TanDEM-X

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TanDEM-X
TanDEM-X
Type: Earth exploration satellite
Country: GermanyGermany Germany
Operator: German Aerospace CenterDLR DLR
COSPAR-ID : 2010-030A
Mission dates
Dimensions: 1,330 kg
Size: Height 5 m, diameter 2.4 m
Begin: June 21, 2010, 02:14 UTC
Starting place: Baikonur
Launcher: Dnepr-1
Status: active
Orbit data
Rotation time : 95 min
Track height: 514 km
Orbit inclination : 97.4 °

TanDEM-X ( English T erraSAR-X- A dd-o n for D igital E levation M easurements , German "TerraSAR-X extension for digital height measurements") is a German Radar satellite that together with the satellite TerraSAR-X by means of SAR the earth's surface is stereographically measured in the X-band . This results in a worldwide terrain model with an accuracy of the heights of one meter. Head of the mission is Alberto Moreira , director of the Institute for Radar Technology and High Frequency Systems in  Oberpfaffenhofen , which is part of the  German Aerospace Center  (DLR).

description

The launch was initially planned for October 2009, but did not take place until June 21, 2010. The TerraSAR-X satellite will be complemented by TanDEM-X to form a twin satellite mission. Similar to TerraSAR-X, TanDEM-X should have a graduated resolution of 1 m, 3 m and 16 m (height resolution better than 2 m) with a swath width of 10, 30 and 100 km. The Airbus subsidiary Infoterra is responsible for marketing the images .

Both satellites fly in an almost identical sun-synchronized orbit, which allows interferometric recordings of the earth's surface and thus the creation of a high-precision elevation model ( DGM ). For this purpose, the satellites have a system ( Tracking, Occultation and Ranging Experiment , TOR) for synchronizing the radar instruments and an autonomous navigation control that keeps the two missiles at an exact distance of 200 m with a tolerance of just a few centimeters. This system consists of a two-frequency GPS receiver which was developed by the Geoforschungszentrum Potsdam and allows the position to be measured down to the centimeter as well as radio occultation (and thus the temperature) of the atmosphere and ionosphere at heights of 0–35 km. TanDEM-X was developed in Germany and, like TerraSAR-X, in a public-private partnership . The DLR participates as a public institution, parts are provided privately by the company Airbus Defense and Space .

The planned lifespan is five years (after three years the entire surface of the earth could be recorded), during which more than 2.5  petabytes of data are to be collected.

The first images from the satellite were published by DLR on July 22, 2010.

On August 10, 2010, the German Aerospace Center (DLR) inaugurated the Inuvik Satellite Station in Inuvik for the satellite mission.

The TanDEM-X project was nominated for the German Future Prize 2012 under the title "Radar Eyes in Space - Revolutionary Technology for Earth and Environment" .

The planned lifespan was reached on June 21, 2015, and the satellite will remain active.

The 13 meter diameter satellite antenna in Inuvik was built to control the satellite with funds from the Helmholtz Association . With this mission, a soil profile of the earth was created up to 2016 that is accurate to one meter. In the future, the data to and from the antenna will be transmitted via an underground fiber optic line through the whole of northern Canada , which will significantly improve the quality of the transmission. An eastern fiber optic branch is fully operational as far as Inuvik, coming from the province of Alberta . At the end of 2018, a western line from British Columbia , also located in the permafrost ground, was only in operation as far as Ferry Hill; another northern section is currently served by radio link that is susceptible to interference . The fiber optic route that is missing here as far as Inuvik is now being expanded, after which there will be a ring-shaped network of high stability, the "Canada North Fiber Loop".

controversy

The opposition parties Bündnis 90 / Die Grünen and Die Linke criticize the fact that the data released for national, non-commercial use belongs to the Ministry of Economic Affairs as the superior ministry to DLR, but the Ministry of Defense again owns the data for multinational military use from EADS Astrium for 475 million euros want to procure.

See also

  • STS-99 - "Shuttle Radar Topography Mission" in 2000 with a similar task
  • WorldDEM

Web links

Individual evidence

  1. ↑ G. Krieger, A. Moreira, H. Fiedler, I. Hajnsek, M. Werner, M. Younis, M. Zink: TanDEM-X: A satellite formation for high-resolution SAR interferometry . In: IEEE Transactions on Geoscience and Remote Sensing . tape 45 , no. 11 , 2007, p. 3317-3341 , doi : 10.1109 / TGRS.2007.900693 .
  2. ↑ DLR: New world map in 3D: Global elevation model TanDEM-X completed . In: DLR Portal . ( dlr.de [accessed on October 10, 2016]).
  3. ↑ Thomas Weyrauch: TanDEM-X is in space. Raumfahrer.net, June 21, 2010, accessed June 21, 2010 .
  4. ↑ In: FlugRevue. October 2009, pp. 78–81 (tandem with stereo view).
  5. ↑ FlugRevue. September 2010, p. 24. 3-D images from TanDEM-X
  6. ↑ Inauguration of the first DLR ground station in Canada . DLR, August 10, 2010. Accessed August 11, 2010.
  7. ↑ TerraSAR-X / TanDEM-X (TSX / TDX) at Gunter's Space Page (English).
  8. ↑ Canada: First glass fiber in permafrost helps German satellites , heise.de , December 31, 2018. With a map of the fiber optic cable route
  9. ↑ Markus Becker: Satellite images for the Bundeswehr: The mysterious 475 million euro deal. In: Spiegel Online. April 27, 2015, accessed on April 27, 2015 : “The deal has been causing astonishment for months - because the Ministry of Economic Affairs already has the data. The federal government financed three quarters of the "Terrasar-X / Tandem-X" project: 313 million came from tax revenues, 90 million from the project partner Airbus Defense & Space. "