China Earth Observation Systems

The PRC has been actively pursuing Earth observation space systems for more than twenty years. Two models of LEO recoverable Earth observation satellites were in use and a sun-synchronous meteorological satellite system was tested. China also receives LANDSAT-5, Japanese JRS-1, French SPOT, European Union ERS 1 and 2, and Canadian remote-sensing satellite data. China has developed the Fengyun (Wind and Cloud), Haiyang (Ocean), Ziyuan (Resources), Yaogan (Remote-Sensing) and Tianhui (Space Mapping) satellite series, plus a constellation of small satellites for environmental and disaster monitoring and forecasting.

China Meteorological Administration (CMA) is operating FENGYUN (or FY for acronym = Wind and Cloud) geostationary and polar-orbiting satellite systems. Currently, six FY satellites are on-orbit with well performance, including four geostationary meteorological satellites and two polar orbiting meteorological satellites. FY satellites take place in series. The odd number series are the polar-orbiting, while the even number series are the geostationary. The capital letter after the serial number refers to the seat of a particular satellite in the launching sequence.

Fengyun satellites are now capable of global, three-dimensional and multispectral quantitative observation. The Fengyun-2 geostationary Earth orbit (GEO) meteorological satellite succeeded in double satellite observation and in-orbit backup; while the Fengyun-3 polar orbit meteorological satellite succeeded in networking observation of morning and afternoon satellites. Ocean water color satellites have obtained their images of doubled width and their revisiting period reduced.

In 2008 China announced plans to launch 22 meteorological satellites by 2020, including four more from the FY-2 series, 12 from the FY-3 series and six from FY-4 series. The satellite meteorological system had established through the combination of self-development and technology introduction. At the very beginning China received and used foreign meteorological satellite data. Then China established the meteorological satellite data receiving system. The system provides effective services for weather forecast, and flood and water logging monitoring.

The FY-1A was equipped with two multi spectral scanning radiometers with 5 frequency channels. The FY-1B was equipped with two multi spectral scanning radiometers with 10 frequency channels. The attitude control of these two satellites is the three-axis stabilization and direction to earth. The FY-2 satellite was equipped with a multi spectral scanning radiometer with 3 frequency channels. It uses the double spin stabilization control system.

The satellite resources system, just like the satellite meteorological system, had played effective role in resources exploration, environment monitor, land management and planning, land use and survey, crops, yield estimation, geological prospecting and serious disaster estimation, etc.

In 1975 China successfully launched and recovered its first recoverable remote-sensing satellite. Then China became the 3rd country to have successfully developed satellite recoverable technology after the U.S and the former Soviet Union. Now China launched 20 FSW recoverable remote sensing satellites into orbit.

In 1985 and 1986, China respectively launched two land survey satellites which obtained large number of remote-sensed pictures and achieved good results in application. This marks that China can use space remote sensing technology to serve the land management and construction of national economy. The CBERS was successfully launched on October 14,1999, which indicates that the development of our remote sensing satellites has reached a new level.

In 1988 and 1990 China launched its first generation of experimental polar orbit meteorological satellites, the FY-1A and FY-1B, which provided valuable experiences for the development and operation of the next generation meteorological satellites. In 1997 China successfully launched the FY-2 geo-stationary orbit meteorological satellite. The function of our meteorological satellite has approached the world level of the early 1990s.

On May 10, 1999, China launched the SJ-5 satellite successfully, indicating that China has reached the advanced world level in small satellite technology. In addition, China has laid certain foundation in the key technology necessary for the development of the oceanic observation satellite system.

China established radiometric calibration sites for remote sensing satellites in 1998. These calibration sites are open to international meteorological satellite operators and will make potential contributions to future polar-orbiting observation system. Dun-Huang calibration site is for absolute radiometric calibration for visible, near IR and short wave IR band. It is located in the southwest of Gan Su Province (to the west of Dun Huang City), 40.1N, 94.3E. The size of calibration field is 30km×40km. Qing Hai Lake site is for absolute radiometric calibration for thermal IR band and the absolute radiometric calibration of low reflectance target in visible and near IR band. It is located in the northeast of Qing Hai Lake of Qing Hai Province, 37N, 100E. The size is 4685 km2. Simultaneous observation at/over the two sites in 1999 and 2000 were finished. The results are used in FY satellite data.

The first Haiyang dynamics environmental satellite launched in August, 2011 is capable of all-weather and full-time microwave observation. The Ziyuan satellite series have seen their spatial resolution and image quality greatly enhanced. The small satellites for environmental and disaster monitoring and forecasting are now capable of disaster monitoring with medium-resolution, wide-coverage and high-revisit rate disaster monitoring. In 2010, China formally initiated the development of an important special project - a high-resolution Earth observation system.

The fields and scope in which Earth observation satellites are used have been constantly expanding; these satellites' capabilities in providing business services have also been growing and an Earth observation satellite application system has initially taken shape. China has built four new satellite data-receiving stations, enhancing its ability to receive data from meteorological, ocean and land observation satellites. China has also established, based on comprehensive planning, the ground data processing system for Earth observation satellites, extending its ability in centralized data processing, data archiving, data distribution and services provision. China has established centers for environmental satellite application, satellite disaster-relief application, satellite mapping application and other application institutes for Earth observation satellites, promoting the spread and utility of Earth observation satellite data. China has improved calibration services of remote-sensing satellite radiation calibration fields, enhancing the quantitative application level of Earth observation satellites.

Earth observation satellite data has been widely used in various fields for economic and social development. Fengyun satellites have effectively monitored typhoons, floods, forest and grassland fires, droughts, sandstorms and other natural disasters; their weather forecasting and climate change monitoring capabilities have also been enhanced remarkably. The ocean satellite series have monitored China's maritime territory and the world's key waters, and their forecasting accuracy for sea ice, ocean temperatures and wind fields have increased greatly, and their time efficiency in monitoring dangerous sea conditions has also been notably enhanced.

The resource satellite series have played an important role in efforts to investigate, monitor and manage the resources of land, minerals, agriculture, forestry, and water conservancy, as well as geological disasters and city planning. Remote-sensing and Tianhui satellites have played an important role in scientific experiments, land censuses, mapping and other fields. The small satellites for environmental and disaster monitoring and forecasting have provided critical technical support for surface water quality and atmospheric environmental monitoring, major pollution events addressing, and major natural disaster monitoring, assessment and relief.

During the priod 2011-2016 China planned to improve its present meteorological, oceanic, and resource satellite series and its small satellites constellation for environmental and disaster monitoring and forecasting. It aims at developing and launching new-generation GEO meteorological satellites, stereo mapping satellites, radar satellites for environment and disaster monitoring, electromagnetic monitoring test satellites, and other new-type Earth observation satellites. It will work to make breakthroughs in key technologies for interferometric synthetic-aperture radar and gravitational field measurement satellites. It will initiate a high-resolution Earth observation system as an important scientific and technological project and establish on the whole a stable all-weather, 24-hour, multi-spectral, various-resolution Earth observation system.

China will improve its ground facilities for receiving, processing, distributing and applying satellite data, and will strengthen the development of calibration fields and other facilities. It will improve the sharing and comprehensive application of data retrieved from Earth observation satellites, make more self-obtained space data, and guide social resources to actively develop market-oriented data application services. It will implement application demonstration projects, and promote the wide utilization and industrialization of Earth observation satellites.

China will put 14 more meteorological satellites into orbit over the next decade, according to a conference on 04 Juy 2016. By 2025, China plans to launch one Fengyun-II satellite, four Fengyun-IIIs, three Fengyun-IVs and another 6 for multiple meteorological purposes, Wu Yanhua, deputy head of the State Administration of Science, Technology and Industry for National Defence, said at a seminar on Fengyun satellite development. Fengyun satellites are a series of remote-sensing meteorological satellites developed by China. The Fengyun series is an important part of the earth observation satellite system. China had launched 14 Fengyun satellites since 1988, with seven still in orbit as part of the World Meteorological Organization network.

On December 14, 2021, it was learned from the China Meteorological Administration: Up to now, the global user "circle of friends" of the China Fengyun meteorological satellite family has increased to 121 countries and regions, including 85 countries and regions along the "Belt and Road" and 92 countries around the world. More than 1,400 trainees from various countries and regions have received relevant technical training. The Fengyun Meteorological Satellite family provides free data to users at home and abroad in real time, and has played an important role in weather forecasting, natural disaster response, and ecological environment governance for these countries and regions and the world.