What are the four global satellite positioning systems?

Global Positioning System (GPS) in the United States, compass system in China, GLONASS system in Russia and Galileo system in Europe.

1. Global Positioning System

GPS is the abbreviation of English Global Positioning System. The Global Positioning System (GPS) was first a project of the US military in 1958, and was put into use in 1964. In 1970s, the United States army, navy and air force jointly developed a new generation of satellite positioning system GPS. The main purpose is to provide real-time, all-weather and global navigation services for land, sea and air, and to be used for some military purposes such as intelligence gathering, nuclear explosion monitoring and emergency communication. After more than 20 years of research and experiments, it cost 30 billion dollars. By 1994, 24 GPS satellite constellations with global coverage of 98% have been deployed.

2. Beidou system

China Beidou Navigation Satellite System (BDS) is a global satellite navigation system developed by China. It is the third mature satellite navigation system after American Global Positioning System (GPS) and Russian GLONASS. Beidou satellite navigation system, American GPS, Russian GLONASS and EU Galileo are the suppliers recognized by the United Nations Satellite Navigation Committee.

Beidou satellite navigation system consists of three parts: space segment, ground segment and user segment. It can provide high-precision and high-reliability positioning, navigation and timing services for all kinds of users around the world, and has the ability of short message communication. It has initially possessed the ability of regional navigation, positioning and timing, with positioning accuracy of10m, speed measurement accuracy of 0.2m/s and timing accuracy of10ns.

Beidou navigation system has the advantages of fewer satellites, less investment, simple and cheap user equipment, etc. It can realize navigation and positioning in a certain area, communication and other purposes, and can meet the current needs of navigation and positioning of land, sea and air traffic in China. The disadvantage is that it can't cover the polar regions, the positioning accuracy near the equator is poor, and it can only be actively positioned in two dimensions, and it needs to provide user elevation data, which can't meet the requirements of highly dynamic and confidential military users, and the number of users is limited to some extent. But the most important thing is that Beidou-1 navigation system is the initial starting system of satellite guidance independently established in China.

3.GLONASS system

The system was originally developed during the Soviet era, and then Russia continued the plan. Russia began to establish its own global satellite navigation system on 1993. The system began to operate in 2007, when only Russian satellite positioning and navigation services were opened. By 2009, its service scope has been extended to the whole world. The main services of the system include determining the coordinates and moving speed information of land, sea and air targets.

GLONASS·GLONASS is the initials of Russian Global Naya Navigation Naya Sputnikovaya Sistema. On 20111/it was officially put into operation in the world. According to the data (20 1 21kloc-0/October 10) provided by the Information Center of the Russian Federal Space Agency, there are currently 24 satellites in normal operation, 3 in maintenance, 3 in standby and1in test.

4. Galileo system

Galileo satellite navigation system is a global satellite navigation and positioning system developed and established by the European Union. The plan was announced by Council of Europe in February 1999, and was jointly undertaken by Council of Europe and ESA. The system consists of 30 satellites with an orbital height of 236 16km, including 27 working satellites and 3 backup satellites. The orbit height of the satellite is about 24,000 kilometers, which lies in three orbital planes with an inclination of 56 degrees. By the end of February, 20 16, 18 working satellites have been launched, with early operational capability (EOC), and it is planned to have full operational capability (FOC) in 20 19. All 30 satellites (adjusted to 24 working satellites and 6 backup satellites) are planned to be launched in 2020.

Galileo system is the world's first civil global satellite navigation and positioning system. After it is put into operation in 2008, users all over the world will use multi-standard receivers to obtain more navigation and positioning satellite signals, which will greatly improve the accuracy of navigation and positioning invisibly, which is the direct benefit brought to users by Galileo plan. In addition, because there will be many sets of global navigation and positioning systems around the world, from the perspective of market development, there will be competition between GPS system and Galileo system, and competition will enable users to obtain more stable signals and better services.

Linkage: Galileo is an independent global multi-mode satellite positioning and navigation system in Europe, which provides high-precision and high-reliability positioning services, realizes completely non-military control and management, and can carry out global navigation and positioning functions. Galileo system can also cooperate with American GPS and Russian GLONASS. Any user can use a multi-system receiver to collect the data of each system or the combination of data of each system in the future to meet the requirements of positioning and navigation.