Performing a Site Calibration

This requires both Global WGS84 and Local control points have been imported into TBC a site calibration can be performed. Importing control points workflow can be found HERE.

You should calibrate a site if any of the following are true:

• It was not calibrated in the field.
• You require a report of quality control records.
• You need to transfer a calibration to the field software (for example, Trimble Access).
• You need to add extra points to a calibration in the field software.

The site calibration process creates a set of local site settings. When a site calibration is complete, the site settings are used in the computation of all other imported GNSS data.

1. Navigate to Survey → Network → Site Calibration.
    
2. If required change the Calibration Settings.
   • Check Horizontal Calibration to perform a horizontal calibration consisting of a translation, rotation, and scale factor.
   • Check Set Scale Factor to 1 to maintain the scale of horizontal distances if required.
   • Check Vertical Calibration to compute a vertical shift and from the drop down choose Vertical Shift + Incline Plane to include inclinations in the north and east directions or Vertical Shift only to compute vertical shift at a defined origin only.
   • Optionally, click the Browse button to display the Project Settings dialog, where you can define a Geoid model for the site calibration.

1. Next, select Point List. Select the GNSS Point field, then in the plan view select the first WGS84 point or input the point name using the keyboard. Then, in the Grid point field and select the corresponding Local grid point in plan view or input the point name using the keyboard.
   
   
2. Select the type i.e. Vertical only, Horizontal only or Horizontal and Vertical to dictate how the point is used in the computations.
   
3. Continue down the list until all the points to be used to compute the site calibration have been selected.
   
4. Click Compute to process the calibration.
   

   The Site Calibration results can be reviewed under the Results tab, including a point by point breakdown. If necessary, adjust the Type fields in the Point List to remove poor point Horizontal or Vertical Residuals and re-compute.

5. Select OK to apply the calibration parameters to the project and close the Site Calibration panel.

Note: A site can be re-calibrated at any time.