February 7, 2017 • 8891 Views
By Paul Rebischung (IGN), Ralf Schmid (DGFI-TUM), and Allison Craddock (NASA JPL, IGS Central Bureau)
The International GNSS Service (IGS) recently adopted a new reference frame, called IGS14, on 29 January 2017 (GPSWeek 1934). At the same time, an updated set of satellite and ground antenna calibrations, igs14.atx, was implemented. The switch from IGb08/igs08.atx to IGS14/igs14.atx was announced with IGSMAIL-7399 on 21 December 2016 by representatives of the IGS Reference Frame and Antenna Working Groups, as well as the Analysis Center Coordinator.
IGS14 is the latest in a series of GNSS reference frames adopted by the IGS. These reference frames form the basis of the IGS products, and are derived from each new version of the International Terrestrial Reference Frame. Updating to IGS14 will align IGS products to ITRF2014, and increase precision of that alignment by integrating additional available reference frame stations with more precise and up-to-date coordinates.
Antenna calibration updates in igs14.atx include robot calibrations for additional ground antenna types, increasing the percentage of ground stations in the IGS network with absolute calibrations to over 90%. This will result in increased coordinate accuracy for stations equipped with these antennas.
Both GPS and GLONASS satellites, in particular those launched since September 2012, have also experienced antenna calibration updates which (in the case of recently launched satellites) will replace the preliminary block-specific values in igs08.atx with new satellite-specific estimates. With this, the scale of the IGS daily terrestrial frame solutions will increase in stability and become closer to that of the ITRF.
SINEX and ANTEX files, as well as network maps, post-seismic deformation models, and offsets are available for download via ftp from Institut National de l’Information Géographique et Forestière (National Institute of Geographic and Forestry Information, IGN) and École Nationale des Sciences Géographiques (National School of Geographic Sciences, ENSG).
The IGS cumulative solution will also be updated during GPS Week 1934, incorporating combined repro2 (ig2) and operational (igs) solutions, as well as a revised discontinuity list that is aligned with ITRF2014, plus the ITRF2014 post-seismic deformation models. This will be released mid-February.
For more information, please see [IGSMAIL-7399] “Upcoming switch to IGS14/igs14.atx.”and “IGS14/igs14.atx: a new framework for the IGS products.”