China’s land reclamation activities in the South China Sea are currently focused on the installation of military infrastructure on its new islands. It has long been known that these new developments include runways, port facilities and military defences, however, in a significant boost to China’s surveillance and intelligence capabilities, as well as its power-projection efforts, new imagery indicates that they also feature a sprawling new network of radars of varying shapes and sizes.

© DigitalGlobe/ScapeWare3d/Contributor via Getty Images

By Alexander Neill, Shangri-La Dialogue Senior Fellow for Asia-Pacific Security, Meia Nouwens, Research Fellow for Chinese Defence Policy and Military Modernisation, and Laurence Taylor, Visiting Researcher.

As part of an effort to strengthen its territorial claims, China has been working apace to expand what were once natural underwater features in the contested waters of the South China Sea. Along with environmental destruction caused by dredging and concreting coral atolls, China’s steady militarisation of the South China Sea features it claims has drawn considerable international concern. Despite President Xi Jinping’s 2015 statement that China did not intend to militarise such features, by 2016 it had turned its Spratly outposts into what some analysts have termed ‘unsinkable aircraft carriers’.

Between 2013 and 2015, it reclaimed 11.74km2 – or 17 times more than the four other Spratly Island claimants combined over the past 40 years. By 2016, China had reclaimed approximately 12.95km2. Despite official statements to the contrary, China’s reclamation activities are continuing, albeit at a significantly slower rate than before. The current focus of Chinese activity is on the completion of infrastructure on its new islands including aircraft hangars, possible missile emplacements, underground bunkers and storage facilities, accommodation, and administrative buildings.

What’s the purpose of China’s new installations?

New installations on the features include 3km-long runways, large naval-grade berthing facilities and a range of military defences, such as large anti-aircraft guns, and close-in weapons systems (CIWS). While such assets are highly visible, radar facilities are more difficult to identify. However, an analysis of the built-up infrastructure on the islands suggests that the seven Chinese-reclaimed islands in the Spratlys today house over 40 different radar facilities (see interactive map below). Such a network would represent a significant enhancement of China’s ‘C4ISTAR’ (a commonly used term for command, control, communications, computers, information/intelligence, surveillance, targeting acquisition and reconnaissance) capabilities, enabling:

  • Interconnectivity between China’s reclaimed features across the South China Sea, probably with the new Southern Theatre Command and the Central Military Commission’s new Joint Battle Center;
  • A new signals intelligence (SIGINT) capability and probable People’s Liberation Army (PLA) SIGINT deployments on the islands, offering considerable new reach into Southeast Asia and beyond, connected to China’s existing SIGINT collection network;
  • Space, cyber and electronic warfare capabilities, with the likely presence of the PLA’s new Strategic Support Force;
  • Connectivity with China’s expanding Beidou Satellite Navigation system, for both military and civilian applications;
  • Command and control for PLAN, coast guard and maritime militia operations;
  • The protection of China’s new seaborne nuclear deterrent including C4ISTAR support for its new airborne and subsurface anti-submarine warfare capabilities in the South China Sea. (This is strategically important for the protection of China’s SSBN fleet of Jin-class submarines operating from Hainan island);
  • Early warning and stealth detection via the high-frequency (HF) arrays on Cuarteron and Fiery Cross reefs. (This could be part of what is perceived by the US to be China’s anti-access area-denial strategy to hold the US Navy at bay should hostilities break out);
  • Connectivity to the PLA Rocket Force command and control network and guidance systems, specifically China’s increasingly lethal precision-strike ballistic missiles the DF-21D and the DF-26;
  • The further enforcement of any air defence identification zone that China chooses to create in the South China Sea. Such radars could be used to further challenge US and Australian patrols near the islands.
A closer look reveals presence of radars

A February 2018 article in the Philippine Daily Inquirer offered an insight of unprecedented clarity and detail into the sheer scale and pace of construction on Chinese-occupied features in the Spratly Islands. The accompanying photos show an impressive level of construction, as highlighted by the CSIS’s Asia Maritime Transparency Initiative, including what look like state-of-the-art garrison facilities, airbases, naval berths, paved roads and even agriculture. The photos also clearly show new radar facilities on all of China’s reclaimed features in the Spratly Islands.

Radomes – possibly housing radar or satellite communications equipment – have sprung up across all of the features, which also bristle with an assortment of antennas and communications arrays. While defence analysts have used satellite imagery to track the progress of big-ticket construction developments, few in-depth analyses of the radar, satellite and communications facilities have been conducted. While most analyses mention ‘radar facilities’, few specify the types of radar and their possible military application.

The ‘big three’ reclaimed islands – Fiery Cross, Subi and Mischief reefs – house C4ISTAR facilities in line with what one would expect to be long-range capabilities. Fiery Cross Reef plays host to seven radomes atop observation towers, a ground-level radome farm of various sizes and a HF array radar facility. Mischief Reef houses four radomes atop observation towers (two small, one tall and large, one short and large) and three radomes atop observation towers on other sites on the island, as well as a ground-level radomes and a radar. Subi Reef boasts an impressive collection, consisting of at least 12 radomes atop observation towers and what appear to be two ‘elephant cage’ direction-finding radars.

The smaller reefs host a significant array of radars too. Gaven and Hughes reefs are each furnished with two radomes and an observation tower, and Johnson South Reef houses two radomes atop observation towers and two stand-alone ground-level radomes. Cuarteron Reef is particularly interesting, boasting the widest range of arrays, including two ground-level radomes, a HF array, as well as one large and one small observation tower topped with radomes.

Little is known publicly about the exact extent of the C4ISTAR capabilities on these islands. Neither radar operating frequencies nor their size can be deduced from the size of the radomes or radar observation towers, and without knowing the angles, height and resolution from which photos of the islands were taken, little mensuration is possible.

Deductions can, however, be made about the types of radars in place on the islands. For example, while some radars might be utilised for weather monitoring such as Doppler radar, HF arrays are typically used for early warning and detection at great distance, sometimes up to several thousand kilometres (see for example the Jindalee Operational Radar Network in Australia, which has a publicised maximum range of 3,000km). Furthermore, when installed on top of observation towers, radomes have an extended operating range and target detection size, giving expanded surveillance and early warning capabilities. Lastly, multiple ground-level domes of various sizes could conceal satellite antennas serving as satellite-communications (SATCOM) ground earth stations, space-tracking systems or SIGINT collection systems

When applying this analysis to Chinese installations on the Spratly Islands, deductions can indeed be made as to the utility of the radars in place. The three centre-most islands (Gaven, Johnson South and Hughes reefs) have similar radar setups consisting of two ground-level radomes and at least one elevated radome on a tower. Given this reduced configuration, it is likely that these are used for surveillance within the island chains.

The easternmost island, Mischief, has a substantial radar setup, partially to support aircraft runway operations, but also to extend its visibility over the water, potentially to as far as the Philippine island of Palawan, some 280km away. Subi Reef, the northernmost island, has multiple elevated radomes, again likely to support aircraft runway operations.

There is likely to be an overlap in ranges between radar on the island and those located at bases on the Paracel Islands. Of particular interest are the radar setups on the two southernmost islands, Fiery Cross and Cuarteron reefs. Along with a substantial number of elevated radomes, these two islands also contain what appear to be HF radar installations consisting of numerous pole antennas indicating increased surveillance of air and sea traffic around the Malacca Straits and the coasts of Malaysia and Singapore.

A 2010 Chinese military report is cited as having suggested the radars located on Chinese islands in the Spratlys had a range of a range of 50 to 300km. Given their size and location, the HF installations on Fiery Cross and Cuarteron reefs are likely to be over-the-horizon surface wave (OTH-SW) systems, as opposed to systems which exploit radio wave reflection off ionized layers in the atmosphere. OTH-SW systems utilise the Earth’s curvature to propagate high frequency radio waves over distances of several hundred kilometres. The Chinese have been developing such systems since the 1960s, with the latest estimates for their maximum operating range lying at around 400km. While the system on Fiery Cross Reef is likely to be smaller, if it is networked with the system on nearby Cuarteron, then the combined capability would allow for improved resolution.

Paving the way for enhanced power projection

The reclaimed islands in the Spratlys are not simply fortified flag markers for China’s claims of sovereignty in the South China Sea, demarcated by the so-called ‘nine-dashed line’. The islands serve as a network of platforms for the PLA’s C4ISTAR capabilities, enhancing significantly China’s projection of military power into the region.

Although the use of radomes by the PLA conceals the type and orientation of C4ISTAR capabilities on China’s new island bases, we can make a number of deductions from the locations of such infrastructure. Some radomes will be part of the CIWS protecting the islands, while others could be used for surface-to-air missile launch sites. Some will be tracking maritime traffic and foreign naval activity in the vicinity, others will be used to cover the airspace above and near to the islands. Others likely support air-traffic control and weather-monitoring activities. Some of the antenna towers will support microwave communications for line-of-site communications, as well as base stations for the 4G telecoms network being installed, according to recent reports. Some of the radomes will conceal SATCOM antennas for connectivity between the islands. The radome farms are of particular significance – are they SIGINT dishes intercepting satellite signals or ground earth Stations? Could they be space-tracking facilities? What is clear is that the militarisation of the Chinese Spratly Islands continues – and a network of surveillance and early warning capabilities will be a game-changer in China’s favour.


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