Before Beidou came out, the positioning system used by China was American GPS, which restricted our country everywhere.
1993, China's "Yinhe" cargo ship was intercepted by the United States while transporting goods to Iran, and the reason given by that country was that Yinhe contained raw materials for chemical weapons. In the face of the country's unwarranted accusations, China's cargo ships naturally ignored it. However, the United States shut down GPS without consulting our country. In the end, in desperation, the galaxy was at the mercy of others. The appearance of this incident has to remind people of a war again. If China continues to use GPS navigation, the United States will shut it down at a critical moment, and the consequences will be unimaginable. Therefore, the development of Beidou satellite is necessary.
From 65438 to 0970, China began to study the technology and scheme of satellite navigation system.
1994, the construction of Beidou-1 system started.
In 2000, two geostationary orbit satellites were launched, and the system was completed and put into use. The function of time service and information transmission in China has changed from the original GPS to Beidou transmission.
In 2004, the construction of Beidou-2 system was started.
By the end of 20 12, a total of 4 networking satellites (5 geostationary orbit satellites, 5 tilted geosynchronous orbit satellites and 4 medium earth orbit satellites) had been launched. On the basis of compatibility with Beidou-1 system, Beidou-2 system adds a passive positioning system to provide positioning, speed measurement, time service and short message communication services for users in the Asia-Pacific region.
In 2009, the Beidou-3 system was started.
In 20 18, China's Beidou-3 network was completed. This indicates that from now on, the Beidou positioning system is no longer China Beidou, but the world Beidou.
In addition, Beidou satellite navigation system, together with American global positioning system, Russian GLONASS system and European Union Galileo positioning system, is a supplier recognized by the United Nations Satellite Navigation Committee.
Just a few days ago, the last networking satellite of Beidou-3 was successfully launched.