GNSS Absolute Antenna Calibration at the National Geodetic Survey

To help meet the needs of the high-precision GNSS community, the National Geodetic Survey (NGS) will soon begin operations of an absolute antenna calibration facility. Located in Corbin, Virginia, this facility uses field measurements and actual GNSS satellite signals to quantitatively determine the carrier phase advance/delay introduced by the antenna element. In this paper we describe the NGS calibration facility and provide the time-difference, single-difference carrier phase observable models and estimation strategy currently used to generate NGS absolute calibrations. Examples of antenna calibrations from the NGS facility provide context for the discussion, and demonstrate that NGS phase center variations (PCVs) agree within 1 mm with other calibration techniques. Finally, user-friendly features of the revamped NGS Calibration Services are discussed.