The US GPS system needs more than 20 satellites, while China's Beidou system needs more than 50, almost doubled.
What is the reason behind this? Is it a technology gap or is there something else? GPS and Beidou, is there a difference between the two? Let's take the evolution of guidance systems together.
The rapid development of navigation and positioning technology originated from the space race during the Cold War. In the 1950s, the United States and the Soviet Union competed fiercely for superiority in the space field.
The Soviet Union's successful launch of Sputnik in 1957, ahead of the United States, put pressure on the United States and decided to go all out to catch up. In 1969, the Apollo 11 of the United States successfully landed the first human moon on the moon, and the space race entered a climax.
In order to achieve victory, both countries have invested a lot of money and human resources in space technology research and development, and navigation and positioning technology has also developed rapidly in this context. "
After the end of the Cold War, the United States was able to go all out to develop space technology. By 1994, 24 GPS navigation satellites had been successfully launched, and a global positioning network had been built.
The GPS system provides the United States with an important strategic advantage, its high-precision navigation data can be used for military operations, and at the same time, the United States also uses GPS technology to exert pressure on other countries.
For example, in the "Yinhe" incident that year, in 1993, China's cargo ship Yinhe was sailing at sea, but the United States suddenly attacked, claiming that the ship was loaded with prohibited items.
They used this as an excuse to ask our ships to be inspected by them. This request can be said to be quite unreasonable, firstly, there are no prohibited items on board as stated by the US side; Second, the U.S. does not have the right to arbitrarily inspect the vessels of another sovereign state, let alone that the waters are not under U.S. jurisdiction.
In the face of the unreasonable demands of the United States, our side remained calm, but the GPS signal of the Galaxy was directly turned off, leaving it trapped in place and forced to be inspected. Although the United States did not find any problems in the end, this is a serious violation of the dignity and security of our country.
Therefore, we began to independently develop the Beidou navigation system to protect the security and dignity of the country. China Tianjiao, China's self-developed Beidou navigation system, will become our pride.
In 1994, China's self-developed Beidou satellite navigation system officially began to operate, aiming to break through the core technology and get rid of the dependence on external navigation systems. The Beidou system is the world's fourth satellite navigation system, and unlike GPS, GLONASS, Galileo and other systems, Beidou adopts a mixed orbit layout in the design, including geostationary orbit, inclined geosynchronous orbit and medium circular earth orbit, which is an innovative design to improve the coverage of the Asia-Pacific region.
The Beidou system consists of a space segment, a ground segment and a user segment, providing global navigation, positioning and timing services for users in China and around the world.
The Beidou Navigation Satellite System consists of multiple satellites located in different orbits, providing accurate navigation services for users around the world 24 hours a day. The ground station is responsible for the supervision and regulation of the satellite, and the user terminal receives and uses the Beidou navigation signal.
The Beidou system has played an important role in both military and civilian fields, ensuring that it provides more accurate and reliable navigation positioning and time synchronization services for the public.
Whether it is the use of navigation software in daily life, or the use of taxi, etc., the existence of the Beidou system is indispensable. Its excellent performance and service quality have also been widely recognized by the international community.
In 2014, the United Nations officially recognized the Beidou system as a global satellite navigation system. The establishment and operation of the Beidou system has demonstrated a major breakthrough in the field of China's aerospace technology, got rid of the dependence on the navigation systems of other countries, and improved the country's scientific and technological strength and national defense capability.
The Beidou system, a symbol of the Chinese nation's self-reliance and self-reliance, will play an important role in the progress of human civilization. So why does China have dozens more Beidou satellites than American GPS?
The number of satellites and orbital layout of China's Beidou system and the American GPS system are different. The United States GPS has begun to be deployed in the 70s of the 20th century, when the medium-circle orbit 20,000 kilometers from the earth's surface is basically empty, and the United States has successfully occupied 6 orbits, each with 4 satellites, thus achieving global coverage.
However, the earliest test satellite of China's Beidou system was not launched until 2000, so it is very challenging to deploy it in a medium-circle orbit that has been occupied by GPS and other systems.
In order to prevent signal interference and the risk of collision, Beidou chose a higher 212-2.The 140,000-kilometer orbit, although farther from the ground, has a longer orbital period, so more satellites are needed to ensure the transmission of signals.
In addition, the BeiDou system also has unique satellites in geosynchronous orbit and oblique synchronous orbit to achieve more navigation enhancement functions. Located at 3The five satellites in the 60,000-kilometer geosynchronous orbit provide a unique short message communication service, which is a major feature of the Beidou system, which can realize the functions of rescue SMS and emergency communication in disaster areas.
The Beidou system, due to the use of three oblique synchronous orbit satellites, the positioning accuracy can be improved to the meter level or even the decimeter level, which enables the Beidou system to provide high-precision enhancement services, while the GPS system cannot provide such a function.
In addition, the Beidou system has also reserved a certain number of spare satellites for new technology testing and the replacement of aging satellites, which is why the Beidou system needs more satellites.
In contrast, the United States GPS technology has matured, 24 is basically enough to use, and China's Beidou still needs continuous improvement and upgrading, and backup resources are particularly necessary.
From the perspective of military navigation function, the Beidou system provides more comprehensive support for China's vast territory and complex terrain, and some additional high-inclination satellites are needed to make up for the blank area of coverage, which is also the reason why the number of satellites in the Beidou system is more than GPS.
So why do we choose to use the Beidou system instead of the free and open GPS of the United States?
As a leader in global navigation, GPS is free and open to users around the world, which has played a huge role in promoting the progress of human society. However, the one-way broadcasting system used by GPS is like a person who is constantly talking, and there is no way to know whether there is an audience around him who is listening.
This is due to technical limitations that make it impossible to charge users. While GPS can send signals continuously, it has no way of knowing who is using and benefiting.
If a fee is charged, then the existing one-way broadcasting system must be renovated and a feedback loop will have to be introduced to enable satellites to track terrestrial users. This will make the system more complex and costly.
Second, opening up GPS means a huge global market that has a significant impact on the economic development of the United States. The various new technologies, new products, and new services generated by GPS will become the key to economic growth.
Fees may inhibit market expansion, increase costs for businesses, increase the burden on consumers, and then affect economic development. Therefore, free and open GPS can maximize its potential and enhance the soft power of the United States.
Although the GPS system in the United States is free and open, it can pose a potential threat to the military security of other countries. In the case of the Galaxy incident, or even the Gulf War, American GPS technology provided soldiers with an omnipresent view of God, allowing them to clearly know where they are and where the enemy is hiding.
As a result, other countries may come under the control of the United States. To make matters worse, the U.S. could cut off the user's signal at any time, which could have serious repercussions for countries that are highly dependent on GPS, both in military operations and in daily life.
The research and development of satellite navigation systems is by no means an easy task, and it is necessary to pour a lot of money and overcome many technical difficulties, but our country can cope with them.