MEDUSA, an ultra light weight multi-spectral camera for a HALE UAV

摘要

The ESA-PRODEX funded MEDUSA project aims to develop a light weight high resolution multi-spectral earth observation instrument, which will be embarked on a solar-powered high altitude long endurance (HALE) UAV, operated at stratospheric altitudes (15 to 18km). The MEDUSA instrument is designed to fill the gap between traditional airborne and spaceborne instruments regarding resolution and coverage. It targets applications such as crisis management and cartography, requiring high resolution images with regional coverage, flexible flight patterns, high update rates and long mission lengths (weeks to months). The MEDUSA camera is designed to operate at a ground resolution of 30 cm at 18 km altitude in the visible spectrum (400-650 nm), and a swath of 3000m. The central part of the payload is a focal plane assembly consisting of two frame sensors (PAN and RGB). The wide swath is realized with a custom designed highly sensitive CMOS sensor of 10000×1200 pixels. A GPS receiver and Inertial Measurement Unit (IMU) provide accurate position and attitude information. A direct downlink allows near-real time data delivery to the user. The on-board data processing consists mainly of basic image corrections and data compression (JPEG2000). The challenge lies mainly in fulfilling the requirements within the extreme environmental and physical constraints of the HALE UAV. Compared to traditional airborne and spaceborne systems, the MEDUSA camera system is ultra light weight (about 2 kg) and is operated in a low pressure and low temperature environment. System modeling and simulation is used to make careful trade-offs between requirements and subsystem performances.On 27th November 2006 the phase C/D for the design, production and test of the camera has started at VITO with the support of 9 industrial partners. The MEDUSA camera is expected to transmit its first images the end of 2008.