Chinese satellite navigation officials say they intend to field an operational system covering all of Asia by 2010, but they are giving few details on the deployment plans for their global system. In addition China has yet to complete frequency coordination with the United States, Europe, Russia and others.
In presentations April 23 here at the Toulouse Space Show, these Chinese officials nonetheless said their global Compass/Beidou system would be fully compatible with the U.S. GPS, European Galileo and Russian Glonass global navigation constellations.
Like GPS, Galileo and Glonass, Beidou/Compass would be free of direct user charges but also feature an encrypted signal for authorized users only, presumably including the Chinese military.
Chengqi Ran, vice director of the China Satellite Navigation Project Center, said the secure Beidou/Compass signal would be "a highly reliable signal dedicated to complex situations."
Beidou/Compass is designed to feature five satellites in geostationary orbit and 30 satellites in medium Earth orbit. Ran and Xiaohan Liao, a deputy director at China's Ministry of Science and Technology, said the first of the medium Earth orbit satellites, launched in April 2007, is functioning well but is still the subject of in-orbit validation.
Liao said China intends to operate a Wide Area Precise Pointing system using geostationary satellites. China operates three Beidou/Compass satellites in geostationary orbit. Liao said the wide-area coverage, to include all of Asia, should be in operation by 2010.
Liao said China wants to ensure that the growing population of GPS users in China will have a smooth transition from GPS-only devices to devices that receive both GPS and Beidou/Compass signals. He said the market for GPS gear in China is expected to reach around $5 billion in 2010.
China's intentions for Beidou/Compass remain a subject of concern in the United States, Europe, Russia and Japan, according to government officials representing those countries at the Toulouse Space Show.
China's plans for an Asian regional system are the most immediate concern to Japanese authorities, who are developing their own regional system, called the Quazi Zenith Satellite System, because its three satellites will be in a highly elliptical orbit whose apogee will be over Japan and Asia.
Satoshi Kogure, associate senior engineer at the Japan Aerospace Exploration Japanese Agency, said some in Japan fear the Chinese system and think "this is an important issue for Japanese national security."
Kogure said China and Japan have had few, if any, talks about their respective systems, although both nations are members of the International Committee on Global Navigation Satellite Systems. This committee is next scheduled to meet in December in Pasadena, Calif.
"All the [satellite system] provider nations have agreed in principle" to seek maximum compatibility and interoperability among the different systems to permit users to take maximum benefit from the proliferation of satellites now planned, said Anthony Russo, deputy director of the U.S. National Coordination Office for Space-based Positioning, Navigation and Timing. "But a lot of details still need to be worked."
Europe's Galileo managers are actively seeking Chinese clarification on plans for Beidou/Compass so European engineers can freeze their plans for the signal structure of Galileo this year, when contracts for the satellites are scheduled to be signed.
"Our position with the Chinese is that we need to make sure we all have the same understanding of the problem," said Paul Verhoef, head of the Galileo unit at the European Commission, which is financing Galileo's development. "It has taken the Chinese awhile for them to realize that it is in their interest to [coordinate signals and other compatibility issues] if they want to be in this community of providers."
Verhoef noted that when the U.S., Russian, Chinese and European medium Earth navigations are added together, there could be 120 operational navigation satellites in medium Earth orbit by the middle of the next decade plus the three Japanese elliptical satellites.
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