Marker detection method and vehicular system

A marker detection method, comprising:

• (1) performing a marker detection process, including
• acquiring, using a plurality of magnetic sensors arranged in a vehicle width direction of a vehicle, a first magnetic distribution in a forwarding direction of the vehicle, the plurality of magnetic sensors being attached to the vehicle,
• determining, using processing circuitry, whether a zero-cross, where magnetism is reversed between positive and negative, or a peak point, where magnetism has a maximum value in a line-symmetric magnetic distribution, exists in the first magnetic distribution,
• in response to determining that the zero-cross or the peak point exists in the first magnetic distribution, determining, using the processing circuitry, that a magnetic marker laid in a road exists, and acquiring, using the plurality of magnetic sensors, a second magnetic distribution in the vehicle width direction of the vehicle,
• identifying, using the processing circuitry, a location in the vehicle width direction of the zero-cross or the peak point in the second magnetic distribution, and
• calculating, using the processing circuitry, a lateral shift amount of the vehicle in the vehicle width direction using the identified location in the vehicle width direction of the zero-cross or the peak point in the second magnetic distribution;
• and
• (2) performing a magnetic generation source detection process, including
• acquiring, using the plurality of magnetic sensors, the second magnetic distribution in the vehicle width direction of the vehicle at a frequency of time,
• identifying, using the processing circuitry, the location in the vehicle width direction of the zero-cross or the peak point in the second magnetic distribution at the frequency of time,
• calculating, using the processing circuitry, a difference between a first location in the vehicle width direction of the zero-cross or the peak point in the second magnetic distribution at a first time and a second location in the vehicle width direction of the zero-cross or the peak point in the second magnetic distribution at a second time after the first time,
• calculating, using the processing circuitry, a change rate of the location in the vehicle width direction of the zero-cross or the peak point in the second magnetic distribution, using the calculated difference, the first time and the second time, and
• determining, using the processing circuitry, using the calculated change rate, a possibility of a presence of a magnetic generation source, other than the magnetic marker laid in the road, wherein
• the method further comprises
• performing control for assisting driving of the vehicular system, and
• switching control contents, including whether or not to perform the control for assisting driving of the vehicular system, in accordance with the possibility of the presence of the magnetic generation source.