Vehicle, estimation method, and non-transitory computer-readable storage medium

A method of estimating a relative yaw angle of a trailer relative to a vehicle towing the trailer,

• wherein a processor performs the method comprising:
• causing a camera provided in the vehicle to acquire a trailer image containing a detection object provided on the trailer;
• causing a sensor provided in the vehicle to acquire travel state information of the vehicle;
• and
• estimating the relative yaw angle based on at least one of the trailer image or the travel state information, and
• wherein in the estimation of the relative yaw angle based on the trailer image, the processor performs:
• specifying a trajectory of the detection object, which moves according to a change in the relative yaw angle, in the trailer image;
• determining whether the specified trajectory matches a predetermined reference trajectory;
• in a case where the specified trajectory matches the reference trajectory, estimating an angle determined according to a position of the detection object on the trajectory, as the relative yaw angle;
• and
• in a case where the specified trajectory does not match the reference trajectory, determining that a second road surface on which the trailer is located is inclined relative to a first road surface on which the vehicle is located, and estimating, as the relative yaw angle, an angle obtained by performing slope correction on an angle determined according to a position of the detection object on the specified trajectory.