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The IGS Ionosphere Working Group (IonoWG) was established end of May 1998, and the working group’s first chairmanship from June 1998 to December 2002 was led by ESOC. According to its Terms of Reference, the primary target of the IonoWG at that time was to set up a new IGS Ionosphere Product, i.e. this task fell into the first chairmanship, as well as to establish the IonoWG as a whole. The IonoWG activities commenced in June 1998 with a pilot project to find out how ionosphere products contributed by several analysis centers (one of these was/is ESOC) could be combined to obtain a new IGS product. In a first step, dedicated combination schemes and software in Fortran and Tcl were worked out in cooperation with the other analysis centers from scratch. The combination algorithm and software were upgraded and extended in the meantime several times. In addition, a program for validations with TOPEX altimeter data (now JASON data are used) was established. Since 2002 the combination results indicated that the required quality for an official IGS product had been achieved. At the end of 2002, the IonoWG chairmanship and the comparison software were delivered from ESOC to the Technical University of Catalonia, Barcelona, Spain. Since 2008 the IonoWG chairmanship is located at University of Warmia and Mazury in Olsztyn , Poland.

During the ESOC chairmanship of the IonoWG, two dedicated high-rate satellite tracking campaigns were organized for monitoring the behaviour of the ionosphere during special events. The first of these two campaigns was during the Solar Eclipse on 11 August 1999 (Refs. [1], [4], [5]) and the second was the High-Rate SolarMax IGS/GPS campaign (HIRAC/SolarMax) in 2001 (Ref. [2]).

From 2004 – 2007 ESOC contributed with routine validations of the analysis centres and combined IGS vTEC maps with ENVISAT altimeter data to the IonoWG activities.

For the actual status of the IonoWG see Refs [3] and [6].

Figure 1 presents a diagram showing the data flow required to generate the IGS vTEC maps.

Figure 1: Diagram showing the data flow required to generate the IGS vTEC maps (Ref. [3])


[1] Feltens,J. and C.Noll (1999): „GPS data collected during August 1999 solar eclipse“, Crustal Dynamics Data Information System (CDDIS) bulletin, 15(1), 1999.

[2] Feltens, J., N.Jakowski and C.Noll (2001): „High-Rate SolarMax IGS/GPS campaign „HIRAC/SolarMax“, Crustal Dynamics Data Information System (CDDIS) bulletin, 16(3), 2001.

[3] Hernández-Pajares, M., J.M. Juan, J. Sanz, R. Orus, A. Garcia-Rigo, J. Feltens, A. Komjathy, S.C. Schaer and A. Krankowski (2009): “The IGS VTEC maps: a reliable source of ionospheric information since 1998”, Journal of Geodesy, DOI: 10.1007/s00190-008-0266-1.

[4] Jakowski,N., S.Schlüter, S.Heise and J.Feltens (1999a): „Satellite Technology Glimpses Ionospheric Response to Solar Eclipse“, EOS, Transactions, American Geophysical Union, Vol. 80, No. 51, December 21, 1999, pp 621 ff.

[5] Jakowski,N., S.Schlüter, S.Heise and J.Feltens (1999b): „Auswirkungen der Sonnenfinsternis vom 11. August 1999 auf die Ionosphäre“, Allgemeine Vermessungs-Nachrichten (AVN), 11-12/1999, Wichmann Verlag, pp 370-373.

[6] Krankowski A., M. Hernández-Pajares, J. Feltens, A. Komjathy, S. Schaer, A. García-Rigo and P. Wielgosz (2010): “Present and future IGS Ionospheric products”, IGS Workshop, 28 June – 2 July 2010, Newcastle upon Tyne, U.K.