| GPS or global locating system, with powerful space satellite navigation and locating function,is gradually going into various applications of the national economic construction and social development because of its characters such as precise global locating, simple observation, excellent real-time and so on, although designed for only military use at the first. It will fundamentally solve the problem of human beings's navigation and locating on earth, capable of meeting the needs of different users,which has tremendous impact on human activity and high application value.With the emergence and application development of GPS, a location-based services(LBS) ,or a locating services named for short,has emerged. LBS is a value-added services provided by mobile communications network, through a set of locating technology to obtain the mobile station location information provided to the mobile user himself or herself or others, as well as communications systems, to achieve a variety of business related with location.Eighty percentage of the daily life information is related with the location,as a result,the importance of the location makes the demand and usage of location-based services increase rapidly. And the rapid development of mobile communications has made the mobile phone become the most important location-based services terminal.Making use of GPS technology to locate and track mobile phones can provide mobile phone users with path guide, information search, emergency assistance,alarm on robbery,as well as other location-related services, greatly facilitating people's life,giving the location-based services with vast market prospects and development space.In the current domestic mobile service environment, the mobile phone locating has been targeting at the growth stage of development.To develope LBS services, technology, products and business development have yet to be digged deeper.Under such background,this subject comes from an experiment part of the location-based services system expanding project planned by a company, based on existing technologies,making the mobile phone with GPS signal receiver module access to the original system to complete the data communication between phones and the control center, in order to realizing the locating and tracking.of mobile phones.In the system design,the GPS and status data is sent to the GSM public network in mobile phone short messages,then received,decoded, transformed and sent by the short message transceiver in the public network,received by the client program through serial interface,resolved and transformed according to existing system protocol form,sent to the server named the control center through Internet and then the monitor platform,at last displayed in map language by GIS,to realize the locating function on mobile phones by system platform.Based on the learning of systems technology and structure of GPS and location-based services,this paper has mainly completed the client program design. The main body of the client software is the network application program based on TCP / IP protocol,realizing data transmission data in the Internet through Windows Sockets in which embedded with the agreement analysis and conversion modules to complete the mutual data transformation between the SMS and system protocol,to achieve data recognition and communication between terminals and the center.With C++ as the the software language and Visual Studio as development tools, the client interface and related function modules design are completed in VC++ environments.The test results has shown that the client program can realize the data communication between mobile phones and the center. |
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