By Ji Jing
After traveling for a week, the final satellite in the BeiDou family reached its intended geostationary orbit on June 30. The 55th one in the constellation, it finally completed the BeiDou Navigation Satellite System (BDS).
The satellite’s payloads and other systems are working normally, the China Aerospace Science and Technology Corporation announced on that day.
The launch on June 23 was watched keenly by people at home and abroad. The UN Office for Outer Space Affairs (UNOOSA) extended congratulations to China on the completion of the BDS constellation.
“Today, we mark the end of a long journey. Initiated in 1994, the BeiDou program has been over 25 years in the making. This result is only possible with a long-standing and sustained commitment to space,” Simonetta Di Pippo, Director of UNOOSA, said.
She called the launch a “historic milestone” and “a significant step toward increasing the availability of precise geolocation services through global navigation satellite systems for people all over the world.”
BeiDou is the Chinese name for the group of seven stars known as the Big Dipper, located in the Ursa Major constellation. In ancient China, people used to navigate following the Big Dipper.
Besides the United States’ GPS or Global Positioning System, Russia’s GLONASS and the European Union’s Galileo, the BDS is the fourth global navigation network in the billion-dollar market for geolocation services. It is the first global navigation system from Asia.
Three-step strategy
The achievement has been made thanks to the efforts of generations of Chinese scientists for decades. Hundreds of thousands of Chinese scientists, engineers and technicians from research institutes, universities and enterprises have been involved in BeiDou’s development.
The roots of the system stretch back to the 1960s and 1970s when China started a project named the Lighthouse Plan to develop satellites for positioning and navigation. However, despite research and experiments, it did not come to fruition. At least four satellites are needed to provide precise geopositioning and China’s economic power and technological strength at that time were insufficient to develop a satellite navigation system of its own.
In 1983, space scientist Chen Fangyun proposed to develop a navigation satellite system with only two satellites and after strenuous theoretical and technological research, the blueprint for a two-satellite navigation system became clear. In the beginning, there were doubts whether it was necessary for China to build its own navigation satellite system. However, the need to lessen dependence on foreign navigation systems became urgent with the consideration that foreign countries providing the services can bar China or any other country from their signals any time if anything untoward happens. To better safeguard China’s national sovereignty, security and development interests, it needed to develop its own satellite navigation system.
There were also debates on whether China should build a global navigation system or a regional one. Sun Jiadong, chief designer of the first Chinese satellite, proposed a phased approach: developing regional service capacities first and then extending the services globally.
In 1994, the BDS-1 system began to be developed. Between October 31 and December 21, 2000, two BeiDou navigation satellites were launched, making China the third country in the world to have its own satellite navigation system, following the U.S. and Russia.
The BDS-1 had a unique feature—its short message communication service, which the others lacked. However, it was still not as effective as the others since it covered only China and surrounding areas. Also, as its orbit was higher than the GPS’, its positioning was not as accurate. Therefore in 2004 work started on an upgraded version.
For the BDS-2, the developers planned to import a core component—an atomic clock—from abroad. However, the attempt failed due to a technological blockade. Yang Changfeng, chief designer of the BDS, told Beijing-based People’s Daily that the BDS-2 project had already started and without the core component, the whole system and the project would fail. So the team started developing an atomic clock on their own and it was ready in two years.
Another problem arose. The most suitable radio frequencies for satellite navigation had already been bagged by the U.S. and Russia. China was assigned one by the International Telecommunication Union (ITU) on April 17, 2000 but with a string attached. The ITU stipulated that China would have to send a satellite into space within seven years to use the frequency.
– The Daily Mail-Beijing Reviews News exchange item
