How many weather satellites are there? Chinese
Fengyun-1 launched two experimental satellites in batch 1, and developed two operational satellites as planned in batch 2. C star has been launched, and the second D star is scheduled to be launched in summer 21.
Fengyun-2 1 has launched two test satellites, and the second satellite was launched in June 2. The on-orbit test has been completed and the satellite is running normally. Three operational satellites were developed in batch 2 as planned, and will be connected by the second generation geostationary meteorological satellite Fengyun-4 in 21. The goal of China's meteorological satellite development is to establish a new generation of Fengyun-3 polar-orbiting meteorological satellite and a new generation of Fengyun-4 stationary meteorological satellite, and finally to establish a long-term and stable operational monitoring system for meteorological satellites.
1. development of the second generation polar-orbiting meteorological satellite Fengyun-3
(l) mission requirements of Fengyun-3
Fengyun-3 is the second generation polar-orbiting meteorological satellite in China. In the early 199s, the National Weather Service began to study the work related to the satellite construction. The project was included in the national space program in March 1993; In July, 1994, 1 batches of application requirements and satellite detection instruments were reviewed and confirmed, and the feasibility study of the overall scheme was started. In August 1996, the feasibility study report of the overall scheme was adopted to confirm the key technologies; In October 1998, the pre-research and tackling key problems of satellite technologies were basically completed, and the conditions were confirmed to enter the engineering development; In September, 2, it was officially approved by the State Council.
Fengyun-3 satellite will provide global parameters such as temperature, humidity, pressure, cloud and radiation, and realize medium-term numerical prediction; Monitoring large-scale natural disasters and ecological environment; Detecting geophysical parameters to support the study of global climate change and environmental change laws; Provide meteorological information for aviation, navigation and military affairs in any region of the world.
Fengyun-3 is an important operational application satellite in China's meteorological satellite engineering construction, which will realize global, all-weather, multi-spectral and three-dimensional quantitative remote sensing. Its construction has important strategic significance, which can shorten the gap with foreign countries and better meet the needs of China's economic construction and national defense construction.
(2) Main remote sensor and satellite technology
Fengyun-3 adopts technologies such as solar array directional tracking control and three-axis stable attitude control, and is loaded with 9 instruments including visible and infrared scanning radiometer, infrared spectrometer, microwave radiometer, medium resolution imaging spectrometer, microwave imager, ultraviolet ozone detector, earth radiation budget detector, space environment monitor and data collection system. It can realize atmospheric vertical detection and obtain global atmospheric vertical detection data; Conduct global radiation budget and ozone content observation; Carrying microwave remote sensor, the orbit test was carried out for the first time, and the demand of obtaining atmospheric water vapor content and precipitation was met through the application of microwave data. The performance of infrared spectrometer and microwave radiometer is equivalent to that of NOAA satellite.
2. development of the second-generation geostationary meteorological satellite Fengyun-4
Fengyun-4 is a new-generation geostationary meteorological satellite used by China Meteorological Bureau and General Staff Meteorological Bureau for military and civilian users. It will be designed according to the principle of "comprehensive application of military and civilian", and the needs of ocean, agriculture, forestry, water conservancy, environment and space science should be fully considered to realize comprehensive utilization. In November, 1999, the National Satellite Meteorological Center held the second expert seminar on the operational requirements of Fengyun-4, and put forward the preliminary operational requirements of Fengyun-4. It adopts a three-axis stable attitude control scheme. The main detection instruments are a 1-channel two-dimensional scanning imager, an interferometric atmospheric vertical detector, a lightning imager, a CCD camera and an earth radiation budget meter. The imaging time of the earth disk diagram is 15 minutes.
According to the development trend of the second generation geostationary meteorological satellites abroad, the emphasis is to expand the detection spectrum, strengthen three-dimensional detection, improve the resolution of time, region and spectrum, and add novel detection instruments to obtain more information.
The advantages of using three-axis stabilization control scheme for geostationary meteorological satellites are obvious, which can greatly improve the observation efficiency of satellites and is also beneficial to the development of payloads. Because of the long residence time of earth observation, the detection sensitivity of remote sensor can be improved, the ground resolution can be improved, and it is beneficial to increase observation channels and realize vertical detection of atmosphere. Because the satellite is always oriented to the ground and has the function of staring at the ground, it can realize rapid observation in a small area, increase the flexibility of observation, provide conditions for using CCD camera and lightning imager, enhance the observation ability of the satellite, and also provide the possibility for loading instruments such as microwave radiation imager.
however, the geostationary meteorological satellite adopts three-axis stable control mode, which is technically difficult and has a long development cycle. Since 1975, the United States has been studying and testing the three-axis stabilized geostationary meteorological satellite, but it was not until April 1994 that the first three-axis stabilized geostationary meteorological satellite, GOES-8 (GOES-I), was successfully launched. There were many problems in the development and in-orbit operation, such as the influence of remote sensor scanning on satellite attitude and image distortion. Image navigation registration and motion compensation technology; Because one side of the satellite is always facing the sun and the other side is always facing the sun, the temperature of the satellite is uneven, which causes the temperature gradient of the scanning mirror to be too large and the thermal deformation of the optical axis of the optical remote sensor affects the image. Especially, the temperature gradient of scanning mirror is too large, which is the direct reason for the delayed launch of GOES-I satellite.
according to the development of satellite technology in China, if Fengyun-4 satellite adopts three-axis stable control mode, all kinds of problems in the development and test of GOES-I satellite will inevitably be encountered, such as the stretching of large-size and small-mass solar sails, high-stability attitude control and flexible dynamics. The development of two-dimensional scanning imager and atmospheric vertical detector also needs to solve the corresponding technical key. Satellite configuration should meet the requirements of remote sensor installation and accuracy, and image motion compensation and pixel registration compensation should also be solved.
according to the fact that the development cycle of satellites in China is generally long, if Fengyun-4 adopts three-axis stable control mode, its development cycle may be longer. According to the plan of FY-2' s 2 batch of 3 business stars working until 21, FY-4 may not catch up with FY-2 in orbit. Therefore, it is necessary to speed up the pre-research and project establishment of Fengyun-4. It took 15 years for the United States to develop the GOES-I satellite. The reason is that American experts believe that the steps are too big. According to the technical ability of China's satellite development, we can gradually increase the types of remote sensors and the functions of satellites, and finally make Fengyun-4 satellite reach or approach the advanced level of foreign geostationary meteorological satellites. Foreign experts also suggested that space-borne instruments can be developed gradually, including three-axis stabilization and imager, and then vertical detectors after success.
esa has done a lot of research and analysis in developing the second generation European meteorological satellite. Since 1987, ESA has worked out a plan for a new generation of European geostationary meteorological satellites. After a long period of investigation and comprehensive analysis, in view of the fact that the application of vertical atmospheric detection is still immature, it decided to continue to adopt the spin stabilization control scheme and only install a high-performance imager to expand the functions of the imager. The time resolution and ground resolution of the imager are better than those of GOES-8, with ***12 channels, of which 2 channels are used for vertical detection test, which is considered to meet the needs of meteorological departments in European countries. Due to the sufficient analysis, the development cycle of the satellite is shortened, the cost is reduced, and the business management of the satellite is simplified accordingly.
after more than 2 years of construction, China's meteorological satellites have established polar orbit and stationary meteorological satellite series, including corresponding ground application systems, and have achieved initial results, which will usher in new development in the next 1 years. The establishment and operation of a meteorological satellite operational monitoring system consisting of a new generation of polar-orbiting meteorological satellites and a new generation of geostationary meteorological satellites will not only provide an important tool for China's weather forecast, meteorological science and environmental remote sensing scientific research, but also provide an important satellite system for the international meteorological satellite observation network, which has attracted the attention of the World Meteorological Organization and other countries in the world and played an important role in international meteorological cooperation. China's meteorological satellites will make important contributions to the national economy and national defense construction and global meteorological observation, and become one of the most remarkable series of Earth observation satellites in China.