Patent ID: 6999779
Filing Date: 2006-02-14
Classification: G01C,G01S,H04L,H04W

Abstract:
1. A position information management system, comprising: a first terminal for transmitting a location indicator to a center; said center for managing information about a location of the first terminal; and a second terminal for requesting from the center the location indicator of the first terminal, wherein said first terminal comprises: an acquiring device for acquiring the location indicators each specifying the location of the first terminal itself using a position determination system of a pre-assigned type; and a reporting device for transmitting the location indicators to the center, respectively, at times separated by a prescribed time interval or when so requested by the center, said center comprises: a history accumulating device for storing the location indicators the first terminal transmits to the center in a log form; a determination device for determining a capability of the first terminal to receive a location indicator transmission request to be transmitted from the center every time when the center receives a request for transmission of the location indicator of the first terminal from the second terminal; an advising device for transmitting the location indicator transmission request to the first terminal when the determination device has determined the first terminal is capable of receiving the location indicator transmission request and transmitting the location indicator received from the first terminal to the second terminal or composing a location indicator of the first terminal by making an estimation based on the location indicators stored in the log form when the determination device has determined the first terminal is not capable of receiving the location indicator transmission request and transmitting the location indicator composed based on the estimation to the second terminal, and said second terminal comprising; a request transmission device for transmitting a first-terminal's location indicator transmission request to the center; and a display device for displaying information corresponding to the location indicator of the first terminal the second terminal receives from the center, wherein, further, the request transmission device constituting the second terminal transmits a monitoring area for specifying an area within which a change in location of the first terminal is monitored, the determination device constituting the center determines if the first terminal has stationed at one location for a pre-assigned length of time based on data stored in the log form and if not, then, if the first terminal is located within the monitoring area; and the advising device constituting the center assumes when the determination device determines the first terminal having stationed at an one location within the monitoring area for the pre-assigned length of time, as an unusual situation has happened with a holder of the first terminal and transmits a warning signal to the second terminal.