Sanya Incoherent Scatter Radar (SYISR)

  The Sanya Incoherent Scatter Radar (SYISR) is a state-of-the-art ground-based ionospheric detection system located in Sanya, Hainan, China, at the geographic coordinate of 18.3°N and 109.6°E. Developed and operated by the Institute of Geology and Geophysics, Chinese Academy of Sciences, the radar system has been officially operational since 2024, serving as a core observation platform of the Chinese Meridian Project. As an advanced incoherent scatter radar deployed in China’s low-latitude region, SYISR fills the gap in high-precision ionospheric monitoring over the low-latitude Asian-Pacific sea area and provides critical support for space physics research and space environment safety guarantee.

  Different from conventional radars, incoherent scatter radar relies on Thomson scattering of free electrons in the ionosphere to invert multiple plasma parameters, earning it the reputation of a powerful ground-based ionospheric detection tool. The SYISR adopts a modular active digital phased array architecture with full solid-state transmission and all-digital receiving technology, representing the cutting-edge level of domestic low-latitude ionospheric observation equipment. Its core operating frequency band ranges from 430 MHz to 450 MHz, with a peak transmission power of 4 MW. The entire antenna system consists of 8320 units, featuring flexible beam scanning, high spatial resolution and stable continuous observation capability. The radar transmits right-handed circularly polarized electromagnetic waves and receives left-handed circularly polarized echoes, effectively capturing weak ionospheric scattering signals that are dozens of orders of magnitude weaker than conventional radar targets.

  Covering an altitude range from 60 km to >1000 km, SYISR can achieve continuous and high-precision measurement of key ionospheric parameters, including electron density, ion and electron temperature, plasma drift velocity, and neutral wind field. Beyond routine ionospheric monitoring, the radar supports diverse extended observation tasks, such as lunar imaging and meteor detection. Equipped with adjustable pulse widths and bandwidth waveforms such as long pulse, alternating code, Barker code and linear frequency modulation chirp signals, it balances signal-to-noise ratio and detection resolution to adapt to multiple scientific observation scenarios. To further enhance three-dimensional ionospheric detection capability, the Sanya Incoherent Scatter Radar Tristatic System (SYISR-TS) has been completed, forming a multi-station collaborative observation network to accurately capture the dynamic changes of low-latitude ionospheric electric fields and neutral winds.

  The SYISR radar station is equipped with a complete set of supporting auxiliary facilities to ensure long-term stable and automated operation of the system. The station is equipped with professional data analysis terminals and remote monitoring systems. All observation data are collected, sorted and stored in real time through the digital receiving and processing module, and can be uploaded to the database for scientific research sharing. Meanwhile, the station has built working area to support on-site debugging, experimental verification and daily operation management.

SYISR Website: www.syisr.ac.cn

Figure 1: Aerial View of Sanya Incoherent Scatter Radar (SYISR) Station

Figure 2: the Sanya Incoherent Scatter Radar Tristatic System (SYISR-TS)