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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