China Ballistic Missiles and Nuclear Arms Thread


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Using ABMs to shoot down guided rockets seems like a bad idea to me. It would be pretty useful against smaller quantities of big ballistic missiles though.


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According to LI Deren, doctor at Universität Stuttgart and academician at the Chinese Academy of Engineering and the Chinese Academy of Sciences, China has already completed tests to identify moving naval targets with its satellites, to an accuracy of 10m , in less than 1 min.
Is he working in this project? If so, isnt this information confidential?


Is he working in this project? If so, isnt this information confidential?
No but he got access to the scientific paper that is available to him since he is member of Chinese academy science and participate in planning, and design of Gaofen series of satellite
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From Earth Observation Satellite to Earth Observation Brain——Interview with Li Deren, Academician of Chinese Academy of Sciences and Academician of Chinese Academy of Engineering
Original Chinese Society of Surveying and Mapping Chinese Society of Surveying and Mapping 3 days ago
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The content of this article is extracted from the 10th issue of China Surveying and Mapping, 2020

I came to Wuhan University again to interview Academician Li Deren, and I felt very cordial. I still remember that the last time was on December 30, 2018. The reporter listened to the theme report of Academician Li Deren on "Review and Prospect of the Development of Surveying, Mapping and Remote Sensing Technology in my country" in the Humanities Museum of Wuhan University. Academician Li Deren was very excited for 2 hours. Gao, speak in one breath and explain profound professional knowledge in a simple way. It is really a feast of surveying and mapping knowledge!

Recently, the "China Surveying and Mapping" magazine invited Academician Li Deren for an exclusive interview with the theme of "Earth Observation Satellite System", which made it possible. In September, Wuhan was overcast and rainy, and the temperature dropped, but perhaps I was yearning for it. I only felt that the sweet osmanthus fragrance all the way and the beautiful scenery everywhere.

Passing through the teaching area of the Department of Informatics, walking into the State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, stepped up the steps quickly, and gently stepped into the office of Academician Li Deren. His secretary told reporters that Academician Li Deren had just finished his long mission and is now Access information.

At that time, the 18th International Committee on Earth Observation Satellites (Committee on Earth Observation Satellites) will be held in China in 2004, and Minister Xu Guanhua will serve as the rotating chairman. Therefore, since 2002, on behalf of Minister Xu Guanhua, I have participated in the preparatory work of the committee. At the same time, I have worked with more than a dozen academicians to write a consultation report and recommend the development of China's high-resolution Earth observation system to the central leadership.

The central leadership approved and supported it and included it in the mid- and long-term science and technology development plan. In 2005, the Ministry of Science and Technology established an expert group to discuss and discuss the country’s medium and long-term development plans from 2006 to 2020. I was fortunate enough to participate in the high-tech group, resources and ecological environment group and national defense group, and finally formed 16 major national special projects. Among them, there are three special projects related to our surveying and mapping-high-resolution earth observation system, manned spaceflight and lunar exploration project, and Beidou global satellite navigation system.

Academician Wang Liheng of the Space Administration of the Ministry of Industry and Information Technology led me and other experts to plan a total of 14 satellites after years of research, which are what we now call high-resolution earth observation satellites, of which 1-7 are civilian satellites and 8-14 are military. satellite. These 14 stars can be said to be "military-civilian integration, complete variety", including optical and radar satellites, from geosynchronous orbit satellites to sun-synchronous orbit satellites, and basically meet the needs of China's national defense construction, economic development, and people's lives.

The spatial resolution of the optical satellite reaches 0.1m~0.5m; the resolution of the radar satellite reaches 0.5m~1m, and has full polarization data; the resolution of the two geosynchronous orbit satellites is 50m and 15m respectively; the imaging band of the hyperspectral remote sensing satellite More than 360; the ground width of the 16m resolution wide remote sensing satellite reaches 800km.

There are two surveying and mapping satellites in the Gaofen special project, one is the Gaofen-7 launched last year, and the other is the Gaofen-14. Gaofen-7 is characterized by a dual-line array three-dimensional surveying and mapping function, and a laser profile altimetry system. The Gaofen-14 satellite was built by Belarus when it was planned and is currently under construction and has not yet been launched into the sky.

Reporter: Among the 14 high-resolution satellites, radar satellites have a relatively small proportion. Are there any plans for follow-up?

Li Deren: Currently we have C-band, S-band, and X-band satellites, but no L-band satellites. We will supplement X-band radar satellites. X-band helps to ensure the accuracy of three-dimensional measurement and deformation measurement; L-band interferometric synthetic aperture radar satellites can measure the terrain and surface changes covered by vegetation. In addition, we have started a satellite plan for space infrastructure from 2020 to 2030, in which there are multiple radar satellites. This year, we have launched a multi-modal and intelligent high-resolution satellite (0.42m resolution), which is a successful case of the national infrastructure satellite after the high-score special project.

Reporter: After 15 years of development, the major special projects of high-resolution earth observation satellites can be said to be fruitful. How would you rate this achievement?

Li Deren: First, we Chinese have made our country's satellite remote sensing and its applications catch up with the world's advanced level through self-reliance and independent innovation. The best satellite in the United States is the Keyhole, which has a resolution of 0.1m. Our Gaofen 11 can also meet this standard. Second, China’s satellite data self-sufficiency rate has reached over 85%, 2005 Before 1 year, we basically bought foreign satellite data, which was expensive. When we participated in the formulation of the national medium and long-term science and technology development plan, we set the goal at that time to increase the satellite data self-sufficiency rate to more than 60%. After 15 years of hard work, the goal is now exceeded. my country's satellite data not only meets the needs of our country, It can also be exported; thirdly, the total amount of data collected by our satellite has reached about 1500PB, which is the country with the largest stock in the world. These data support the needs of my country's national defense construction, economic development, and people's livelihood. Fourth, the high-scoring special technology of Earth observation satellites has also supported a new generation of national space infrastructure plans and promoted the development of the commercial aerospace industry that began in 2014.
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From Resource No. 3 to Gaofen No. 7

Surveying and mapping satellites realize high-precision satellite surveying and mapping

Reporter: The three-dimensional surveying and mapping of the Gaofen-7 satellite is likened to "James Cameron of the aerospace industry." Could you please talk about the applications of the three-dimensional surveying and mapping in the industry and civilian fields?

Li Deren: Gaofen-7 belongs to a surveying and mapping satellite, which involves another topic one-the achievements of China's surveying and mapping satellites. The road of China’s civilian surveying and mapping satellites began on January 7, 2005. At that time, Zeng Peiyan, a member of the Political Bureau of the CPC Central Committee and Vice Premier of the State Council, inspected the State Bureau of Surveying and Mapping. Experts analyzed the development trend of international surveying and mapping in the 21st century at the forum. Suggestions: As an important department of our country, the National Bureau of Surveying and Mapping must build the country and serve the people. It must be self-reliant, have its own good data sources and cannot rely on foreign countries. my country should develop six major satellites, including surveying and mapping satellites, altimetry satellites, and gravity satellites, and it is recommended to launch a 1:50,000 surveying and mapping satellite with a resolution of about 2.5m. On the spot, Vice Premier Zeng Peiyan gave instructions to support the development of my country's surveying and mapping satellite business.

The project was completed. Academician Gong Jianya and Yang Bingxin, a satellite camera development expert of the Institute of Aerospace 508, worked together to design parameters for the satellite. We designed a three-line array camera with a front-view and rear-view resolution of 3.5m and a front-view resolution of 2.1m. The ground width is 60km and the image quantization level is 10Bit. In order to achieve fast and accurate color stereo mapping, we have added an "eye" to this camera-a multispectral camera with a resolution of 5.8m. Because the data of surveying and mapping satellites must be used for map drawing, there must be requirements for accuracy. Therefore, after solving the problem of sensors on the satellites, we also use domestic dual-frequency GPS receivers and PANDA software from Academician Liu Jingnan of Wuhan University to improve orbit determination. Accuracy. In order to further ensure accuracy, academician Gong Jianya, experts from the Fifth Academy of Aerospace Science and Technology, and PLA Information Engineering University went to the Henan Songshan Calibration Field to perform geometric calibration of on-orbit satellites. The final calibration accuracy was better than 0.3 pixels.

The high-precision design requirements and standards of the Ziyuan-3 satellite have greatly improved the speed of post-data processing. We have independently developed a large area network adjustment software based on artificial intelligence image correlation and automatic elimination of gross errors. It uses 60 computer nodes based on GPU+CPU solved it and processed the 20TB satellite data of China’s land in 7 days, generated a digital orthophoto with a precision of 3.5m and a digital surface model with a precision of 4m, and used this technology to achieve 1:1 without ground control points. 50,000 global surveying and mapping to support the construction of the "Belt and Road" and national defense needs.

Gaofen-7 inherits the advantages of Ziyuan-3. The difference is that the resolution is increased (0.7m), the camera is large, and the satellite can’t fit three “eyes” stereo cameras, so it is replaced with a dual-line array stereo camera. , Added a laser altimeter (height accuracy reaches 0.3m). The goal of Gaofen No. 7 is to produce a 1:10000 topographic map for the country.

The goal of the next generation of surveying and mapping satellites is miniaturization, light weight, and intelligence. We hope to achieve this on the Luojia-3 intelligent small satellite to be launched next year. The Luojia-3 satellite weighs only 230 kilograms, and the satellite is equipped with an area array camera, which can achieve 80% stereo mapping, 20% planar mapping and staring video imaging. In addition, this small satellite can quickly locate and search for targets and changes in orbit, and send information to the user's mobile phone within 1 minute through satellite-to-ground communication and ground 5G technology.

From Ziyuan-3 to Gaofen-7, to Luojia-3 small satellite, the development process represents the three generations of surveying and mapping satellites, and they complement and cooperate with each other.

Let’s talk about the application of three-dimensional surveying and mapping technology. The three-dimensional surveying data of Gaofen No. 7 has been successfully completed by the Shaanxi Surveying and Mapping Geographic Information Bureau. The earth is originally three-dimensional, and the three-dimensional real-life images are more realistic. This provides more realistic data for social management, economic construction, and ecological environment surveys, and its development prospects are very bright.



Li Deren: Let’s start with the characteristics of the human brain. The brain is like a super-intelligent computer, capable of storing, cognizing, analyzing, reasoning, and making decisions about the data of the five senses. For example, when you see an acquaintance, you blurt out: "Xiao Wang You seem to have lost weight recently.” This is the intelligent embodiment of the human brain. First, the brain obtains the image data of this person, and then quickly searches and compares it from the database. Which image in the database is consistent with this? What are the changes now compared to the original? In just a few milliseconds, the brain made intelligent judgments.

By analogy, the Earth observation satellite system we originally established is just a means to perceive the earth. It can only obtain data. Later, people need to reprocess the data and make decisions. A series of processes takes too long, especially when faced with an emergency. When the situation and every second counts, things can easily go wrong. I would like to cite two examples to clarify. The first one was the 2008 Wenchuan earthquake. The local remote sensing images were not obtained in time, so the epicenter was not accurate. The People's Liberation Army received an order to go to Wenchuan for disaster relief, but after going there discovered that the epicenter was actually in Beichuan Town and Yingxiu Town under Wenchuan County, and thus lost the golden 72 hours of life rescue. Disaster emergency requires us to answer questions quickly, accurately and intelligently. The second is the Chinese Navy’s mission to capture pirates in Africa. The Chinese satellite has captured the location of the pirates, but it must wait until the satellite transits to the sky over China before this data can be downloaded to the ground station for processing and interpretation. Four or five Hours passed, and the pirates were no longer there. This reflects that the current remote sensing, navigation, and communication satellite systems operate independently, with separated information, and cannot provide timely services.

These two examples enlighten us, can the earth observation satellite system become an earth observation brain? Now there are navigation satellites, remote sensing satellites, and communication satellites in the sky. Just like human eyes (remote sensing, navigation satellites) and ears (communication satellites), they integrate the communication and navigation satellites into a system to form a brain that can respond to " The data perceived by the eyes and ears are processed intelligently to provide users with the function of PNTRC-P (position) represents position, N (navigation) represents navigation route, T (time) represents time, and R (remote sense) represents remote sensing Image, status, C (communication) stands for communication, that is, this information can be sent to the receiving device in your hand-this is the process of earth observation brain.

But doing it well is not easy. There are 7 key technologies that need to be solved. I have invited academicians and experts in various fields to overcome the difficulties together——

The first one is on-orbit intelligent processing. Simply put, it is how to use artificial intelligence technology to do in-orbit intelligent processing in the sky, such as tracking and identifying targets, change detection, etc. This is my lead, and collaborative innovation through geospatial information technology The center organized a large number of young scholars to solve this problem;

The second is the integrated network communication between heaven and earth. After the data is processed in the sky, it needs to be linked to the communication satellite to transmit it back to the ground, and then use the 5G signal to transmit it on the ground. Currently, Lu Jianhua, an academician of the Chinese Academy of Sciences at Tsinghua University, is leading the research on this issue;

The third is space-based resource scheduling. Ground users have many needs. Which satellite should be used to serve them? I asked Zhang Jun, an academician of the Chinese Academy of Engineering of Beijing Institute of Technology, to solve it, because academician Zhang Jun once managed all the aircraft dispatching in China;

The fourth is space environment security, which involves many issues of space physics and network security. We invited President Dou Xiankang, academician of the Chinese Academy of Sciences of Wuhan University, to study;

The fifth is satellite-based navigation enhancement. In order to increase the Beidou satellite navigation accuracy to 0.5m, in addition to ground-based enhancement, it is necessary to use low-orbit satellites to enhance the high-orbit Beidou navigation satellite to ensure that it is impossible to establish a ground-based augmentation system. Obtain real-time high-precision navigation and positioning. At present, Academician Liu Jingnan and Director Chen Ruizhi of our laboratory are overcoming this problem;

The sixth is the space-based information intelligent terminal service. It is necessary to send information to the user's mobile phone to realize the information intelligent service. This problem is handed over to Academician Gong Jianya;

The seventh is the design and development of payload-based satellite platforms. What should the new generation of miniaturized and intelligent satellites do and how to break the original rules? For this problem, I invited researcher Zhang Qingjun of the Academy of Aerospace Science and Technology to solve it. The National Natural Science Foundation of China has a major project to support this research.



Li Deren: This work is an original and innovative problem, and we are working on it with relevant experts across the country. There are now three successful cases. The first is that we have realized the search for moving targets at sea on multiple satellites in China, with an accuracy of 10m, and then sent the compressed data to China's geostationary orbit communication satellites, landed through satellite-to-ground communications, and then used optical fibers. Or 5G will be given to users within 1 minute. The second is that on the infrared remote sensing satellite "Jilin No. 1" of Changguang Satellite Technology Co., Ltd., we use thermal infrared images to autonomously identify high-temperature forest fires, and at the same time, we can calculate the coordinates of forest fires, and then use Beidou SMS It only takes 20 seconds to transmit directly from the low-orbit satellite to the forest firefighters. It turned out that the image landed after satellite scanning, and people came to find the fire point and then reported it. It took 1 to 2 hours. Now this system has greatly improved the efficiency. The third is to use the Luojia-1 small satellite to do a low-orbit enhancement experiment of high-orbit navigation satellites. On the satellite, we installed a 2.5 kg payload, which can simultaneously receive Beidou and GPS dual-frequency signals for real-time autonomous precise orbit determination and timing, and then launch two L-band navigation signals to the ground, using these two signals To enhance the reception of ground users, the navigation accuracy is improved to 2m of the pseudo-range method. If the carrier phase method is used, the accuracy of 3cm can be achieved.

These three cases prove that our earth observation brain is completely achievable. In order to achieve this goal, we are now planning the PNTRC trilogy of earth observation brain——

The first step is to make a local (local) coverage from the South China Sea to North China. This requires about 20 remote sensing satellites and 1 to 3 geostationary orbit communication satellites to achieve a 15-minute time resolution, and a 1-minute processing time High-resolution target images and sub-meter navigation and positioning accuracy are sent to users' mobile phones and other smart terminals;

The second step is regional coverage of China and the surrounding countries along the Belt and Road. This requires about 100 remote sensing satellites. Among them, half of the remote sensing satellites are optical satellites and half are radar satellites to ensure that there are images during the day and night, plus 150 communication satellites;

The third step is global. If it is to realize global service, it is estimated that 200 remote sensing satellites and 300 communication satellites will be needed. The service index is the time resolution of 5 minutes, that is, the required image target is found within 5 minutes, the resolution and navigation accuracy reach 0.5m, and the on-orbit processing and communication time is less than 1 minute before being delivered to the user's mobile phone, opening up B2B, B2G and B2C The intelligent services of aerospace information have created trillions of output value for the country. This is the ultimate goal we are continuing to strive for.

Through the "spectrum" and the trilogy of earth observation brains, and the realization of "one-satellite multi-purpose, multi-satellite networking, multi-network integration, and intelligent service", we can realize the leap from a space power to a space power, and serve General Secretary Xi Jinping The country's precise governance and the realization of the goal of a community with a shared future for mankind, and the realization of China's two centennial goals

The one and a half hour interview went so fast!

There is a large globe on Academician Li’s desk. During the interview process, he encountered the reporter’s doubts. He stood up from time to time and used his fist like a satellite to place it above the equator of the globe, rotating the globe to explain to reporters, very grand knowledge and topics. After Academician Li's disassembly and explanation, it became clear and easy to understand, making people involuntarily immersed in the ocean of surveying and mapping. This reminded the reporter of the academicians of the School of Surveying and Mapping of Wuhan University who taught a basic course, turning the boring and unpopular "Introduction to Surveying and Mapping" into a popular news of the listening course. The students in the audience must feel the same as me!

At the end of the interview, when I walked to the gate of the Department of Information Science, I looked back and found that there were two long red banners hanging on the building of the School of Remote Sensing and Information Engineering, which were hidden from the short green laurel trees downstairs, which was really beautiful. The banner reads: Establishing aspirations and sailing in the information age to catch turtles in the five oceans, and ambition to capture the elites of remote sensing science to capture the moon in nine days. I remembered the words that Academician Li Deren said in an interview: "One person should use his own skills to do more for the country!" Surveyors dedicated to surveying, mapping and remote sensing. In the next decade, my country's satellite remote sensing business will surely reach a new level, we will wait and see!