Method for determining a synchronization accuracy, computer program, communication unit and motor vehicle

1. A method for determining a synchronization accuracy of a time synchronization of a first communication unit, the method comprising:

transmitting a time request via a communication channel at a corresponding instant of time of transmission from the first communication unit to a second communication unit;

receiving a time response at a corresponding instant of time of reception at the first communication unit, wherein the time response comprises a synchronization time specification of the second communication unit;

determining the synchronization accuracy based on the instant of time of transmission and the instant of time of reception; and

using the synchronization time specification of the second communication unit for executing a function of the first communication unit depending on the synchronization accuracy; wherein

a wired network is used as the communication channel which wired network comprises at least one component with a functional safety level that is below a functional safety level that is required by the function of the first communication unit.

2. A non-transitory medium with a computer program for carrying out the method of claim 1 when the computer program is executed on a computer, a processor, or a programmable hardware component.

3. The method of claim 1 , wherein a synchronization error determined from the synchronization accuracy is taken into account for the time synchronization as a function of the function to be executed.

4. The method of claim 3 , wherein a new time request is sent in the case of the synchronization accuracy being less than a synchronization accuracy required for the function to be executed.

5. The method of claim 3 , wherein, to determine the synchronization accuracy, a time period between receiving the time request and sending the time response at the second communication unit is taken into account, which time period is inserted as a dwell time into the time response, and/or wherein an instant of time of reception of the time request and an instant of time of transmission of the time response are taken into account, which are inserted into the time response.

6. The method of claim 1 , wherein a new time request is sent in the case of the synchronization accuracy being less than a synchronization accuracy required for the function to be executed.

7. The method of claim 6 , wherein, to determine the synchronization accuracy, a time period between receiving the time request and sending the time response at the second communication unit is taken into account, which time period is inserted as a dwell time into the time response, and/or wherein an instant of time of reception of the time request and an instant of time of transmission of the time response are taken into account, which are inserted into the time response.

8. The method of claim 1 , wherein in case of a deviation of the synchronization time specification of the second communication unit from a time specification of the first communication unit the time specification of the first communication unit is gradually adapted the synchronization time specification.

9. The method of claim 1 , wherein one or more of respective identification features, checksums, and signatures, by which a time response is clearly assigned to a corresponding time request, are attached to the time request and the time response.

10. The method of claim 1 , wherein, to determine the synchronization accuracy, a time period between receiving the time request and sending the time response at the second communication unit is taken into account, which time period is inserted as a dwell time into the time response, and/or wherein an instant of time of reception of the time request and an instant of time of transmission of the time response are taken into account, which are inserted into the time response.

11. The method of claim 1 , wherein, to determine the synchronization accuracy, a time period between receiving the time request and sending the time response at the second communication unit is taken into account, which time period is inserted as a dwell time into the time response, and/or wherein an instant of time of reception of the time request and an instant of time of transmission of the time response are taken into account, which are inserted into the time response.

12. The method of claim 1 , wherein manipulation security of the time response and/or the time request is increased by using at least one cryptographic method, wherein the respective message is signed with a cryptographic method.

13. The method of claim 1 , wherein a rate variation of a timer of the first communication unit compared to a timer of the second communication unit is compensated by using a deviation rate, wherein the deviation rate is determined based on at least one further time-delayed sending of a time request and a corresponding further reception of a time response.

14. A communication unit for connecting to a communication channel, wherein the communication unit comprises at least one timer and is further configured to execute the method of claim 1 .

15. A motor vehicle with at least one communication channel, wherein the motor vehicle comprises at least one communication unit of claim 14 .

16. The method of claim 1 , wherein a plurality of time requests is sent from the first communication unit via the communication channel to a corresponding plurality of communication units, which are configured accordingly at least with respect to of sending the time response of the second communication unit.

17. A method for determining a synchronization accuracy of a time synchronization of a first communication unit, the method comprising:

transmitting a time request via a communication channel at a corresponding instant of time of transmission from the first communication unit to a second communication unit;

receiving a time response at a corresponding instant of time of reception at the first communication unit, wherein the time response comprises a synchronization time specification of the second communication unit;

determining the synchronization accuracy based on the instant of time of transmission and the instant of time of reception; and

using the synchronization time specification of the second communication unit for executing a function of the first communication unit depending on the synchronization accuracy; wherein

a synchronization error determined from the synchronization accuracy is taken into account for the time synchronization as a function of the function to be executed.