Method and system for performing time-synchronization

Patent metadata

Field	Value
Publication number	US-12301339-B2
Application number	US-202017798955-A
Country	US
Kind code	B2
Filing date	Feb 21, 2020
Priority date	Feb 21, 2020
Publication date	May 13, 2025
Grant date	May 13, 2025

Abstract

A method performs time-synchronization between a master clock and a plurality of slave clocks. The method performs a forward time-synchronization from the master clock to the plurality of slave clocks. Further, the method performs a reverse time-synchronization from the plurality of slave clocks to a corresponding plurality of validator clocks. In addition, the method validates the time-synchronization between the plurality of slave clocks, notably between the master clock and the plurality of slave clocks, based on the plurality of validator clocks.

First claim

The invention claimed is:

1. A method for performing time-synchronization between a master clock and a plurality of slave clocks, the method comprising:
performing a forward time-synchronization to time-synchronize respective slave clock times of the plurality of slave clocks to a master clock time of the master clock;
performing a reverse time-synchronization to time-synchronize, for each of a plurality of validator clocks, a validator clock time to the slave clock time of a corresponding slave clock of the plurality of slave clocks; and
validating a time-synchronization between the plurality of slave clocks by comparing the validator times of the plurality of validator clocks.

2. The method according to claim 1 , wherein forward time-synchronization is performed using precision-time-protocol, and/or reverse time-synchronization is performed using precision-time-protocol.

3. The method according to claim 1 , wherein
forward time-synchronization and/or reverse time-synchronization are performed over an Ethernet communication network, and
forward time-synchronization and reverse time-synchronization make use of different EtherTypes.

4. The method according to claim 1 , wherein a message used for reverse time-synchronization has a higher priority with regard to processing and/or transmission than a message used for forward time-synchronization.

5. The method according to claim 1 , wherein
forward time-synchronization and/or reverse time-synchronization are performed over a communication network, and
a validator comprising the plurality of validator clocks has a higher integrity level than at least one or more components of the communication network.

6. The method according to claim 5 , wherein the higher integrity level is a higher automotive-safety-integrity-level.

7. The method according claim 1 , wherein the plurality of validator clocks are implemented in a corresponding plurality of different time domains of a Synchronized Time-Base Manager of an automotive-open-system-architecture standard.

8. The method according to claim 1 , wherein validating the time-synchronization between the plurality of slave clocks comprises:
comparing the validator times of the plurality of validator clocks;
determining that the plurality of slave clocks are time-synchronized when the validator times of the plurality of validator clocks are operatively equal; and/or
determining that the plurality of slave clocks are not time-synchronized when the validator times of at least two of the plurality of validator clocks are not operatively equal.

9. The method according to claim 1 , wherein
the plurality of slave clocks are associated with a plurality of sensors, and
each of the plurality of sensors is configured to provide sensor data with a time stamp generated by the associated slave clock.

10. The method according to claim 9 , further comprising:
performing a forward time-synchronization to time-synchronize a fusion time of a fusion clock to the master time of the master clock, wherein the fusion clock is part of a fusion unit configured to perform sensor fusion of the sensor data provided by the plurality of sensors, and wherein the forward time-synchronization of the slave clocks is performed via the fusion unit; and
performing a reverse time-synchronization to time-synchronize the validator time of a corresponding validator clock to the fusion time of the fusion clock.

Assignees

• Bayerische Motoren Werke Ag

Inventors

• Abdelhameed Mohamed-Saad
• Bilra Manjeet Singh
• Budweiser Karl
• Laengst Wolfgang
• Schurius Markus
• Unger Nils

Classifications

• H04W56/001

  Synchronization between nodes · CPC title

• H04L12/40

  Bus networks · CPC title

• H04J3/14

  Monitoring arrangements {(for SDH/SONET rings H04J3/085)} · CPC title

• H04L12/403

  with centralised control, e.g. polling · CPC title

• H04J3/0667 Primary

  Bidirectional timestamps, e.g. NTP or PTP for compensation of clock drift and for compensation of propagation delays (arrangements for monitoring round trip delays in packet switching networks H04L43/0864) · CPC title