The Gulf War of 1990, when Iraq had a strong armament:
More than 1.45 million regular and reserve troops;
More than 5,000 tanks of various types;
More than 8,000 armored vehicles;
More than 3,500 large-caliber artillery pieces;
More than 700 fighters and a large number of advanced missiles.
As a result, many countries, led by the United States, took only 42 days to defeat Iraq.
This was because the United States used an immature GPS system at that time to provide accurate navigation services for the US military and help the US military carry out a precise strike on Iraq. This war also makes the mainland understand a truth: having its own global satellite navigation system is a matter of national security and a manifestation of national defense capabilities.
On July 31, 2020, the mainland's Beidou-3 was fully completed, making the mainland the third country to have a global satellite navigation system. However, due to the late start of the mainland in the field of global satellite navigation systems, in the development process of the continental global satellite navigation system, there are many technologies in the state of neck pinch, such as: atomic clocks, chips, traveling wave tubes and so on.
After years of unremitting efforts by scientific researchers, the core components of Beidou have achieved 100% autonomy and controllability, completely getting rid of the situation that the key components are stuck in the neck of European and American countries. Among them, Beidou-3 also uses the "Dragon Core" independently developed by the mainland.
The "heart" of Beidou-3
Beidou-3 consists of a total of 30 satellites, including 24 satellites in the middle circular orbit of the Earth, 3 satellites in inclined geosynchronous orbit and 3 satellites in geostationary orbit.
After the satellite is launched into the sky, the ground control system does not need to care about it, it can operate on its own. Among them, the vast majority of the time of the satellite is in the sun, and can use solar energy to power itself.
But there are also times in the shadow of the sun, when the two wings of the satellite solar charging panel can no longer be powered, and the satellite's battery needs to power itself, which requires the chip on the satellite to operate these steps.
In addition, many functions of satellites, such as interstellar links, orbit calculations, operation management, wave velocity pointing and routing, require the powerful computing power of satellite chips to achieve.
Therefore, the chip is like the "brain" or "heart" of the satellite. Before we used the European SC80c32 chip, if this kind of chip wants to meet the functional needs of the Beidou-3 satellite, it is necessary to use several SC80c32 chips together.
In addition, based on past experience, the use of sc80c32 chips on satellites will have a calculation error about once a week. This error was made because the Beidou satellite is in a medium orbit, referring to the orbit of an artificial satellite located between low Earth orbit and geostationary orbit, about at an altitude of more than 2,000 kilometers and below 35,786 kilometers.
The space radiation environment here is very harsh, and the big reading will have a single particle flip once a week. The so-called "single particle flipping" refers to the situation in which high-energy particles hit the chip, causing the computer to change from "0" to "1" or "1" to "0" in binary calculations. This is when the program has a problem, causing problems with the satellite. This also shows that the use of aerospace-grade CPUs on navigation satellites requires very strong radiation resistance.
Of course, these problems can actually be overcome in ways, for example, to design a fault-tolerant mechanism. But the biggest problem is actually the risk of the sc80c32 chip being stuck in the neck,
Especially when we start the project quickly, the Suppliers in Europe cannot guarantee that the product will be provided according to the planned time, so that the progress of our project will be slowed down, and the price of the SC80C32 chip is not cheap.
On April 20, 2015, the Big Dipper twin star adopted the "Loongson + Flash architecture" to replace the imported "CPU and PROM" scheme, of which loongson uses models: "Loongson 1E" and "Loongson 1F".
In November 2017, researchers decided to use the mainland's self-developed "Loongson" on the first star of Beidou-3. The "Loongson" is a quad-core CPU chip SoC2012, as well as an operating system spaceOS2 with independent intellectual property rights, which has strong anti-irradiation ability. Later, the second star of the Big Dipper 3 also used the chip, counting the global network star of the Big Dipper 3, the cumulative life of the Loongson has reached 30 years, while the single particle flip is zero, which is far better than the Sc80c32 chip in Europe.
Not only that, the performance of a Loongson is equivalent to 10 sc80c32 chips, which is still in the case of a threefold increase in the area of the Loongson and a threefold reduction in performance. That is to say, if a normal Dragon Core that does not change the area is 30 times the performance of the European SC80C32 chip, and there will be no weekly single particle flipping, it can be said that it is quite reliable.
You know, the aerospace-grade CPU has always been considered the "diamond crown" in the chip. The most expensive chip products are basically aerospace-grade chips, before the United States Xilinx company's aerospace-grade FPGA chip created the most expensive chip record, the price is 5 million yuan a piece, and the beidou-level CPU used on the aerospace-grade CPU "Loongson" broke the record with 9 million yuan.
That is to say, the chip on Beidou is not only not stuck in the neck, but also the "Dragon Core" used is also in a leading position in aerospace-level CPU technology.
Not only that, in addition to the chips on the satellite, the terminal equipment also needs chips that can receive the Beidou signal, which was completely monopolized by European and American countries before, and because this belongs to the high-tech field, European and American countries have been implementing a harsh technical blockade on the mainland.
The "chips" in terminal equipment mainly include RF chips and baseband chips. Under the efforts of the researchers for many years, they have also successfully broken through the technical blockade of European and American countries, independently developed in addition to the star navigation baseband processing chip "Pilot One" and the full-frequency point navigation radio frequency chip, replacing the imported chip and getting rid of the situation of the card neck.
How does Beidou perform?
Some people may have to ask the question, what is the level of the independently developed Beidou satellite?
Looking at the world, there are only four global satellite navigation systems, namely China's Beidou, the United States' GPS, Russia's GLONAS and the European Union's Galileo. Japan's QZSS and India's IRNSS are merely regional satellite navigation systems.
The global positioning accuracy of Beidou is comparable to GPS, and the accuracy of Beidou in local areas (mainly in the Asia-Pacific region) is better than GPS. Not only that, Beidou also has its own characteristic advantages. The commanding height technology of navigation satellites is atomic clocks, and Beidou is equipped with dual-frequency hydrogen atomic clocks independently developed by the mainland, which is the leading technology among the four global satellite navigation systems.
Secondly, Beidou navigation also adopts the Ka phased array inter-satellite link, connecting the satellite into a large network, realizing "one-star communication, star communication", so that Beidou has reached centimeter-level accuracy, which is nearly an order of magnitude ahead of several other global satellite positioning systems.
In addition, beidou satellite can also provide global short messages, that is to say, it can have communication functions, which makes Beidou widely used in natural disasters and major events, such as: in the Wenchuan earthquake, to provide rescue information; During the epidemic in Wuhan, help hospital construction to provide support for eye-catching measurement; Provide strong data support when measuring the height of Mount Everest.
Therefore, although Beidou started later than the GPS of the United States and the GLONAS of Russia, it is not only not backward in technology, but also belongs to the echelon of technological leadership, and in the four major satellite navigation systems, technology is at the top two levels.
#Beidou-3 global satellite navigation system officially opened ##Loongson##US##科技 #