A People's Liberation Army soldier jogs past a model of a missile on display in Beijing. Photo: Reuters
China has opened its domestic satellite navigation network to commercial use across the Asia-Pacific region in a move that underscores its emergence as an independent space power challenging the primacy of the United States, Russia, Europe and Japan.
The network offers the region a still-to-be-proven alternative to the well-established and highly accurate US global positioning system, and similar satellite-based constellations being developed by Russia and Europe.
Until now, use of the Beidou network has been restricted to the Chinese armed forces and government. It has 16 navigation satellites in operation and the number is due to reach 35 by 2020 to become a functional GPS.
China only launched the first spacecraft in its network in 2000. It did so to ensure it would not need to rely on a foreign system that would be critical for co-ordinated military operations and precise targeting, as well as for civilian uses. China was concerned it could be denied access to a foreign GPS in a conflict.
Beidou's expansion also reflects a surge in the launching of other Chinese satellites that are of even greater military significance. They are used for space-based intelligence gathering, surveillance, reconnaissance and communications.
They carry a variety of advanced sensors including synthetic aperture radar to see through clouds and electronic signals collection to monitor radar and radio transmissions on land and at sea.
Reliable satellite communications are vital as Chinese forces operate further offshore to enforce island and maritime resource claims disputed with Japan in the East China Sea and a number of south-east Asian nations in the South China Sea.
To keep US or other outside forces from intervening in a crisis, China is reported to have developed anti-ship ballistic missiles that have a range of several thousand kilometres, are very difficult to defend against, and can be directed against aircraft carriers and the large warships that guard them.
SAR sensors use a microwave transmission to create an image of sea and ground targets. They work night or day, in all weather, so they are well suited to detect ships over a wide area and observe their wakes, from which information on speed and direction can be derived.
Chinese electronic reconnaissance satellites are designed to track and target accurately US carrier strike groups in near real time from low-earth orbit as part of China's evolving long-range, precision-strike capability, including ASBMs and hundreds of cruise missiles. Major surface vessels, such as aircraft carriers, have prominent electromagnetic, acoustic and infra-red heat signatures, as well as radar reflections.
The latest annual report from the US Department of Defence to Congress on Chinese military developments said China was improving its coverage of the western Pacific with over-the-horizon radars, early-warning planes and unmanned aircraft. It said the radars ''can be used in conjunction with reconnaissance satellites to locate targets at great distances from China, thereby supporting long-range precision strikes, including employment of ASBMs.''
A Beijing-based researcher with the World Security Institute's China Program, Matthew Durnin, said he and a colleague had identified more than 30 Chinese satellites launched since 1999 that could be used for reconnaissance.
As many as 17 appeared to be still active in the middle of last year and more had been put into orbit since then, including three in November. By comparison, Mr Durnin estimated that the US military had between 12 and 15 reconnaissance satellites in operation.
A report prepared last year for the US-China Economic and Security Review Commission in Washington concluded that while the overall level of China's space technology might not match that of the US and other space-faring nations, its relative advances were significant.
''Trends indicate that China's basic satellite coverage of waters and land within the Asia-Pacific region could, over time, approach that of the United States,'' the report said. ''The range of China's precision-strike assets is expanding out to Guam [a US island territory and key military base in the western Pacific], Australia, south-east Asia and India.''
Mr Durnin said the US and China had very different demands for space-based reconnaissance. ''The US system prizes high-resolution and cutting-edge technology,'' he said. ''The Chinese system, while certainly improving technologically, seems to be more about putting a lot of 'good enough' satellites into space for a relatively cheap price tag.''
Mr Durnin said that, although China had incorporated in its space craft the three main sensor technologies (electro-optical, synthetic aperture radar and electronic intelligence) carried by US spy satellites, they trailed US models in performance and longevity.
But for a large and electronically noisy target such as an aircraft carrier, China's average daily satellite surveillance time did not lag the US by much. ''This is a remarkable feat considering China had no such satellites just a little over a decade ago,'' Mr Durnin said.
With many billions of dollars invested in satellite communications and sensors, the US and China had an interest in maintaining a peaceful orbital environment. But if serious conflict erupted between them in the terrestrial world, space could quickly become a new frontier for battle.
>> Michael Richardson is a visiting senior research fellow at the Institute of Southeast Asian Studies in Singapore.
