Design And Development Of Vehicular Wireless Terminal In Network-based Central Navigation

In recent years,with the development of the satellite navigation industry,global position system(GPS) has become one of the popular technologies in the world.Applications of satellite navigation have grown to be a large scope of industry in both our nation and abroad.Vehicular navigation has experienced from simple navigation to multi-media navigation,and thereafter the network-based central navigation is formed with the development of wireless communication and internet.In this paper,we design the vehicular wireless terminal(VWT) in the vehicular network-based central navigation(VNCN) system.Based on the first generation self-navigation system and the second generation- multi-media navigation system,the VNCN system provides many service for vehicular customers,such as network navigation,remote information service,remote security defense and vehicular handfree phone,ect..The author of this paper is responsible for the development of wireless terminal product of VNCN system.The structures and principles of the VNCN system are presented in this paper.And we focused on circuit-board design of the wireless terminal hardware and software system design.Thereafter,we analyze and compare several popular short-distance wireless technologies.In the implementation of short-distance wireless communication of VWT,we use the new 2.4GHz radio frequency transceiver chip-nRF24El produced by NORDIC Corp.of North-European.In the design of hardware,we elaborate the hardware circuit structure according to the requirement and the property of embedded hardware.Then we design many circuit modules,such as central processor unit(CPU),radio frequency(RF),keyboard scanning(KS),liquid crystal display(LCD),and power supplying.The modules are low cost,low power consumption and high stability.In the design of software,we investigate the design method of embedded software system.Then we implement several different modules,such as KS,the basic point drawing,line drawing and region fill in graphics user interface(GUI),RF,baseband,and data link layer of wireless communication.We solve the problems of automatic repeat request(ARQ) of wireless data,frequency matched control,clock synchronization between the transmitter and the receiver.The VWT has satisfies the requirements of productivity.Then it has been applied to the batch production,promoted into market and accessed to users.