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Weapons of Mass Destruction (WMD)

Over-the-Horizon Backscatter Radar [OTH-B]

China may have deployed as many as three Over-the-Horizon (OTH) sky-wave radar systems by 2005. China aspires to use to target aircraft carriers. These systems could be used in an early warning capacity. China also may have deployed at least one surface-wave OTHR.

While protesting the deployment of the THAAD missile defense system in South Korea -- calling it a threat to its national security -- Chinese state media reported 15 March 2017 that China had installed another over-the-horizon Tianbo radar in Inner Mongolia. Its main objective was detecting an opponent's missile launch and the localization of an intercontinental ballistic missile. Within a minute, Tianbo can confirm the target to strike, as it detects the launched missile.

The over-the-horizon radar, which was installed in January 2017, has a range of about three-thousand kilometers, enabling it to detect not only South Korea and Japan but even the Western Pacific. That's far bigger than the coverage of THAAD's X-band Radar,.. which has a range of 600 to 800 kilometers. According to the Chinese media, the Tianbo radar can also detect U.S. F-35B stealth fighters deployed at the Iwakuni base in Japan. It can also monitor aircraft carriers and warships within its radius.

China has deployed an Over-the-Horizon Backscatter Radar [OTH-B] to provide surveillance of the South China Sea. The precise location of this facility remained unclear.

China began development of HF ground wave OTH sensors in November 1967. A group led by Deputy Director of the Space and Missile Industry Qian Xuesen was assigned the responsibility of developing a ground wave OTH sensor able to detect targets at 250 kilometers. The radar was to provide targeting data for their embryonic anti-ship cruise missile program. In the 1970s, an experimental ground wave OTH radar, with an antenna length of 2300 meters, was deployed. Foreign export restrictions, however, prevented China from obtaining technology which was needed for further improvements.

Several technical papers have appeared in Western publications concerning OTH-B systems, including:

  • Zhao Shuqing, Liu Yongtan and Duan Fengzeng (1990) Digital beamforming in the OTH radar ICSP-90 Beijing, 655-656.
  • Jiao Peinan (1991) A new method of track processing in HF skywave OTH-B radar ACTA CIE 19, 1, Jan 91, 1-6.
  • Zhao Shuqing and Liu Yongtan (1991) Frequency domain digital beamforming in the OTH radar SEE 13, 1, Jan 91, 47-51.
  • Zhou Wenyu and Mao Xu (1991) Bistatic FMCW OTH-B experimental radar ICR-91 CIE, 138-142.
  • Wang Jiliang and Duan Fengzeng (1993) Application of maximum entropy in angular superresolution of OTH radar SEE 15, 10, Oct 93, 21-30.

A large over-the-horizon (OTH) backscatter (OTH-B) radar faces south near the southern coast of China. In the 1970s, the experimental OTH radar had a 2,300-meter antenna and could pick up surface ships at 250 kilometers. A series of technical papers describing a skyway OTH radar in the early 1990s leads to the conclusion that operational deployment would have been in that period.The fact that Guangzhou is the headquarters of the South China Fleet indicates a major complex of tactical and strategic space and land-based communication and long-range radars in that area. They would be focused south into the South China Sea.

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