New instruments for a world-wide remote sensing satellite support measurement network to be developed at Tartu Observatory

Kairi Janson, Anu Reinart | 12.04.2018

Before a satellite starts its work on orbit, everything that might happen out of reach of the researchers and engineers has to be thought through. In the new HYPERNETS project which includes Tartu Observatory as a partner, an instrument for the support measurements of optical remote sensing satellites is created. The support measurement instruments will form a world-wide network with unified data processing and management.

Sentinel-2. ESA/ATG medialab.

„The biggest problems of optical satellite remote sensing are that the satellite sensor can be calibrated at the optics laboratory only before going on orbit and that objects on ground are measured through hindering atmosphere – people who have looked out of an airplane window and seen a bluish forest over a large field should recognize the problem,“ said Joel Kuusk, Senior Research Fellow at Tartu Observatory’s Department of Remote Sensing.

Thereof ground support measurements need to be done and the results compared with satellite data. This way the quality of atmosphere correction can be controlled and the possible change of the satellite sensor calibration in the course of time can be observed. Unlike satellite sensors, it is possible to calibrate the ground support measurement instrument periodically at the laboratory.

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This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 775983.

The new type of autonomous spectrometer created within the project will be tested in the most extreme ground conditions: in Antarctica, the Namib desert, the Argentine rain forest, the North Sea, and of course on the test sites of our own environmental observatory located in Järvselja. It is necessary to ensure that the complex optics, mechanics and the software that keeps them running work without a glitch.

“This type of autonomous devices are like small clever robots that need to be able to manage themselves and send researchers both the measurement data and information about their own conditions,” said Viljo Allik, Senior Research Fellow at Tartu Observatory’s Department of Space Technology and supervisor of ESTCube. Allik will consult the HYPERNETS project partners about testing of electronics, software and electromagnetic compatibility.

Riho Vendt, Head of Tartu Observatory’s Department of Space Technology stated that the observatory has a key role to play in the project. In the optical radiometric laboratory of the observatory, close research on different parameters of remote sensing instruments and calibration opportunities has been done, ordered by the European Space Agency or as part of European Union cooperation projects. This is why Tartu Observatory has a lot of experience in building instruments as well as dealing with possible measurement errors, their causes, and correction algorithms. “This gives us a chance to get the best possible result with using cheaper components and therefore provide high-quality data for an affordable price,” Vendt said.

The HYPERNETS project is coordinated by the Royal Belgian Institute of Natural Sciences. Besides Estonia, there are project partners from six countries: France, Argentina, Italy, Germany, and the United Kingdom.

More information: project website and