APEX (Airborne Prism EXperiment) is an airborne (dispersive push broom) imaging spectrometer developed by a Belgian-Swiss consortium on behalf of ESA. The instrument is operated by VITO since 2010.
Imaging spectroscopy greatly extends the scope of traditional remote sensing. It is based on the detection of many narrow, contiguous spectral bands. This presents opportunities for more precise identification of surface materials than is possible with broadband multispectral sensors.
The APEX instrument is intended as a simulator and a calibration and validation device for future spaceborne hyperspectral imagers. Furthermore, APEX is an advanced scientific instrument for the European remote sensing community, recording hyperspectral data in approximately 300 bands in the wavelength range between 400 nm and 2500 nm and at a spatial ground resolution of 2 m to 5 m. It is a key instrument for data collection over the Belgian BELAIR sites.
In a joint effort to develop Imaging Spectroscopy expertise and to foster the use of IS data in Belgian remote sensing, VITO and the Belgian Science Policy Office organize flight campaign almost yearly since 2002.