Method for verifying the validity of sensor data of an ethernet onboard network

A control unit for an Ethernet onboard network, which, as a first control unit, is designed:

• to send a signal to a second control unit of the Ethernet onboard network and to receive the signal from the second control unit;
• to determine a delay time of the signal on a connecting path to the second control unit;
• to determine a maximum speed of the connecting path on the basis of the delay time;
• and
• to determine a type of a transmission medium of the connecting path on the basis of the maximum speed,
• and at least includes
• a microprocessor,
• a volatile memory and nonvolatile memory,
• at least two communication interfaces,
• a synchronizable timer,
• the nonvolatile memory containing program instructions that, when executed by the microprocessor,
• characterized in that cause checking of the validity of time synchronization of sensor data of an Ethernet onboard network in a motor vehicle, by performing operations comprising:
• determining a delay time of a first signal on a first connecting path between a first control unit of the Ethernet onboard network and a second control unit of the Ethernet onboard network;
• determining a maximum speed of the first connecting path on the basis of the delay time;
• and
• determining a type of a transmission medium of the first connecting path on the basis of the maximum speed,
• characterized in that the following steps are carried out:
• identifying at least the first control unit of the Ethernet onboard network;
• synchronizing at least the first control unit of the Ethernet onboard network;
• ascertaining a synchronization interval;
• ascertaining a drift of a timer of the first control unit;
• ascertaining a timestamp of the first control unit;
• reading a timestamp or querying the time of the first control unit;
• comparing the timestamp with a reference clock of the Ethernet onboard network;
• carrying out a delay time measurement;
• ascertaining the speed of an associated clock generator;
• ascertaining a time difference of the synchronization interval;
• ascertaining a last synchronization.

An Ethernet onboard network for a motor vehicle, having a first control unit and a second control unit, wherein the control units are connected to one another by way of at least one connecting path, wherein the Ethernet onboard network is configured to perform operations comprising:

• determining a delay time of a first signal on a first connecting path between the first control unit of the Ethernet onboard network and the second control unit of the Ethernet onboard network;
• determining a maximum speed of the first connecting path on the basis of the delay time;
• and
• determining a type of a transmission medium of the first connecting path on the basis of the maximum speed,
• characterized in that the following steps are carried out:
• identifying at least the first control unit of the Ethernet onboard network;
• synchronizing at least the first control unit of the Ethernet onboard network;
• ascertaining a synchronization interval;
• ascertaining a drift of a timer of the first control unit;
• ascertaining a timestamp of the first control unit;
• reading a timestamp or querying the time of the first control unit;
• comparing the timestamp with a reference clock of the Ethernet onboard network;
• carrying out a delay time measurement;
• ascertaining the speed of an associated clock generator;
• ascertaining a time difference of the synchronization interval;
• ascertaining a last synchronization;
• and
• wherein the first control unit is in a form such that the delay time of the first signal is determined using the first control unit and a delay time of a third signal on a third connecting path, which is connected to the first control unit only indirectly, between the second control unit and a third control unit of the Ethernet onboard network is determined using the third control unit, the determination of the delay time of the third signal being triggered by a service message sent from the first control unit to the third control unit.

A non-transitory computer-readable medium having stored thereon computer-executable instructions that, when executed by a computer, cause said computer to perform operations comprising:

• determining a delay time of a first signal on a first connecting path between a first control unit of the Ethernet onboard network and a second control unit of the Ethernet onboard network;
• determining a maximum speed of the first connecting path on the basis of the delay time;
• and
• determining a type of a transmission medium of the first connecting path on the basis of the maximum speed,
• characterized in that the following steps are carried out:
• identifying at least the first control unit of the Ethernet onboard network;
• synchronizing at least the first control unit of the Ethernet onboard network;
• ascertaining a synchronization interval;
• ascertaining a drift of a timer of the first control unit;
• ascertaining a timestamp of the first control unit;
• reading a timestamp or querying the time of the first control unit;
• comparing the timestamp with a reference clock of the Ethernet onboard network;
• carrying out a delay time measurement;
• ascertaining the speed of an associated clock generator;
• ascertaining a time difference of the synchronization interval;
• ascertaining a last synchronization.

A vehicle having multiple control units comprising an Ethernet onboard network, wherein a control unit for the Ethernet onboard network, which, as a first control unit, is designed:

• to send a signal to a second control unit of the Ethernet onboard network and to receive the signal from the second control unit;
• to determine a delay time of the signal on a connecting path to the second control unit;
• to determine a maximum speed of the connecting path on the basis of the delay time;
• and
• to determine a type of a transmission medium of the connecting path on the basis of the maximum speed,
• and at least includes
• a microprocessor,
• a volatile memory and nonvolatile memory,
• at least two communication interfaces,
• a synchronizable timer,
• the nonvolatile memory containing program instructions that, when executed by the microprocessor,
• characterized in that cause checking of the validity of time synchronization of sensor data of an Ethernet onboard network in a motor vehicle, by performing operations comprising:
• determining a delay time of a first signal on a first connecting path between the first control unit of the Ethernet onboard network and a second control unit of the Ethernet onboard network;
• determining a maximum speed of the first connecting path on the basis of the delay time;
• and
• determining a type of a transmission medium of the first connecting path on the basis of the maximum speed,
• characterized in that the following steps are carried out:
• identifying at least a first control unit of the Ethernet onboard network;
• synchronizing at least the first control unit of the Ethernet onboard network;
• ascertaining a synchronization interval;
• ascertaining a drift of a timer of the first control unit;
• ascertaining a timestamp of the first control unit;
• reading a timestamp or querying the time of the first control unit;
• comparing the timestamp with a reference clock of the Ethernet onboard network;
• carrying out a delay time measurement;
• ascertaining the speed of an associated clock generator;
• ascertaining a time difference of the synchronization interval;
• ascertaining a last synchronization.