Internet time service can achieve an accuracy of more than one second. The time shown on the smartphones we usually use comes in this way. It's convenient to obtain, but its accuracy is too low and can only meet daily use. Shortwave time service can reach an accuracy of 1 millisecond. Its accuracy is just so-so. Moreover, it requires the use of shortwave receiving equipment, along with shortwave radio stations and receiving antennas. Longwave time service can achieve an accuracy of 1 microsecond, which is relatively high. However, its antennas are too large and its power consumption is too high. It is mainly used on ships or you have to build a special house for it...

Compared with these methods, how about the effect of using Beidou satellite time service? First, let's look at the accuracy. Beidou time service equipment can achieve an accuracy of more than 10 nanoseconds, which is quite high among the commonly used wireless time service means and can be directly applied to various precision operation scenarios. Meanwhile, since the length of the receiver antenna is proportional to the wavelength, the wavelength of shortwave is 10 - 100 meters, the wavelength of longwave is more than 1,000 meters, and the wavelength of Beidou navigation satellite signals is about 0.2 meters. Therefore, its receiving antenna can be made into a centimeter-level size and put into your mobile phone. Generally, for time service, the diameter of the mushroom-head antenna plus the rainproof antenna cover is only about 10 centimeters.

Therefore, Beidou receivers are far smaller than shortwave and longwave equipment in terms of volume and power consumption. They have the characteristics of high precision, small size and easy installation. In terms of cost, the price is also much lower than that of longwave time service equipment, but the accuracy is two orders of magnitude higher.

The power grid is a huge and complex system, which contains various relay protection devices, automation devices, security and stability control systems, energy management systems (EMS) and production information management systems that need to take actions. Without a unified time benchmark, once the actions are not synchronized, it's very easy to cause power grid accidents. In fact, all countries have experienced such situations before. In addition, China's power grid spans across regions, covers a wide area and the system is even larger, so accurate time service is particularly important.

Before using Beidou, China's power time service completely relied on the American GPS and the Russian GLONASS satellite navigation systems, resulting in huge security risks and seriously affecting the safe and stable operation of the power system. Now with Beidou time service, the history that China's power operation time completely relied on the American GPS global positioning system has ended, turning the previously unsecured "American time service" into "Chinese time service". For example, the power time service products we produce can achieve time service accuracy at the nanosecond level, which is no worse than that of GPS at all.

Think about the large-scale power outage in the northeastern United States and southern Canada that lasted for dozens of hours. Think about how often India has power outages and how many times its power grid fails in a year. Then think about how long it has been since you experienced a sudden power outage. China's power grid can be regarded as the most stable and safe among power grid systems of the same scale. In ensuring the safe operation of the power grid system, Beidou time service has made indelible contributions.

Even for Beidou receivers that are not specifically for high-precision time service, it's quite easy to achieve an accuracy of more than 1 microsecond. 1 nanosecond is 10 to the power of minus 9 seconds, and 1 microsecond is 10 to the power of minus 6 seconds. The human reaction speed is only 0.1 seconds. So what's the use of such high accuracy?

For example, in China, there are so many infrastructure projects, such as building bridges and roads. When closing the bridge or laying immersed tubes on the seabed, many construction machines need to cooperate. For example, if a 100-meter-long immersed tube needs to be translated 1 meter northward, how can it be implemented? Maybe four or five cranes need to work together. Then the question comes: how can we make them act together? Shouting "1, 2, 3, get ready, go!" on the walkie-talkie definitely won't work. At least we need to synchronize the time. For example, set all the machines to start moving at 1:00:30. If each machine gets the time from the Internet through its own computer, then there will be a difference of plus or minus 1 second in the so-called "simultaneous" actions of these cranes. Although it's much better than using the walkie-talkie, it's far from enough. Using Beidou time service is different. The time accuracy difference between each sub-machine is reduced to the nanosecond level. Such "synchronization" accuracy is even much smaller than the electrical signal transmission delay caused by connecting them one by one with long cables for so-called "synchronous control". This is the "true synchronization". It seems that each machine is working on its own and ignoring each other, but in fact, they are "in tune with each other" and their actions are exactly the same.

On the construction sites of various cross-sea bridges and undersea tunnels, the working surfaces are often thousands of meters long. A slight difference in time can lead to a huge error. Therefore, the significance of Beidou time service is quite significant. You may not directly use it, but it has been always ensuring your life.