【作者】 何钦；

【导师】 王丹；

【作者基本信息】 西南交通大学 ， 微电子学与固体电子学， 2012， 硕士

【摘要】 随着社会的发展,人们对精确导航的需求与日俱增,现在许多国家国都在争相建立自己的卫星导航系统。卫星导航定位技术因为其在军事领域的重要应用,是关系国家安全的重要战略资源；同时在民用领域也具有广阔应用空间,有着非常好的的市场前景。GPS作为世界上最成熟的卫星导航系统,越来越多的人开始GPS接收机的相关研究。GPS信号捕获算法作为接收机中频信号处理的关键技术,也越来越受到重视。本文首先对GPS及其他卫星导航系统进行简单的介绍。接着详细介绍了GPS卫星信号的结构,及生成方式,为后面要介绍的捕获算法打下基础。设计过程中首先分析了各种捕获算法的结构、性能、适用范围等,对信号捕获的方法有了一个大体的认识。通过对这些算法的研究,在自己要设计的捕获模块的指标的约束下确定了要采用的捕获方法,即基于相干积分与非相干积分结合的FFT伪码快速捕获方法。本算法理论上可以在40秒的时间内完成单颗卫星整个多普勒频域和所有码相位的搜索,如果在实现中用多路并行通道,这个时间还会大幅减少。接着论文从理论上推导了该种方法中各种参数对捕获性能的影响,综合各种考虑,确定模块的各个设计参数。同时也验证了各模块在不同参数下的性能,比如将相干积分时间提高到1毫秒,对整个捕获模块的影响。算法确定后,第三章GPS卫星信号进行Matlab建模,对捕获算法进行了仿真验证,其中包括卫星中频信号的生成和卫星信号的捕获模块,证明了该方法的可行性。第四章以Xilinx公司的Vertex5XUPV5-LX110T开发板为平台,以modelsim为仿真软件,编写了各个模块的verilog代码,实现了算法。更多还原

【Abstract】 The requirement to accurate navigation becomes stronger nowadays Along with society’s progress and development. Many countries compete with foundation of their own satellite navigation system. The technology of satellite navigation and positioning is important strategic resources with national security because of its application in military field. It has very good market prospect with wide application in civil field as well. As is the most mature satellite navigation and positioning system in the world more and more people start to do research on GPS receiver. And they have big concern to acquisition algorithm of GPS signal which is the key point of IF signal processing in receiver.The paper introduces the GPS and other satellite navigation and positioning system briefly initially. Then it elaborates the structure and generation method of GPS signal as the background of acquisition algorithm. The design part gives analysis to structure, performance and application scope with different acquisition algorithm firstly as a general view. The design adopts fast acquisition algorithm method of FFT PN code based on coherent and incoherent integration according to the goal and constraint. This algorithm implement search with whole Doppler frequency domain and code phase of single satellite in forty seconds theoretically. The time length could be reduced with parallel multi-channel.And then the paper deduces the impact to the performance with different parameters by verification of performance under each parameter such as setting1macro second as coherent integration time. Thus the final parameters are fixed in design with optimization. The acquisition algorithm including IF signal generation and satellite signal acquisition is verified by simulation with modeling GPS signal based on Matlab in the third chapter. the design is implemented by verilog language based on Vertex5XUPV5-LX110T design kit of Xilinx company and Modelsim simulation platform in the fourth chapter.更多还原