China has been building a series of surveillance platforms spanning parts of the South China Sea (SCS). Many of these are in Chinese waters, but several are floating in international waters.
This is controversial, not least the dual-use military context of the network. While ostensibly civilian, these can be viewed as part of the Chinese Navy’s (PLAN) efforts to control the SCS.
It is unrealistic to assume that their sensor data cannot be accessed by the PLAN for military purposes. And they may be part of a much larger sensor network, most of which is unseen beneath the waves.
This reinforces China’s strategic advantage over other countries in the region, and can be used to monitor U.S. Navy movements.
According to research by CSIS’ Asian Maritime Transparency Initiative, the surveillance platforms are part of what China calls the “Blue Ocean Information Network” (蓝海信息网络). Some information about them was revealed at the Langkawi International Maritime and Aerospace exhibition in 2019.
The platforms carry a range of sensors and communications. These include electro-optical / infrared sensor turrets, high frequency radio and cellular masts. Most also have a large radar dome on them, which may be the primary sensor. The platforms are unoccupied, and rarely need maintenance.
With these platforms China has greatly increased its radar coverage of the South China Sea. They now have an uninterrupted chain between Hainan and its bases in the Paracel and Spratly Islands. Many of these islands already have radar sites. And one unoccupied atoll, Bombay Reef, now has one of the platforms on its shoreline. For context, Woody Island in the Paracels is where China recently deployed Flanker fighter jets during the U.S. Navy carrier USS Ronald Reagan (CVN 76)’s exercises in the area.
The unseen element below the waves is often called the Underwater Great Wall. This will be a network of sonar arrays laid on the sea floor. In some respects it is similar to the famous SOSUS system deployed by the U.S. Navy during the Cold War. But the technology involved will be much newer and fit the local environment. That China is planning this seabed sensor network is not hidden, but naturally the technology, location and status is a military secret. And unlike the sensor platforms it cannot be seen from a passing ship.
The South China Sea is hotly contested with competing territorial claims from Philippines, Vietnam, Malaysia, Brunei and Taiwan. China claims almost the entire area including many islands and reefs which are, defacto, parts of other countries. The exact boundaries of the Chinese claims are ambiguous and generally referred to as the nine-dash line. But the spirit of their claim is clear: in Beijing’s eyes the SCS belongs to China.
In recent years China has been building air bases and radar stations on the reefs which it has physical control over. This island building has attracted world wide attention. The surveillance platforms have not.
The area where the platforms are is a particular hot spot. According to Indo-Pacific News, which tracks the disputes, this is where many of the incidents between China and Vietnam occur. Many go unreported. China recently rewrote its shipping regulations to designate the area as ‘coastal waters’. Indo-Pacific News suggests that “China has struggled to exercise its control of these waterways. So changing the status from offshore to coastal may be another step to validate its sovereignty claims over Vietnam.” Whether the surveillance platforms directly figure into the decision or not, they are symbolic in these seas where presence matters.
Dr Collin Koh, a Research Fellow at the S. Rajaratnam School of International Studies, believes that it is not just political symbolism however. “This zone fully encompass sensitive areas” Koh points out. “Hainan is a crucial base for the PLA Navy not just a hub of naval forces but the country’s sea-based nuclear deterrent”. He believes that it reflects China’s growing ability to keep the waters under closer tabs. And if necessary, respond quickly to security scenarios.
These new surveillance platforms are built, fittingly, on an artificial island off the east coast of Hainan. Combined with the artificial islands and Underwater Great Wall, they provide China with the infrastructure to control the area, even in international waters. And so China may be going from mere presence, to omnipresence.