How does the "Tianhe" in the vast sky keep in touch with the ground? Here we need to introduce a technical term-space TT&C communication. From the perspective of disassembly, it is not difficult to understand that the ground station carries out orbit measurement, telemetry and remote control and data transmission for spacecraft such as spacecraft and space station.
Astronauts need to talk to the ground, transmit pictures, and the ground station needs to position the spacecraft, adjust its attitude and send instructions, all of which are inseparable from this system. Just like the kite line, TT&C communication in space is the only connection between the spacecraft and the ground, so it is also called the "lifeline" of the spacecraft.
This "lifeline" connecting the sky and the core cabin was cast by the Tenth Research Institute of Sichuan Central Enterprise China Electronics Technology Group Corporation (hereinafter referred to as the "Tenth Institute").
Pictures of TT&C and communication research team of the 10th Research Institute of Sichuan Central Enterprise China Electronics Technology Corporation were provided by the respondents.
Well, speaking of which, everyone should not understand again. Let's first understand the development history of TT&C communication system in manned space flight.
The first generation: in the late 1990s, it was first applied to Shenzhou-1, called "Residual Carrier Measurement and Control System";
The second generation: 20 1 1 year, which was first applied to Shenzhou-8 and developed into a "spread spectrum measurement and control system", with greatly improved measurement accuracy and anti-interference performance.
If the first two generations of systems are protecting and improving the basic operation of measurement and control communication, then the third generation is the embodiment of high quality and intelligence.
According to Chai Lin, the top ten deputy chief engineers, at present, China has built the third generation of "integrated measurement and control system", which has four characteristics of "multiple reorganization, deep integration, localization and high reliability". Scientists always say one thing, so let's take it apart one by one.
system upgrade
They let the astronauts feel the care of the motherland all the time.
"multiple reorganization"
It means that the system can realize the cross combination of all links of equipment. In short, you can always "find body double next door".
TT&C communication system consists of three parts: antenna, channel and baseband. The traditional equipment is an independent system composed of "one antenna+one channel+one baseband" vertically. Its problem is that any link has gone wrong and the whole equipment can't be used. Not only the reliability of the task is low, but also a lot of resources are wasted.
In the new generation system, various equipment forms can be cross-combined and reconstructed, and the system composition is flexible and diverse. If one link fails, other components can be replaced immediately, which greatly improves the equipment utilization rate and task reliability.
"deep synthesis"
That is, integration is the core of the third generation system. As you can imagine, the connection between the ground and the space station is essentially signal transmission, just like making a phone call on the ground. It is impossible for us to build a large number of base stations and "information superhighways" in space, as we did on earth. Therefore, the TT&C communication channel of spacecraft is often narrow. Because the road is too narrow, only one car can pass at a time, that is, measurement and control, data transmission, and only one thing can be done at a time.
According to Chai Lin, the third generation system has both traditional measurement and control functions and high-speed data transmission functions. These two types of data are transmitted together, which saves channel resources very much.
More importantly, the integrated equipment has brought great convenience to the operators. "When the operator performs the measurement and control task, it is like playing with a mobile phone."
Integrated devices, such as smart phones, are "general hardware platforms with software-defined functions". In other words, a set of TT&C communication equipment can install multiple APPs, and the functions of different signal forms, working modes and technical systems can be used at the same time or in a time-sharing manner.
"domestic production"
In the new generation of measurement and control system, from software to hardware, from basic components to the whole machine and system, localization has been realized, and now the stability and reliability of domestic operating system and domestic components have been greatly improved.
"high reliability"
In the existing launch mission, all the sites except the launch site have achieved "zero guarantee".
That is, with high-level technology and remote technical support, all the equipment on the core cabin can be monitored from the ground control center, and the health status of each component can be evaluated in real time. If the equipment is found to be beyond the normal value, the astronauts will be warned and maintained in advance. If there is a fault, the expert case base will be used to diagnose the fault and the troubleshooting plan will be provided to the astronauts.
Chai Lin explained that "zero guarantee" is by no means adventurism, let alone a big nerve, but is based on a series of advanced technical means.
In addition to the aforementioned resource reorganization technology, deep integration technology and stable and reliable domestic software and hardware, there are also health management technology and remote support technology. Health management system integrates traditional fault tree, expert system and modern big data technology, and changes the mode of "onset-treatment" into the mode of "real-time physical examination to prevent problems before they happen".
Chai Lin said that the four characteristics of "multi-reorganization, deep integration, localization and high reliability" reflect the highlights of the TT&C communication system of the new generation of manned space flight from the perspective of use. In fact, from the performance point of view, the technical indicators of the new generation of equipment are much higher than before. Through efforts in recent years, TT&C coverage rate of manned space flight can reach 100% in theory and practice.
In other words, astronauts can enjoy the meticulous care of the motherland anytime and anywhere. Moreover, whether it is a critical arc or normal operation, it can ensure high-quality voice, image and Internet services between astronauts and the ground, which is no different from that on the ground.
"It can be said that the new generation of TT&C communication system for manned spaceflight is ready to open the space station era in China with its superb technical ability and perfect intimate service." Chai Lin said.
Tailor-made two systems for "Fat Five B"
Build a "bridge" for high-speed transmission
In this launch mission, "Fat Five B" contributed a lot, and behind it, it is also inseparable from the T0 console and time synchronization equipment tailored by Tianao Electronics, which is controlled by ten companies, and the ground optical transmission combination provided by ten companies.
How to ensure the smooth entry of the Long March V launch vehicle into orbit? The key depends on the T0 console.
The T0 console is used to obtain the contact signal of rocket takeoff, generate the T0 time of takeoff, and transmit the T0 time to the launch control center, command center and measurement and control system. It can be said that time T0 determines the actuarial accuracy of rocket flight trajectory and the deviation of time flight trajectory, which is the key factor for the correct control of rocket flight.
On the other hand, the time synchronization system plays the role of "setting the stage", providing standard time and frequency signals for the task development, so that all equipment can work synchronously under a unified time reference, thus realizing the time synchronization of the whole launch, measurement and control system.
In addition, the 10th Academy of Sciences also provided front-end video optical transmission equipment, back-end video optical transmission equipment, front-end RF optical transmission equipment and back-end RF optical transmission equipment for the Long March 5 rocket.
This combination of ground optical transmission sets up a "bridge" for signal transmission among single-machine comprehensive test equipment, technical position, launch position tower and rocket transponder. Long-distance optical signal transmission not only provides a high-speed channel for data transmission and processing, but also improves the safety of rocket testers.