US Patent 7860628 System for guiding a farm implement between swaths

An apparatus, method and tangible medium using GPS for guiding a farm implement along a turn path between swaths. The apparatus includes a GPS receiver and a turn computer. The turn computer calculates or stores a turn path between swaths, calibrates GPS positions to a swath end position and uses the calibrated GPS positions to guide the implement along the turn path to the start of the next swath. A steering wheel autopilot may be included to steer a powered vehicle according to a cross track error between the calibrated GPS positions and the turn path.