导航接收机数字化射频前端的设计与验证  

Design and Validation of Direct Digitization Scheme for GNSS Receiver Front-Ends

作　　者：于渊[1] 常青[1] 张其善[1] 齐巍[1] 

机构地区：[1]北京航空航天大学电子信息工程学院,北京100191

出　　处：《天津大学学报》2012年第10期888-894,共7页Journal of Tianjin University(Science and Technology)

基　　金：国家高技术研究发展计划(863计划)资助项目(2007AA12Z336;2009AA12Z313);国家自然科学基金资助项目(60872062)

摘　　要：针对传统导航接收机射频前端在实现多频点信号接收时复杂度高、灵活性差的问题,提出了一种基于直接射频采样的数字化射频前端设计方法.该方法针对整个导航频段信号主要集中在低频和高频2个频段的特点,将这2个频段视为2个整体的带通信号,通过多带通信号采样率选择算法选定射频直采的采样率;由于采样率较高,设计了一种滤波抽取网络来降低数据速率,它利用了射频直采专用A/D可输出半采样率数据的特性,最终实现了各频点导航信号的下变频和分离.该设计方法只需修改软件就可实现多频信号接收,使得系统灵活性大大增加.实验证明该方法是有效的.Traditional global navigation satellite system （GNSS） receiver front-ends is very complex and inflexible when receiving multi-system signals. To solve such a problem, a digitized radio frequency （RF） front-end design was proposed based on the direct RF sampling. Considering that GNSS signals primarily concentrate on low frequency band and high frequency band, like two integral band-pass signals, the sampling rate of such signals can＇t be low due to the wide band. In this paper, firstly, the sampling rate selection algorithm for multiple band-pass signals was discussed. Then the direct RF sampling rate for such two GNSS band-pass bands was determined. For the purpose of lowering the aforementioned high sampling rate, a decimation and filtering network was designed. Finally, based on the fact that analog to digital converter （A/D） specially designed for direct RF sampling is capable of outputting the data at half the sampling rate, the digital down-conversion of the signal of interest as well as its separation from the entire band was realized. Thus multi-frequency signal receiving can be achieved by software implementation of the design and the system flexibility will be greatly improved. Experiments have proved the effectiveness of the design.

关 键 词：直接射频采样 多速率信号处理 射频前端 采样率选择 导航接收机 

分 类 号：TN965.5[电子电信—信号与信息处理] TN962[电子电信—信息与通信工程]