| CPC G01C 21/387 (2020.08) [G01C 21/3896 (2020.08)] | 11 Claims |
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1. A map data usage system comprising:
a map data distribution server configured to transmit map data of each of a plurality of areas having a predetermined magnitude; and
a vehicle including a storage device in which the map data transmitted from the map data distribution server via a network is stored, the storage device having a storage capacity and comprising a temporary storage portion and a map data storage portion, a position acquisition device configured to acquire a current position, and a control device configured to execute a predetermined vehicle control by use of the map data stored in the storage device, wherein:
in a case where the map data distribution server receives a first acquisition request or a second acquisition request for map data that is transmitted from the vehicle, the map data distribution server is configured to transmit, to the vehicle, map data of an area corresponding to the acquisition request thus received; and
the control device is configured to:
acquire a first frequency index value of each of a plurality of drivers in a current area corresponding to a current position of the vehicle, and a second frequency index value of the vehicle in the current area;
transmit the first acquisition request for acquiring map data of a first area when the first frequency index value is equal to or less than a first threshold and the second acquisition request for acquiring map data of a second area or a third area when the first frequency index value is larger than the first threshold;
determine, in a case where the control device transmits the second acquisition request, that the current area is the second area when the second frequency index value is equal to or less than a second threshold, and that the current area is the third area when the second frequency index value is larger than the second threshold;
the control device is further configured such that,
in a case where, among the areas, map data of an area to which the current position of the vehicle belongs is not stored in the storage device, the map data being acquired by the position acquisition device, the control device transmits, to the map data distribution server as the first acquisition request or the second acquisition request, a request to acquire map data of an acquisition area including at least the area to which the current position of the vehicle belongs,
the control device receives the map data of the acquisition area that is transmitted from the map data distribution server in response to the acquisition request and then stores the map data in the storage device,
in a case where a second frequency index value indicative of how frequently the vehicle runs in an area to which a position of the vehicle at a time of transmission of the first acquisition request or second acquisition request belongs is equal to or less than a predetermined deletion threshold, the control device stores the map data in the temporary storage portion, and when a predetermined deletion condition is established, the control device deletes the map data of the acquisition area from the temporary storage portion, and
in a case where the second frequency index value in the area to which the position of the vehicle at the time of transmission of the first acquisition request or second acquisition request belongs is larger than the deletion threshold, the control device stores the map data in the map data storage portion, and the control device maintains the map data of the acquisition area to be stored without deleting the map data of the acquisition area from the map data storage portion regardless of whether the deletion condition is established or not;
wherein the predetermined deletion condition comprises a size of the map data stored in the storage device equals or exceeds a predetermined portion of the storage capacity of the storage device.
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