Patent ID: 8504864
Filing Date: 2013-08-06
Classification: B60T,H04J,H04L

Abstract:
1. A method for synchronizing time in an unsynchronized vehicle controller area network system, the system having a plurality of electronic control units in communication within one another via a plurality of controller area network buses, the electronic control units are in communication with sensing devices for collecting sensed data obtained by the sensing devices, each electronic control unit transmitting messages on the plurality of controller area network buses for sharing sensed data with other electronic control units, and the plurality of electronic control units are in communication with a master control unit vehicle via the plurality of controller area network buses, the method comprising the steps of: the master control unit receiving a global time from a time synchronization source; the master control unit estimating a respective time delay in transmitting messages by the electronic control units in each controller area network bus, the time delay being a difference between a time when a message is generated by a respective electronic control unit for transmission on a respective controller area network bus and a time when the message is transmitted on the respective controller area network bus; adjusting the global time for each respective controller area network bus based on the estimated time delays associated with each respective controller area network bus; and transmitting global time messages from the master control unit to each electronic control unit that include the adjusted global times for an associated controller area network bus, wherein each electronic control unit connected to the controller area network receiving a respective global time message synchronizes a local clock based on the adjusted global time in the respective global time message.