Geometrical performance of the VEGETATION products

VEGETATION data are mainly used for multidate applications, which induces high level geometrical specifications, especially for multitemporal registration. To comply with them, the VEGETATION 1 image location is improved by a systematic use of ground control points. These are provided by a ground control points data base generated through VEGETATION 1 chips using space triangulation method. Consequently, since its launch onboard SPOT 4 in March 1998, VEGETATION 1 has showed a very good and stable geometrical performance. VEGETATION 2, launched onboard SPOT 5 in May 2002, completes now VEGETATION 1 for operational production. It is so essential to ensure geometrical continuity between both sensors. On SPOT 5, a stellar sensor provides a very good estimation of satellite altitude, implying a very good absolute image location: it is not necessary to improve VEGETATION 2 images using ground control points. However, it was necessary to perform a fine geometrical calibration of VEGETATION 2 cameras that was realized during the commissioning phase using ground control points of the VEGETATION 1 data base. Today we can say that VEGETATION 2 geometrical performance is at least as good as VEGETATION 1´s and geometrical continuity is guaranteed. The object of this paper is to present VEGETATION 1 geometrical performance and the methods and results of VEGETATION 2 geometrical commissioning phase.