Antenna Committee
Established: 2008
Chair: Arturo Villiger
Mailing List: IGS Antenna Committee Mailing List
Charter
Tasks
The IGS Antenna Committee maintains the relevant IGS files concerning receiver and satellite antenna information, it constitutes recommendations for the content of the official IGS antenna files, for the appropriate procedure to include antenna information for newly launched satellites, and related questions. The Antenna committee establishes a contact point to users of IGS products, providing guidance for antenna calibration issues and for a consistent use of IGS products.
Antenna phase center issues are related to topics such as reference frame, clock products, calibration, monumentation. The Antenna committee therefore closely cooperates with the respective committees (Reference Frame, Clock Product, Bias and Calibration, Reanalysis), with antenna calibration groups, with the Analysis Center Coordinator and the Analysis Centers for analysis related issues, and with the Network Coordinator concerning maintenance of relevant files.
Responsibilities
- The maintenance of the receiver and satellite antenna model for IGS routine processing which includes updating and adding receiver and satellite antenna information and the assurance of the internal consistency of satellite models as well as consistency the terrestrial reference frame.
- The assistance of the Network Coordinator in maintaining the relevant files available tthe users such as rcvr_ant.tab and antenna.gra.
- Setting up rules for the IGS antenna model files, i.e., define recommendations
- for the question whether the files should contain information only for those antennas that are in use within the IGS or for all geodetic-type antennas,
- for the assurance of consistency between different reference frame institutions such as EUREF and NAREF,
- for the continuation of maintaining the old relative antenna model.
- Setting up rules and recommendations
- for the handling of new satellites in official antenna models,
- for the handling and consistent use of satellite antenna offsets,
- for the inclusion of azimuth-dependent satellite antenna PCVs,
- for the inclusion of frequency specific PCVs.
- Setting up rules and recommendations concerning
- the issues related the use of radomes and radome calibrations,
- the definition of the antenna northing direction.
- The investigation of the incorporation of LEantenna calibration results in the absolute antenna model to allow for larger satellite antenna nadir angles.
- The promotion of pre-launch calibration of transmitter antennas.
- The development of the ANTEX file format definition tallow the inclusion of additional information such as, GLONASS- and Galileo-PCVs, calibrations of side band frequencies, linear combinations, carrier-to-noise patterns.
- The establishment of recommendations for antenna mounts for mitigating near-field multipath effects, investigation of in situ calibrations of antenna installations.
- The support for the user community concerning the use of IGS antenna information and promotion of IGS antenna standards.
- Establishment of a contact point for user questions.
- To act as a contact antenna manufacturers.
- To interface with the Reference Frame WG, the Bias & Calibration WG, the GNSS WG, the Reprocessing WG. Support the ACC, the ACs and the NC on antenna issues.
Members
The working group consists of:
- The chair
- Representatives from Analysis Centers, in particular from those involved in estimating antenna antenna PCVs and offsets, currently CODE, GFZ, JPL.
- Representatives from antenna calibration agencies, institutions, companies (NGS, Geo++, Unavco).
- Representatives from related Committees.
- Any others who contribute to the success of the Committee, e.g., representatives from industry.
Ex officio:
- Analysis Center Coordinator
- Network Coordinator
ANTENNA FILES
| ANTEX (igs20.atx.gz) | Antenna calibrations- absolute IGS phase center corrections for satellite and receiver antennas; to be used with the ITRF2020 terrestrial reference frame. |
| ANTEX Format Description (antext14.txt) | ANTEX: The Antenna Exchange Format, Version 1.4 |
| Naming Convention (rcvr_ant.tab) | IGS naming conventions for GNSS equipment (receivers, antennas, radomes, satellite antennas); only valid names to be used in IGS site logs, RINEX headers, SINEX files, etc. |
| Reference points and Dimensions (antenna.gra) | antenna reference point (ARP) definition, north reference point (NRP) definition, physical antenna dimensions |
rcvr_ant.tab
Responsibility: IGS Central Bureau
Contact: cb [at] igs.org
Requirements for new entries to rcvr_ant.tab
- geodetic equipment relevant to the IGS and users of IGS products with cm-level capabilities
- unique hardware model
- unique description
- unchangeable naming
- consideration of format specifications
- agreement with naming of calibration institutions, if possible
- authorization of manufacturer, if possible
- New antenna entries require an IGS approved antenna calibration in the IGS ANTEX file
- New antenna entries must provide an antenna drawing for the antenna.gra file
Checklist for Requesting Additions to rcvr_ant.tab
[Last Updated 6 August 2007]
Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not constitute or imply its endorsement by the United States Government or the Jet Propulsion Laboratory, California Institute of Technology.
- I am a representative of the manufacturer of the equipment, familiar with the products, and authorized to interface with the IGS regarding standardized equipment naming.
- The additions I am requesting are geodetic equipment relevant to the IGS.
- I have reviewed rcvr_ant.tab and verified that the equipment I am requesting to be added is not already in rcvr_ant.tab.
- I understand that changes are not ordinarily permitted after a code has been added to rcvr_ant.tab. I have checked carefully for typographical errors, etc. I am not requesting addition of preliminary names that might change.
- I have verified that the additions I am requesting have a one-to-one correspondence with unique hardware models.
- The codes I am providing meet the format specifications found in the header of rcvr_ant.tab.
- The codes and descriptions I am providing will allow an equipment owner to easily identify the correct code based on markings on the equipment.
- The codes I am providing are what my company’s translation software will place in the RINEX header under ordinary usage.
- The antenna codes and radome codes I am providing are identical to those used in NGS’s Antenna Calibration tables (http://www.ngs.noaa.gov/ANTCAL/).
- The antenna codes and radome codes I am providing are identical to those used in Geo++’s GNPCVDB database (http://anton.geopp.de/gnpcvdb/pcvdb/GNPCVDB.html).
- If the antenna codes and radome codes I am providing are not yet in NGS’s or Geo++’s calibration tables, I can ensure that the proposed codes meet NGS’s and Geo++’s format requirements and that the same codes will be provided to the calibration laboratories.
- I am providing complete proposed entries, comprised of codes and descriptions in the format of rcvr_ant.tab.
- Antenna model names shall start with A-Z or 0-9, unless if otherwise allowed by the Central Bureau. Please contact us for more info.
igs20.atx
igs20_wwww.atx (wwww = GPS week of the last file change) (latest version is symbolically linked to the generic filename igs20.atx for convenience)
Responsibility: IGS Antenna Working Group
Contact: awg [at] igs.org
Requirements for new entries (receiver antennas)
- antenna name contained in rcvr_ant.tab
- definitions of antenna reference point (ARP) and north reference point (NRP) contained in antenna.gra
- consistent phase center offsets (PCOs) and variations (PCVs)
- consideration of ANTEX format specifications (e.g., IGS sign convention)
- availability of zenith- AND azimuth-dependent calibration values down to the horizon (with a resolution of at least 5 and 10 degrees, respectively)
- availability of consistent calibration values for multiple GNSS (at least GPS and GLONASS)
- in order to guarantee high accuracy for low elevations, the antenna should be tilted during the calibration procedure
- addition of calibrations not matching the above criteria is only possible in a few exceptional cases (e.g., if a calibration for a combination of an antenna with a specific radome became available whose effect was ignored within the IGS before then)
- replacement of existing values is only allowed in a few exceptional cases (e.g., major model update, reference frame change, etc.) in cooperation with the IGS Reference Frame Working Group
- radome calibrations can only be added for combinations that are not (yet) in use within the IGS (otherwise the addition is a matter of a replacement, as the calibration for the antenna without the radome was used within the IGS before then)
- Geo++ GmbH only permits its type mean calibrations to be published in the public domain for the antenna types used within the IGS and EPN networks; calibrations for other antenna types are generally not openly available
- antenna manufacturers are encouraged to provide type mean calibrations for all their models using one of the available calibration services
Where to get approvable calibrations?
(list will be extended as soon as additional institutions meet the requirements)
- Geo++ GmbH
- Leibniz Universität Hannover, Institute of Geodesy
- Senatsverwaltung für Stadtentwicklung Berlin, GNSSLandeskalibriereinrichtung
- University of Bonn, Institute of Geodesy and Geoinformation
- Geoscience Australia
Procedure for newly launched satellites
- antenna name contained in rcvr_ant.tab
- as soon as launch date, satellite designations (PRN/SVN number, slot/GLONASS number, etc.) and COSPAR ID are known, a rounded block mean PCO is added together with the corresponding block mean PCVs, if available
- in the case of a new antenna/block generation, manufacturer values have to be applied for the PCO together with zero PCVs
- no earlier than six months after the satellite launch, the block mean PCO is replaced by an individual offset value from the combination of weekly IGS Analysis Center SINEX solutions
- PCVs for new satellite antenna type: procedure tbd.
Intended procedure for major model update
- compilation of an unofficial file containing the best possible receiver antenna corrections (regardless of any consistency problems) and updated satellite antenna PCVs
- reprocessing campaign of the IGS Analysis Centers with receiver antenna corrections kept fixed
- estimation of consistent satellite antenna z-offsets with the latest reference frame kept fixed
- release of the complete antenna phase center model together with the corresponding reference frame
antenna.gra
Responsibility: IGS Central Bureau
Contact: cb [at] igs.org
Requirements for new entries:
- antenna name contained in rcvr_ant.tab
- authorization of manufacturer, if possible
- either an antenna drawing or the necessary information for the creation of the drawing have to be provided
- New antenna entries require an IGS approved antenna calibration in the IGS ANTEX file
antex14.txt
Responsibility: IGS Antenna Working Group
Contact: awg [at] igs.org
Last Updated on 8 Nov 2024 19:03 UTC