Since it is vital to make sure that the eventual data meets the users' exacting requirements, efforts were put into field and airborne campaigns to assess the future performance of an instrument. This means that many airborne and ground measurements have to be acquired so that the final data products could be simulated and evaluated.
The field campaigns for Sentinel-2 involved taking measurements over fields and forests with an airborne imaging spectrometer. These data were complemented by coincident measurements taken from the ground to calibrate and validate those from the aircraft.
The field campaigns formed an essential role in preparing the user community for upcoming data products. Such campaigns continue even when both Sentinel-2 satellites are in orbit to help validate their data.