A corner unit guidance control system for use with a corner unit that is part of a center pivot irrigation system includes an antenna, a receiver, and a controller. The antenna is located along a vertical axis through the center of a wheel of the corner unit and operable to receive signals from at least one external positional information source. The receiver communicates with the antenna and operable to process the signals to produce position data corresponding to a current position of the wheel. The controller communicates with the receiver and is programmed to steer the wheel to a heading corresponding to a difference between the current position of the wheel and a point along the path.
