## 3 Results and Discussion
### Overlapping  
Figure 16a shows the field boundary, the cultivated tracks, and the lateral and headland overlaps. For a more detailed representation, Figure 16b presents a zoomed area at the lower northeast corner of the field. It must be stated that the color highlighting of the headland overlaps is virtually dominant. Figure 16: **(a)** Field boundary, cultivated area and lateral and headland overlaps; and **(b)** a zoomed area at the lower northeast corner of the field. Figure 15: Satellite view of the examined field and the detected boundary (green line). In Figure 16b, the fact that the used function for the determination of the boundary could not deliver the closest fit possible is illustrated. Beyond an overestimation of the field size, this also caused an overestimation of the gaps' area \(A_{gaps}\) and, thus, an underestimation of the summed area of lateral overlaps \(A_{overlap,lat}\). Furthermore, there are noticeable distortions at the tops of several headland tracks, which was a further source of error concerning the boundary. They could be traced back to the error behavior of the used receiver. The discrepancy between different errors depending on the rover's movement has been examined previously (e.g., [22; 23]). A further possible source of error was the overall additional excitation of the tractor cabin during headland overlapping. In Figure 16b, passes can be distinguished where there is an excessive lateral overlap alternating with gaps in the magnitude of the plow's working width. This was mainly due to the erroneous D-GNSS positioning, as discussed in previous sections. The pass-to-pass error of low-cost receivers has been considered previously (e.g., [21]). Furthermore, it can be recognized that two of the first main part passes in the south are almost entirely overlapping, whereas there seems to be no corresponding gap. For the rest of the field, this was also a common pattern for some of the first and last few passes of the main part or a headland, indicating again a specific driving scheme at these sites. This pattern fits the observations discussed in Section 3.1 and led to an overestimation of \(A_{overlap,lat}\). A typical problem with moldboard plows are the undesirable triangular shapes of unplowed segments at the headlands [15]. Headland overlapping is generally an important indicator of the performance of the driver, having a remarkable effect on the field efficiency and causing additional cost. The alignment of the beginning and the end of the main part tracks, which can be observed at the top of the polygons, is highly variable in Figure 16b. Possible reasons for this observation were a varying track-error of the D-GNSS positioning and improper timing by the driver. In general, the headland overlaps seem to be quite long. An obvious reason for that was the remaining error for the setting of the in-work threshold of the RHP, as described in Section 2.5. However, a minimization of the threshold would have had little effect on the length of the pass and probably would have led to an exclusion of points that were only just tilted. The main results in terms of the overlapping indicators are listed in Table 3.  
\(A_{overlap,lat,perc}\) contains the same information as the efficiency of width use, which is documented in [24]. When transferring the values given in this reference to the \(A_{overlap,lat,perc}\), it should not exceed a value of 5%. Considering the numerous previously mentioned error sources and simplifying assumptions, the value of 2.05% seemed usable for a first estimation. \(A_{overlap,head,perc}\) refers only to the overlapping between the main part and the headland passes and was set in relation to the total cultivated area. When comparing the value of 3.96% to the \(A_{overlap,lat,perc}\), it became obvious that the headland overlapping had an even bigger influence on the total overlapping within the field than the lateral overlapping between neighboring passes.