VENμS (vegetation and environment monitoring on a new micro satellite) image quality

VENµS is a demonstration mission developed in cooperation between Israel (ISA) and France (CNES). VENµS scientific mission unique feature is to acquire high resolution (5.3m) multi-spectral images (12 bands in the visible and NIR spectrum) continuously every second day with constant viewing angles. At least 50 sites of interest all around the world will be viewed. It aims at demonstrating the relevance of such observation capabilities in the framework of the European Global Monitoring for Environment and Security Program (GMES). The satellite also flies a technological mission that aims at qualifying an Israeli electric propulsion technology (IHET) and demonstrating its mission enhancement capabilities. The satellite will be launched in January 2010. The imaging scientific mission will last 2.5 years with the satellite at 720 km. Next, the technological mission will bring the satellite at 410 km. The scientific mission will then go on for one year with an improved resolution (3m). This paper presents the main geometric and radiometric image quality requirements for the scientific mission. The strong multi-spectral (2m) and multi-temporal (3m) registration requirements constrain the stability of the platform and the ground processing which will refine the geometric physical model using an image matching method based on correlation. The location of the images will take benefits from the capacity of the system to produce Digital Elevation Models at a low 'Base to Elevation' ratio (0.026). These processings are detailed through the description of the level 1 production which will provide users with ortho-images of Top of Atmosphere reflectances. Finally we propose different radiometric (relative and absolute camera sensitivity,...) and geometric (line of sight, focal plane cartography,...) in-flight calibration methods to answer the severe mission requirements.