Patent ID: 11943687
Assignee: TOYOTA JIDOSHA KABUSHIKI KAISHA
Field: Measurement (Instruments)
Classification: CPC H  G | IPC G  H

Claim 7:
8. The data collection system according to claim 1, wherein
the server controller does not update the master map in real time and instead performs write-ahead logging in which, when an update to a respective segment in the master map occurs, content of the update is recorded in a log entry, and at a time at which a number of log entries has reached a fixed number, the log entries are reflected in the respective segment of the master map;
the log entry includes a log sequence number which is an integer value that is monotonously incremented each time an update occurs in the respective segment of the master table; and
the vehicle processor in the respective probe vehicle is further programmed to:
identify the segment ID to be sent to the server device along with the request for the partial map;
determine whether the partial map corresponding to the identified segment ID exists in the respective probe vehicle;
in response to determining that the partial map corresponding to the identified segment ID exists in the respective probe vehicle, transmit the request with both the identified segment ID and a log sequence number associated with the identified segment ID, to the server device; and
in response to determining that the partial map corresponding to the identified segment ID does not exist in the respective probe vehicle, transmit the request with only the identified segment ID, to the server device.