动态环境下GPS软件接收机研究

载体的动态性所引入的多普勒频移给GPS接收机的载波跟踪带来了很大的困难。首先介绍了GPS软件接收机捕获与跟踪策略,提出了一种新的基于模糊逻辑控制器和三阶锁相环的动态载波跟踪方案,分析了模糊逻辑控制器的设计原理,推导了适合软件实现的三阶锁相环的数字形式。实验结果证明提出的设计方法与传统环路相比可大幅度缩短载波跟踪时间,减小环路滤波器带宽,并能消除周跳。

Research of Software GPS Receiver in Dynamic Environments

It is difficult for GPS receivers in dynamic environments to realize carrier tracking. A signal acquisition and tracking in a software GPS receiver was introduced. A new carrier tracking algorithm was put forward based on fuzzy logic controller and third-order phase lock loop, and the design process of fuzzy logic controller was analyzed, and the digital form of third-order loop filter suitable for software implement was proposed. Simulation results demonstrate that the proposed fuzzy-based loop achieves shorter settling time and noise bandwidth than the conventional tracking loops, and prevents the occurrence of cycle slipping.