The site calibration process establishes the relationship between global coordinate data collected by GNSS receivers and local control positions (expressed as a local map grid with elevations above sea level). This relationship is defined by a series of mathematical transformations. Calibrate a site by specifying each global GNSS point and its matching local grid control point to be used in the calibration.

Following are the basic steps for this workflow. For more detailed instructions, see Calibrate a Site.

Steps:

Commands:

1.

Use the Site Calibration command pane to perform the site calibration.

Site Calibration

2.

On the Points List tab, enter the point pairs to be used in the site calibration. Each point pair consists of a global GNSS point and its matching local grid point. Keep the default calibration type of Horizontal and vertical.

3.

Click the Compute button to calibrate the site.

If the calibration results in one or more residuals exceeding 0.1 m (0.328 ft), a warning message is displayed. This can indicate that some sort of blunder occurred either in the office or when selecting point pairs.

4.

View the results of the site calibration on the Results tab, which displays the residuals for each point pair both numerically and graphically.

If the calibration results in one or more excessive residuals, check for errors in the observation properties for the points (for example, instrument, target, and antenna information). Also, verify that the correct information was entered on the Points List tab.

A minimum combination of three point pairs with no excessive horizontal residuals and four point pairs with no excessive vertical residuals is required for a verifiable site calibration. As longs as these conditions are met, you can select to disable horizontal or vertical calibrations for any of the point pairs on the Point Listtab and re-calibrate the site.

5.

View site calibration details in the Site Calibration Report.

Site Calibration Report

6.

Optionally, click the Save as Site button to save the new calibration as a site that can be used by other projects in the same area

7.

You can also clear a site calibration, if needed.

Clear Site Calibration