The PROBA-V Mission: Data Continuity for Daily Global Vegetation Monitoring

The VEGETATION instruments on board of the SPOT-4 and SPOT-5 satellites have provided researchers and operational users daily low resolution (1 km ground sampling distance, GSD) remote sensing images on a global scale for vegetation monitoring for more than 10 years. To ensure the continuity of this service, the ESA PROBA-V (V for Vegetation) mission is under development, due to be launched in 2012.

The system will satisfy the original VGT requirements, i.e.:
 Daily coverage of the terrestrail surface, at least over EuropeRequirement
 Equator crossing time 10:30 +/- 20 mn
 GSD better than 1 km at Nadir
 Geo-localisation < 0.3 pixel
 Bands co-registration < 0.3 pixel
 Spectral bands: blue, red, NIR and SWIR

The instruments, however, will be different: the PROBA-V minisatellite will fly a very compact and lightweight camera system consisting of three Three-Mirror-Anastigmatic (TMA) telescopes (to cover the 2250 km swath width), each equipped with blue, red, near-infrared line sensors and an array of staggered short-wave infrared (SWIR) sensors.

In order to ensure the continuation of VEGETATION products, the historical data set with 1km ground resolution will be continued but complemented with products featuring 300m ground resolution. Hereto, a user segment will be developed similar to the one for SPOT-VEGETATION. This user segment will consist of three modules: the image quality control center, the processing facility and the product distribution facility. The processing facility contains three submodules: the archive, the processing itself and the product quality control.

The user segment will generate the following products at two resolutions, 300 m and 1 km: P (primary) products, S1 (daily) synthesis and S10 (decadal) synthesis. P products are adapted for scientific applications requiring highly accurate physical measurements. S1 and S10 products are compiled by merging “segments” acquired over a period of one day, respectively ten days. All the segments of this period are compared pixel by pixel to pick out the "best" ground reflectance observations.