Design And Implementation Of RF Front-end For The "Compass Ⅱ" Navigation System

Since the formal establishment of the transit navigation system,satellite navigation systems have experienced fifty years of rapiddevelopment. Global Positioning System (GPS) was introduced into Chinain1980s, and quickly got extensive use in fields such as transportation,geodesy and military positioning. Currently, there are many types ofnavigation system receiver, just as location-type, geodesic-type,multi-functional and so on. Satellite navigation system has become a highprecision, real time and global positioning system.COMPASS, with full name of the Beidou navigation system followingGlobal Positioning System (GPS) of the United States, GLONASS of Russianand GALILEO of EU, is a self-development, completely independent radionavigation satellite system (RDSS) in China now. It is a dual-banddual-use system which has more satellites and short-message communicatingtechnology compared with GPS. With the increasing of satellite quantity,ground terminals become one of the international popular research topics.this paper studies the Beidou ground terminal of the receive and transmithigh performance front-end is of great significance and broad prospects.This paper first describes the significance of research, development,related knowledge about the Beidou satellite navigation system, and thenintroduced radio frequency technology in the field of satellitecommunications’ application and development. The principles of the RFreceiver in this article are described. In the following, the detailedanalysis of four RF receiver structures and terms about RF technology aregiven. on that basis of analyse, superheterodyne architecture isdetermined in this article. In chapter IV，a bulk acoustic wave filter is designed to suppress the out-of-band noise, which can significantlyimprove the signal-to-noise ratio of system. Chapter V and VI is mainlydesined by established RF circuit, and use of Altium Designer09softwarefor schematic and PCB drawing. Finally, the physical RF receiver system,test results and analysis are given, and the summary and outlook is alsomade in this paper.