Networking of automated instruments on unmanned platforms has proved to be the most effective way to provide validation data for Copernicus optical missions. The re-use of data from each site for many optical missions (S2, S3, PROBA-V, MODIS, VIIRS, L8, Pléiades, ENMAP, PRISMA, SABIAMAR,etc.) gives a huge economy of scale. The existing networks (e.g. AERONET-OC, RADCALNET, …) are based on multispectral instruments requiring modelling associated uncertainties to cover all spectral bands of all sensors. The objective of the HYPERNETS project is to develop a new lower cost hyperspectral radiometer and associated pointing system and embedded calibration device for automated measurement of water and land bidirectional reflectance and, subsequently, for validation of all optical bands on all satellite missions. The instrument will be tested in a prototype network covering a wide range of water and land types and operating conditions. Quality controlled data with associated uncertainty estimates will be provided automatically for the validation of all optical satellite missions. Preparations will be made a) for the new instrument design (and associated calibration service) to be commercialized with an expected lifetime of at least 10 years and b) for the networks to be further expanded to fill the very important gap in the current Sentinel-3&2 Validation plans and the in situ component of the Copernicus programme and become the main source of surface reflectance validation data for all spectral bands of all optical missions for at least the next 10 years.
