Vehicular orientation detection system

A vehicular posture detection system of a vehicle, comprising:

• a first magnetic sensor configured to detect a plurality of magnetic markers laid in or on a road surface of a road on which a vehicle is traveling, the first magnetic sensor being located at a first position of the vehicle;
• a second magnetic sensor configured to repeatedly perform magnetic marker detection processes with a predetermined period of cycles for detecting the plurality of magnetic markers, the second magnetic sensor being located at a second position of the vehicle, the first position and the second position being separated in a longitudinal direction of the vehicle;
• and
• processing circuitry configured to
• calculate a first lateral shift amount of the vehicle with respect to a first magnetic marker of the plurality of magnetic markers using a first detection result of the first magnetic sensor,
• set, in response to the first magnetic sensor detecting the first magnetic marker, a temporal duration including a predicted time point when the second magnetic sensor is predicted to detect the first magnetic marker after the first magnetic sensor detecting the first magnetic marker as a detection duration for the second magnetic sensor to detect the first magnetic marker, the temporal duration starting at a start time before the predicted time point and ending at an end time after the predicted time point so that the second sensor detects the first magnetic marker during the temporal duration,
• after the first magnetic sensor detecting the first magnetic marker, wait to perform the magnetic marker detection processes with the predetermined period of cycles until the start time for the second magnetic sensor, start controlling the second magnetic sensor to repeatedly perform the magnetic marker detection process with the predetermined period of cycles at the start time, and stop controlling the second magnetic sensor to repeatedly perform the magnetic marker detection process with the predetermined period of cycles at the end time,
• calculate a second lateral shift amount of the vehicle with respect to the first magnetic marker using a first detection result of the second magnetic sensor,
• calculate a third lateral shift amount of the vehicle with respect to a second magnetic marker of the plurality of magnetic markers using a second detection result of the first magnetic sensor, the second magnetic marker and the first magnetic marker being separated in a route direction of the road,
• calculate a first difference between the first lateral shift amount and the third lateral shift amount, the first difference indicating a difference between the route direction of the road and a traveling direction of the vehicle,
• determine whether the first difference is smaller than a predetermined threshold, and
• in response to determining that the first difference is smaller than the predetermined threshold, calculate, as a vehicle posture which indicates an angle between an axis of a vehicle body of the vehicle in a longitudinal direction and the traveling direction of the vehicle, a second difference between the first lateral shift amount and the second lateral shift amount, and use the calculated second difference for controlling the vehicle.