How many weather satellites are there? Chinese

Development Planning and Mission Requirements of China's New Generation Meteorological Satellite

Fengyun-1 0 1 launched two experimental stars, 02 developed two operational stars as planned, and C star has been launched. The second D star is planned to be launched in the summer of 200 1 year.

Fengyun-2 0 1 has launched two experimental satellites, and the second satellite was launched in June 2000. The on-orbit test has been completed and the satellite is running normally. According to the plan, three operational satellites will be developed in 02 batches, working until 20 10, and connected by the second generation geostationary meteorological satellite Fengyun-4. The development goal of China Meteorological Satellite is to establish a new generation of Fengyun-3 polar orbit meteorological satellite and a new generation of Fengyun-4 stationary meteorological satellite, and finally to build a long-term and stable meteorological satellite monitoring system.

1. Development of the second generation polar-orbiting meteorological satellite Fengyun-3

(l) Mission requirements of FY-3

Fengyun-3 satellite is the second generation polar-orbiting meteorological satellite in China. In the early 1990s, the National Weather Service began to study the related work of satellite construction. Project1993 was included in the national space plan in March; 1July, 1994, the use requirements of 0 1 batch and satellite detection instruments were reviewed and confirmed, and the feasibility study of the overall scheme was initiated. 1In August 1996, the feasibility study report of the overall scheme was adopted to determine the key technologies; 1998 10 basically completed the pre-research and key research of satellite key technologies, and confirmed that it has the conditions to enter the engineering development; In September 2000, it was officially approved by the State Council.

Fengyun-3 satellite will provide global parameters such as temperature, humidity, air pressure, cloud and radiation to 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 part 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 sensors and satellite technologies

Fengyun-3 is equipped with nine 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 on-orbit test was carried out for the first time. Through the application of microwave data, the demand for obtaining atmospheric water vapor content and precipitation was met. The performance of infrared spectrometer and microwave radiometer is equivalent to NOAA satellite.

2. Development of the second generation geostationary meteorological satellite Fengyun-4.

Fengyun-4 is a new generation of geostationary meteorological satellite used by China Meteorological Bureau and General Staff Meteorological Bureau for military and civilian users. The design will be carried out in accordance with the principle of "comprehensive application of military and civilian", and the needs of ocean, agriculture, forestry, water conservancy, environment and space science will be fully considered to realize comprehensive utilization. 1999165438+10. In October, the National Satellite Meteorological Center held the second expert seminar on the operation requirements of Fengyun-4, and put forward the preliminary operation requirements of Fengyun-4. It adopts a three-axis stable attitude control scheme. The main detection instruments are 10 channel two-dimensional scanning imager, interferometric atmospheric vertical detector, lightning imager, CCD camera and earth radiation budget meter. The imaging time of the earth disk map is 15 minutes.

From the development trend of the second generation geostationary meteorological satellites abroad, the key points are to expand the detection spectrum, strengthen stereo detection, improve the resolution of time, region and spectrum, and add novel detection instruments to obtain more information.

The three-axis stability control scheme for geostationary meteorological satellite has obvious advantages, which can greatly improve the observation efficiency of the satellite and is also conducive to the development of payload. 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 always faces 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 cameras and lightning imagers, enhance the observation ability of satellites, and make it possible to load instruments such as microwave radiation imagers.

The geostationary meteorological satellite adopts three-axis stable control mode, which is technically difficult and has a long development cycle. The United States began to research and test the three-axis stabilized geostationary meteorological satellite from 1975, but it was not until 1994 that the first three-axis stabilized geostationary meteorological satellite GOES-8 (GOES-I) was successfully launched, and many problems were encountered 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 leads to the excessive temperature gradient of the scanning mirror and the thermal deformation of the optical axis of the optical remote sensor, which 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 FY-4 satellite adopts three-axis stable control mode, then various problems will inevitably be encountered in the development and test of GOES-I satellite, such as the deployment of large-size and small-mass solar sails, high-stability attitude control, flexible dynamics and so on. 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 long development cycle of satellites in China, if FY-4 adopts three-axis stable control mode, its development cycle may be longer. According to the plan that Fengyun-2 02 batch of three business stars will work until 20 10, Fengyun-4 may not catch up with Fengyun-2 in orbit. Therefore, it is necessary to speed up the pre-research and project establishment of Fengyun-4. It took the United States 15 years to develop the GOES-I satellite. The reason is that American experts think 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 suggest that space-borne instruments, including three-axis stabilization and imager, can be gradually developed, and then vertical detectors can be developed after success.

ESA has done a lot of research and analysis on the development of the second generation European meteorological satellite. ESA began to formulate a new generation European geostationary meteorological satellite program from 1987. After a long period of investigation and comprehensive analysis, in view of the immature application of vertical atmosphere detection, we decided to continue to adopt the spin stability 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 GOES-8 and *** 12 channels, two of which are used for vertical detection and testing, and are considered to meet the requirements of meteorological departments in European countries. Due to 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 20 years of construction, China's meteorological satellites have established polar orbit and geostationary meteorological satellite series, including corresponding ground application systems, and achieved initial results, which will usher in new development in the next 10 year. 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 Meteorological Satellite will make an important contribution to national economy and national defense construction and global meteorological observation, and become one of the most striking series of Earth observation satellites in China.