New Earth Surveying: first common height model in 3D is ready
For six years have sent non-stop two radar satellites in the framework of the TanDEM-X mission data to Earth. During this time, they have repeatedly crossed the entire earthly land mass of 150 million square kilometers. Now, an extremely accurate global elevation model of the blue planet emerged from the gigantic mass of data.
Now it is the whole earth in 3D really ready and available. 150 million m2 of land surface have been precisely mapped by the German Centre for Aviation and Astronautics (DLR) in the past six years. Now, the peaks and the valleys of the planet are reflected in an unprecedented resolution. The height accuracy of terrain map is one meter.
“New chapter in the remote sensing”
“TanDEM-X has opened a new chapter in remote sensing. The technology for the radar operation of two satellites in close formation flight is unique and was the key to the high-precision new survey of Earth. Thus the DLR has demonstrated its pioneering role and created the conditions for the next major development step in the satellite-based Earth observation for the targeted radar mission tandem L”, the DLR Executive Board Chairman Prof. Pascale said honorary friend.
Minimum distance of 120 metres
The height accuracy of measurement is especially excellent calibration of the system. The distance of the two satellites in formation flight was exactly determined. The nearly identical, about 1,3 kg satellite, orbiting the Earth at an altitude of about 500 km at a minimum distance of 120 meters.
During the overflights, all land areas were multiple recorded and processed to height models. Between January 2010 and December 2015, the twin satellites through the worldwide network of reception have transferred more than 500 terabyte data to Earth.
Data volume exceeds 2.6 Petabyte mark
For about two years, remote sensing specialists of the DLR from sit to create a systematic elevation model from the flood of data. There are special processing chains, which distill the final elevation models from the satellite data. Here, the data volume has grown now to over 2.6 petabytes.
“The processing of these data was an exciting challenge for us,” Prof. Richard Bamler, Director of the DLR Institute of methodology of remote sensing. “All the more our first scientific analysis results fascinate us but now. The current elevation model we have demonstrated that in some regions of the world, glaciers lose up to 30 meters per year in thickness in the area of the glacier tongues.”
Over 1,000 scientists around the world use the mission data
Already, more than 1,000 scientists around the world use the data from the mission. “With the completion of the TanDEM-X global elevation model, we expect a significant increase of scientific interest again. Accurate topographic data are essential for all geo-scientific applications”, says Prof. Alberto Moreira, Director of the DLR Institute for high-frequency engineering and radar systems, which manages the mission.
There are diverse application possibilities of this super precise elevation profile of the Earth. This starts with the climate and environmental research, goes to the surveying and ends in infrastructure planning in the urban and road construction.
“The Earth system is highly dynamic”
With the now created 3D earth mark of the earth not the end is for the TanDEM-X satellite mission still long. In future the follow-up mission of tandem-L could create a news height image of the entire land mass of the Earth every eight days. Dynamic processes could be collected then in a timely manner. Moreira: “the Earth system is highly dynamic, which is reflected in the topography. With regular updates, we could collect such dynamic processes systematically in the future. This is the primary goal of the mission proposed by us tandem L.”
To polluters at sea and fire Devils who want to turn forests into fields, satellite cares Sentinel-3 A, by the way.