In September 2022, Huawei and Apple successively released
the Huawei Mate 50 series and the iPhone 14 series of smartphones. The
satellite communication functions of the two have become a hot spot in the
technology field.
Satellite communication system refers to a system
composed of multiple satellites that can process real-time information, among
which low-orbit satellites can be used for mobile phone communication. The
orbit height of low-orbit satellites is concentrated at 1000-1500km. The low orbit
height makes the transmission delay between the ground and the satellite short,
and the path loss is small. It is suitable as an efficient communication and
interconnection tool. However, due to the low altitude, a single low-orbit
satellite The coverage area is small, and a large number of satellites are
required to form a constellation system to achieve global coverage.
The embryonic form of civil satellite communication
Lai Haiguang, CTO of Konwei Communication, pointed out
that Huawei Mate5 uses the Beidou constellation, and the iPhone 14 uses the
Globalstar satellite constellation. The difference between the two is that the
Beidou constellation is a mixed constellation system of medium orbit and
synchronous orbit. Its main function is navigation and has the ability to
transmit short messages. The satellite constellation of Globalstar is a low
orbit constellation, which is specially used for voice and low-speed data
transmission
From the past to the present, satellite communication has been
an emergency communication method in special scenarios. In the past, if you
wanted to realize satellite communication, the equipment you needed to use was
a satellite phone that was expensive. Now it has been replaced by a smart phone
with more functions, and the price has not been increased because of the
addition of this function. It seems to be an "itch upgrade".
But in the future, the capability of satellite
communication is far more than just sending emergency information. In addition
to text messages, phone calls, and satellite communication, it can also realize
the function of surfing the Internet, and it is likely to develop into a very
important communication method.
Heaven and Earth complement each other
The advantage of the traditional communication method
through the base station mainly lies in the speed. Through the optical cable
connection, high-speed communication of up to 20Gbps can theoretically be
achieved. However, the problem is that the construction cost is relatively
high, and each 5G base station can only cover a small area. Many third world
countries cannot afford the cost of infrastructure construction. According to
the "Global Development Report" issued by the China International
Development Knowledge Center, as of Some 38% of the world's population, or 2.9
billion people, will still be without internet access by the end of 2021.
Satellite communication is mainly wireless signal
transmission by low-orbit communication satellites. The current maximum speed
is about 0.3Gbps, which is far behind 5G. However, the advantage is that there
is no need for infrastructure such as base stations and optical cables on the
ground, and it can cover a wider area.
This also means that base station communication and
satellite communication, covering speed and breadth respectively, just
complement each other.
At present, the main factor restricting the development of
satellite communication is the unit cost of satellite launch, of which the
thrust ratio of the rocket and whether it is recyclable are the most important
determinants. The launch cost per kilogram of the European Ariane-5 carrier
rocket is about 10,313 US dollars, the Russian main carrier rocket is 7,246 US
dollars per kilogram, and the Kuaizhou 11 carrier rocket under China Aerospace
Science and Industry Corporation is launched per kilogram The price is about
$5000. The U.S. Falcon 9 rocket currently costs $2,700 to launch due to its
recyclable design.
At present, the Starlink company of Tesla founder Musk
plans to launch a total of 42,000 satellites for the Starlink system. As of
January 1, 2022, more than 1,400 Starlink satellites have been launched, while
the total number of satellites in orbit in China is 499 pieces.
At present, China is stepping up its deployment of the
satellite communication industry. In September 2020, a Chinese company
code-named "GW" submitted a spectrum allocation file to the
International Telecommunication Union (ITU). The total number of satellites
launched by the Exposure Program in the archives reached 12,992. On April 29,
2021, China Satellite Network Group Co., Ltd. was officially established in
Xiong'an. At this time, the outside world was able to confirm that "GW"
is the code name of "State Grid".
It should be pointed out that due to the limited capacity
of satellites in low-Earth orbit, the scientific community generally believes
that there are about 60,000 satellites. The International Telecommunication
Union (ITU) implements a "first-come, first-served" system for
satellite orbit allocation. Therefore, if both China and the United States
complete satellite launches as planned, most of the Earth's low-Earth orbit
will be occupied by the two countries.
In terms of satellite manufacturing, my country already
has the capability of mass production at low cost. On January 19, my country's
Galaxy Aerospace self-developed 6 low-orbit broadband communication satellites
rolled off the production line for satellite R&D. my country's first
low-cost mass development and production of satellites.
The future of the sky, more than communication
On June 6, 2021, the "6G Overall Vision and
Potential Key Technologies" released by the China Academy of Information
and Communications Technology pointed out that 6G will achieve global seamless
coverage of air-space-ground integration, and the satellite-ground integration
networking technology will become the 6G network. One of the most important
potential technologies. Base station communication and satellite communication
will jointly form my country's future communication network.
In the aspect of car networking, satellite communication
will also play a certain role. With the continuous improvement of the level of
automatic driving, the high-precision positioning provided by low-orbit
satellites can assist the image recognition system to clearly identify
reference objects such as guardrails, trees, elevated roads, and road edges,
improve the vehicle's environmental perception ability, and then improve the
automatic driving ability.
With the development of the satellite communication
industry, it will also drive the surrounding aerospace technology. For example,
the recoverable rocket technology used to launch communication satellites is
generally optimistic by the outside world. By reducing the cost of space
transportation, industries such as high-precision metal processing and
biopharmaceuticals can achieve production in a gravity-free environment at a
lower cost in the future. Perhaps the fourth industrial revolution will be
driven by the ability of humans to enter space for production operations at a
lower cost.
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