基于FPGA的GPS软件接收机跟踪捕获算法研究

发布时间：2018-04-02 12:20

本文选题：GPS　切入点：跟踪　出处：《南京邮电大学》2013年硕士论文

【摘要】：全球定位系统（Global Position System，GPS）是一种全球性，全天候的实时性连续定位系统，具有在海陆空三维空间进行全方位实时导航与定位功能的新一代卫星导航定位系统。随着GPS更加广泛的应用，对GPS软件接收机的实时性和定位精度的要求也越来越高。因此，寻找更高精度和效率的定位方法成为软件接收机的重要任务。GPS软件接收机由射频前端、基带信号处理和导航解算三个部分组成。跟踪算法是基带算法中的一部分，是实现导航定位的关键技术之一。本文主要完成了基于FPGA的GPS软件接收机跟踪算法的设计及实现。首先详细介绍了跟踪算法的基本原理，完成了跟踪算法中噪声带宽、环路增益、快捕范围、环路滤波器等关键参数的设置。接着完成对GPS跟踪系统中各个模块的FPGA(Field－ProgrammableGateArray)设计。本文提出了一种基于CORDIC算法的码环鉴相器，该鉴相算法具有精度高，结构简单，容易实现等优点。同时，本文还对环路滤波器的参数进行了优化，进而较大的改善了跟踪环路的实时性。最后，在跟踪环路的整体测试中，设计了控制模块，协调各子模块的工作，很好的解决了实时性问题和非整数采样频率下的失配问题。本文设计的GPS跟踪系统具有快速锁定，跟踪精度高的特点。将捕获跟踪系统下载到FPGA平台上，，经过实时数据流的测试，跟踪系统能够正确的实现对导航数据的解调，解调后的导航数据经过导航解算模块解算得到的定位精度可以达到m级，这也说明了跟踪系统设计的正确性。
[Abstract]:Global Position system GPS is a global, all-weather real-time continuous positioning system. A new generation of satellite navigation and positioning system with the function of omnidirectional real-time navigation and positioning in the three-dimensional space of sea, land and air. With the wider application of GPS, the requirement of real-time and positioning accuracy of GPS software receiver is becoming higher and higher. Finding more accurate and efficient positioning methods becomes an important task of software receiver. GPS software receiver consists of three parts: RF front-end, baseband signal processing and navigation solution. Tracking algorithm is a part of base-band algorithm. It is one of the key technologies to realize navigation and positioning. This paper mainly completes the design and implementation of GPS software receiver tracking algorithm based on FPGA. Firstly, the basic principle of the tracking algorithm is introduced in detail, and the noise bandwidth, loop gain, fast capture range of the tracking algorithm are completed. The design of FPGA Field-Programmable Gate Arraybased on GPS tracking system is completed. A phase discriminator based on CORDIC algorithm is presented in this paper, which has high precision and simple structure. At the same time, the parameters of the loop filter are optimized, and the real-time performance of the tracking loop is greatly improved. Finally, the control module is designed in the overall test of the tracking loop. Coordination of the work of the sub-modules, a good solution to the real-time problem and non-integer sampling frequency mismatch problem. The GPS tracking system designed in this paper has the characteristics of fast locking and high tracking accuracy. The acquisition and tracking system is downloaded to the FPGA platform. After real-time data flow testing, the tracking system can correctly demodulate the navigation data. The positioning accuracy of the demodulated navigation data can reach m level through the navigation solution module, which also shows the correctness of the design of the tracking system.
【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：P228.4

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