are very high, and at present only a few countries have mastered the development of communication satellites and launching technology, and our country is one of them
and has successively taken three big steps in the field of communication satellite development.
The satellite's equivalent radiated power
has also been improved a lot, which has brought our
country's satellite communication and TV
rebroadcasting into a new stage
.
In radio and television broadcasting,
the domestically produced communication satellites transmitted
the 30-channel foreign broadcasts of the Central Broadcasting Station (CBN), the first and second sets of programs of the Central Television Station (CTS), and relayed programs of the CTS to the regions of Yunnan, Guizhou, Qinghai
Tibet, and Xinjiang.
This has made it possible for China's satellite communications and television broadcasting to reach a new level.
By the end of 1995, more than 8,000 domestic live routes had been opened with domestic satellites, as well as more than a dozen specialized satellite communication networks for petroleum, coal, water conservancy, electric power and other sectors
and thousands of satellite very small aperture antenna terminal (VSAT) stations.
In the past, due to the lack of information and slow scheduling, China's daily funds in transit amounted to
50 billion yuan. The application of China's communication satellites has greatly reduced the funds in transit, adding 25 billion yuan of activity to the
banks.
While Dongfanghong 2A belongs to the small-capacity communication satellites, it once made the degree of localization in the application of satellite
communication transponders to reach 2/3. the transponders they carried
accounted for 50% to 55% of the total number of transponders used in the country at that time and all of them exceeded the time limit for service
service, which greatly accelerated the speed of development of China's communication industry.
The second step of the tested and widely used
Development of medium-capacity communications satellite Dongfanghong 3 is the second step in the development of China's communications satellites.
May 12, 1997, the first Dongfanghong 3 communications satellite was launched and operated
successfully, so that China's level of communications satellites by a leap of 2O years. The satellite carries 24
C-band transponders and has a working life of eight years. Compared with the Dongfanghong No. 2A communications satellite, the number of transponders on the Dongfanghong No. 3 communications satellite has increased by five times, and the designed life span
has been extended by a factor of one, which has greatly eased the tension in China's satellite communications. The Dongfanghong-3 communication satellite adopted many new technologies at that time, such as full three-axis stabilization
technology, common platform design, and so on. Its successful development marked a new stage in China's communication
satellite technology.
Dongfanghong 3 is also China's 1st commercial satellite for the whole society.
The 24 C-band transponders on the satellite are all put into use for TV transmission, telephone,
telegraph, fax and data transmission and other communication services, of which 22 are used for public communication services in the telecommunication sector, one for temporary TV program transmission, the other one is used for half of the temporary ah TV program transmission, and the other half is used for very small aperture terminal communication. Aperture Terminal (VSAT) communications.
Public communications services, including 35,000 one-way voice paths, mainly for 23 provincial capitals
The first level of trunk communications network, but also for Xinjiang, Inner Mongolia and other remote areas and Xiamen,
Load-carrying capacity of 220-~ grams, can provide the effective load of glucose power jang in 8. watt {shu Shu
Measurement of the life of 8 years, is after a number of flight-tested Mature medium-capacity geostationary orbit a
channel satellite platform, has been used for the "China Star" series of communications satellites, Xinnuo 3 communications
satellite sky chain 1 relay satellite "Beidou" series of navigation satellites and Chang'e
lunar exploration satellites and so on. p>Lunar exploration satellites, etc. The successful development of Tianchain-1 relay satellites has not only greatly increased the coverage of China's spaceflight measurement and control network from l5% to about 50%,
but also enhanced the real-time measurement and control of spacecraft and the real-time transmission of satellite and ground data, which is of great significance in reducing the risk of spacecraft operation and improving the efficiency of ground measurement and control command and decision-making. A
Dongfanghong 3 satellite platform was introduced, realizing China's geostationary orbit communication satellite
star from spin-stabilized to three-axis stabilized leap, payload capacity significantly improve
win
Now, the more advanced technology of the Dongfanghong 3A, 3B satellite platform will also be flash
bright debut of the payload carrying capacity, power, life, etc., have been greatly improved on the basis of the Dongfanghong 3
satellite platform.
The third step of the new generation of former volume wide
Dongfanghong 4 satellite platform is China's third generation of large-scale geostationary orbit satellite public
platform, with a large output power, carrying capacity and long service life and other characteristics,
the overall performance of the satellite has reached the advanced level of international communications satellites of the same kind, so that China's communication
Plant Satellite and Applications Aplication of satelite
The development of communication satellite technology has taken the third step. The platform adopts high-efficiency gallium arsenide
solar battery wings and hydrogen-nickel battery packs; through the on-board data management system, it can automatically
control the working temperature of normal equipment on the star and carry out the management of battery charging and discharging; and it is equipped with a V-type momentum wheel control system and an on-board computer, which can provide a higher accuracy of the attitude
and orbital control. It has a payload carrying capacity of 595 kilograms and can provide
payload power of 8 kilowatts, with a design life of 15 years, and can be used for high-capacity communication satellite
satellites, live broadcasting satellites, relay satellites and mobile communication satellites, etc.
Currently, the satellite is used in a wide range of applications, such as the development and production of mobile communication satellites.
At present, three satellite satellites using the Dongfanghong 4 platform have been developed and launched, the third of which is the Venezuelan Satellite 1 communications satellite, which was launched on January 30, 2008, with a design life of 15 years and is equipped with 14 C-band, 12 Ku-band and 2 Ka-band transponders, and carries four sets of communications antennas with an output power of 7.75 kilowatts. Communication antenna, output power of 7.75
kilowatts. Compared with the first two communication satellites using the platform of Dongfanghong 4, the main technical status of Venezuela's Rila I has two changes: firstly, it is the first time to use the C-band double-grid antenna of international advanced level on the satellite researched and developed in China; and secondly, it has made significant technical improvements to the solar cell wing of the
sun battery. Venezuela has erected 1,580
antennas to receive the satellite's signals, of which 1,238 are used for school education,
88 for security defense and communications in border areas, and some are used in remote villages and towns of the states of Amazonas
Sun, Bolivar XXXI and the Amacuro Delta for telephone, Internet
services, and telemedicine, among other utilities. The Venezuelan government's goal is to set up 16,000 antennas to receive the satellite's signals over a five-year period
.
In recent years, China and Pakistan, Laos, Bolivia and other countries have signed
whole star export contracts, the export of communications satellites are used in the Dongfanghong 4 satellite platform
Taiwan, which will greatly improve the communication and broadcasting services in these countries.
At present, focusing on the work of high reliability and long service life, we are further perfecting and improving
the various performances of the Dongfanghong 4 platform, forming the finalization of the basic type as soon as possible,
and optimizing the performance of the satellites on the basis of which we will form the enhanced type of the Dongfanghong 4 satellite platform type spectrum that can satisfy a variety of demands, so as to satisfy the multiple demands of the international market. Demand