| 摘要 |
PROBLEM TO BE SOLVED: To substantially reduce power consumption in a mobile object monitoring system that monitors the entrance/exit of a mobile object to/from a monitoring area 200 that is set for a predetermined region. SOLUTION: The system comprises a GPS positioning part 12 that carries out GPS positioning based on a GPS signal received from a GPS satellite 5; a monitoring area storage 14 that stores information on a monitoring area indicating the monitoring area 200; a control unit having an entrance/exit judgment means that judges the entrance/exit to/from the monitoring area by the mobile object based on the present location of the mobile object obtained by the GPS positioning and the previous positioning location, a distance calculation means that calculates a distance between the present location and the border of the monitoring area, and a positioning interval determination means that determines the time to next GPS positioning with the distance as a judgment criterion; and a history storage that stores results of the GPS positioning sequentially. By extending time interval to next GPS positioning, the number of times the positioning is carried out can be decreased, thereby reducing the power consumption of the mobile object. COPYRIGHT: (C)2005,JPO&NCIPI
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