Design And Implementation Of Gps Data Processing Module Based On Cdma Terminal

With the fast development of society, the automobile cars become an indispensable vehicle for people. In order to release the burden of modern city's traffic, and satisfy the users'need of the digitization,information,visual management of vehicles, the vehicle management system gets more and more attention and recognition, and has become an important part of modern intelligent transport system(ITS). The vehicle management system has many functions towards the vehicle such as real time examination,management,scheduling,guarding against the theft,first aid,broadcast etc., and these functions are very important in enhancing the efficiency of vehicle's management and debasing the cost of management.This paper puts emphasis on the collecting,processing and transmitting of location data in vehicle management system, using the embedded ARM processor in CDMA terminal module instead of extra processor at vehicle terminal. This method not only guarantees the reliability, but also reduces the cost of vehicle terminal.According to the selection of locating technology, this paper first analyzes the advantages and disadvantages of the generally used locating technologies, especially focus on GPS. Based on the performance and precision of locating, and the requirement of system operating cost, we present a position locating method that we use GPS to get location data. In order to reduce the data transmitted between vehicle terminals and control center, release the burden of transmission network, depress the system operating cost, this paper proposes a turning angle distinguishing method to reduce the location data, by request of recovering vehicle track. We validated the method according to the location data collected from road test. After investigated kinds of data compress algorithms and the characteristic of the location data's storage structure, we propose the increment compress algorithm to compress the data more. Then this paper gives the way of how to transmit the compressed location data to control center via SMS, and uses circular queue technology to resolve the problem caused by SMS sending failure. At last, this paper introduces the way of how to use C language and embedded system developing tools to realize the collection, compress and transmission of position location data on CDMA terminal module. Also, we studied the way of how to use CDMA wireless packet data service to transmit the location data, just expecting that the vehicles manage system can fit in with more applications.