The trip code is based on the communication services provided by the telco carrier.

As we all know, the normal communication services of a cell phone (calls, text messages, Internet access) are realized by relying on the operator's communication base station. The base station is what we call a "cell tower", and with a cell tower, our cell phone will have a signal.

Each of us has our own ID number, which is unique, and can be used to accurately locate a person. Similarly, each communication base station has its own "ID number" (base station number), and the base station number of each base station is also unique, with the base station number you can quickly find the location of the base station.

The trip code works by identifying the location of the cell phone we're experiencing, based on the cell phone signals we've received over the course of 14 days, so we can make a list of the approximate trips we've made.



An example: Zhang San has been in a place in Hebei for 14 days, and has received signals from two base stations, whose numbers are 12345/23456. This way, when he applies for his own trip code, he has to authorize the operator to query it first, and then, through the two base station numbers, he can roughly know that he's travelling to a place in Hebei.

There's another scenario. Let's say you're driving from Shijiazhuang in Hebei to Beijing, but your trip code will have Baoding in Hebei. But in your consciousness, you have never been to Baoding at all. Because you passed through Baoding on your way to Beijing, your cell phone received signals from base stations in the Baoding area, so there would be a record of the Baoding area in your trip.

Of course, the trip code is only an auxiliary means of epidemic prevention and control, once there is an epidemic, the most accurate is the flow of professional staff to carry out the flow of work. So, to cooperate with the implementation of the policy during the epidemic and to cooperate with the work related to the circulation is not only responsible for oneself, but also responsible for the society and other people.

This is not known? The first thing you need to know is that you are not going to be able to get your hands on a new one. For example, if you are from Nanjing and you have a cell phone card in Nanjing, your cell phone signal is covered by Nanjing Telecom. If you go from Nanjing to Hunan, your cell phone signal is covered by Hunan. For example, if you go to Zhangjiajie, Hunan, your cell phone will send you a text message to the effect that:Welcome to Zhangjiajie, Hunan. So, wherever you go there is signal tracking, localization, it's as simple as that. Whenever you go to a risky area, your health code will change color. Currently, the health code in Wuhan has been changed from the original green color to yellow with a golden edge. If it's a closed neighborhood, the health code is probably red.

When you open the interface to get the trip card, there will be a need for you to check the box, where it says "agree and authorize the operator to query the information of the place I visited during the 14 days of the epidemic", and we should be able to know from this information that the relevant data should be obtained with the relationship between the major carriers.

So how do carriers know where you've been? This is actually simple, because the operator can change the cell information through your cell phone occupancy to know what you have been to, the operator of each cell is a number, and this number can be done uniquely, this number is in fact the global cell identification number.

The Global Cell Identifier is abbreviated as CGI, which is composed of MCC+MNC+LAC+CI. The MCC is the Mobile Country Code, the MNC is the Mobile Network Code, the LAC is the Location Area Code, and the CI is the Cell Identifier Code, for example, the MCC code in China is 460, and the same operator can have one or more MNCs, and the most common MNC code for China Mobile is 00, the most common MNC code for China Unicom is 01, and the most common MNC code for China Telecom is 11.

The LAC is the Location Area Code. As for the LAC is the location area code, which will be the entire network can be further subdivided, such as each city tends to have more than one LAC, LAC can be divided according to the administrative boundaries to divide, such as a city below a few districts and counties, then we can LAC area and the relevant districts and counties corresponds to the way as long as you have occupied the LAC below the cell signal, the operator can know that you probably go to the LAC, and then the operator will be able to know that you have to go to the LAC. The carrier will know which area you've been in.

The next step is a more detailed CI, that is, you occupy a specific cell signal, and the operator is related to the latitude and longitude of the cell, which can be more detailed to know your location, you can be specific to which street you went to the information, this is actually the base station positioning technology, so the relevant technology behind the trip code is not a new technology, which is in fact a very mature technology.

This is the first time I've seen the technology in the world.

Such as the above figure as an example, assuming that China Unicom's network, the figure of two boxes, each box for a LAC, respectively, LAC 00001 and LAC 00002, and then each LAC below the cell, each arrow on behalf of a cell, assuming that a cell in the LAC 00001 below the number of 20001, then the CGI of the cell is 460 01 00001 20001. is 460 01 00001 20001, and this code is globally unique, so it's still relatively easy for the operator to know where you went.

Through high-tech big data.

First of all, the satellite navigation big data, through the satellite navigation big data, can know your positioning, regardless of your phone on or off does not affect your positioning.

The second is communication data analysis, through communication data analysis, big data will accurately analyze your trip.

The most typical example is that if you take a train or drive through a certain place, you will receive a cell phone welcome text message to welcome you to the local area, which is the same thing.

For security reasons, you'll see leaders of countries talking to each other using landlines that are wired , for the same reason, to avoid being located and bugged.

As long as you have a cell phone with you, the phone will always be linked to the signal base station, through a link to the base station to know that you have a moment to the base station how many meters within the circle, through the two base stations will be able to locate more accurately, the bias is not too big.

The state only needs to let the various communications companies upload these data to the big data server, and then a variety of authorized APP through the ID card number, cell phone number or a variety of personal information will be able to query the data for comparison.

If an infected person is found, and then his itinerary is determined through this infected person, the big database is queried through the time and place, and as long as the person who meets this time and place is found, the health code of these people will be labeled, and the closer the time and place where the infected person is to be found, the more the code will be labeled red, and the farther away it is, the code will be yellow.

In the end it's very simple, unless you don't have your phone with you, it's a link to generate data at any time, like I was in Shanghai, but you went to a neighboring Jiangsu province, the system will have a text message to tell you that Nantong, Jiangsu province, welcome you, and then go to other provinces, and then have a text message to tell you that this is

Big data

I went to a place once, and I didn't want to have to travel to a place where the code was not displayed, and then turn the phone off.

The problem is that I don't want the phone to be turned off, but the trip code is still there

I'm going to use the simplest, most vernacular way to talk to you about this.

We take China Unicom, Unicom Telecom and mobile are the same ha, we take Unicom to take the example of Unicom a base station can make an analogy that can cover 3 kilometers in diameter is 6 kilometers 6 kilometers within the scope of the people's cell phone to go to this range, he will be received signals, which means that you are in the scope of the activities of the base station on the management of the area, you leave the 6 kilometers after another base station to receive signals, you will not be able to get a signal. After you leave this 6 kilometers, there will be another base station to receive your signal, this one base station to see a place, he has a name. As for how the signal is transmitted that learning is relatively large, he is received through the satellite after the transmission to the base station and then transmitted to your phone or so a process.

The situation is that this is the case, you will have a lot of eggs along the way to serve you, you have not encountered this situation in the two provinces of the junction of the provinces will have a variety of provinces to give you the information you send before roaming charges can not be charged across the province, the old charge you more than the phone bill is the case, because this side of the province to provide you with the type of province there are also providing you with signals, so that causes two signals

To be clearer is to follow your phone to cross for you.