Shi Qinghao, a special writer for The Paper
【Editor's Note】
General Secretary Xi Jinping pointed out that history is the best textbook and the best sober agent.
Studying the "Four History" of Party History, New China History, Reform and Opening Up, and Socialist Development History is a compulsory course for party members and cadres.
Following the opening of the "Political Keyword" column for the first time during the National Two Sessions in 2019 and the second "Political Keyword" column on the 70th anniversary of the founding of New China, The Paper continued to cooperate with the Shanghai Federation of Social Sciences and Shanghai Political Science Learn to jointly open the "Four History" keywords.
Today, the 59th "Four History" keyword is published, the keyword is Beidou satellite navigation system.
Why does China want to establish the Beidou satellite navigation system?
Currently, the United States, Russia, China, and the European Union have all established their own satellite navigation systems.
In 1994, when China was financially tight, why did it build its own satellite navigation system?
The direct reasons can be explained by two things: First, the Gulf War triggered a new military revolution.
In 1991, the Gulf War created a precedent for decisive victory by air strike force; the most eye-catching was precision guided weapons, and the US GPS provided key technical support for precision guidance.
The Gulf War triggered a new worldwide military revolution, and GPS positioning systems have become the focus of attention of all countries.
Second, the "Yinhe" incident forced China to develop autonomous satellite navigation.
On July 23, 1993, the Chinese freighter "Yinhe" sailed into the Indian Ocean. Suddenly, there was no signal from the navigation system and the ship could not continue to sail.
Later, I learned that it was the US embargo on Iran and deliberately stopped the GPS signal in this sea area.
The news of the "Yinhe" came back to China. Academician Sun Jiadong and Shen Rongjun, deputy director of the Commission for Science, Technology and Industry for National Defense jointly signed a letter, suggesting to start China's satellite navigation project.
In December 1994, the Beidou navigation experimental satellite system project was approved by the state.
Although the satellite navigation system originally originated from the needs of war, its role is far more than the military field, and it plays an important role in many fields of national production and life.
In many fields such as unmanned driving, surveying and mapping, navigation, and disaster relief, satellite navigation systems play an irreplaceable role; today, when driving through large cities, many "road blinders" have left satellite navigation and it is difficult to move; Satellite navigation systems are also inseparable from shared bicycles and electronic fence parking; satellite navigation systems also provide convenience for large-scale agricultural mechanized farming.
Why does the Beidou satellite navigation system take "three steps"?
The reason why China has to take "three steps" is simply because of two reasons: one is because our country was poor at the time; the other is because although our country is poor, Chinese scientists are still striving to improve themselves.
As early as the 1960s, China began to study satellite navigation.
But this project was too "burning money" and this plan was not implemented.
However, our scientists have never given up on satellite navigation research.
By October 1985, the Chinese Academy of Sciences and the Bureau of Surveying and Mapping of the former General Staff of the People’s Liberation Army held a joint meeting. Chen Yunfang, an advocate of the “863” project and an academician of the Chinese Academy of Sciences, put forward a relatively “money saving” concept: just use two geostationary satellites. Covering the Chinese region.
This idea, later known as the "double star positioning" theory, became the prototype of the Beidou-1 in the future.
In 2000, the two satellites of Beidou-1 were successfully launched, and China became the third country in the world to have an autonomous satellite navigation system after the United States GPS and Russian GLONASS.
After the project was established in 1994, the Beidou people began to work with real swords and guns, and immediately encountered the embarrassment of being embarrassed.
The United States began to develop GPS in 1973. By 1994, it had invested more than 20 billion U.S. dollars, and the annual maintenance cost was as high as 500 million U.S. dollars. In 1994, China’s "863" program budget for 7 major technological fields, including aerospace, was only 100. 100 million yuan.
There are ways to be poor. Since you can't eat a fat man in one bite, eat in three bites.
Therefore, China divides the construction of satellite navigation system into "three steps": the first step is to cover the country, the second step is to cover the Asia-Pacific, and the third step is to cover the world.
This is the origin of Beidou No. 1, Beidou No. 2 and Beidou No. 3.
What difficulties and obstacles has the Beidou satellite navigation system experienced?
The Beidou satellite navigation system has experienced too many difficulties and obstacles, and we can only understand the "tip of the iceberg."
The first obstacle is the development of an atomic clock.
The accuracy of the atomic clock directly determines the accuracy of the satellite navigation system.
According to the goal set by the chief designer of Beidou, Yang Changfeng, the error of the atomic clock should reach the minus 12th power of 10, that is, only one second error occurs every 100,000 years.
The atomic clock is as important to the entire project as the human heart. This kind of core technology will never be given to us. China can only rely on itself.
China has formed three teams of the Chinese Academy of Sciences, Aerospace Science and Technology, and Aerospace Science and Industry to tackle key problems at the same time.
After two years of hard work, a domestically-made satellite-borne atomic clock was developed, which has better performance than the European atomic clock.
At the beginning we wanted to buy, but Europe did not sell; now Europe immediately agreed to sell and cut the price by half, but China still insists on using its own atomic clock.
Another thrilling moment is the race against time to win the frequency defense battle.
Any country that wants to develop its own satellite navigation system must first apply for frequencies from the International Telecommunication Union (ITU). Therefore, frequencies have become a valuable resource that the United States, Russia, China, and Europe must compete for.
On April 17, 2000, China submitted a frequency band application to the International Telecommunication Union; on June 5 of the same year, the European Union Galileo satellite navigation system also submitted a frequency band application.
Regarding frequency, the International Telecommunication Union has two rules: "First use, first served" and "Void if overdue."
The so-called "overdue invalidation" means that the validity period of the frequency starts from the date of application, and 7 years is not used for invalidation.
In other words, the first satellite of China's Beidou-2 must be successfully launched and successfully broadcast the signal before midnight on April 18, 2007, otherwise it will be invalidated after the deadline.
The so-called "first use, first serve" means that China has to compete with the European Union, because there is a high degree of overlap between the application frequency of China and the EU, and the two sides need to compete frequently.
China Beidou 2 was launched in 2004 and has lost the EU Galileo system at the starting line for two years.
On December 28, 2005, the first experimental satellite of the European Union's Galileo program was successfully sent into space.
Surprisingly, the satellite did not open the frequency because it costs money to open the frequency. At this time, the EU is tight.
China must seize the opportunity quickly, but prefers to do more things: The first satellite of China's Beidou-2 has already been on the launcher, and the transponder on the satellite is found to be abnormal.
After a race against time for repairs, at 4:11 on April 14, 2007, the first Beidou 2 satellite was successfully launched; at 20 o’clock on April 17, the satellite issued the first set of signals, which was higher than the "seven-year limit" set by the International Telecommunication Union. "Four hours ahead.
China's frequency defense war has been successful.
The successful launch of Beidou-2’s first satellite solved the frequency problem and cleared major technical obstacles.
Subsequently, China gradually entered the "Beidou speed" mode: throughout 2018, Beidou launched a total of 18 satellites, setting a world record.
At 9:43 on June 23, 2020, the last Beidou networking satellite was successfully launched in Xichang.
So far, China's autonomous satellite navigation system, which took 26 years and launched 59 satellites, has finally been completed.
This means that Beidou will launch a new impact on the global satellite navigation market-the output value of this market is more than 270 billion US dollars per year, the United States accounts for 90%.
(The author is an associate professor of the Shanghai Municipal Party School of the Communist Party of China)