Patent ID: 8315785
Filing Date: 2012-11-20
Classification: G01C,G08G

Abstract:
1. A data communication device that is capable of being mounted on a vehicle, comprising: a first memory configured to store road map information indicating locations of a plurality of nodes assigned with numbers in a road network that is represented by the plurality of nodes and a plurality of links each connecting two adjacent ones of the nodes; a second memory configured to store a time when the vehicle enters a link among the plurality of links, and identification data about the link corresponding to the time; a third memory configured to store a location of the vehicle at a certain time and identification data about the link corresponding to the location; a position measuring unit configured to periodically acquire position data indicating a location of the vehicle; a determining unit configured to identify a link corresponding to an acquired latest position data based on the road map information every time position data is acquired, and compare the identified link with the link stored in the third memory to determine whether the vehicle has passed through a node; a first updating unit configured to receive an indication that the vehicle has not passed through the node, and rewrite the position data and acquired time stored in the third memory to the last acquired position data and the acquired time; a calculating unit configured to receive an indication that the vehicle has passed through the node, determine an exit time based on the acquired time stored in the third memory and a time the last acquired position data is obtained, and calculate a travel period indicating a time required for the vehicle to pass through the link from which the vehicle has last exited including while the vehicle is traveling through the link, based on the determined exit time and the entry time stored in the second memory; a second updating unit configured to write the exit time last determined by the calculating unit as an entry time in place of the entry time stored in the second memory after the the travel period calculation, and rewrite the link identification data stored in the second memory to the identification data about the link last identified by the determining unit; and a transmitting unit configured to transmit the calculated travel period and the identification data about the corresponding link to a given communication destination.