文档介绍：GPS接收机基带信号处理算法的研究及实现
摘要:
全球定位系统(Global Positioning System—GPS)作为全球最重要的定位系统经过二十多年的发展已经日臻成熟和完善。因其所具备的高可靠性、高精度、低成本的、具有便携可移动能力的特点,逐渐被越来越多的用户所采用。目前在航空航天、交通、通信、气象等许多领域它作为一项重要的技术而被广泛的使用。随着人们应用领域的不断广泛和深入,人们希望在许多恶劣环境下GPS接收机也能提供良好的定位导航服务,这就对GPS技术带来了新的挑战,因为在许多恶劣环境下比如信号遮蔽、多径干扰、卫星信号间的互相关串扰等,传统接收机的性能将严重下降,甚至不能工作。为了克服这些应用上的限制,就必须在设计GPS接收机技术上有所创新,而GPS接收机的核心是基带信号处理算法。本文的研究内容是GPS接收机的基带数字处理算法及相应的芯片实现方案。根据GPS信号结构特点,从基带解扩解调的角度建立相应的数学模型,针对GPS信号处理的两大关键技术捕获和跟踪,推导出每一部分性能与相应参数的关系,尤其分析了在噪声环境下的各个部分的性能特性,同时还介绍了GPS基带芯片的电路结构和实现方案。本文首先介绍GPS基本原理和信号结构,给出了GPS接收机基带的信号处理流程,并详细介绍了GPS基带需要完成的任务和功能。接着重点介绍GPS信号捕获算法,详细分析了传统的穿行搜索算法和改进的FFT快补算法的各自性能。根据估计检测理论分析误警概率和检测概率,提出了最优的搜索检测器。然后又详细分析了GPS跟踪环路的性能,介绍了锁相环理论的一些基本理论,并根据实际的应用重点分析了三阶环路的性能,同时给出了伪距测量误差和环路跟踪误差的关系。最后给出了详细的测试结果。
三段式,背景(10%)、工作(50%)、结果(40%)
关键字:
GPS,基带算法,GPS捕获,GPS跟踪
ABSTRACT
The global positioning system(GPS) has tended to be more and more important after about twenty years’ development. Because of its good accuracy, reliable quality, low cost and portability, it is gradually used in more and more fields such as transportation, aviation, communication, rescue, weather forecast, et la. It has e a pivotal technology. However the GPS receiver also has great challenge when it is used in severe circumstance such as weak signal, multi-path interference and the interference between different satellite signals. Under these situations the performance of GPS receiver maybe greatly deteriorated. One of the critical parts of GPS receiver is the base-band signal processing algorithm. To e the constrains mentioned above, the base-band algorithm must be fully studied. This thesis focuses on the algorithm of GPS receiver base-band signal processing and its chip realization. First it introduces the GPS signal structure and its characteristics and describes the main signal process flow; then it elaborates the principle of GPS signal acquiring and tracking, including the traditional serial acquiring method and the new fast acquiring using FFT, the analysis of dete