Time stamp generation without GNSS signal

• US 10,405,294 B2
• Filed: 04/09/2015
• Issued: 09/03/2019
• Est. Priority Date: 04/30/2014
• Status: Active Grant

• Current Assignee: Continental Teves AG & Co. OHG (Continental AG)
• Original Assignee: Continental Teves AG & Co. OHG (Continental AG)
• Inventors: Zalewski, Michael, Scherping, Richard, Kretschmar, Sven, Bauch, Nils
• Primary Examiner(s): Phan, Dao L
• Application Number:
  US15/307,939
• Publication Number:
  US 20170280416A1
• Time in Patent Office: 1,608 Days
• Field of Search: 34235773
• CPC Class Codes: G01S 19/46 the supplementary measurement being of a radio-wave signal type
• CPC Class Codes: H04L 43/106 using time related information in packets, e.g. by adding timestamps
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 4/40 for vehicles, e.g. vehicle-to-pedestrians [V2P]
• CPC Class Codes: H04W 4/44 for communication between vehicles and infrastructures, e.g. vehicle-to-cloud [V2C] or vehicle-to-home [V2H]
• CPC Class Codes: H04W 4/46 for vehicle-to-vehicle communication [V2V]
• CPC Class Codes: H04W 4/80 Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication
• CPC Class Codes: H04W 64/006 with additional information processing, e.g. for direction or speed determination
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

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.

Claims

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.