Automatic steering apparatus using reflected signals

Apparatus for automatically steering a farm crop vehicle between rows of corn by sensing the locations of the rows ahead of the vehicle. The apparatus senses the location of the plants as the crop vehicle approaches them. The data thus obtained are processed by an on-board microcontroller to determine the lateral location of the crop vehicle relative to the rows and provide a feedback signal. Another feedback signal is provided by integrating that lateral error data. In addition to the plant sensors, the harvester has a Doppler radar system on its left side that provides ground-velocity information for the left side, and a similar system on the right side. The radar outputs enable the microcontroller to measure the turning of the vehicle. This is used to produce yet another feedback signal that improves the automatic steering. This turning-feedback signal stabilizes the loop. The microcontroller provides steering commands for automatically tracking the rows.