A method for automatically guiding a vehicle along at least a first of a plurality of rows comprising predefined centerlines. At least a second of the rows comprises a number of objects of known dimensions positioned at known locations along the centerline thereof. The method comprises the steps of scanning the objects from the vehicle, generating a set of data points representative of the locations of the objects relative to the vehicle, determining a sensed position and heading of the vehicle from the data points, comparing the sensed position and heading of the vehicle to a position and direction of the first row centerline, and generating offset and heading errors for the vehicle based on differences between the sensed position and heading of the vehicle and the position and direction of the first row centerline.