Gaofen
Gaofen (高分, meaning "high resolution") is a series of civilian high-resolution Earth observation satellites developed by China as the space-based component of the China High-resolution Earth Observation System (CHEOS), a national program focused on acquiring detailed remote sensing data for land resources, agriculture, and environmental monitoring.[1][2] The initiative began with the launch of Gaofen-1 in April 2013 from the Jiuquan Satellite Launch Center, marking China's first medium-resolution optical satellite in the CHEOS framework with a design life of eight years and capabilities for multispectral imaging in sun-synchronous orbit.[2][3] Subsequent satellites have diversified the constellation's functionalities, including Gaofen-2's sub-meter optical resolution for precise mapping, Gaofen-3's C-band synthetic aperture radar for all-weather imaging, and Gaofen-4's geosynchronous orbit for continuous regional surveillance, enabling applications in urban planning, disaster relief, ecological assessment, and resource management.[4][5][6] By 2025, over a dozen Gaofen satellites have been deployed, significantly bolstering China's autonomous Earth observation infrastructure with enhanced spatial, spectral, and temporal resolutions, though some advanced models like Gaofen-11 and Gaofen-12 incorporate microwave sensing with limited public details on specifications.[7][8][9] While primarily civilian, the high-fidelity data supports broader national priorities including infrastructure development and security, with recent launches such as Gaofen-14 in October 2025 underscoring ongoing expansions for stereo mapping and multi-purpose utility.[8][10]Program Overview
Objectives and Scope
The Gaofen program forms a core component of the China High-resolution Earth Observation System (CHEOS), which was approved by the Chinese government in 2010 to develop an autonomous capability for high-resolution remote sensing.[2] The primary objectives include achieving nationwide coverage with 2-meter resolution in optical imaging and 1-meter resolution in synthetic aperture radar (SAR) imaging, enabling detailed Earth observation independent of foreign satellite data.[11] This initiative emphasizes indigenous technological development to enhance self-reliant innovation in satellite sensors, platforms, and ground systems, addressing limitations from international export controls on advanced imaging technologies.[12] CHEOS, through the Gaofen satellites, targets applications such as resource surveying, including agriculture and mineral exploration; disaster prevention and emergency response; urban and rural planning; and environmental protection, including climate change monitoring.[5] These goals support major national demands for near-real-time data to inform policy and operational decisions, with SAR capabilities providing all-weather, day-and-night observations to complement optical systems.[13] The program's scope encompasses building a large-scale constellation of dozens of satellites across optical, SAR, hyperspectral, and other specialized types to ensure persistent global coverage, contrasting with reliance on intermittent access to overseas commercial imagery.[14] By integrating space-based assets with stratospheric airships and aerial platforms, CHEOS aims for comprehensive, high-temporal-resolution monitoring to meet civil and economic needs.Development Framework
The Gaofen program operates under the China High-resolution Earth Observation System (CHEOS), a state-led initiative coordinated by the China National Space Administration (CNSA) as the primary oversight body, with satellite development primarily handled by the China Academy of Space Technology (CAST) and technical inputs from the Chinese Academy of Sciences (CAS). This structure emphasizes centralized planning and resource allocation to align with national priorities in Earth observation.[2][3] Funding and strategic direction derive from China's Five-Year Plans, with foundational support originating in the 11th Plan (2006-2010), which prioritized advancements in space-based remote sensing infrastructure as part of broader science and technology development goals, enabling initial system design and prototyping phases. Subsequent plans, including the 12th (2011-2015) and 13th (2016-2020), expanded investments to support constellation buildup and application integration.[4][15] A key policy evolution involves the adoption of military-civil fusion (MCF), formalized as a national strategy during the 13th Five-Year Plan, which integrates civilian Gaofen assets with military requirements to streamline resource sharing, technology transfer, and rapid prototyping-to-deployment cycles without separate parallel systems. This approach, directed by the Communist Party of China, has facilitated efficient scaling by leveraging dual-use technologies, though it maintains civilian designation for international optics while enabling defense applications.[16][17] Gaofen's framework also incorporates selective international dimensions through alignment with the Belt and Road Initiative (BRI), promoting data access and cooperative projects with participating nations for applications like disaster monitoring and infrastructure mapping, yet with stringent controls on high-resolution data dissemination to preserve domestic sovereignty and strategic autonomy.[18][19]Historical Development
Inception and Early Planning
The civilian High-Definition Earth Observation Satellite (HDEOS) program, which laid the groundwork for the Gaofen series, was proposed in 2006 to enhance China's independent capabilities in high-resolution remote sensing, addressing gaps in domestic imaging technology amid reliance on foreign systems.[2] This initiative aimed to integrate space-based, near-space, and airborne platforms for improved spatial, temporal, and spectral resolution in Earth observation.[11] In May 2010, the Chinese government formally approved the China High-resolution Earth Observation System (CHEOS), encompassing the Gaofen satellites as its core orbital component, with the objective of building an autonomous system for applications in mapping, agriculture, and environmental monitoring.[3] Early planning emphasized surpassing the resolutions of international benchmarks such as NASA's Landsat series (30-meter multispectral) and France's SPOT satellites (10-meter panchromatic), targeting sub-5-meter capabilities, including 2-meter panchromatic imaging for the inaugural Gaofen-1 satellite.[2] From 2006 to 2013, pre-launch research and development prioritized indigenous sensor technologies, payload integration, and compatibility with Long March launch vehicles (such as the Long March 2D for Gaofen-1) to achieve reliable sun-synchronous orbital insertions, while navigating constraints in miniaturizing high-resolution optics and ensuring data processing infrastructure scalability.[20] These efforts were coordinated by the China Academy of Space Technology and state agencies, focusing on technological self-reliance to mitigate external dependencies in precision Earth imaging.[14]Key Milestones in Launches
The Gaofen program initiated its operational phase with the launch of Gaofen-1 on April 26, 2013, from the Jiuquan Satellite Launch Center aboard a Long March-2D rocket, marking the first satellite in China's Civil High-Resolution Earth Observation System (CHEOS).[2][21] This optical imaging satellite achieved 2-meter panchromatic and 8-meter multispectral resolution, enabling wide-area land monitoring and establishing the foundation for high-definition Earth observation capabilities.[2] Subsequent launches advanced resolution and versatility, with Gaofen-2 deployed on August 19, 2014, from Taiyuan via Long March-4B, introducing sub-meter (0.8-meter) panchromatic imaging for detailed urban and agricultural applications.[22][23] The program's diversification began in 2016 with Gaofen-3, China's inaugural civil synthetic aperture radar (SAR) satellite, launched August 10 from Jiuquan on a Long March-4C, providing all-weather, day-night imaging at 1-meter resolution in spotlight mode using C-band multi-polarization.[5][24] This was followed by Gaofen-5 on May 9, 2018, from Taiyuan aboard Long March-4C, incorporating advanced hyperspectral sensors for atmospheric and environmental monitoring with over 300 spectral bands.[25][26] The constellation expanded rapidly post-2018, incorporating additional optical, SAR, and specialized satellites to enhance revisit times and coverage; by June 2023, 37 Gaofen satellites had been launched under CHEOS, supporting persistent global observation.[2] Recent missions have focused on redundancy and advanced maneuvering, exemplified by Gaofen-14 02, a stereo-mapping satellite launched October 26, 2025, from Xichang on Long March-3B, which bolsters agile, high-precision topographic data collection for disaster response and infrastructure planning.[8][27] These developments reflect a progression from single-satellite proofs-of-concept to a robust network enabling near-real-time Earth imaging.Satellite Constellation
Optical Imaging Satellites
The Gaofen program's optical imaging satellites employ visible and near-infrared sensors to deliver high-resolution panchromatic and multispectral imagery, primarily supporting land mapping, resource surveying, and environmental monitoring over China and adjacent regions. These satellites feature pushbroom or frame cameras capable of sub-meter to multi-meter resolutions, with agile attitude control systems enabling targeted stereo pair acquisition for topographic modeling. Key examples include the Gaofen-1, Gaofen-2, Gaofen-4, Gaofen-6, and Gaofen-7 series, which collectively enhance temporal resolution through constellation coordination, achieving near-daily revisits for priority areas within China.[2][1][28] Gaofen-1, launched in April 2013, pioneered the series with a panchromatic/multispectral (PMS) camera offering 2-meter panchromatic and 8-meter multispectral resolution across a 60-kilometer swath, complemented by a wide-field view camera (WFVC) at 16-meter resolution for broader 800-kilometer coverage. Subsequent Gaofen-1 variants, including those launched in 2018, expanded the constellation to support 2-day global revisits and finer full-color imaging at 2 meters. Gaofen-2, operational since August 2014, advanced capabilities with a 0.81-meter panchromatic resolution and 3.24-meter multispectral bands (visible to near-infrared) over a 45.3-kilometer swath, facilitating precise urban and agricultural mapping.[29][2][22] Gaofen-4, deployed in December 2015 into geosynchronous orbit, provides persistent wide-area surveillance with a 50-meter visible/near-infrared resolution and 400-meter mid-wave infrared imaging, covering up to 400 by 400 kilometers per scene for real-time disaster response over eastern Asia. Gaofen-6, launched in June 2018, mirrors Gaofen-1's architecture but incorporates radiometric enhancements for improved data quality in multispectral bands, aiding in crop yield estimation and land use classification. These low-Earth orbit assets synergize with Gaofen-4's stationary vantage for hybrid coverage strategies.[30][31][32] Gaofen-7, launched in November 2019, specializes in three-line stereo imaging with forward-view panchromatic resolution better than 0.8 meters, nadir at approximately 0.65 meters, and backward views enabling digital elevation models accurate to 3 meters vertically for 1:25,000-scale mapping. Its agile pointing allows flexible baseline adjustments for stereo pairs up to 20 kilometers wide, supporting infrastructure surveying and 3D urban modeling. The integrated constellation of these optical satellites yields daily or sub-daily revisits over Chinese territory through orbital phasing and multi-satellite tasking, outperforming single-satellite cycles of 4-5 days.[33][34][28]| Satellite | Launch Date | Key Resolutions (PAN/MS) | Swath Width | Notable Features |
|---|---|---|---|---|
| Gaofen-1 | April 2013 | 2 m / 8 m | 60 km (PMS); 800 km (WFVC) | Wide-field complement for regional surveys[29] |
| Gaofen-2 | August 2014 | 0.81 m / 3.24 m | 45.3 km | High-precision panchromatic for detailed mapping[22] |
| Gaofen-4 | December 2015 | 50 m (VNIR) | 400 × 400 km | Geosynchronous for continuous regional monitoring[30] |
| Gaofen-6 | June 2018 | 2 m / 8 m | 60 km (PMS); 800 km (WFVC) | Enhanced radiometrics over Gaofen-1[32] |
| Gaofen-7 | November 2019 | <0.8 m (stereo PAN) | 20 km (stereo) | Three-line scanner for 3D terrain generation[33] |