The HYUAV: a novel UAV-based spectroscopy tool for environmental monitoring

The objective of the present contribution concerns the development and preliminary testing of a novel UAV-based non-imaging hyperspectral system (HYUAV) for collecting near range Earth reflected radiance in the VNIR domain coupled with RGB images. The optical payload comprises the Ocean Optics spectrometer which features a 1.5 nm FWHM (Full Width at Half Maximum) covering the 350 to 1000 nm spectral range and the RGB camera (Canon S100). A custom designed spectrometer entrance fore-optics was assembled to: i) reduce the USB4000 IFOV providing 1 m sampled area from a flight height of 10 m; ii) hold the neutral-density filter (transmittance 40%) avoiding saturation for high light levels; iii) hold a shutter allowing a regular in-flight dark-current measurements. The Anteos UAV platform (Aermatica S.p.A., Italy) is a small four-rotor with hovering capability, a maximum payload of 2 Kg and flight time of 20 min. A dedicated software application was developed: i) combining flight path and spectral measurements planning; ii) matching the hyperspectral data and the RGB images with the UAV navigation data to geolocated the optical data. The HYUAV was tested in laboratory to assess the impact of platform vibrations to the USB4000 spectral (i.e. shift and band broadening) and radiometric stability. The capability to collect reflectance signatures of different land cover type (i.e. grassland, asphalt, roofs and inland water) was assessed during field campaign comparing HYUAV data to ground based ASD FieldSpec measurements