Agriculture Reference
In-Depth Information
Chapter 4
Precision in Guidance of Farm Machinery
Hermann J. Heege
Abstract
Georeferencing by GNSS has opened up possibilities for precise guidance
of farm machinery along virtual lines in the fi elds. The guidance takes place either
manually with the help of lightbar indications or in an automatic way. The driver
concentrates on supervising the machinery.
In prior pass guidance, each run across the fi eld follows the respective prior path
offset by the operating width of the machine. Contrary to this, in fi xed line guidance,
the courses across the fi eld are not defi ned by the respective prior path but instead
solely by the fi rst pass. Prior pass guidance is indispensable in irregularly shaped
fi elds, whereas in rectangular fi elds fi xed line guidance should be preferred.
On slopes, using more than one GNSS antenna allows to compensate for roll,
pitch or yaw of the tractor. Downward drifting of implements on side slopes can be
counteracted by passive- or active guidance corrections.
Keywords
Automatic guidance • Fixed line guidance • Guidance on slopes •
Lightbar indications • Pitch • Prior-pass guidance • Roll • Section control • Yaw
4.1
Principles of Guidance
Precision farming implies accurate guidance of farm machinery. The wider the
width of operation is, the more diffi cult it is for the driver to navigate without
inaccuracies between adjacent runs. Therefore, many farmers in Europe use
tram-
lines
in small cereals or rape (colza). These tramlines are created each year at the
time of drilling by disengaging the respective seed metering rollers precisely there,
