Recently, rapid increase in traffic demands causes traffic congestion and economic loss (e.g. loss of energy) due to poor distribution of products. Furthermore, in spite of such traffic congestion, an increasing number of vehicle drivers violate traffic regulations (e.g. regulations related to speeding, signals, or lanes), in order to reach their destination quickly. The resulting increase in traffic accidents has become another social problem.
In order to solve such problems, new roads must be constructed in accordance with the increase in traffic demands. However, constructing new roads needs a vast amount of funding and time, and there are many practical difficulties.
As an alternative approach, various service methods for providing vehicle drivers with a series of traffic information regarding road traffic conditions have been proposed, including a method using a radio broadcasting system, a method using a text message call service system, a method using large display boards, and a method using a vehicle navigation system.
Although the method using a radio broadcasting system can provide vehicle drivers with substantially real-time information on traffic congestion, users of that traffic information service cannot be provided with traffic information regarding a desired region at a desired time, because traffic information is transmitted in a predetermined order by a broadcasting station, and even the traffic information is related to limited regions (e.g. specific expressways or highways).
The method using a text message call service system can provide users of that traffic information service with traffic information regarding a desired region at a desired time. However, it is difficult to provide accurate and detailed traffic information in a text message call mode. The method using large display boards as means for providing traffic information has a problem in that, since the large display boards are fixed at predetermined locations, the range of provision of traffic information is spatially limited and vehicle drivers cannot be provided with desired traffic information.
The method using a vehicle navigation system has been proposed to overcome the problems of the above-mentioned traffic information service methods. The method uses a CNS (car navigation system), which interwork with a DRM (digital road map), GPS (global positioning system) module, and a navigation system, all of which are installed on terminals inside vehicles, to provide traffic information. The current location of each vehicle is displayed on the terminal using the DRM. If necessary, the shortest or optimal path can be calculated to guide the vehicle diver to the destination. In addition, real-time traffic information is received via a communication network for convenient driving environment.
However, conventional methods for providing a traffic information service using a CNS have a problem in that the service is solely provided to vehicle drivers having a GPS module and a car navigation device or users of a mobile communication terminal who have subscribed to a specific traffic information service. In addition, detailed traffic information regarding a specific region or location cannot be provided on a nationwide scale, because traffic information can solely be collected or received via vehicles equipped with a car navigation device or via mobile communication terminals. This makes it difficult to accurately grasp the current traffic.
Furthermore, the above-mentioned conventional traffic information service methods cannot predict the traffic at a specific point of time in the future, although they can provide traffic information regarding a specific region or location at the current point of time and information on expected time to be taken before arrival or on the optimal path to the destination. Therefore, service subscribers cannot forecast future traffic flow and properly cope with it.
Meanwhile, as communication technology develops and wireless network infrastructure is reinforced, portable communication terminals including portable telephones, PDAs (personal digital assistants), and laptop computers are increasingly used. The portable communication terminals, which must always have guaranteed access to a wireless communication network, frequently transmit wireless signals for reporting their position information so that they can be managed within service regions. Particularly, information on the position of a device, which transmits position information, is managed in real time by a position information server corresponding to the terminal so that, based on the information, the position of a movable body (e.g. a person or object) can be tracked.
Position information servers for managing position information use PDT (position determination technology) for grasping the position of mobile communication terminals, network-based technology using base station reception signals, GPS using satellites, or cell search technology, according to the characteristics of position information generation devices to be managed by the servers.
In this regard, means for providing services related to wireless networks incorporate a position tracking function for locating an object, which carries a position information generation device, as an additional service function. This function can be used for various purposes including locating a missing child, guiding a group of persons, and managing staff, vehicle services, or distribution of products.
However, in the case of conventional position information services, there is a problem in that, since respective position information servers provide position information only to position information generation devices under their management, a user, who needs position tracking, must access each position information server, which corresponds to the type of position tracking transmission device carried by himself, to request position tracking.
In addition, in the case of conventional position information provision services, the information provision path is limited to wired/wireless Internet. This means that, when a user needs position tracking, he must use a medium which enables wired or wireless Internet access, such as a portable telephone, a PDA, a dedicated terminal, or a PC, in order to request position tracking and receive position information. It is inconvenient to carry a separate wired/wireless Internet access medium all the time and access a site or home page, which provides the corresponding service, to receive the service.