China News Service, Beijing, May 10th (Ma Shuisha and Wang Xixi) On May 10th, the Tianzhou-4 cargo spacecraft was successfully launched and docked with the Tianhe core module of the space station, becoming the first visitor to the Chinese space station in 2022. Provide a "delivery" service for it.

In this mission, the relay terminal and antenna network developed by the Xi'an Branch of the Fifth Academy of China Aerospace Science and Technology Corporation escorted Tianzhou-4 throughout its expedition.

 Relay Terminal: Building a "Space Road" for Tianzhou-4

  Before the Tianzhou-4 cargo spacecraft, China has successfully launched three cargo spacecraft and conducted on-orbit verification.

After the Tianzhou-4 cargo spacecraft launched this time entered space, the relay terminal was turned on at the first time.

Subsequently, the relay terminal and the Tianlian relay satellite achieved a "space handshake" to establish an inter-satellite link, thus building a "space sky road" from the Tianzhou-4 relay terminal to the relay satellite to the ground.

  The ground measurement and control personnel mainly use the space-based measurement and control system to implement on-orbit flight control of Tianzhou-4, control the attitude of the spacecraft through ground telemetry and remote control, and establish communication with the ground to realize the flight control of Tianzhou-4 cargo spacecraft. "Remote Driving".

After the Tianzhou-4 cargo spacecraft entered the predetermined orbit, it rendezvous and docked with the Tianhe core module of the space station in space.

  The space-based measurement and control communication system built by the relay terminal can realize the "remote driving" of Tianzhou-3, Tianzhou-4 and the Tianhe core module of the space station at the same time, and conduct communication measurement and control of the entire aircraft at the same time. The link can transmit data such as rendezvous and docking pictures to the ground in real time, and provide a communication link guarantee for the whole process of space rendezvous and docking between Tianzhou-4 and the Tianhe core module of the space station.

  It sounds simple to realize the remote control of Tianzhou-4 by building a "space sky road", but it not only needs to span nearly 400 kilometers, but also needs to complete the rapid construction in less than an hour, and it is necessary to ensure the stability of the whole process. Operation, the complexity of the system can be imagined.

  The space-based measurement and control communication system composed of Tianzhou-4 relay terminal and relay satellite is the key to realize "remote driving".

After the completion of the system, the monitoring and control coverage of the Tianzhou-4 cargo spacecraft on the ground has been increased by more than 90%, ensuring that Tianzhou-4 can maintain real-time communication with the ground most of the time.

 Antenna Network: Signal Repeater Connecting Heaven and Earth

  In order to complete the "delivery" service, find the "Space Home" at one time and complete the docking, Tianzhou-4 must establish contact with the ground, build various command and communication signal channels, and under the accurate guidance of the ground measurement and control station, communicate with the "Meet" the space station day and the core module.

  The Xi'an Branch of the Fifth Academy of Aerospace Science and Technology Group has established a high-speed and unobstructed command and feedback information channel for Tianzhou-4 by providing a dedicated measurement and control and communication signal transmission channel to ensure the smooth completion of the mission. .

  The antenna network is a small signal repeater on the spacecraft, but it is the key product connecting the transponder and the antenna in the measurement, control and communication subsystem.

When Tianzhou-4 receives the ground communication signal or measurement and control command signal, the antenna network will classify and sub-channel transmit it to the transponder.

Conversely, various signals from different channels of the transponder will be aggregated and sent to the ground antenna, and then sent to the ground through the antenna.

  In this mission, Tianzhou-4 mainly implements on-orbit flight control with space-based measurement and control, and the antenna network mainly completes the upload and release of spacecraft measurement and control command signals to ensure "precise delivery" of Tianzhou-4.

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