To configure the survey style for a site calibration

1. Tap and select Settings / Survey styles. Select the required survey style.
2. Tap Site calibration.

3. Select whether the calibration computation should fix or compute the horizontal scale factor and the horizontal rotation.

   To fix the values, select the Fix horizontal scale to 1.0 check box and the Fix horizontal rotation to 0 check box. To compute the values, clear the check boxes.

   Selecting these check boxes is recommended if you are working in a modern well-defined coordinate system with a reliable transformation from the global reference frame and using a high quality local control within that coordinate system. You should clear these check boxes if GNSS measurements need to be scaled and/or rotated to fit the local control.

4. Select the type of Vertical adjustment to be computed and applied:

   • The Constant adjustment only option will compute a vertical shift value to best fit the calibration point measured elevations to the control elevations. This setting is recommended if you have an accurate geoid model.
   • The Inclined plane option will compute a vertical shift plus north and east inclinations to best fit the calibration point measured elevations to the control elevations. Use this model if you do not have an accurate geoid model, or if the geoid model is not a good fit to your vertical control.

   Clearing the Fix horizontal scale to 1.0 and Fix horizontal rotation to 0 check boxes and selecting the Inclined plane option will generally result in smaller residuals. However, unless you have high quality control, precise measurements, and a large project area, these smaller residuals are a result of overfitting your measurements rather than being a true indication of the quality of your site calibration.

5. For the Trimble Access software to automatically perform a calibration when you measure a calibration point, select the Auto calibrate check box. To switch automatic calibration off, clear the check box.

6. Select an observation type appropriate to a calibration point. The options for a calibration point are topo point or observed control point.

   If you set the observation type to Topo point, all settings are defined in the survey style for a topo point.

7. If necessary, set the tolerances for maximum horizontal and vertical residuals, and maximum and minimum horizontal scale settings. These settings only apply to automatic calibration and do not affect manual calibration.

   You can also specify the maximum slope of the vertical adjustment plane. The software warns you if the slope in the north direction or the slope in the east direction exceeds this. Generally the default settings are appropriate.

8. Specify how the calibration points you measure will be named:

   • In the Method field, choose one of the following options: Add prefix, Add suffix, or Add constant.

   • In the Add field, enter the prefix, suffix, or constant.

   The table below shows the different options and gives an example of each.

   Option	What the software does	Example value in the Add field	Grid point name	Calibration point name
   Same	Gives the calibration point the same name as the grid point	–	100	100
   Add prefix	Inserts a prefix before the grid point name	GNSS_	100	GNSS_100
   Add suffix	Inserts a suffix after the grid point name	_GNSS	100	100_GNSS
   Add constant	Adds a value to the grid point name	10	100	110