MTG (Meteosat Third Generation) is the follow-up system to the Meteosat MSG series of geostationary satellites.

The satellite system will consist of a twin configuration of 3-axis-stabilised satellites: the Imaging mission satellite (MTG-I) and the Sounding mission satellite (MTG-S).

The payload proposed for MTG-S would have an Infrared Sounder (IRS) and Ultra-violet Visible Near-infrared (UVN) Sounder, the later of which is included as the Sentinel-4 mission

The Sentinel-4 mission focuses on monitoring trace gas concentrations and aerosols in the atmosphere to support operational services covering air-quality near-real-time applications, air-quality protocol monitoring, and climate protocol monitoring. The specific objective of Sentinel-4 is to support this with a high revisit time over Europe.

The Sentinel-4/UVN instrument is a high-resolution spectrometer system operating with 3 designated bands in the solar reflectance spectrum, covering the ultraviolet (305-400 nm), visible (400-500 nm), and near-infrared (750-775 nm) bands. The central Sentinel-4/UVN instrument parameters are a spatial sampling of 8 km over Europe and a fast repeat cycle over Europe and North Africa (Sahara) of 60 minutes.

The respective spectral resolution is 0.5 nm in the ultraviolet and visible bands, with the goal of 0.12 nm in near-infrared.