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Airborne Prism Experiment helps to observe Planet Earth: Newton’s Theory goes Airborne

Netcetera supplies Hardware & Software

  • Media Release
  • Zürich (CH), Mol (B) and Emmen (CH), 02.07.2009

In a joint Swiss‐Belgian effort, a combined scientific and industrial consortium is building a new class of an airborne imaging spectrometer for environmental monitoring: the Airborne Prism Experiment Airborne imaging spectrometers measure and map the Earth surface in many, contiguous spectral bands, allowing to retrieve relevant spatial information on the state of the environment. Netcetera delivers the necessary hardware and software to collect and safe the scientific data as well as to coordinate the operating information on the airplane.

Logo Apex

APEX is built as a pushbroom dispersive imaging spectrometer recording more than 330 spectral bands contiguously. The principle of APEX relies on the dispersion of light using prisms as described in Isaac Newton’s Treatise of Light in 1704. Today’s computing power, software and detector technology allow flying this theory in a spatial fashion on an aircraft, creating continuous images of the Earth’s surface.

APEX will contribute to the systematic mapping and monitoring of environmental parameters and processes at unprecedented accuracy. These include – but are not limited to – mapping of soil mineral composition, total suspended matter in lakes, plant pigments and non pigments (Water, Protein, Chlorophyll, Lignin, Cellulose, Nitrogen, etc.), vegetation structure, hydrocarbon content, net and gross primary production, aerosol concentration, and atmospheric water vapour.

A typical APEX mission acquires 934 km2 of the Earth’s surface at 2x2 m spatial resolution. Multiple missions can be integrated in one flight. 1000 pixels are recorded across‐track with a data rate of 0.42 GBytes/km flight path. Flexible spectral configurations (user defined binning patterns) allow a maximum of 534 spectral bands to be acquired simultaneously, while a typical setup contains 115 spectral bands ranging from 380‐1000 nm, and 199 spectral bands ranging from 900‐2500 nm. An advanced calibration procedure allows delivering spatially and radiometrically coherent measurements for each pixel.

APEX experimental flights have been carried out in the course of June 2009 in the framework of an ongoing acceptance procedure. APEX flight opportunities and data will be available to the scientific community, research institutions, and commercial users as of 2010.

Under the scientific lead of the University of Zurich (Zurich, CH) and VITO (Mol, B), an industrial consortium was contracted through the European Space Agency’s (ESA) PRODEX programme to implement APEX. The industrial consortium is headed by RUAG Aerospace (Emmen, CH) with subcontractors such as OIP Sensor Systems (Oudenaarde, B) and Netcetera AG (Zurich, CH). Special contracts where issued by ESA for the development of a shortwave‐infrared detector (Sofradir, F), and a calibration facility at the German Aerospace Center (DLR, Oberpfaffenhofen, GER). The initial APEX operations were performed using a leased aircraft from the German Aerospace Center. A variety of European research aircraft will be used in the future to cover all APEX flight operations.