Time stamp generation without GNSS signal

Patent metadata

Field	Value
Publication number	US-10405294-B2
Application number	US-201515307939-A
Country	US
Kind code	B2
Filing date	Apr 9, 2015
Priority date	Apr 30, 2014
Publication date	Sep 3, 2019
Grant date	Sep 3, 2019

Abstract

The disclosure relates to a method for generating a time stamp in a vehicle which participates in a vehicle ad-hoc network. The method includes associating, by giving out the time stamp, an event, which is transmitted in a message, with a clock time. The clock time is generated by updating a global time base that may be derived from a global satellite navigation signal (GNSS). The method includes checking whether a GNSS signal may be received. The method also includes generating the clock time based on a local time base if an insufficient number of global satellite navigation signals for deriving the global time base is available.

First claim

The invention claimed is:

1. A method for generating a time stamp in a vehicle participating in a vehicular ad hoc network, the method comprising:
determining a global timebase based on one or more GNSS signals received at a vehicle antenna from a GNSS;
determining a time based on the global timebase associated with the received one or more GNSS signals;
when the vehicle antenna fails to receive the one or more GNSS signals from the GNSS:
receiving a radio signal from a time-signal transmitter or a message from another vehicle in communication with the vehicle, the radio signal associated with a local timebase of the time-signal transmitter or the other vehicle;
adjusting the received local timebase;
determining the global timebase based on the adjusted local timebase; and
determining the time based on the global timebase associated with the received radio signal or the received message; and

sending a transmit message including an event, the transmit message associated with the time.

2. The method of claim 1 , wherein the vehicle is started before verifying whether the GNSS signal can be received, and the local timebase is a time updated before the vehicle is started.

3. The method of claim 1 , further comprising retrieving the local timebase from a clock that outputs a local time.

4. The method of claim 3 , comprising:
retrieving modification information, which indicates a modification time instant at which the clock was last modified; and
preventing the time being generated when the modification time instant lies after a last receive time instant at which a GNSS signal was last received.

5. The method of claim 3 , wherein the clock transmits the local time in a radio signal.

6. The method of claim 5 , wherein the local time is transmitted in a radio signal by another node of the vehicular ad hoc network.

7. The method of claim 6 , comprising requesting the radio signal from the other node of the vehicular ad hoc network.

8. The method of claim 6 , wherein the local time is a time stamp generated by the other node of the vehicular ad hoc network.

9. The method of claim 1 , comprising locating the vehicle on the basis of the local timebase and the GNSS signal.

10. A control device configured to implement instructions for processing a vehicle-to-X message, the instructions comprising:
determining a global timebase based on one or more GNSS signals received at a vehicle antenna from a GNSS;
determining a time based on the global timebase associated with the received one or more GNSS signals;
when the vehicle antenna fails to receive the one or more GNSS signals from the GNSS:
receiving a radio signal from a time-signal transmitter or a message from another vehicle in communication with the vehicle, the radio signal associated with a local timebase of the time-signal transmitter or the other vehicle;
adjusting the received local timebase;
determining the global timebase based on the adjusted local timebase; and
determining the time based on the global timebase associated with the received radio signal or the received message; and

sending a transmit message including an event, the transmit message associated with the time.

11. The control device of claim 10 , wherein the vehicle is started before verifying whether the GNSS signal can be received, and the local timebase is a time updated before the vehicle is started.

12. The control device of claim 10 , further comprising instructions for retrieving the local timebase from a clock that outputs a local time.

13. The control device of claim 12 , further comprising instructions for:
retrieving modification information, which indicates a modification time instant at which the clock was last modified; and
preventing the time being generated when the modification time instant lies after a last receive time instant at which a GNSS signal was last received.

14. The control device of claim 12 , wherein the clock transmits the local time in a radio signal.

15. The control device of claim 14 , wherein the local time is transmitted in a radio signal by another node of the vehicular ad hoc network.

16. The control device of claim 15 , further comprising instructions for requesting the radio signal from the other node of the vehicular ad hoc network.

17. The control device of claim 15 , wherein the local time is a time stamp generated by the other node of the vehicular ad hoc network.

18. The control device of claim 10 , further comprising instructions for locating the vehicle on the basis of the local timebase and the GNSS signal.

Assignees

• Continental Teves Ag & Co Ohg

Inventors

• Zalewski Michael
• Scherping Richard
• Kretschmar Sven
• Bauch Nils

Classifications

• H04W84/18

  Self-organising networks, e.g. ad-hoc networks or sensor networks · CPC title

• H04W4/44

  for communication between vehicles and infrastructures, e.g. vehicle-to-cloud [V2C] or vehicle-to-home [V2H] · CPC title

• H04W4/02 Primary

  Services making use of location information · CPC title

• H04L43/106

  using time related information in packets, e.g. by adding timestamps · CPC title

• H04W4/80

  Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication · CPC title