What is GPS? What are the current global positioning systems in the world?

The Global Positioning System, also known as the Global Positioning System, is a medium-range circular orbit satellite navigation system. The system includes 24 GPS satellites in space; There is 1 main control station, 3 data injection stations, 5 monitoring stations on the ground and a GPS receiver as the user side. Only 3 of these satellites are needed to quickly determine the location and altitude of the user on the earth. The more satellites that can be connected, the more accurate the decoded position will be.

The GPS system has the following advantages:

1.The use of low-frequency signals can maintain considerable signal penetration even in bad weather.

2.Global coverage is 98 percent.

3.Three-dimensional fixed speed timing and high precision.

4.Fast, time-saving, high efficiency, wide application, multi-functional, mobile positioning.

5.Different from the dual-satellite positioning system, the receiver does not need to send any signal during use, which increases the concealment and improves the efficiency of its military application.

Global Positioning System: Timing Ranging Navigation Satellite Global Positioning System.

US Global Positioning System (GPS), Russia".GLONASSsystem, the European "Galileo" system and the Chinese "Beidou".

As of 2020, the United States has put into use 24 GPS networking satellites, and another 4 are backup satellites, so the total number of positioning system satellites in the United States has reached 28. These satellites are all medium-earth satellites, distributed on a plane at an altitude of 20,200 kilometers, and they are networked over the earth to ensure "full coverage" within the visual range of landmarks. According to official U.S. data, the current accuracy of these satellites.

At around 10 meters, the U.S. side is making technical improvements and hopes to be able to achieve an accuracy of 1 meter in the near future.

And with the help of the former Soviet Union.

The development results of the "US-Soviet rivalry" period, Russia also relied on strong confidence in the global navigation system.

Occupy a place in the battle for supremacy. In 1993, Russia collapsed with the collapse of the Soviet Union.

The cutting-edge space technology left behind after that boldly put forward the blueprint for the erection of the "GLONASS" satellite navigation system, and later, with an investment of about $3 billion, the networking of the "GLONASS" navigation system was completed in less than three years. It can be said that Russia's efficiency is quite high, but in terms of technical content, there is still a certain gap with the GPS of the United States and China's Beidou series.

In addition to Russia and the United States, the West has a satellite navigation system called "Galileo". "Galileo" does not belong to a single country, but to a large number of European countries. Because the technology, economy, and politics of European countries are relatively scattered, and no country has the ability to independently set up a satellite navigation system, so major European countries, including France and Germany, have proposed to jointly develop the "Galileo" satellite navigation system.

However, due to the improper distribution of interests among countries, the project was also unbalanced, resulting in many shelving problems.

GPS:

GPS system in the United States;

Russian GLONASS system;

China's Big Dipper system;

European Galileo System.

The Global Positioning System (GPS) is a technology that combines the development of satellites and communications, using navigation satellites for time and ranging.

The four major global positioning systems are: the United States GPS, the European Union Galileo, the Russian GLONASS, and the Chinese Beidou.

1. U.S. GPS

It was designed and developed by the U.S. Department of Defense in the early 70s of the 20th century and completed in 1993. In 1994, the United States announced that it would provide GPS access to the world free of charge for 10 years, but the United States only provided low-precision satellite signals to foreign countries. It is said that the system has a "back door" set up by the United States, and in the event of a war, the United States can turn off information services to a certain region.

2. Galileo of the European Union.

In 1999, the European Union first announced the Galileo satellite navigation system plan, the purpose of which was to get rid of Europe's dependence on the US global positioning system, break its monopoly, and form the "Galileo" satellite positioning system. The project will launch a total of 30 satellites with a position accuracy of several meters and will also be compatible with the GPS system in the United States.

3. GLONASS, Russia.

GLONASS is a satellite navigation system developed and deployed by Russia alone, which was launched in the 70s of the last century, and Russia has 22 GLONASS satellites in orbit, but only 16 are operating normally. The system requires 18 satellites to meet the needs for continued navigation services for all of Russia, and at least 24 satellites to provide global navigation services.

4. China Beidou.

At 00:34 on 25 May 2003, China successfully launched the third Beidou-1 navigation and positioning satellite into space with the Long March-3A carrier rocket at the Xichang Satellite Launch Center, and the first two Beidou-1 satellites were launched on 31 October and 21 December 2000 respectively.

1.U.S. Global Positioning System (GPS). There are 24 satellites, distributed in 6 intersection points separated by 60 degrees of the orbital plane, the accuracy is about 10 meters, military and civilian dual-use, is currently testing the second generation of satellite system; The United States "Global Positioning System" (GPS) is currently the world's most widely used and most mature navigation and positioning system.

There are currently 30 navigation satellites in the GPS space segment with 4 models. In March 1994, the deployment of the navigation "constellation" consisting of 24 satellites was completed, marking the official completion of GPS.

2.GLONASS, Russia: strong anti-jamming capabilities.

It is composed of 24 satellites, with an accuracy of about 10 meters, for military and civilian use, and the service scope is designed to be expanded to the world by the end of 2009; It is also a dual-use navigation and positioning satellite system developed and controlled by the military. Although its positioning accuracy is slightly lower than that of GPS and Galileo, its anti-interference ability is the strongest. The GLONASS project was launched by the Soviet Union in 1976.

3.European Galileo System. It consists of 30 satellites, with a positioning error of no more than 1 meter, mainly for civilian use.

The first test satellite was successfully launched in 2005. It is expected to open positioning services before 2008; The Galileo positioning system is a satellite positioning system under construction in the European Union, known as the "European version of GPS". The Galileo positioning system has launched a total of 30 satellites, of which 27 are working satellites and 3 are alternate satellites.

In addition to 30 medium-altitude circular orbit satellites, the system also has 2 ground control centers.

4.Chinese "Beidou" system. It consists of 5 geostationary orbit satellites and 30 non-geostationary orbit satellites. Positioning accuracy 10 meters. It is planned to cover China and surrounding areas around 2008, and then gradually expand to a global satellite navigation system.

The Beidou Navigation Satellite System is a global satellite navigation system that China is implementing independently developed and operated. The goal of the system construction is to build an independent, open and compatible, technologically advanced, stable and reliable Beidou satellite navigation system covering the world.

The Beidou Navigation Satellite System consists of three parts: the space segment, the ground segment and the user segment.