Le portail francophone de la géomatique

Bonjour,

peut-être la page http://itrf.ensg.ign.fr/ vous aidera à trouver un début de solution.

Toutefois, il ne semble pas y avoir de grosses différences entre ces deux systèmes, mais je ne suis pas exert en géodésie ! le texte ci-après issu de ftp://lareg.ensg.ign.fr/pub/itrf/WGS84.TXT semble aller dans ce sens :

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In general the ITRS (and its realizations ITRFyy) are identical to WGS84
at one meter level.

Meanwhile there are two types of WGS84 realization:

- old realization based on U.S. Navy Navigation Satellite System,
  commonly known as DOPPLER Transit, and provided station coordinates
  with accuracies of about one meter. With respect to this realization
  we published, some years ago, transformation parameters between
  ITRF90 and this Doppler realized system:


Parameters from ITRF90 to WGS84-Doppler realized system



             T1      T2      T3       D         R1       R2        R3   
UNITS -----> (m)     (m)     (m)     (ppm)     (")       (")       (") 
   
-----------------------------------------------------------------------
            0.060   -0.517  -0.223  -0.011    0.0183  -0.0003    0.0070



- New realizations of WGS84 based on GPS data, such as WGS84(G730 or G873).
  These new WGS84 realizations are coincident with ITRF at about
  10-centimeter level. For these realizations there are no official
  transformation parameters. This means that one can consider that
  ITRF coordinates are also expressed in WGS84 at 10 cm level.

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yvan.