北斗三号PPP-B2b信号跟踪环路的极点分布法设计

Design of pole distribution method of BDS-3 PPP-B2b signal tracking loop

2020年7月,北斗卫星导航系统空间信号接口控制文件精密单点定位服务信号PPP-B2b(1.0版)正式公布,PPP-B2b可以实现中国及其周边地区静态厘米级、动态分米级的高精度定位,其播发的BDS、GPS增强信息可用性分别达到97.5%和91.5%。为解决PPP-B2b接收机跟踪环路参数设置复杂的问题,从PPP-B2b信号接收处理的层面入手,采用极点分布法进行信号跟踪环路设计,将传统跟踪环路的多个参数统一到一个参数。通过实时采集卫星播发的PPP-B2b信号,对比分析极点分布法和经典理想锁相环数字化设计的环路。结果表明:与经典理想锁相环数字化方法相比,极点分布法跟踪环路只需设置环路噪声带宽B_(L)就可实现PPP-B2b信号的快速解扩与解调,物理意义明确且简单易行,利于PPP-B2b接收机的工程实现。

In July 2020,“Beidou Navigation Satellite System Signal In Space Interface Control Document Precision Point Positioning Service Signal PPP-B2b(Version 1.0)”was officially announced.PPP-B2b can achieve high-precision positioning at the centimeter level in the static mode and decimeter level in the dynamic mode in China and its surrounding areas.The availability of the BDS-and GPS-enhanced information reaches 97.5%and 91.5%.To solve the problem of PPP-B2b receiver tracking loop parameter setting,starting from the level of the PPP-B2b signal reception and processing,the pole distribution method is used to design the signal tracking loop,and multiple parameters of the traditional tracking loop are unified into one parameter.Through the real-time acquisition of the PPP-B2b signals,the pole distribution method and the loop of the classic ideal phase-locked loop digital design are compared and analyzed.The results showed that:compared with the classic ideal phase-locked loop digitization,the pole distribution method tracking loop can realize fast despreading and demodulation of PPPB2b signal only by setting the loop noise bandwidth.The physical meaning is clear and simple,which is beneficial to the engineering realization of the PPP-B2b receiver.