北斗卫星导航信号CUDA模拟算法与北斗软件接收机设计

发布时间：2018-10-12 10:10

【摘要】：随着北斗卫星导航系统的快速发展,各类北斗终端和相关算法的研究也面临更多的挑战。本文针对北斗导航信号模拟和北斗软件接收机进行了研究,这两项技术均具有一定的研究价值,其中:北斗导航信号模拟技术不仅可以为北斗终端研制提供测试环境,也可以为相关算法的研究提供数据;而北斗软件接收机则克服了硬件接收机不易升级、参数固定、灵活性差的缺点,并且可以用于导航算法验证。本文具体研究内容为:1.设计了北斗模拟源系统方案,由基于AV1443的硬件系统和北斗导航信号模拟软件组成。其中硬件系统采用FPGA+DDR2的读写式结构,由FPGA模块控制DDR2的读写;导航模拟软件采用CPU+GPU的异构结构,由显卡加速运行效率。2.完成了北斗中频信号模拟算法。在分析北斗中频信号结构的基础上,建立了信号传播模型和误差修正模型,实现了精确信号几何传播时延计算;为了实时控制模拟信号的码相位和载波多普勒,建立了动态多普勒模型。3.为改善北斗导航信号模拟算法的执行效率,使用CUDA平台对北斗中频信号模拟算法进行加速。在分析CUDA计算模型和储存器类型的基础上,将算法并行化,设计相应的线程结构以执行核函数,并采用相应优化,实现了算法效率的有效提升。4.利用本地补零序列实现了北斗信号捕获,消除了NH码对信号捕获的影响;通过频域分析,实现了NH码相位和精确载波频率的二维搜索。5.在实现北斗信号稳定跟踪的基础上,对跟踪得到的数据进行位同步、NH码剥离、帧同步等处理,并最终实现定位解算。
[Abstract]:With the rapid development of Beidou satellite navigation system, many kinds of Beidou terminals and related algorithms are facing more challenges. In this paper, the Beidou navigation signal simulation and the Beidou software receiver are studied. These two techniques have certain research value. Beidou navigation signal simulation technology can not only provide a test environment for the development of Beidou terminal, Beidou software receiver can overcome the disadvantages of hardware receiver which is difficult to upgrade, fixed parameters, poor flexibility, and can be used to verify the navigation algorithm. The specific contents of this paper are as follows: 1. The scheme of Beidou analog source system is designed, which is composed of hardware system based on AV1443 and simulation software of Beidou navigation signal. The hardware system adopts the read-write structure of FPGA DDR2, the FPGA module controls the reading and writing of DDR2, and the navigation simulation software adopts the heterogeneous structure of CPU GPU, which accelerates the running efficiency by the graphics card. Beidou if signal simulation algorithm is completed. On the basis of analyzing the structure of Beidou intermediate frequency signal, a signal propagation model and an error correction model are established to calculate the geometric propagation delay of the accurate signal, in order to control the code phase and carrier Doppler of the analog signal in real time. A dynamic Doppler model was established. In order to improve the efficiency of Beidou navigation signal simulation algorithm, the CUDA platform is used to accelerate the Beidou if signal simulation algorithm. On the basis of analyzing the CUDA computing model and storage type, the algorithm is parallelized, and the corresponding thread structure is designed to execute the kernel function, and the corresponding optimization is adopted to realize the efficient improvement of the algorithm. 4. The Beidou signal acquisition is realized by using local complementary zero sequence, and the influence of NH code on signal acquisition is eliminated, and the 2-D search of NH code phase and accurate carrier frequency is realized by frequency domain analysis. 5. On the basis of the steady tracking of Beidou signal, bit synchronization, NH code stripping, frame synchronization and so on are processed, and finally the location solution is realized.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN967.1

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