Gaofen_12

Gaofen

Gaofen

Chinese satellites

Gaofen (Chinese: 高分; pinyin: Gāofēn; lit. 'high resolution') is a series of Chinese high-resolution Earth imaging satellites launched as part of the China High-resolution Earth Observation System (CHEOS) program.[1][2] CHEOS is a state-sponsored, civilian Earth-observation program used for agricultural, disaster, resource, and environmental monitoring. Proposed in 2006 and approved in 2010, the CHEOS program consists of the Gaofen series of space-based satellites, near-space and airborne systems such as airships and UAVs, ground systems that conduct data receipt, processing, calibration, and taskings, and a system of applications that fuse observation data with other sources to produce usable information and knowledge.[2][3]

Quick Facts Program overview, Country ...

Although the first seven Gaofen satellites and their payloads have been heavily detailed, little to no details on Gaofen 8 and later satellites have been revealed prompting suggestions that Gaofen satellites may be dual purpose supporting both civilian and military missions.[2][4][5][6][7]

In 2003, the China National Space Administration (CNSA) agreed with Roscosmos to share Gaofen data for data from Russia's Earth observation satellites of similar capability. This agreement was expanded in August 2021 when leaders from BRICS space agencies agreed to share space-based remote sensing data.[8]

Notable satellites

Gaofen-5

Gaofen-5 has been lauded as the "flagship of the environment and atmosphere observation satellite in the CHEOS program". Launched on 8 May 2018 from Taiyuan Satellite Launch Center (TSLC) into Sun-synchronous orbit, Gaofen-5 carries six payloads: an Advanced Hyperspectral Imagery sensor (AHSI), Atmospheric Infrared Ultraspectral Sensor (AIUS), Directional Polarization Camera (DPC), Environment Monitoring Instrument (EMI), Greenhouse-gases Monitoring Instrument (GMI), and Visual and Infrared Multispectral Sensor (VIMS).[2][9]

The Advanced Hyperspectral Imagery (AHSI) sensor payload aboard Gaofen-5 claims to be the first space-based hyperspectral imaging sensor utilizing both convex grating spectrophotometry and a three concentric-mirror (Offner) configuration.[10] The AHSI uses spectrophotometry to measure the light spectra reflected, transmitted, or emitted by an imaged object to detect or identify objects on the ground.[10] In civilian applications, the AHSI allows analysts to conduct environmental monitoring and resource discovery while in a military application would allow analysts to detect and identify an adversary's equipment or spot non-multi-spectral camouflage.[10][11][12] AHSI has a 30 meter spatial resolution and 5 nanometer spectral resolution in the visible, near-infrared (NIR), and short-wave infrared (SWIR) wavelength ranges.[12]

The Atmospheric Infrared Ultraspectral Sensor (AIUS) payload aboard Gaofen-5 is China's first hyperspectral occultation spectrometer meaning it measures the spectra of imaged atmospheric particles between the sensor and the Sun.[13][14] AIUS allows scientists to monitor atmospheric circulation by tracing H
2O (water vapor), temperature, pressure, and various carbon and halogen-containing gas pollutants such as chlorofluorocarbons (CFCs), dinitrogen pentoxide, and chlorine nitrate.[14][15] A Michelson interferometer, AIUS images wavelengths between 2.4 and 13.3 micrometers (near to mid-wave infrared) at a 0.3 centimeter resolution and a ±10° field of view.[14]

Gaofen-5's Directional Polarimetric Camera (DPC) is China's first space-based multi-angle polarimetric camera.[9] Prior to GF-5's launch, in September 2016, China had experimented with polarimetric imaging in 2016 aboard the Tiangong-2 space laboratory and launched its Cloud and Aerosol Polarimetric Imager (CAPI) aboard TanSat in December of that year.[9][16] CAPI imaged clouds within 670 and 1640 nanometer channels but was restricted to fixed-angle imaging. The DPC aboard Gaofen-5 enables atmospheric spectroscopy in three polarized bands (90, 670, and 865 nm; polarized at 0°, 60°, and 120°) and five non-polarized bands (443, 565, 763, 765, and 910 nm), all wavelengths from green to near-infrared (NIR). A step motor rotates the 512 × 512 pixel charge-coupled device (CCD) imager ±50° providing a 1,850 km swath of imagery at 3.3 km resolution.[9][17]

Satellites

Since the program's start in 2013, the People's Republic of China has launched 30 Gaofen-series satellites and has not yet experienced a launch failure. Jilin-1 satellites described as 'Gaofen' are not part of the government's Gaofen series, rather are described as having high resolution (Chinese: 高分; pinyin: Gāofēn).[18]

More information Designation, Launch date (UTC) ...

See also

References

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    "China launches another Gaofen Earth observation satellite". Spaceflight Now. 8 September 2020. Archived from the original on 10 September 2020. Retrieved 9 September 2020.
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    Chen, Liangfu; Letu, Husi; Fan, Meng; Shang, Huazhe; Tao, Jinhua; Wu, Laixiong; Zhang, Ying; Yu, Chao; Gu, Jianbin; Zhang, Ning; Hong, Jin (8 April 2022). "An Introduction to the Chinese High-Resolution Earth Observation System: Gaofen-1~7 Civilian Satellites". Journal of Remote Sensing. 2022: 1–14. Bibcode:2022JRemS202269536C. doi:10.34133/2022/9769536. S2CID 247446513.
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    Zhen, Liu (12 October 2020). "China is sending more of its Gaofen satellites into space. Here's why". South China Morning Post. Archived from the original on 4 September 2022. Retrieved 4 September 2022.
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    Jones, Andrew (22 November 2021). "China launches new Gaofen-11 high resolution spy satellite to match U.S. capabilities". SpaceNews.
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    Iderawumi, Mustapha (19 August 2021). "BRICS Space Agencies Leaders Signed Agreement to Share Remote Sensing Satellite Data". Space in Africa. Archived from the original on 19 August 2021. Retrieved 19 May 2022.
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    Zhengqiang, Li; Hou, Weizhen; Hong, Jin; Zheng, Fengxun; Luo, Donggen; Wang, Jun; Gu, Xingfa; Qiao, Yanli (12 April 2018). "Directional Polarimetric Camera (DPC): Monitoring aerosol spectral optical properties over land from satellite observation" (PDF). Journal of Quantitative Spectroscopy & Radiative Transfer. 218 (218). University of Iowa, Chinese Academy of Sciences (published 7 July 2018): 22–23. Bibcode:2018JQSRT.218...21L. doi:10.1016/j.jqsrt.2018.07.003. S2CID 126349523. Archived (PDF) from the original on 23 October 2022. Retrieved 23 October 2022 – via Elsevier Science Direct.
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    Liu, Yin-Nian; Sun, De-Xin; Hu, Xiao-Ning; Liu, Shu-Feng; Cao, Kai-Qin (1 June 2020). "AHSI: the Hyperspectral Imager on China's GaoFen-5 Satellite". Earth and Environmental Science. 509 (1): 012033. Bibcode:2020E&ES..509a2033L. doi:10.1088/1755-1315/509/1/012033. S2CID 225552086.
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    Hsu, Su May; Kerekes, J.P.; Berke, Hsiao-Hua; Crooks, S. (April 1999). "SAR and HSI data fusion for counter CC&D". Proceedings of the 1999 IEEE Radar Conference. Radar into the Next Millennium (Cat. No.99CH36249). pp. 218–220. doi:10.1109/NRC.1999.767320. ISBN 0-7803-4977-6. S2CID 15912558. Archived from the original on 24 October 2022. Retrieved 25 October 2022.
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    Ge, Xiangyu; Ding, Jianli; Teng, Dexiong; Xie, Boqiang; Zhang, Xianlong; Wang, Jinjie; Han, Lijing; Bao, Qingling; Wang, Jingzhe (1 August 2022). "Exploring the capability of Gaofen-5 hyperspectral data for assessing soil salinity risks". International Journal of Applied Earth Observation and Geoinformation. 112: 102969. doi:10.1016/j.jag.2022.102969. ISSN 1569-8432. S2CID 251557178.
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    Li, Xiaoying; Xu, Jian; Cheng, Tianhai; Shi, Hailiang; Zhang, Xingying; Ge, Shule; Wang, Hongmei; Zhu, Songyan; Miao, Jing; Luo, Qi (January 2019). "Monitoring Trace Gases over the Antarctic Using Atmospheric Infrared Ultraspectral Sounder Onboard GaoFen-5: Algorithm Description and First Retrieval Results of O3, H2O, and HCl". Remote Sensing. 11 (17): 1991. Bibcode:2019RemS...11.1991L. doi:10.3390/rs11171991. ISSN 2072-4292.
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    Chen, Liangfu (13 October 2016). Mission Overview GaoFen-5 (PDF). 12th Meeting of the CEOS Atmospheric Composition Virtual Constellation (PowerPoint presentation). Seoul, Korea. Archived (PDF) from the original on 23 October 2022. Retrieved 23 October 2022.
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