More Nations Crave Independent Satellite Navigation Systems
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European officials have put joint Chinese-European collaboration on the Galileo system on pause because of questions over China's satellite navigation plan. CREDIT: ESA. |
SUMMERLAND KEY, Fla. -- Europe is not the only focus of efforts to build a rival to GPS, the U.S. constellation of navigation satellites. U.S. control of the world's only fully functional satellite navigation system is fueling efforts by China, Japan and India to develop alternatives to GPS for regional coverage, and in China's case as a stepping stone to a global system, U.S. satellite navigation experts said.
"There is a symbolic reason to deploy these systems. That is the idea that they would like to be independent of any dependencies on U.S. controlled assets," said Brad Parkinson, a retired U.S. Air Force officer and one of the original architect's of the U.S. Global Positioning System (GPS), corresponding by email.
Parkinson is among those who consider unfounded the fears expressed by leaders of other countries in recent years that the United States would deny commercial access to free GPS signals in a crisis, or as an economic warfare tool. All strategy considerations aside, the collateral effect would be to grind U.S. industry to a halt, Parkinson said.
U.S. government officials have labored to make that point around the globe. "We're involved in two wars right now and the system has not been disrupted or turned off," added Robert "Doc" Mirelson, the NASA representative to the U.S. National Coordination Office, which is pushing for any new systems to be compatible with GPS.
Nevertheless, other nations are trying to wean themselves from GPS, or in some cases improve its accuracy by combining GPS signals with those from new satellites. China, at least in the eyes of one U.S. official, appears to be the closest to an operational alternative. It has deployed a cluster of four navigation satellites over Asia, called Beidou, with the four carrying designations 1a through 1d. Beidou means Big Dipper in Chinese.
By contrast, Europe's proposed Galileo global constellation is years behind schedule. Europe certainly will miss the promised date of 2008 for the start of operations, and no new firm date is in place, a European Commission official said. In late 2005, Europe launched a demonstration satellite called the Galileo In-orbit Validation Element.
"They [Chinese officials] have [four] satellites and Galileo has one. I think there's a lot of debate out there over who's going to have the system first," Mirelson said.
A wild card in the race is Russia, where President Vladimir Putin has been pushing for completion of the country's Global Navigation Satellite System, or Glonass, constellation to reduce dependence on GPS inside Russia. In a March speech to his policymaking council, Putin bemoaned the reliance on U.S. satellite technology: "It is true that we do not yet have a choice in this matter. I hope that our navigation system will start working in 2007," he said according to an English language Kremlin transcript.
Glonass is not the only global proposal. Chinese officials have described the Beidou satellites as an "experimental" regional system meant to pave the way for an operational constellation called the Compass Satellite Navigation System. China's Xinhua News Agency reports that the long-term plan is to "gradually extend" Compass into a global system for applications from commercial fishing to national security.
The most recent Beidou was launched Feb. 3 on a Long March 3A rocket as a backup to the three primary satellites, according to Xinhua.
The Beidou launches have complicated China's relationship with European officials in charge of developing Galileo. Until recently, Chinese and European engineers had been collaborating on technical projects under an agreement to support Galileo. European officials have put those joint efforts on pause partly because of questions over China's Compass plan, a European Commission official said. "There's going to be some other system out there, and we want to make sure it's going to be compatible with Galileo. We are asking for information from them," the official said.
In the United States, at least one member of Congress is concerned that Europe, through its Galileo contacts with China, already might have unwittingly helped China improve its military capabilities.
"I would oppose any cooperative efforts with dictatorships like China because they inherently lead to technology transfers," said Rep. Dana Rohrabacher (R-Calif.).
Meanwhile, Japan is working on the first of three spacecraft planned for a regional navigation constellation called the Quazi-Zenith Satellite System (QZSS). The first QZSS satellite is scheduled for launch in 2009 into a highly elliptical orbit.
In Parkinson's opinion, it is "very probable" that the Japanese and Chinese will continue their programs. "In part this is because of the world perception that the [Department of Defense] controlled system can be easily disrupted," he said.
In India, space officials have two navigation projects in mind. They plan to launch a system of geosynchronous satellites to improve the accuracy of GPS signals for use at Indian airports and airspace. Development of the GEO Augmented Navigation system appears to have U.S. blessing. Raytheon, based in Waltham, Mass., is providing the ground terminals.
In 2006, India also announced it would develop an Indian Regional Navigation Satellite System by putting a seven-satellite constellation in place by 2011.
In some ways the orbital architecture debates that are no doubt taking place in China, India and Japan might mirror those that took place in the United States in the 1970s.
"For regional deployment, geo-synchronous is a very reasonable approach," Parkinson said. In fact, some U.S. officials had advocated that as a test of U.S. navigation-satellite capabilities, he said.
Instead, U.S. officials decided to launch a first batch of six medium Earth orbit satellites that would provide four to six hours of "representative coverage," Parkinson said.
If other nations do succeed in setting up regional, and then global systems, and those signals are made interchangeable with GPS signals, that would a boon to satellite navigation customers, especially those in canyon or mountainous terrain, Parkinson said.
"The extra satellites will greatly strengthen the geometry for these impaired users," he said.
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