| The vehicle terminal is a part of the vehicle monitoring system. It is also an importantpart of intelligent transportation system (ITS). It is applied to the global satellite positioningtechnology, database technology and communication technology. They and embeddedcomputer system are set in one body. It achieves the function such as vehicle positioning,navigation and real-time information. It provides users with convenient services, helpingusers to be able to accurate, safety, vehicle information quickly and then reaches thedestination.This thesis mainly discusses the characteristics of the vehicle terminal system. Accordingto the requirements of low cost, small volume, reliable performance, this dissertation putforward a design scheme based on beidou and GPRS car terminal.The program usesembedded system design ideas with ARM9processor as the hardware platform, expansion ofother peripherals to complete the design of the hardware circuit. Based on the embeddedLinux operating system, this dissertation designs the application software. The data of Beidoucan be received and recorded by the car terminal and then realize the positioning function ofthe vehicle terminal system. Combining with GPRS wireless transmission technology andEthernet information transmission technology, the car termical system can realize datatransmission. This multi-channel communication method can improve the efficiency andsafety of the data transmission, reducing the error rate of data transmission.This topic on hardware design for samsung S3C2440A processor as the core of controlcircuit, including memory and power supply circuit and achieves the UM220beidou module,GPRS module and Ethernet module WG-8010with the S3C2440Aprocessor data exchange.As for software design, this dissertation uses linux operating system to achieve cutting,compiling and transplanting of it. It makes use of QT to design user interface program for Linux operating platform. Completing serial communication design and beidou positioningdata extraction and send by using the method of multithreaded programming.This vehicle terminal has many kinds of communication mode, consisting of GPRS,Ethernet communication and Beidou communication is complementary to prevent thecommunication interrupt occur under special circumstances. Channel selection uses grayrelational analysis to deal with the value of their individual properties, which can determineby the degree of association channel selection.Finally, this embedded vehicle terminal system validated by experiment. The experimentproves that the Linux system with the QT graphical user interface can be transplanted into theARM processor.It successfully collects vehicle positioning information. Through thisexperiment of the analysis for the beidou and GPRS application in the vehicle terminal laidthe foundation for the application, some suggestions and prospect for further researches canbe put forward. |
