MEGATOR (Mesure de l'Évolution des Glaciers Alpins par Télédétection Optique et Radar, des archives à ORFEO, http://www.gipsa-lab.inpg.fr/megator ) is a 3-years project, funded by the french national program « ACI  Masse de Données » (now part of the ANR), which started in 2004. Four laboratories have been involved:

-LISTIC-UdS (Laboratoire d'Informatique, Systèmes, Traitement de l'Information et de la Connaissance, Polytech’Savoie / Université de Savoie) which was the project leader,

-GIPSA-INPG (Grenoble Image Parole Signal et Automatique, INPG / CNRS / UJF / US),

-MAP-PAGE (Photogrammétrie Architecturale et GEomatique, INSA Strasbourg / CNRS),

-LTCI-ENST (TII/TSI group at GET Télécom Paris)

This project started with an rather huge image data base involving SPOT, ERS and airborne optical images. The MEGATOR scientists have already proposed more than 20 publications and/or conference presentations (see for example http://www.gipsa-lab.inpg.fr/megator ).

A very noticeable result of MEGATOR project is its success to expand the initial database, mainly with SAR data. Indeed, MEGATOR has systematically sent proposals at the Spatial agencies “Announcements of Opportunity” (AO) devoted to scientific use of SAR data. At each time, the spatial agencies gave a positive answer so that, at present time, the data that will be added to the database is expanded by:

-16 ALOS data (the Japanese SAR satellite), L-band,

-11 ENVISAT data (the European satellite), C band,

-48 Terrasar-X data (the German satellite, to be launched in April 2007), X band,

-10 PolInsar RADARSAT-II data (Canadian satellite, to be launched in 2007), C band, fully polarimetric data.

MEGATOR teams also proposed to the DLR a cooperation to organise airborne SAR campaigns over the Argentière glacier test site. Two campaigns have been organized in October 2006 and February 2007. The DLR acquired with its E-SAR sensor high resolution data in different bands (X, C, L and P band) and with different polarisations. During these acquisitions, the MEGATOR scientists led physical measurements on the glacier (daily displacements, stratigraphic snow profiles, basal velocity of the ice obtained with the help of Luc Moreau’s cavitometer, …) to complete this image data base.

Moreover, during the February 2007 campaign, a satellite corner reflector (CR) provided by the DLR has been fixed on the ice in the uper part of the Argentière glacier, together with a continuous GPS antenna temporarily borrowed from IPGP (figure 15-1). This experiment allows a continuous measurement of the position of the CR which is moving down with the glacier and can be detected with a high accuracy in satellite SAR images (figure 15-2). A second continuous GPS antenna has to be installed in Chamonix valley in order to study the electromagnetic path delay variations and to correct the atmospheric perturbations in the SAR based glacier motion measurements.

MEGATOR project will be finished in August 2007. This exceptional data base, devoted to Alpine glacier displacement measurement by SAR imagery, the only one of its kind in the world, will be available for EFIDIR project.