The VEGETATION system: A global monitoring system on-board SPOT 4

The SPOT 4 satellite has been launched on the 24th of March 1998. It offers extended capabilities with upgraded HRVIR (High Resolution in the Visible and Infra-Red) instruments and also a new payload based on a large field of view imaging instrument (101 degrees) for the monitoring of terrestrial biosphere at global scale. This so-called VEGETATION payload is specifically designed for vegetation studies. It provides images, with a high radiomatric accuracy and a 1 km spatial resolution, in 4 spectral bands : red, near infrared and mean infrared bands identical to those of the HRVIR instruments and a blue band dedicated to atmospheric measurements. Capabilities for scale integration is so made possible by the combination with simultaneous HRVIR data. VEGETATION is designed to be independent of the host satellite and, in addition of the imaging instrument, it includes its own recording, transmission and management equipments. But VEGETATION is not just a payload on-board SPOT 4, it is a complete system with a specific ground segment for data programming, processing and distribution. It allows the availability of images acquired all over the world through its capability of on-board recording and the centralisation of the images reception and archiving. The mission objective is to provide accurate measurements of basic characteristics of vegetation canopies,on a daily and operational basis, covering the entire land areas. The quality of the images tested during the in-flight assessment phase is very good and all the users requirements are met. The geometrical performances are particularly suitable for an accurate multitemporal use of the data without any complementary processing. Conducted under CNES responsability, the VEGETATION system development is funded by the European Union and by individual contributions of France, Sweden, Belgium and Italy.