It is reported that this launch is the 4th17th launch of the Long March series of launch vehicles. The biggest highlight is the record of the shortest separation interval between two satellites and three objects in the same section within 3 seconds. It can be seen that China can achieve high-precision and accurate launch in the launch vehicle mission, and the task difficulty coefficient is getting higher and higher.
The Long March II carrier rocket that completed this launch mission can be said to have contributed greatly. What is special about the completion of 4D01and 4D02 satellites in this launch mission?
Four-dimensional 0102 satellite is the main commercial agile optical satellite in China, which mainly provides commercial remote sensing data services for domestic natural resources, surveying and mapping, marine, environmental protection and other industries as well as emerging markets such as urban security and digital countryside. The four-dimensional 0 1/02 satellites are in the same state and are used for global high-precision optical imaging.
With the development of China in recent years, optical imaging remote sensing satellites have developed rapidly, but their geometric positioning accuracy is closely related to the satellite's hardware and data processing capabilities.
Since the 1990s, China has developed some key technologies, such as determining the geometric coordinates, attitude, orbit and time synchronization of satellites in orbit, and the remote sensing images of optical satellites have undergone qualitative changes. The geometric positioning and processing of optical satellites gradually get rid of the dependence on a large number of ground control points.
Why are optical satellites still related to ground control points? In fact, in the past 20 years, China has made a lot of technological breakthroughs in optical satellite technology, and achieved a breakthrough from scratch.
However, a large number of military and civilian optical satellites are closely related to ground control. According to statistics, the optical satellite with ground control can reach 2.36 meters for civilian use, and the geometric positioning accuracy is still at the level of 100 meters without ground control points.
In the end, there is still a big gap between China and foreign countries in geometric positioning, for example, it can not meet the high-precision application needs such as stereo mapping, target detection and disaster warning.
Therefore, China has increased its research and development based on high-precision attitude and orbit, time measurement technology and on-orbit geometric calibration technology. In recent years, in the field of high precision, the ground control accuracy of Ziyuan-3 surveying and mapping satellite is better than 15 m, and the internal accuracy is better than 1 pixel, reaching the international advanced level.
High-precision optical imaging satellites can support the implementation of global surveying and mapping projects without ground control, and gradually improve the theory and method of high-precision geometric processing of satellite photogrammetry. The history of China's remote sensing satellites being unable to be used for accurate mapping due to their low geometric accuracy is over.
According to statistics, as of April, 20021year, among the global satellite users, the number of commercial satellites accounted for the largest, reaching 68.27%; Followed by government satellites, accounting for11.66%; Third, military satellites, accounting for 9.26%.
In recent years, with the development of space industry in various countries, the "national teams" of space industry in various countries have encountered bottlenecks and made breakthroughs in key technical fields. Due to some factors, it cannot be widely used.
For example, in the field of manned space flight of NASA, NASA manned the moon in the 1960s and 1970s, but now it has become an astronaut who can only go to the space station by relying on the Dragon Spacecraft of Space Exploration Technology Company and the Soyuz Spacecraft of Russia.
Commercial aerospace is usually operated by commercial companies in various countries. The main reason is that the commercial aerospace industry chain is very extensive, with a large amount of funds, much time invested and abundant resources.
For example, Space Exploration Technology, an American space exploration company, not only owns the reusable launch vehicle Falcon 9, but also owns the world-famous electric car Tesla, and recently acquired the social media platform Twitter for $44 billion.
Secondly, a large number of commercial satellites fly in space for commercial purposes, collecting a large number of global data, and their data value is very high. For example, some time ago, Google opened high-definition satellite maps, and the details of Russian military deployment were all made public; The sinking of Moscow, Russia, is the guide of the satellite chain of space exploration technology company.
It can be seen that the data collected by commercial satellites plays a key role at a critical moment and can seriously threaten national security. Therefore, the importance of developing commercial high-precision optical satellites is self-evident.
In recent years, China has made a major breakthrough in the number of satellites developed and launched, laying a technical foundation for the construction of global spatial data infrastructure and the implementation of China's "going out" strategy.
However, in space, not only our satellites, but also most of them are foreign satellites. In order to prevent foreign satellites from obtaining accurate data of our country, we should strictly control our behavior, do not take photos and upload information at will, and avoid obtaining accurate data of our country with the cooperation of satellites and mobile phones.