GLONASS and Galileo systems

　　GLONASS system (GLONASS) was first developed in Soviet times, and the program was continued by Russia. Russia began to build its own global satellite navigation system in 1993. The system began operations in 2007, when only satellite positioning and navigation services were available in Russia. By 2009, its service scope had expanded to the whole world. The main services of the system include determining the coordinates and motion speed information of land, sea and air targets. However, it is used less in our country, and it may not be involved too much in the exam.

　　Galileo satellite navigation 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 the European Commission in February 1999, and the European Commission and ESA are jointly responsible. The system consists of 30 satellites with an orbital altitude of 23,616km. But so far, the Galileo system is still immature, and many satellites still need to be further laid.