EUROPE鈥橲 Galileo satellite positioning system is meant to break the unspoken tyranny of America鈥檚 GPS, which can be switched off at the whim of the US government. But the European Space Agency鈥檚 decision to keep the transmission codes from its test satellite secret riled some academics in the US, leading them to indulge in some nifty code-breaking. Galileo, it seems, is truly free now.
Signals from the system鈥檚 30 satellites, which should be in orbit by 2010, were supposed to be 鈥渙pen source鈥� like GPS, meaning that anyone can develop technology to receive and use them. But when the first test satellite, Giove-A, went into orbit in January, ESA refused to publish the codes needed to decipher its signal. They argued that the signal format was incomplete and best handled by two receiver-makers that it had appointed.
鈥淭he Europeans said Galileo would be open source. Most people, me included, thought that applied to the test system too,鈥� says Mark Psiaki of the GPS Lab at Cornell University in New York. 鈥淧eople who want to build and test prototype receivers before 2010 need these open source codes to see if their systems work.鈥�
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鈥淭hey have done a good student job. I鈥檓 happy they got data from Galileo鈥�
Undaunted, Psiaki鈥檚 team decided to capture signals from the orbiting Giove-A and, after a little trial and error, were able to isolate location data from them. The codes to do so are now on the web and allow anyone to develop Galileo receivers at a time when ESA was attempting to restrict development to a handful of companies. 鈥淲e have been thanked by receiver-makers many times over,鈥� says Psiaki.
ESA鈥檚 response is lukewarm. 鈥淭hey have done a good student job,鈥� says a spokesman. 鈥淚鈥檓 happy they got data from Galileo.鈥�
The agency has now made codes for the 30 Galileo satellites public, but as Psiaki points out, none of those spacecraft is yet in orbit, so receiver-makers cannot test equipment with them.
