U.S. Hopeful New UN Panel Will Prevent Interference with GPS

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  Space News Business

U.S. Hopeful New UN Panel Will Prevent Interference with GPS

By PETER B. de SELDING
Space News Staff Writer
posted: 14 March 2007
02:39 pm ET


MUNICH — U.S. officials hope a new United Nations-affiliated body to coordinate existing and planned satellite navigation systems by the United States, Russia, China, Europe, Japan and India will rein in any single nation’s temptation to erect a system that poses problems for others.

The International Committee on Global Navigation Satellite Systems (ICG), created in November, has scheduled a first formal meeting in September in India and may provide the first detailed exchange of views on how China’s Compass/Beidou system intends to operate, officials said.

In notifications sent to the U.N.-affiliated International Telecommunication Union, which regulates orbital slots and radio spectrum, the Chinese government has signaled its intention to supplement its existing Beidou regional navigation system in geostationary orbit with Compass, a full constellation of satellites in medium-Earth orbit to provide global navigation, positioning and timing services.

Compass bears at least superficial resemblance to the U.S. GPS, Russian Glonass and future European Galileo systems. Chinese officials have vaguely described Compass as a national-security asset that bears no relation to China’s commercial involvement in Galileo.

Compass has raised concerns in Europe and in the United States because some of its proposed broadcast frequencies appear to overlap frequencies to be used by the GPS military code and Galileo’s government-only Public Regulated Service.

When Europe proposed that Galileo use frequencies that overlapped the GPS M-code, the U.S. government reacted strongly and said the move would make impossible any cooperation between GPS and Gaileo.

Overlaying one signal on another does not necessarily violate International Telecommunication Union protocols because both signals can operate without interfering with each other. The trouble comes in times of war or other emergency, when GPS managers would seek to use the M-code while jamming other navigation frequencies.

In the case of an M-code overlay, the U.S. could not jam others’ frequencies without jamming the M-code as well.

Europe eventually dropped the idea and since 2004 Europe and the United States have been working together to make GPS and Galileo interoperable and compatible so that inexpensive dual-mode receivers can be manufactured worldwide.

Japan’s future Quasi-Zenith Satellite System and India’s Gagan also are being developed with an eye to collaborating with existing systems, especially GPS. Russia too has adjusted regulations regarding its Glonass system to make it more compatible with GPS, and more attractive to users worldwide.

That leaves China and Compass.

European governments, which invited China into Europe’s Galileo system in return for financial commitments from China, have been unable to obtain assurances from the Chinese that Compass will not pose problems for Galileo through an overlay of Compass frequencies on Galileo’s encrypted, quasi-military Public Regulated Service.

“Beidou/Compass compatibility worries us,” said Matthias Ruete, director-general for energy and transport at the European Commission, whose directoratte leads Europe’s Galileo project. “We are prepared to work hard with our Chinese colleagues [on compatibility issues]. We very much hope the Chinese government will take up this invitation.”

For the moment, the U.S. government has not made any formal inquiries as to China’s plans for Compass, preferring to leave such discussions to a multilateral body such as the recently created ICG, according to Ralph Braibanti, director of space and advanced technology at the U.S. State Department.

In an interview here March 7, Braibanti said the United States prefers to take a wait-and-see attitude on Compass, but in principle has no reason to oppose its development.

“It is important that the Chinese conduct the same type of meticulous consultations with other [Global Navigation Satellite System] providers, including the United States, to ensure that its signals are interoperable and compatible with our own,” Braibanti said.

One U.S. government official said U.S. policymakers learned from their experience with Galileo that appearing to oppose the proliferation of regional and global navigation systems — as was the case initially with Galileo — is counterproductive.

“Our message now is to welcome everyone, but to encourage coordination, transparency and interoperability,” this official said. “We are not going to oppose Compass. If they do indeed seek to overlay Compass signals on the GPS M-code or the Galileo PRS, we will have to deal with that situation as it arises. For now, we are just seeking to learn more about what they plan to do.”

Michael E. Shaw, director of the U.S. National Space-Based PNT [positioning, navigation and timing] Coordination Office, which reports to the U.S. defense and commerce departments, said the United States’ key motivation now with respect to other nations’ satellite navigation plans is interoperability.

“The existing and new systems could be a real benefit to users if they are introduced in a way that maximizes compatibility,” Shaw said here March 8.

Braibanti said that bilateral discussions on satellite navigation will continue on specific issues but that this format has its limits.

“We’ve had bilateral talks only up to now,” Braibanti said. “They have been helpful, but when you have as many as six system providers, bilateral talks probably aren’t sufficient. You need to have all system providers in the same room. This is what we hope to do with the ICG.”