Design And Implementation Of GPS/BD-2Dual-mode Receiver Base On Processor Platform

GPS Global Positioning System in the late1980s in China, in geodesy,transportation,forest fire prevention and other areas has been more widely used. China’ssatellite navigation market with huge potential. After years of development, China’s satellitenavigation industry has entered a period of rapid development. Currently, GPS receivers havemultiple types of geodesic type, regular type, location type, integrated type. It has been builtinto a high-precision, all-weather and global radio navigation, positioning and timing of themulti-function system.. However, in the receiver field of production technology is not mature,and dependent on foreign imports. Therefore, the receiver’s R&D work has importantpractical significance.Currently, mobile phone users have begun to use GPS chips into thenavigation industry a new economic growth point.Currently, there are the U.S. GPS, Russian Glonass system, the European Galileo andChinese Beidou system generation/second generation satellite navigation system, four majornavigation systems."Compass" system known as the compass system is a satellite navigationsystem being set up in China will be global. Beidou-2will be a one-way ranging system ofglobal downstream, and eventually built a dual-use system.With the gradual Beidou satellitelaunch, BD-2receiver into the development of hot spots navigation receiver.As GPS receivertechnology has matured, and has an extensive global satellite network. GPS/BD-2dual-modereceiver became a trend of research and development. Multi-system receivers are, comparedwith single-system receiver technology, with obvious location advantage. Multiple satellitepositioning system compatible with each other in an irregular state in a system of satellite andother positioning systems can be used as a useful supplement. It can improve the positioningperformance of the receiver, making it a true all-weather navigation and positioningnavigation receivers.At the same time,based on software radio receiver design has goodprogrammability and flexibility, is the future direction of development,.The subject of thebaseband processor system design FPGA-based software radio,designed to meet the needs ofmulti-mode receiver. It through the software updates the hardware configuration change canbe achieved the future direction of development.This paper introduces the basic principles of GPS-direct spread-spectrumcommunications, given the pseudo-random code analysis and research. Then the GPS receiveris designed based on the principle given GPS/BD-2dual-mode baseband receiver systemdesign. Proposed a dual-mode baseband receiver acquisition and tracking algorithms. GPS/BD-2signal acquisition algorithm using FFT-based parallel code phase acquisitionalgorithm, the tracking algorithm using the delay-locked code algorithm, Costas loop andfrequency-locked loop (FLL). Using the FPGA multiprocessor theory, design and implementthe acquisition and tracking algorithm. By the microprocessor to control the basebandprocessor system gives the software implementation.The implementations of the ARM+FPGA hardware platform GPS/BD-2dual-modereceiver baseband processor platform are given in the last part of the article.Digital correlatorsystem is by the FPGA,and the ARM is microprocessor chip. The software portion of thetracking algorithm GPS/BD-2capture is achieved.