3D Mapping
June 22, 2010
A Russian rocket has succesfully launched a new German satellite on a mission to create the world's most precise three-dimensional topographical map of the Earth.
The new satellite, called TanDEM-X, is twinned with a previous German satellite launched in 2007. Together, the pair of satellites will follow a parallel orbit around the globe, slowly circling the planet in ever-changing arcs to cover ever square inch.
"It'll be the first time we will ever have had a globally standardised 3D digital elevation model of Earth, and with a measuring point density of 12 metres, it will be incredibly accurate," said Dr. Alberto Moreira, science director of the TanDEM-X mission, in a statement released by the German Aerospace Center.
Surveying from orbit
The two satellites, which will fly just a few hundred meters apart at all times, work by sending microwave pulses from orbit to the planet's surface. By measuring the time the signal takes to make the round-trip, the satellite's computers can determine the height of the ground, ranging from the lowest valleys to the highest mountains. With two satellites doing this instead of one, they can complete the land survey of the 150 million square kilometers of the Earth's surface with much greater accuracy than before.
Prior to this new German survey, the best digital elevation survey came from the US Shuttle Radar Topography Mission (SRTM) completed in 2000.
Future applications
German space authorities say that the project will take three years to both complete the satellite-based survey and that the data from the global elevation model will take an additional year, and will reach a total of 15 terabytes, or approximately 60 computer hard drives.
The raw data will be processed by three ground stations in Sweden, Canada and Antarctica and then will be sent for final processing to the German Remote Exploration Data Center (DFD) in Oberpfaffenhofen, just outside of Munich, in southern Germany.
The new three-dimensional land map will be made available to planetary scientists and to the private sector as well, with potential applications in mobile phone network construction, flight plan creation and urban planning. Previously, the first satellite, known as TerraSAR-X, has been used to monitor the progress of the Eyjafjallajoekull eruption in Iceland and the Gulf of Mexico oil spill.
Author: Cyrus Farivar
Editor: Mark Mattox