The performance of the hitch yaw sensor was quite good
and allowed the estimated plant map accuracy in the curved
sections of the rows to be comparable to the straight sections
of the trial. Since the heading of the rows in the experiment
was primarily due North, errors in easting values (i.e., the
transverse-track direction) were sensitive to yaw deviations
particularly in the curved sections of the trial, while yaw
deviations would have a minor effect on errors in northing
values (i.e., the travel direction) due to the large distance
between the tractor GPS and the planting wheel of the transplanter
relative to the magnitude of the row offset (4 cm) in the
curved sections of the trial. Comparing the mapping performance
from trial tow with the data in Table 1 shows that the
mean RMS easting displacement errors for the curved
portions of the beds were similar to those obtained in the
straight sections. Results from the ANOVA showed that there
was no significant (a ¼ 0.05) difference in mean easting values
between bed shape treatments and that the variance about
the mean was also not significantly different between bed
shapes. Furthermore, no trend was observed in the displacement
errors associated with curve direction (right vs. left).
Similarly, when the displacement errors in the Northing
direction were compared, there were no significant (a ¼ 0.05)
differences observed between the mean northing displacement
errors for the different path treatments (straight vs.
curved).