As we all know, the global satellite navigation system plays an important role in modern society, providing people with accurate positioning and navigation services, helping the rapid development of modern society, and making people's lives extremely convenient. The Global Positioning System (GPS) of the United States and China's Beidou Satellite Navigation System are two representative satellite navigation systems. However, some people may wonder why the GPS system in the United States only needs 24 satellites to cover the world, while China's Beidou system needs 56 to complete the network.
The development of satellite navigation systems originated from the military needs of the Soviet Union during the Cold War, but with the advancement of science and technology, this technology has gradually been applied to the civilian field. The satellite navigation system realizes the positioning and navigation of ground targets by distributing multiple satellites in orbit and transmitting precise signals. This technology is used in a wide range of applications, including aerospace, land transportation, military operations, and other fields.
And GPS is one of the earliest and most complete satellite navigation systems. Developed in the 70s of the last century, after 20 years and a cost of 20 billion US dollars, it was completed in 1994, upgraded in 2007, and the anti-interference was enhanced, it consists of 24 working satellites and several spare satellites. These satellites are spread over six different near-Earth orbits, each about 17,000 kilometers above the ground, ensuring that signals can be received almost anywhere in the world. GPS provides high-precision positioning and navigation services and is widely used in both civilian and military applications.
Today's GPS systems are technically and operationally improved and optimized over the years to be quite reliable and accurate. Although there are only 24 satellites, their proximity to the ground means that they already cover the rest of the world. Its users also reach hundreds of countries, including military, civilian, etc. GPS systems not only provide positioning and navigation services, but can also be used for time synchronization, weather forecasting, and other fields.
China's Beidou satellite navigation system is also a global satellite navigation system. The BeiDou system includes different types of satellites, such as navigation satellites, signal satellites, and communication satellites, to meet different application needs. It was officially launched in 2020 and successfully launched its 56th satellite in May 2023. At present, the Beidou system has built a global coverage network, providing high-precision positioning and navigation services, and has the ability to time, and the positioning accuracy has also reached the centimeter level. At present, 137 countries have established cooperative relations with us.
The Beidou system is completely independently developed and operated by China, reflecting China's technical strength and independent innovation capabilities in the field of satellite navigation. It is designed to provide positioning and navigation services to users around the world, including in China and the rest of the world. It has a wide range of applications, including land transportation, fishing, aerospace, and more. So why does China's Beidou need to launch 56 artificial satellites, while the United States only needs 24 GPS?
First of all, the distribution of satellites is not chaotic, and they cannot be launched at any location, they have their own special orbits, so that they will not be launched and collide during operation, reducing the possibility of polluting space. Moreover, in the field of space, it also pays attention to the first come, first served, and the first to launch occupies an innate advantage, and the United States was the first to launch artificial satellites, so the closest low-earth orbit to the ground has long been occupied by the United States. After that, Russia and the European Union launched satellites one after another, and in the end, the orbit left for us was far from the ground, and we could only launch close to space.
The United States has six low-earth orbits, and each of them has four launches, which can fully meet the needs of global coverage. Because the Beidou satellite is far from the ground and the orbital circumference is too long, in order to achieve the purpose of covering the global signal, it can only launch more satellites, so the number of satellites needed has reached 56. Actually, we only need 35 pieces. However, considering the future satellite system upgrades, failures and other problems, it is necessary to prepare a few more.
In addition, the layout of the two is also different, the United States GPS is all composed of dynamic satellites, and China's Beidou is divided into a moving state and a non-moving state. The advantage of this layout is that it is more anti-interference and more flexible in application.