The reporter learned from the China National Defense Science and Technology Industry Bureau on the 23rd that China’s “Practice No. 13” satellite has successfully conducted the first international high-speed satellite-to-ground high-speed laser two-way communication experiment.
Satellite laser communication has the advantages of large communication capacity, long transmission distance and good confidentiality. It is an irreplaceable means of building the “spatial information highway” and is also a frontier science and technology in the current international information field.
The satellite laser communication team led by Prof. Ma Jing and Professor Tan Liying of Harbin Institute of Technology successfully completed the experiment of laser communication of the "Ocean II" low earth orbit satellite. "The trial was about 2,000 kilometers away. This time our trial link was nearly 40,000 kilometers from the ground," Ma Jing told the China News Service.
On April 12, 2017, "Practice No. 13" was successfully launched at the Xichang Satellite Launch Center. The satellite was equipped with a laser communication terminal. Up to now, Ma Jing and his satellite laser communication team have achieved a number of technological breakthroughs.
First of all, they intercepted the high-precision capture problem of the beam “needle-to-grass” between satellites and ground stations at an altitude of nearly 40,000 kilometers, effectively overcoming the influences of satellite movement, platform jitter, and complex space environment, and successfully implemented the beam. Fast signal locking and stable tracking, with an average acquisition time of 2.5 seconds and 100% tracking stability for 1 hour.
Secondly, for the first time in the world, they have achieved high-speed satellite-to-ground laser bi-directional communication with a maximum speed of 5 Gbps (1 Gbps equals 1024 megabits per second) and the first time in the world that high-altitude satellites have reached 1.25 Gbps, 2.5 Gbps, and 5 Gbps. A variety of data rates for laser communications.
Finally, they use wavelength division multiplexed laser communication technology between satellites and the ground to verify several key technologies such as high-speed laser information reception and transmission, and atmospheric impact compensation for long-distance high-speed laser communications.
Wu Yanhua, deputy director of the National Defense Science and Technology Industry Bureau of China, stated that the satellite laser communication realizes a leapfrog development in innovation and is a model for China’s aerospace science and technology independent innovation and the development of civil-military integration. The mission of this experiment has achieved the desired results and achieved a complete success. It symbolizes that China is at the forefront in the field of space high-speed information transmission, the cutting-edge field of aerospace technology, and has laid a solid foundation for the implementation of major national science and technology projects for the integrated information network of the world.
