The accuracy of the GNSS may vary over time, especially for systems without IsoPoint signal correction. From one day to the next, or even within the period of a single event, there can be considerable variations in the coordinates.
To circumvent the deviations inherent in the positioning of GNSS, the monitor GeoNave has position adjustment tools.
Line Shift
The Line Shift tool is used to adjust the position of the coordinates of GNSS to a point on the nearest line to the currently configured tab in the navigation. An example of the need for functionality is when the user verifies that, even after aligning the tractor wheels with a physical tire track on the ground previously realized, he realizes that the deviation to the guide shown on the navigation screen is different from zero. In this situation, the Line Shift corrects the difference, and positions the navigation map again on the trail to be traversed..
Pressing the position adjustment button 
on the navigation screen, the Vertical Menu Position Adjustment, in which the user must select the Line Shift option and press the confirm button 
, as the image below.
After pressing the confirm button, the coordinates of GNSS will be moved perpendicular to the target guide line, shown in red on the screen. The navigation screen will show the Alert Board with the message Line offset: OK, as shown in the following figure.
Free Displacement
The position of the GNSS it can change in any direction, including in the direction of the guides themselves. A common situation in the field is when the application is carried out first in the field perimeter, also called the boundary. Variations in the coordinates of GNSS they can lead to the condition that, when they get close to the area applied on the perimeter, it is noticed that there is a failure or an overlap of the implement bar in relation to the trail already made. In this type of situation, the user can use the Free Displacement tool.
By pressing the position adjustment button on the navigation screen, the Vertical Menu Position Adjustment, in which the user must select the Free Moving option and press the confirm button , as the image below.
After pressing the confirm button, the navigation screen will be displayed in 2D view. The two side button bars will assume the configuration shown in the figure below, and the Alert Board will be displayed with the message Displacement: 0.00 m | 0.00 m.
With each press of one of the four scroll buttons, the navigation map will be moved 5 cm in the direction indicated by the corresponding button design, as shown in the following table. At the Alert Board, the accumulated value so far will be shown, and arrows indicating the direction of the total displacement in both directions.
| Button | Occupation | Alert Board Text |
|---|---|---|
 |
Shifts the map 5 cm to the right | Deslocamento: → 0.05 m | 0.00 m |
 |
Shifts the map 5 cm to the left | Deslocamento: ← 0.05 m | 0.00 m |
 |
Move the map up 5 cm | Deslocamento: 0.00 m | ↑ 0.05 m |
 |
Shifts the map 5 cm down | Deslocamento: 0.00 m | ↓ 0.05 m |
After making the displacements using the four buttons to position the navigation map correctly aligned with the implement bar, when pressing the confirm button 
the displacement will be saved and will be used in navigation from this moment on. The message Free movement: OK will be displayed on Alert Board, as the figure below.
