reduce the probability of slot collision based on polarization diversity, a binary linear array with three intersections is used to receive signals in different polarization directions, and then the satellite's field of view is divided into several zonal regions by digital beamforming. The probability of slot collision is reduced based on spatial diversity. Finally, the AIS signal of slot collision is extracted one by one with the variable step size complex value FastICA separation algorithm. The simulation results show that the method is feasible and feasible.
【学位授予单位】：天津理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U675.7
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2 付卫红;史凡;刘乃安;;适用于时变信道环境的盲源分离算法[J];电子科技大学学报;2012年04期
本文编号：2201846
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