20 October 2008
1 Earth, 1 metre, 1 week
Since 2006, CNES engineers engaged in long-term research have been mulling an idea: might it not be possible, with tomorrow’s technologies, to take pictures of the entire globe in unrivalled detail and disseminate them directly over the Internet? For although Google Earth works very well, its resolution varies greatly from one region to another and its imagery is updated randomly.
After studying and reviewing the e-CORCE1 project for 2 years, CNES has delivered its verdict: it will be possible by 2014 to photograph all of the continents in colour at a resolution of 1 metre, every week. How? With a constellation of 13 Earth-orbiting microsatellites at 600 km, imaging everything in their path and downlinking compressed data to processing centres around the world. “The satellites are our eyes and the ground network is the brain,” says Jean-Pierre Antikidis, the man who dreamed up e-CORCE.
Lightening the data load
The idea underlying e-CORCE is simple and affords 2 advantages: it reduces costs and, above all, data volumes. “Acquiring an image of the globe every week would require 1.3 million hard disks side by side,” explains Jean-Pierre Antikidis. “We therefore had to find technical solutions capable of handling such vast quantities of data.”
e-CORCE performs 2 tricks to achieve this feat. The 1st involves image compression—ocean imagery is compressed more than images of cities—on board the satellites, a “psycho-visual” compression that is transparent to Web users.
The other trick is to dispatch the data to 50 centres connected to the Internet all around the globe. As Jean-Jacques Favier, Deputy Director of Advanced Concepts and Strategy at CNES, explains:
“Using ground stations to break up the volume of data and the Internet to make them accessible anywhere in the world is a highly original concept in the space sector. That’s why CNES has filed 4 patents to protect it.”
e-CORCE promises to deliver detailed, easily accessible and regularly updated imagery of the entire Earth cheaper than what is available in the professional market. The ball is now in the manufacturers’ court, as €400 million in funding will be needed to make e-CORCE a reality.
1 e-Constellation d’Observation REcurrente Cellulaire (recurring cellular observation e-constellation.)