calibrated site

A site definition that uses an existing coordinate system definition plus correction transformation. This makes the best fit for GNSS data in a specific area (or site).

The extra correction transformations are required because a coordinate system is designed to apply over a very large area. It does not allow for variations in the local coordinates. You need to have new work fit with the existing control, so the extra correction transformations will correct for these local variations. Extra corrections are only valid over a limited area. This explains the “site” terminology.