Detection device, in-vehicle system, and detection method

1. A detection device to be used in an in-vehicle network including a CAN (Controller Area Network) bus and a plurality of function units connected to the CAN bus, the detection device comprising:

a measurement unit configured to measure a signal waveform of a frame transmitted in the CAN bus;

a calculation unit configured to calculate a plurality of kinds of feature amounts of the signal waveform measured by the measurement unit; and

a detection unit configured to detect an abnormality regarding the CAN bus, based on each of the feature amounts calculated by the calculation unit, wherein

the measurement unit

detects a start of the frame,

determines, as a start position of a Control field in the frame, a position of the frame after a specific time elapsed from the start of the frame, and

measures a pulse signal waveform in a range from the start position of the Control field to a CRC (Cyclic Redundancy Check) field in the frame.

2. The detection device according to claim 1 , wherein

the detection device further includes

an acquisition unit configured to acquire a reference distribution being a distribution of each feature amount that has been generated in advance, and

the detection unit detects an abnormality regarding the CAN bus, based on each feature amount calculated by the calculation unit and the reference distribution acquired by the acquisition unit.

3. The detection device according to claim 1 , wherein

the calculation unit calculates, as the feature amount, at least two of mean, variance, skewness, kurtosis, irregularity by Krimphoff, irregularity by Jensen, spectrum crest factor, and root mean square, of voltage values obtained by sampling the signal waveform.

4. The detection device according to claim 1 , wherein

the measurement unit measures the signal waveform of each of a plurality of the frames respectively transmitted from a plurality of the function units,

the calculation unit calculates a plurality of kinds of the feature amounts of each signal waveform measured by the measurement unit, and

the detection unit detects an abnormality regarding the CAN bus, based on the plurality of kinds of the feature amounts, of each signal waveform, calculated by the calculation unit.

5. An in-vehicle system comprising:

a plurality of function units connected to a CAN bus; and

a detection device, wherein

each function unit transmits a frame to another function unit via the CAN bus,

the detection device

detects a start of the frame transmitted in the CAN bus,

determines, as a start position of a Control field in the frame, a position of the frame after a specific time elapsed from the start of the frame, and

measures a pulse signal waveform in a range from the start position of the Control field to a CRC (Cyclic Redundancy Check) field in the frame,

the detection device calculates a plurality of kinds of feature amounts of the measured pulse signal waveform, and

the detection device detects an abnormality regarding the CAN bus, based on each of the calculated feature amounts.

6. A detection method to be performed in a detection device to be used in an in-vehicle network including a CAN bus and a plurality of function units connected to the CAN bus, the detection method comprising the steps of:

measuring a signal waveform of a frame transmitted in the CAN bus;

calculating a plurality of kinds of feature amounts of the measured signal waveform; and

detecting an abnormality regarding the CAN bus, based on each of the calculated feature amounts, wherein

the measuring includes

detecting a start of the frame,

determining, as a start position of a Control field in the frame, a position of the frame after a specific time elapsed from the start of the frame, and

measuring a pulse signal waveform in a range from the start of the Control field to a CRC (Cyclic Redundancy Check) field in the frame.