Geometrical performance of the VEGETATION products

Abstract

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.