In existing moving object tracking, there is a great communication load between a terminal and a platform, because the terminal should report its location to the platform every second or every minute and the platform should frequently process the location form the terminal. It is possible to reduce the great communication load on the server, by calculating an error between the current GPS location and the estimated location at a specific time on the basis of the estimated arrival time of the moving object. It allows that the terminal report its location to the server only when the error between current GPS location and the estimated location is greater than a predetermined threshold value.