An optimum algorithm for reporting of automobile position

This paper presents a car navigation system for a future integrated transportation system as an intelligent transportation system-ITS. The system focuses on the mechanisms how to detect the current position of each vehicle and to navigate each vehicle. The individual vehicular data is collected using Global Positioning System-GPS for location data and then transmitted to the control center by the mobile phone. For the purpose of this paper, the device will be referred to "Reporting Equipment for current geographic Position" or REP. In the case where every vehicle within the transportation network is equipped with a REP it will be referred to as "Comprehensive REP Environment" or CREPE. If a great number of cars report their positions to the control center, it causes a heavy load of network. This paper proposes an algorithm to reduce the network load. If a car skips some reports, the control center cannot estimate its correct position. The algorithm aims to decrease the frequency of the reporting without sacrificing the proper level of accuracy for the position. The effectiveness is evaluated as 1/2 or 2/3 times compared to periodical reporting algorithms.