Aliasing determination device

An aliasing determination device comprising:

• an information acquisition section configured to repeatedly acquire observation point information of an object that is present within a predetermined detection region from a radar device mounted on a vehicle, the observation point information including an observation direction, which is an observed value of a designated direction, wherein the designated direction corresponding to the observation direction is at least one of a horizontal direction and a vertical direction;
• an axial misalignment acquisition section configured to obtain an orientation of the radar device when the radar device is mounted at a reference position as a reference mounting direction and an actual orientation of the radar device as an actual mounting direction and to acquire an axial misalignment amount of the actual mounting direction with respect to the reference mounting direction toward the designated direction;
• an aliasing calculation section configured to calculate an aliasing direction, which is a direction estimated when there is phase aliasing in the observation direction included in the observation point information;
• and
• an instantaneous determination section configured to determine, as an actual direction, one of the observation direction and the aliasing direction corresponding to the observation direction that is closer to the reference mounting direction, which is estimated from the axial misalignment amount and the actual mounting direction.