Patent ID: 8442722

Claim:
A guidance control system to guide a corner unit of a center pivot irrigation system along a path, the guidance control system comprising: a rail positioned at a right angle with respect to a central vertical plane through a wheel of the corner unit; a primary antenna coupled to the rail and operable to receive signals from at least one external positional information source; a secondary antenna spaced apart from the primary antenna on the rail, the secondary antenna operable to receive signals from at least one external positional information source; a receiver in communication with the primary antenna and the secondary antenna and operable to process the signals to produce position data corresponding to a current position of the wheel and to produce altitude data about the height of the primary antenna and the secondary antenna; and a controller in communication with the receiver, the controller 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 and further programmed to calculate a tilt angle from the altitude data and adjust the heading based on the tilt angle.