04 May 2021

04 May 2021

Review status: a revised version of this preprint is currently under review for the journal ESSD.

The cooperative IGS RT-GIMs: a global and accurate estimation of the ionospheric electron content distribution in real-time

Qi Liu1, Manuel Hernández-Pajares1,2, Heng Yang3,1, Enric Monte-Moreno4, David Roma-Dollase2, Alberto García-Rigo1,2, Zishen Li5, Ningbo Wang5, Denis Laurichesse6, Alexis Blot6, Qile Zhao7,8, Qiang Zhang7, André Hauschild9, Loukis Agrotis10, Martin Schmitz11, Gerhard Wübbena11, Andrea Stürze12, Andrzej Krankowski13, Stefan Schaer14,15, Joachim Feltens16, Attila Komjathy17, and Reza Ghoddousi-Fard18 Qi Liu et al.
  • 1Universitat Politècnica de Catalunya (UPC-IonSAT), Barcelona, Spain
  • 2Institut d’Estudis Espacials de Catalunya (IEEC), Barcelona, Spain
  • 3School of Electronic Information and Engineering, Yangtze Normal University, 408100 Chongqing, China
  • 4Department of Signal Theory and Communications, TALP, Universitat Politècnica de Catalunya, 08034 Barcelona, Spain
  • 5Aerospace Information Research Institute (AIR), Chinese Academy of Sciences (CAS), Beijing, China
  • 6Centre National d’Etudes Spatiales, Toulouse, France
  • 7GNSS Research Center, Wuhan University, No. 129 Luoyu Road, Wuhan 430079, China
  • 8Collaborative Innovation Center of Earth and Space Science, Wuhan University, No. 129 Luoyu Road, Wuhan 430079, China
  • 9German Aerospace Center (DLR), German Space Operations Center (GSOC), 82234 Wessling, Germany
  • 10European Space Operations Center, European Space Agency, Darmstadt, Germany
  • 11Geo++ GmbH, Steinriede 8, 30827 Garbsen, Germany
  • 12BKG, Federal Agency for Cartography and Geodesy, Frankfurt, Germany
  • 13Space Radio-Diagnostics Research Centre, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland
  • 14Astronomical Institute of the University of Bern, Sidlerstrasse 5, Bern 3012, Switzerland
  • 15Federal Office of Topography (swisstopo), Wabern, Switzerland
  • 16Navigation Support Office, Telespazio Germany GmbH c/o European Space Agency/European Space Operations Centre, Robert-Bosch-Strasse 5, 64293 Darmstadt, Germany
  • 17Near Earth Tracking Systems Group (335S), NASA - Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, M/S 138-317, Pasadena, CA 91109, USA
  • 18Canadian Geodetic Survey, Natural Resources Canada, Ottawa, Canada

Abstract. The Real-Time Working Group (RTWG) of the International GNSS Service (IGS) is dedicated to providing high-quality data, high-accuracy products for Global Navigation Satellite System (GNSS) positioning, navigation, timing, and Earth observations. As one part of real-time products, the IGS combined Real-Time Global Ionosphere Map (RT-GIM) has been generated by the real-time weighting of the RT-GIMs from IGS real-time ionosphere centers including the Chinese Academy of Sciences (CAS), Centre National d’Etudes Spatiales (CNES), Universitat Politècnica de Catalunya (UPC), and Wuhan University (WHU). The performance of global Vertical Total Electron Content (VTEC) representation in all of the RT-GIMs has been assessed by VTEC from Jason3-altimeter during one month over oceans and dSTEC-GPS technique with 2-day observations over continental regions. According to the Jason3-VTEC and dSTEC-GPS assessment, the real-time weighting technique is sensitive to the accuracy of RT-GIMs. Compared with the performance of post-processed rapid Global Ionosphere Maps (GIMs) and IGS combined final GIM (igsg) during the testing period, the accuracy of UPC RT-GIM (after the transition of interpolation technique) and IGS combined RT-GIM (IRTG) is equivalent to the rapid GIMs and reaches around 2.7 and 3.0 TECU (TEC Unit, 1016 el/m2) over oceans and continental regions, respectively. The accuracy of CAS RT-GIM and CNES RT-GIM is slightly worse than the rapid GIMs, while WHU RT-GIM requires a further upgrade to obtain similar performance. In addition, the strong response to the recent geomagnetic storms has been found in the Global Electron Content (GEC) of IGS RT-GIMs (especially UPC RT-GIM and IGS combined RT-GIM). The IGS RT-GIMs turn out to be reliable sources of real-time global VTEC information and have great potential for real-time applications including range error correction for transionospheric radio signals (such as GNSS positioning, search and rescue, air traffic, radar altimetry, and radioastronomy), the monitoring of space weather (such as geomagnetic and ionospheric storms, ionospheric disturbance) and detection of natural hazards on a global scale (such as hurricanes/typhoons, ionospheric anomalies associated with earthquakes). All the IGS combined RT-GIMs generated and analyzed during the testing period are available at (Liu et al., 2021b).

Qi Liu et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on essd-2021-136', Anonymous Referee #1, 16 Jun 2021
    • AC1: 'Reply on RC1', Manuel Hernández-Pajares, 08 Jul 2021
  • RC2: 'Comment on essd-2021-136', Anonymous Referee #2, 05 Jul 2021
    • AC2: 'Reply on RC2', Manuel Hernández-Pajares, 08 Jul 2021
  • EC1: 'Comment on essd-2021-136', Christian Voigt, 16 Jul 2021

Qi Liu et al.

Data sets

Global Ionosphere Maps of vertical electron content combined in real-time from the RT-GIMs of CAS, CNES, UPC-IonSAT, and WHU International GNSS Service (IGS) centers (from Jan 3 to Feb 2, 2021) Qi Liu; Manuel Hernández-Pajares; Heng Yang; Enric Monte-Moreno; David Roma; Alberto García-Rigo; Zishen Li; Ningbo Wang; Denis Laurichesse; Alexis Blot; Qile Zhao; Qiang Zhang

Qi Liu et al.


Total article views: 547 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
393 135 19 547 4 6
  • HTML: 393
  • PDF: 135
  • XML: 19
  • Total: 547
  • BibTeX: 4
  • EndNote: 6
Views and downloads (calculated since 04 May 2021)
Cumulative views and downloads (calculated since 04 May 2021)

Viewed (geographical distribution)

Total article views: 495 (including HTML, PDF, and XML) Thereof 495 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
Latest update: 01 Aug 2021
Short summary
The upper part of the atmosphere, the ionosphere, is partially ionized and it is being crossed by many multi-frequency signals of the Global Navigation Satellite Systems (GNSS) satellites. This unique source of data can be acquire in real-time from hundreds of permanent GNSS receivers. The real-time processing providing the distribution of the ionospheric free electrons (Global Ionospheric Maps) can be done as well in real-time. We present their updated real-time assessment and combination.