Why is the picture so clear in this “World Talk”?

On June 23, the first batch of astronauts Nie Haisheng, Liu Boming, and Tang Hongbo in the era of the Chinese space station ushered in a “high light moment” after they moved into the Chinese space station. At 9:35 in the morning, a world-to-earth call was staged between Beijing and 400 kilometers away in space. Many viewers who watched the real-time live broadcast were pleasantly surprised to find that not only the sound and picture were not stuttered in this world call, but the picture and sound transmitted back from the multi-camera on the China Space Station in real time were clearer than before. On the screen of the command hall of the Beijing Aerospace Flight Control Center, the three relay satellites of Tianlian-2 01, Tianlian-1 03 and 04, as well as measurement and control stations and control stations in many places around the world, such as Weinan, Xiamen, and Namibia, are marked. The Yuanwang-6 survey ship is silently providing protection for this historic moment. The new generation of “Skylink” participated in the manned space mission for the first time “Thanks to the Samsung network of relay satellites, astronauts can communicate with the ground for a longer period of time.” Zheng Yonghui, general engineer of the Beijing Space Information Transmission Center, told the Global Times reporter that in 2003, China’s first astronaut Yang Liwei When I entered space, I made several calls between the sky and the earth, but each time had a very strict time window. It is understood that in the early stage of China’s manned space project, China mainly used land-sea-based measurement and control of the world-earth communication link. Since China does not have measurement and control stations and measurement ships all over the world, spacecraft with an orbit height of 300 to 400 kilometers are affected by the curvature of the earth. The occlusion and the field of sight are affected. Only when entering the field of view of the Chinese measurement and control station (ship) can a short-term space-to-earth communication link be established within the flight arc. Said almost ignorant. In order to change this situation, China’s “Tianlian No. 1” relay satellite system project was formally established. From 2008 to 2019, there have been two generations of five “Tianlian” satellites successfully entering space, and they continue to play a high role. The advantages of orbital coverage and high-speed and large-capacity data transmission provide safe and reliable space-based measurement and control and data relay services for manned space missions. The time that astronauts can talk to the ground has been greatly increased. In 2013, the relay satellite system of the Samsung network was realized, which guarantees for the first time the world-to-earth communication between the ground and the astronauts, with clear picture quality and smooth voice… Greetings and expectations from the ground were transmitted to the sky in the first time. “This time, my country’s self-developed second-generation relay satellite’Tianlian-2′ 01 star participated in the manned space mission for the first time. With its existence, the audio and video transmission rate between the sky and the earth has been higher, and the effect of the communication between the sky and the earth is higher. The length of the talk time has been improved,” Zheng Yonghui said. The bandwidth rate of the China Space Station is better than that of the International Space Station According to the Global Times reporter, the Tianlian-2 01 satellite, which participated in the manned space mission for the first time, is my country’s second-generation relay satellite. It has a wider coverage panoramic beam, higher transmission speed and stronger multi-target support. Ability and other characteristics. After the first-generation relay network with Tianlian and the formation of a world-to-earth link, this “Skylink” system has previously become the main measurement and control communication system for the autonomous rapid rendezvous and docking of the Shenzhou 12 manned spacecraft and the core cabin. In this “space-to-earth call”, the “space base station” composed of Tianlian-1 03, 04, and Tianlian-2 01, located at an orbital altitude of 40,000 kilometers, is between the core module of the Chinese space station and the ground station. Establish a network link. Voice, video, e-mail data between the space station and the ground, as well as downlink scientific experiment data can be transmitted at high speed through this link. Yi Yusheng, chief designer of the space station system measurement, control and communication sub-system of the Fifth Academy of Aerospace Science and Technology Group, said in an interview with the media that there are more than 10 wired and wireless network cameras, mobile phones, PADs, and laptops on the space station’s core capsule. Mobile devices such as computers can be used as network terminals. These terminals connect the collected image and voice data to the in-cabin Ethernet switch through wired or wireless Wi-Fi, and then transmit it to the ground via a relay link through a high-speed communication processor. The downlink rate of this relay communication link is 1.2G, which is equivalent to the 5G communication rate on the ground. The relay satellite ground station receives space data in real time, then transmits the data to the Beijing Flight Control Center, and then automatically distributes it according to different identifiers, with a delay of only seconds. In addition, after the stable flight of the Chinese space station, the coverage rate of space and earth measurement and control can reach more than 90% through the three relay satellites and the relay antenna of the core module. After the three cabins of the space station form a combination, through the partial installation of the relay antennas of the other two experimental cabins, the measurement and control coverage can be close to 100%. The Chinese space station will no longer have any interruption in the communication between the sky and the earth when it orbits the earth in one and a half hours. Yi Yusheng added. Earlier, Bolin Hou, deputy chief designer of the China Space Station Tianhe Core Module, said in an interview with a reporter from the Global Times. The application of the latest information technology to the China Space Station is a unique advantage of the China Space Station compared to other space stations in orbit. According to Berlin Hou, the information technology currently used on the China Space Station has a bandwidth rate higher than that of the International Space Station. The concept of the Tiandi high-speed network has now been applied to the Chinese Space Station. (Source: Global Times reporter Fan Wei) Source: Global Times