He led the traditional surveying and mapping of the mainland
to the fundamental change of information-based surveying, mapping and remote sensing
Pushed the continent by remote sensing powers
Leapfrog development to a remote sensing power
Facing the problem of "stuck neck" in the field of earth observation
He has accelerated to catch up with the international advanced level
Recently, the main station's "My Family and My Country"
Interview with an academician of the Chinese Academy of Sciences
Li Deren, academician of the Chinese Academy of Engineering
His doctoral dissertation
Solve the century-old problem of the world's metrology
Academician Li Deren is an internationally renowned photogrammetry and remote sensing scientist, and although he is 85 years old, he is still active in the front line of scientific research.
△ Li Deren in middle school
In 1939, Li Deren was born in a scholarly family in Tai County, Jiangsu, and had excellent grades since childhood. When he graduated from high school, he was admitted to Hubei from Jiangsu, and he was unexpectedly admitted to the Wuhan Institute of Surveying, Mapping and Cartography, which had just been established for one year, majoring in aerial photogrammetry.
△ Li Deren's transcript in middle school, Chinese, geometry, trigonometry, algebra, and geography are all five points.
In the early days of the founding of the People's Republic of China, large-scale economic construction and national defense construction urgently needed map data, and the development of surveying and mapping technology was imminent. After arduous preparation, in 1956, Wuhan Institute of Surveying and Mapping was established, and Li Deren met his mentor Wang Zhizhuo here.
In 1982, Li Deren was given the opportunity to go to the Federal Republic of Germany for exchange and study, and under the recommendation of Wang Zhizhuo, he studied under Professor Ackermann, an internationally renowned photogrammetry and remote sensing scientist.
At that time, Ackermann gave him a challenging problem in the field of aerial surveying. "The problem is to find a theory that can distinguish between accidental error, systematic error, and gross error at the same time." Li Deren responded.
The problem of error was a worldwide problem at that time, and as a visiting scholar, Li Deren only spent more than two years in Germany. However, his supervisor, Professor Ackermann, provided support to Li Deren by allowing him to sit in a chair and use three terminals at the same time, and also provided him with financial assistance.
Li Deren worked more than ten hours a day, and finally completed his doctoral thesis in German in only one year and four months. And his doctoral dissertation solved a century-old problem in the world's surveying.
Devoted to the construction of the motherland
China's remote sensing satellites are catching up with the world's advanced level
Li Deren's fate with his lover Zhu Yixuan began when he was studying and helping to occupy a seat in the library. Zhu Yixuan recalled, "He was a member of the study committee, so I was a little lazy. At that time, I asked Li Deren to help me get a seat in the library, and later found a small note in the book, and he asked me to meet at the back of the library. ”
Since then, like-minded people have come together. When Li Deren graduated from Germany, many foreign scientific research institutions extended olive branches to him. In the face of the invitation, Li Deren resolutely chose to return to China and devote himself to the construction of the motherland.
His wife, Zhu Yixuan, wrote in a letter to him at the time: "You are a cow that eats the grass of the country until you are 45 years old, why don't you produce some milk for the country and the people?" You should come back to milking now, it's time for you to contribute. ”
△ Li Deren and his wife Zhu Yixuan
After returning from Germany, Li Deren's main research area is aerial photogrammetry. After returning to China, he received an important and arduous task of mapping the border between China and a neighboring country.
Li Deren proposed to "put GPS on the plane" and used the "GPS aerial triangulation" technology to complete the boundary mapping task, and then successively completed the aerial survey and mapping of Hainan Island and Tiger Leaping Gorge on the mainland. This is the first time that the Chinese have reduced manual field survey work through the airborne GPS system, and it is also a struggle to catch up with the advanced level of international aerial surveying.
In 2008, the United States had more than 400 satellites in orbit. At that time, many developed countries in the world already had their own high-resolution earth observation satellite systems, while China could only catch up.
At that time, the mainland's core components relied on imports, and they could only buy inferior hardware, but Li Deren said: "It must be as good as others, and the hardware is insufficient and the software is supplemented!" The problem of the device is made up by computer theories and algorithms, and artificial intelligence methods, and we solve this problem. ”
In 2010, the major project of the mainland's high-resolution earth observation system was fully launched, and Li Deren served as the deputy leader of the project. With the implementation of the "high-resolution project", China's remote sensing satellite research, which is nearly 30 years later than that of Western countries, has achieved leapfrog development from "have" to "good", the satellite resolution has been increased to 0.5 meters for civilian use, and the remote sensing information service time has been shortened from several hours to 8 minutes, catching up with the world's advanced level.
Luojia-2 satellite
More than 6,000 people have turned the corner
In recent years, Li Deren has proposed that various types of satellites be networked to realize the integration of communications, navigation, and remote sensing, which is becoming a hot spot of competition for major powers. The mainland has launched the "Luojia" series of scientific research satellite missions.
In the summer of 2023, the Luojia-2 satellite played an important role in the flood control and disaster relief in Hebei Province, when the Luojia-2 satellite obtained radar images over the disaster-stricken areas in Hebei Province, observed a breach of the embankment, and helped more than 6,000 people move safely on the day of the early warning, eliminating potential safety hazards. "This is one of the advantages of radar remote sensing, all day, all-weather, can be applied at the engineering level."
Luojia-3 01 is a scientific experiment star of the "Oriental Eye" constellation project. The "Oriental Eye" constellation project will be officially launched in 2023, and Li Deren proposed a plan that by 2030, the entire constellation will have more than 200 satellites in orbit, integrated communication, navigation and remote sensing, and interconnected space-ground networks.
As a remote sensing expert, Li Deren said that after returning to China, his sense of mission was the strongest, "When I understood the gap between China and foreign countries, we had to catch up and surpass in the shortest possible time. ”
▌Source of this article: CCTV News WeChat public account (ID: cctvnewscenter) comprehensive "My Family, My Country"