Calibration and characterization of the EnMAP hyperspectral imager

The Environmental Mapping and Analysis Program (EnMAP) is a German space borne science mission that aims to characterize the Earth’s environment on a global scale. The single payload of the satellite is the Hyperspectral Imager (HSI). It is capable of measuring the solar irradiance reflected from the Earth’s surface as a continuous spectrum in the spectral range of 420nm to 2450nm, with an average spectral sampling of 6.5nm (VNIR) and 10nm (SWIR). The EnMAP swath of 30km is sampled with 30m in along and across track direction. In these proceedings, we first give a brief overview the instrument design. We then explain the calibration strategy, which is a combination of on-ground and in-flight calibration measures. The on-ground calibration is presented in more detail. It aims to create a complete baseline calibration of the EnMAP instrument comprising a radiometric, spectral, geometric, polarimetric and straylight characterization. In orbit, a diffuser is used for absolute radiometric calibration via sun viewing. On-board calibration light sources ensure radiometric stability in between sun-viewings and spectral stability over the mission lifetime. Finally, we share first characterization data which are prototypical of the final instrument calibration.