The launch of the first artificial Earth satellite in 1957 marked the beginning of the space age, and since then mankind has begun to re-recognize the Earth, on which it depends for its own survival, from a new perspective. Space information technology is a new science and technology developed in the 1960s, and remote sensing technology, including geographic information systems and global positioning systems, is an important means of earth observation. China's remote sensing technology started in the 1970s, and after more than a decade of hard work, it has developed to the current stage of practicality and internationalization, which is specifically manifested in the practical ability to serve the construction of the national economy and the internationalization ability to carry out all-round international cooperation to make it go global.
* Providing scientific decision-making basis for the sustainable development of national economy
China's current economic development and population growth have affected the country's resources and environment to a greater extent than at any other time in history. Dynamic monitoring of national land resources is an issue that has always been emphasized by our government. China's land resources have a large area and many types, remote sensing technology in the dynamic monitoring of land resources has considerable advantages and potential market, such as, during the period of 1980-1985, China has used Landsat MSS data to carry out a nationwide survey of land resources, and according to the 1:500,000 scale into a map, macroscopically reflecting China's basic situation of the earth's resources; in 1984 by the State Land Bureau under the auspices of a nationwide survey of land resources, and the State Land Bureau to carry out a nationwide survey of land resources, and by the State Land Bureau under the auspices of a nationwide survey of land resources. In 1984, a nationwide land resources survey was carried out under the auspices of the State Land Bureau, which adopted the methods of aerial films and ground field measurements, and made maps at a scale of 1:10,000 for agricultural land, 1:50,000 for forest land and grassland, and 1:100,000 in the western region, using a combination of aerial films and Landsat data. However, due to the large regional scope, the implementation of the project has taken as long as 10 years, which shows that there is an urgent need for high spatial resolution satellite remote sensing images for the implementation of the nationwide land resources survey. It is estimated that covering the whole land area of our country needs 600 scenes of TM images, while Spot images need more than 6000 scenes, so it can be seen that remote sensing technology in our country has a considerable market, and therefore the launch of China's own resource satellites as soon as possible is a very urgent task in front of us. During the "Eighth Five-Year Plan" period, the Chinese Academy of Sciences and the Ministry of Agriculture's "National Resource and Environment Remote Sensing Macro-Survey and Dynamic Research" team completed a national resource and environment survey in the three-year period from 1992 to 1995, and established a complete resource and environment database, which is more comprehensive than the one carried out in the past for a single topic. This was a great improvement over the 5 to 10 years required to conduct a single-topic national resource and environment survey in the past. In the implementation of the project, all the latest Landsat TM images received in the 1990s were used as the main source of information, and high-resolution images from several returnable resource survey satellites launched by China in recent years were also used, and 1:250,000 scale was chosen east of the Daxing'an Mountains, Qinling Mountains, and Hengduan Mountains line, and 1:500,000 scale was used west of the line for the interpretation of remote sensing images, cartography, and the establishment of a database. The work. For this purpose, it is necessary to complete the survey, cartography and data analysis of nearly 500 panels of international standardized sectional maps of the land part of the country. In addition to the nationwide survey of land resources, major provinces and cities, such as Beijing, Tianjin, Zhejiang, Shaanxi, Inner Mongolia and many other provinces and autonomous regions have also carried out land resources survey work.
In addition, in the late 80's, the "Three North" protection forest belt comprehensive remote sensing survey and "Loess Plateau soil erosion remote sensing survey" as well as "remote sensing technology in the Tibet Autonomous Region land use status survey" and other projects are the application of remote sensing technology. and "Application of Remote Sensing Technology in the Survey of Land Use Status in Tibet Autonomous Region" are relatively significant remote sensing projects. However, from the point of view of the needs of national economic construction, large-scale projects such as the National Land Resources Survey should increase the capacity of dynamic monitoring, such as in the eastern part of the country should be surveyed once a year, and in the western part of the country once every five years. It can be seen that we are facing a very difficult task, the market for remote sensing applications is very broad.
* Ability to dynamically monitor and assess major natural disasters
China is a country where natural disasters are frequent and serious, and the losses caused by disasters amount to hundreds of billions of yuan each year. Dynamic monitoring and assessment of major disasters to reduce the losses caused by natural disasters is an important area of application of remote sensing technology.
During the Eighth Five-Year Plan period, China established a remote sensing monitoring and assessment system for major natural disasters (floods, forest fires, droughts, earthquakes, snowstorms, etc.). For floods, we have adopted multi-height and three-dimensional monitoring means, including Landsat, meteorological satellites and airborne synthetic aperture radar (SAR) remote sensing with all-weather observation capability and emergency response capability, which not only has the ability to monitor macroscopic and dynamic observation, but also enables real-time images of the disaster situation to be transmitted to the centralized command department in real time through the real-time transmission system of the machine-star-earth. Since 1987, China has carried out large-scale flood control remote sensing experiments in Yongding River, Yellow River, Yangtze River, Huaihe River and other areas. Especially in the flood monitoring and assessment work in Fujian Minjiang River, Guangdong's Xijiang and Beijiang River in 1994, and Poyang Lake, Dongting Lake and Liaohe River in 1995, the time of initial assessment and fine assessment of flood disaster has been compressed to 2 days and 2 weeks respectively. The whole technical method and process have reached the practical level. For example, in the remote sensing monitoring of the flood disaster in Taihu Lake basin in 1991, multiple time-phase NOAA satellite images, Landsat TM images and side-view radar images were used, and accurate disaster data were obtained through the composite of remote sensing information in multiple time phases.
The first discovery of the May 1987 forest fire in Daxinganling, Northeast China, was made by NOAA Meteosat images. During the period of the fire, it continuously received transit meteorological satellite and Landsat images, and provided daily information on the scope of the fire area, changes in the fire situation, the movement of the fire head position, the emergence of new fires, and the effectiveness of fire-fighting measures, etc. After the fire, in 1988 and 1989, NOAA's meteorological satellite imagery was used to monitor the fire. After the fire, in 1988 and 1989, the remote sensing survey on the restoration of the burnt traces was carried out by using the Landsat TM images, which realized the remote sensing dynamic observation on the early warning of the forest fire, dynamic monitoring during the disaster, post-disaster damage assessment and post-disaster ecological restoration survey, which was highly evaluated by the national leaders.
In addition, we have also used the combination of meteorological satellite remote sensing data and ground meteorological data to establish a drought remote sensing dynamic monitoring and evaluation system in the Huanghuaihai Plain, which provides a decision-making basis for agricultural management and rational irrigation.
In short, the number of natural disasters and the harm they cause in China is astonishing, and the effect of applying remote sensing technology for disaster mitigation is remarkable, while the potential for application is also enormous.
* Use of remote sensing technology for crop yield estimation and forestry resources survey
China is a large agricultural country, and the food problem is an issue to which our government attaches great importance. As early as in the mid-1980s, under the support of the State Economic Commission, the China Meteorological Administration (CMA) mainly organized and carried out winter wheat yield estimation experiments in 10 northern provinces and cities. This marked the beginning of the engineering application of meteorological satellites in non-meteorological fields, and it was also the first time that large-scale remote sensing was carried out for yield estimation in China. At present, the use of meteorological satellites for crop yield estimation application has been popularized and deepened, and formed a means of operationalization, the object of yield estimation is also extended from winter wheat to corn, rice and other crops.
During the Eighth Five-Year Plan period, China established an information system for estimating the yields of major crops (wheat, rice and corn) in major grain-producing areas. Among them, the large area winter wheat remote sensing estimation operation system is a product of the combination of remote sensing technology and geographic information system (GIS) technology, which will be the entire remote sensing estimation of various operational aspects into the operation of the computer system, so that the whole has the ability to digitize the operation, and can output a variety of estimation results. 1992-1995 in the Huanghuaihai region in the last three years of remote sensing estimation of winter wheat experiments have shown that the use of remote sensing technology on the The accuracy of crop yield estimation in large area can reach more than 95%, and whether it is estimated in large area or in provinces (districts), it can reach the specified accuracy index. With the accumulation of years of system operation, the accuracy of yield estimation will be gradually improved and the operation cost will be reduced year by year. At the same time, in response to the country's urgent need to understand the changes in the structure of agricultural cultivation and the requirements for cultivated area estimation, growth monitoring and yield modeling, remote sensing estimation of China's major crops has been carried out, which constitutes a practical operational system for crop estimation with the support of geographic information system (GIS) technology. In addition, other crops such as rice, corn, etc. have also been established in the Taihu Lake Plain in Jiangnan and the Sanjiang Plain in Northeast China to estimate the yield information system, and achieved very good results.
In 1995, the National Remote Sensing Center completed the Atlas of China's Agricultural Situation, which used a combination of charts and graphs to visually reflect the comprehensive level of China's agricultural development, as well as the situation and changes in grain, cotton, oilseeds, etc., and revealed the problems of arable land reduction faced by the development of agriculture, which provided scientific basis for the macro-decision-making of the Central Government and local governments. This work has been recognized by the leading comrades of the central government.
* Remote Sensing Survey of Geological and Mineral Resources
China is rich in mineral resources, and the application of remote sensing technology is very promising. The application of remote sensing technology in regional geologic mapping has been relatively mature, and achieved very good results. For example, in Inner Mongolia, Shandong, Jiangxi, Sichuan and other provinces and districts to carry out 32 1:50,000 map of the geological mapping work, the use of remote sensing technology not only improves the efficiency and quality of the mapping, but also saves the cost of filling the map, the actual cost of each map is only two thirds of the cost of the conventional method; in the Chengde area, the use of TM imagery to carry out the 1:250,000 scale regional geologic mapping, in addition to the establishment of the remote sensing stratigraphic unit in line with the 1:250,000 scale, the remote sensing of the geological map is not a good idea. In addition to the establishment of the remote sensing stratigraphic unit in accordance with the technical requirements of the 1:250,000 scale regional geological mapping unit in Chengde area, more discoveries have been made in the research of geological structure and minerals, and the cycle has been shortened greatly and funds have been saved. This will certainly play an important role in the implementation and completion of the 1:50,000 regional geological mapping of 2 million square kilometers and the nationwide 1:250,000 regional geological mapping project in this century.
In the geological and mineral resources survey, remote sensing technology in China has developed from indirect detection to direct detection stage, such as the use of fine infrared and multi-spectral scanning technology in Xinjiang Jungar directly detected the alteration zones of the rock gold ore, and made significant progress in the use of remote sensing technology to directly search for gold ore. China has also conducted remote sensing direct detection tests of oil and gas resources in Xinjiang using short-wave infrared imaging spectral scanners. The remote sensing image data were utilized to capture hydrocarbon anomalies caused by micro-seepage of oil and gas reservoirs on the surface through information enhancement and extraction, thus achieving the purpose of direct detection. The project has been confirmed in several production tests in the Tarim Basin in Xinjiang. The successful application of these technologies has played a positive role in accelerating the development of western China.
In addition, the interferometric radar technology developed in recent years has shown great potential for application in such application areas as environmental monitoring of large-scale projects such as the Three Gorges Dam and ground subsidence in oil and gas areas.
China's remote sensing technology application outlook
"Ninth Five-Year Plan" period, China's National Science and Technology Commission has been "remote sensing, geographic information systems and global positioning system technology integrated application research" as "" National Science and Technology Research Program. Ninth Five-Year Plan" national science and technology research projects, so far remote sensing information technology has been included in four consecutive five-year plan of national priority projects, indicating that the country's remote sensing cause of importance. It can be predicted that the implementation of this project can effectively apply this high and new technology to all aspects of national economic construction, and make it embark on the road of industrialization.
* Promoting the Formation of Operational Remote Sensing Information Comprehensive Service System
During the Ninth Five-Year Plan period, the focus of remote sensing scientific and technological research will be on the dynamic information service of resources and the environment, with agricultural resources as the main body. At that time, a national macro information service system will be set up, and at the same time, the remote sensing monitoring and assessment system for water and drought disasters will be put into operational operation.
(1) Establishment of a national-level remote sensing dynamic information service system for basic resources and environment
We will establish a spatial information system for the basic land resources and ecological environment on a nationwide scale, forming the ability to dynamically update the system once a year, and on the basis of which, we will provide high-level national departments with digital maps focusing on the nation's agricultural land resources, urbanization development and their dynamic changes, including 1,000,000 maps and 1,000,000,000 maps, including 1,000,000 maps and 1,000,000,000 maps. On the basis of this system, we will provide high-level national departments with digital maps of the country's agricultural land resources, urbanization development and its dynamic changes, including 1:250,000 maps and data of land resources and their ecological environment in the country's sub-regions and key regions; 1:100,000 maps and corresponding databases of the key development zones and the areas around big cities; 1:250,000 maps and databases of the dynamics of arable land and urbanization in Eastern China at a scale of 1:250,000 once a year; and a more complete database of the country's basic land resources and ecological environment. National resource hotspot issues, such as the dynamic change of arable land, urbanization, etc., will be provided with a special report once a year. According to the plan, we will establish a networked national information service system by 1999, provide corresponding resource and environmental information and auxiliary decision-making information, and ensure the continuous and stable operation of the system.
(2) Improvement of the Operational System for Monitoring and Evaluation of Major Natural Disasters
The operational and comprehensive monitoring and evaluation system focusing on the monitoring and evaluation of water and drought disasters will be completed and put into use by the relevant operational departments in 1999, so that it will have the ability to regularly release national drought conditions, and to readily monitor and evaluate the emergency response to floods and major natural disasters. The system has the following functions: for sudden floods, it provides information on the extent of inundation and the area of various types of land within two days after the system is put into operation, and within a week it provides a detailed report including information on the affected population and flooded houses; for key areas, it implements the information service of reporting on the inundated area and its size on a daily basis; at the time of a crisis, it provides a real-time display of images of the scene of the disaster and notations; and, since 1998, it has been reporting data on the national drought situation once every 10 days. Since 1998, it has been reporting drought data nationwide every 10 days, and reporting drought data on farmland in disaster-affected areas every 5 days; monitoring and providing timely information on natural disasters such as major forest fires and earthquakes, so as to minimize the losses caused by natural disasters.
* Continue to catch up with the world's leading edge of remote sensing science and technology
In the "Ninth Five-Year Plan" period in accordance with the 863 program will be increased to the construction of earth observation system tilt, in addition to continue to strengthen support for the development of star-carried SAR prototype, but also to develop the development of advanced airborne earth observation system.
Currently, ocean monitoring has been included in the 863 program, and remote sensing monitoring of ocean resources has been given high priority by our government, which is an important part of Earth observation. We will develop the early warning of marine disasters, monitoring the marine environment of the much-needed high technology, for the establishment of China's marine three-dimensional monitoring system to provide technical support to improve the environmental security capabilities of the sustainable development of the ocean, to accelerate the convergence with the global ocean observing system, and strive to the end of the century in the marine automatic observing system, hydroacoustic telemetry and ocean remote sensing technology applications in the main aspects of the mid-1990s to reach the international advanced level.
During the Ninth Five-Year Plan period, China will also support research on new technologies in the following four areas: identification of rice by high-resolution remote sensing information based on high spectral resolution remote sensing, determination of small-plot planting area and technical research on monitoring of crop growth; new radar remote sensing technology for identification of rice and cotton under cloudy weather conditions; and technical research on measurement of agricultural land area. Research on agricultural land area measurement technology; research on rapid processing, analysis and extraction technology of large data volume information of new remote sensing technology; research on fusion processing technology of remote sensing and geographic information system (GIS) based on new remote sensing information, and research on rapid generation and updating technology of GIS based on the extraction of remote sensing information.