How does travel itinerary Code know where you have been?

Trip code is implemented according to the communication service provided by telecom operators.

As we all know, the normal communication services of mobile phones (call, SMS, Internet access) are realized by the communication base station of operators. The communication base station is what we call a "signal tower". With the cell tower, our mobile phones will have a signal.

Each of us has our own ID number, and the ID number is unique. We can find a person accurately through the ID number. Similarly, each communication base station also has its own "ID number" (base station number), and the base station number of each base station is unique. With the base station number, you can quickly find the location of this base station.

The working principle of trip code is to determine the location we have experienced according to the base station signal received by our mobile phone within 14 days, thus listing our approximate trip. For example, Zhang San received signals from two base stations in a certain place in Hebei 14 days, and the base station numbers were 12345/23456 respectively. In this way, when applying for his own travel itinerary code, he must first authorize the operator to inquire, and then through the two base station numbers, he can roughly know that his travel itinerary is somewhere in Hebei.

There is another situation. For example, if you drive from Shijiazhuang, Hebei Province to Beijing, your travel itinerary code will include Baoding, Hebei Province. But in your mind, you have never been to Baoding at all. Because you passed Baoding on your way to Beijing, your mobile phone received the signal from the base station in Baoding area, so there will be a record of Baoding area in your trip.

Of course, run-length encoding is only an auxiliary means of epidemic prevention and control. In the event of an epidemic, the most accurate is the flow adjustment work carried out by professional flow adjustment personnel. Therefore, during the epidemic period, it is not only responsible for yourself, but also for society and others to cooperate with the implementation of policies and the adjustment of epidemic situation.

You don't even know this? I know everyone who is seventy years old. For example, if you are from Nanjing, you have a mobile phone card in Nanjing, and your mobile phone signal is covered by Nanjing Telecom. If you go from Nanjing to Hunan, your cell phone signal will be covered by Hunan. For example, if you go to Zhangjiajie, Hunan, your mobile phone will send you a short message to the effect that you are welcome to Zhangjiajie, Hunan. So, no matter where you go, you have signal tracking and positioning, it's as simple as that. Every time you go to a risky area, your health code changes color. At present, the health code of Wuhan has also changed from green to yellow Phnom Penh. If it is a closed community, the health code is estimated to be red.

When you open the interface of obtaining travel itinerary, there will be a place for you to inquire, which says, "I agree and authorize the operator to inquire about the information of my visiting place during the epidemic period 14 days". From this information, we should know that the acquisition of relevant data should be related to several major operators.

So how does the operator know where you have been? This is actually very simple, because operators can know where you have been through the changes in the cell information occupied by your mobile phone. Each cell of the operator has a number, and this number can be unique. This number is actually a global cellular identification code.

The abbreviation of global cell identification code is CGI, which consists of MCC+MNC+LAC+CI. Among them, MCC is the mobile country code, MNC is the mobile network code, LAC is the location area number and CI is the cell identification code. For example, the MCC code in China is 460, and the same operator can have one or more MNCs. The most common MNC code of China Mobile is 00, that of China Unicom is 0 1, and that of China Telecom is 1 1.

As for LAC, it is the location area code, which can further subdivide the whole network. For example, each city often has multiple LACs, which can be divided according to administrative boundaries. For example, if there are several districts and counties under a city, we can correspond LAC district with relevant districts and counties. In fact, as long as you occupy the cell signal under this LAC, the operator can know which district and county you probably went to.

Then there is a more detailed CI, that is, you occupy a specific cell signal, and the operator has the latitude and longitude of the relevant cell, so that you can know your location more accurately, and you can know which street you went to and other information. This is actually the base station positioning technology, so the related technology behind the trip code is not a new technology, but it is actually a very mature technology.

For example, in the above picture, suppose it is the network of China Unicom. There are two boxes in the figure, one for each LAC, namely LAC 0000 1 and LAC 00002. Then there is a cell under each LAC, and each arrow represents a cell. Suppose a cell is under LAC 0000 1, and its number is 2000 1. Then the CGI of this community is 46001000120001,and this code is unique in the world, so operators can know where you have been relatively easily.

I know it through high-tech big data.

The first is satellite navigation big data. Through satellite navigation big data, you can know your location, no matter whether your mobile phone is on or off, it will not affect your location.

Followed by communication data analysis, through communication data analysis, big data will accurately analyze your itinerary.

The most typical example is that when you pass a place by train or by car, your mobile phone will receive a welcome message, welcoming you to this place. This is the same reason.

For security reasons, you will see that leaders between countries use fixed telephones instead of wired ones, which is also the reason to avoid being located and eavesdropped.

As long as you take your mobile phone with you, it will always keep in touch with the signal base station, so you can know how many meters Fiona Fang you are at this base station at a certain moment through a linked base station, and you can also accurately locate it through two base stations with little deviation.

The country only needs to let the communication company upload these data to the big data server, and then various authorized apps can query the data through ID number, mobile phone number or various personal information for comparison.

If an infected person is found, then his itinerary is decided by the infected person, and the big database is queried by time and place. As long as people who meet this time and place are found, their health codes will be marked. The closer to the infected person's time and place, the red team will be marked, and the farther away, the yellow code will be marked.

In the final analysis, it is very simple. Unless you don't have your mobile phone, you can generate data links at any time, just like I was in Shanghai, but you went to the neighboring Jiangsu Province, and the system will tell you that Nantong, Jiangsu Province welcomes you, and then go to other provinces, and there will be a text message telling you that this is it.

big data

Once I went to a place, I turned off my mobile phone because I didn't want it to be displayed on the travel itinerary code, but the travel itinerary code was still there.

I will tell you this question in the simplest and most vernacular way.

Let's take China Unicom as an example. Unicom, Telecom and Mobile are all the same. We take Unicom as an example to connect a base station. For example, it can cover people with a diameter of 3 kilometers, that is, 6 kilometers and 6 kilometers. When their mobile phones come within this range, they will receive signals, which means that this base station is responsible for this area. After you leave here for 6 kilometers, another base station will receive your signal. This base station has a name. As for how the signal is transmitted, the knowledge is relatively large. It's still a process. After the satellite receives it, it is transmitted to the base station and then to your mobile phone.

This is the case. You will have many eggs to serve you along the way. Have you ever been in this situation? At the junction of the two provinces, there will be messages from each province. In the past, roaming charges could not be collected across provinces, and they were always overcharged. Well, because the province here also provided you with the model and the province there also provided you with the signal, so you can use it locally for free, but he recognized you when you crossed the province, because.

To put it bluntly, it is to cross-serve you with mobile phones.