7

Equipment accepted within the EPN

The GNSS equipment used at the EPN stations complies with the EUREF standards. This means that :

• the GNSS receiver and antenna must be known to the IGS and included in the receiver/antenna table (rcvr_ant.tab file). This table contains the IGS/EPN naming conventions for GNSS equipment (receivers, antennas, radomes, satellite antennas); they are the only valid names to be used in IGS station logs, RINEX headers, SINEX files, etc. Checklist for including new entries in rcvr_ant.tab.
  A description of the antenna (physical dimensions and antenna reference point (ARP) definition) is given in the antenna.gra file.
• the receiver and antenna should at least allow dual frequency geodetic-type GNSS observations.
• the antenna+radome pair should have zenith and azimuth-dependent absolute calibration values down to the horizon available from the EPN Central Bureau (antenna/radomes fulfilling this requirement).

The usage of antenna radomes is discouraged, but not forbidden.

Antenna/radome calibrations used by the EPN

The antenna calibrations used within the EPN are given in the epn_20.atx file (in usage since November 27, 2022), available in the standard format used to exchange antenna calibrations, the ANTEX format.
This file contains :

• The antenna calibration values used within the IGS, available from the IGS Central Bureau, and given in the igs20.atx file (linking to the file igs20_wwww.atx, with wwww the GPS week of the last file change).
• Antenna calibrations not included in igs20.atx (but necessary to process some EPN stations), available from the EPN CB, and given in the file epnc_20.atx. For more details, see EUREF mail 11348.

If no calibrations are available for a specific antenna+radome combination, then the calibrations for the corresponding antenna without a radome (radome code: NONE) should be applied.

The map shows for each EPN station what kind of absolute antenna/radome calibrations are are in use in the data analysis since Nov. 27, 2022. For black stations, individual antenna calibrations are used (0%), for green stations, antenna/radome pairs with absolute type calibrations are used (97.39%), for orange stations, antenna/radome pairs with absolute calibrations converted from relative values are used (0.24%), and for red stations, no absolute calibrations for the antenna/radome pairs are available. In this case, the radome is neglected and the calibration values of the antenna with radome 'NONE' is used.

Although since Nov. 27, 2022, the EPN primarily uses IGS type mean calibrations, EPN station managers are still invited to provide individual antenna calibrations to the EPN CB ([email protected]) for archiving in https://epncb.oma.be/ftp/station/general/indiv_calibrations/.