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Proceedings Paper

Laboratory characterisation of the MEDUSA optical system for multi-spectral earth observation from a stratospheric HALE UAV
Author(s): B. Delauré; S. Livens; J. Everaerts; T. Van Achteren; D. Beghuin
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Paper Abstract

MEDUSA is the lightweight high resolution camera, designed to be operated from a solar-powered Unmanned Aerial Vehicle (UAV) flying at stratospheric altitudes. It targets applications such as crisis management and cartography as a technology demonstrator within the Pegasus program. From an operational altitude of 18 km MEDUSA will deliver images with a ground sampling distance of 30 cm and cover a swath of 3 km. The innovative UAV poses high demands on the instrument characteristics such as mass (< 2,5 kg), volume and power consumption. Furthermore the MEDUSA instrument design needs to guarantee its optical performance within the specific environmental conditions of the stratosphere. Well limited chromatic aberrations require the use of anomalous partial dispersion glass. Those glasses unfortunately suffer from large variations of their refractive index as well as their volume with temperature, causing strong focus variations of the optical system. Furthermore, the weight constraints impose compact system (minimizing the distance between lenses for mount weight reduction) and very thin lenses. Manufacturing each of the lenses was challenging. The very thin aspherical lens has required few manufacture iterations to achieve sufficiently low waviness, after that it became clear that this lens was the dominant factor for image contrast limitation. After all subsystem tests have been completed the MEDUSA shall be integrated and finish its ground test program in autumn 2009. This paper will describe the results of the laboratory characterization of the optical system and an outlook on the MEDUSA instrument development.

Paper Details

Date Published: 22 September 2009
PDF: 8 pages
Proc. SPIE 7474, Sensors, Systems, and Next-Generation Satellites XIII, 74741I (22 September 2009); doi: 10.1117/12.830443
Show Author Affiliations
B. Delauré, Flemish Institute for Technological Research (Belgium)
S. Livens, Flemish Institute for Technological Research (Belgium)
J. Everaerts, Flemish Institute for Technological Research (Belgium)
T. Van Achteren, Flemish Institute for Technological Research (Belgium)
D. Beghuin, LAMBDA-X SA (Belgium)

Published in SPIE Proceedings Vol. 7474:
Sensors, Systems, and Next-Generation Satellites XIII
Roland Meynart; Steven P. Neeck; Haruhisa Shimoda, Editor(s)

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