| 摘要 |
PROBLEM TO BE SOLVED: To allow quick rescue action for a vehicle by defining by defining that GPS positioning is impossible when an emergency condition happens on the vehicle and an on-vehicle device using position data only from a GPS transmits emergency information. SOLUTION: A communication part 21 receives vehicle information transmitted from the on-vehicle device 1 and transmits travel locus information to a vehicle existence range calculation part 22. The vehicle existence range calculation part 22 finds a final position where positioning is finally impossible from the travel locus information, calculates a vehicle existence range consisting of the travel range, angle range and initial error of the vehicle in accordance with the position information for the final position and transmits display information to a map plotting control part 23. The map plotting control part 23 reads a map around the final position, draws plotting data with the display information and the travel locus combined and transmits it to a display part 24. The display part 24 displays the plotting data acquired by the map display control part 23 and also displays a map around the final position, the travel locus and the vehicle existence range.
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