Delete search term

Header

Main navigation

School of Engineering

AVIRIS-4 (a.k.a. CWIS-II): Compact Wide-Swath Imaging Spectrometer

In collaboration with UZH (Remote Sensing Laboratories, Dept. of Geography), EPFL and NASA/JPL, ISC is developing the data acquisition and control software for an advanced airborne imaging spectrometer and is responsible for the complete system integation

100’s of parallel spectrometers

Sunlight reflected from the Earth’s surface is imaged by a telescope and spectrometer system onto a two-dimensional detector array that is sensitive from the visible to short wavelength infrared portion of the electromagnetic spectrum.

Using the CWIS-II mounted in an aircraft, scanning images are captured for which the imaging spectrometer instrument measures a spectrum for every point.

Each column of the detector array records the spectrum for a sample of 1240 cross-track instrument swath. The along-track dimension of the image is built up with the forward motion of the airplane. The hyperspectral image cubes measured by the imaging spectrometer are calibrated to spectral radiance, then atmospherically corrected and analyzed to determine multiple properties of the imaged surface, e.g. the mineral composition or biological properties.

Technical Hand-Over at NASA/JPL, California

In May 2022, the technical hand-over of the CWIS-II Sensor Head built by NASA/JPL took place in Pasadena, California.

ISC’s contribution

A specialized software developed by ISC acquires the raw sensor data at >200 MB/s, processes it on-the-fly to get an appropriate visible image for live monitoring and safely stores it redundantly during the flight missions. Multiple auxiliary sensor values such as GPS/IMU, gimbal angles, temperature and pressure, are monitored and merged to the spectrometer data. A specialized software interface allows to connect to the airplane’s flight management system in order to automatically start and stop the data acquisition and instrument calibration.

Mounting the CWIS-II in an airplane requires multiple additional electronic devices e.g. a flexible and powerful UPS, a liquid chiller, a gimbal mount. ISC is responsible for the sensor head integration into a complete system which can be certified for airborne operation.

Successful First Flight over Zurich

On Feburary 29, 2024, AVIRIS-4 has been tested in the air and spectral data of the city of Zurich has been successfully acquired. 

The complete AVIRIS-4 system has been installed in the HB-TEN Cessna 208B Grand Caravan EX aircraft and is operated based on a Minor Change Approval certification. Here are a few impressions from the first flight: