What is the basis for judging where the big data travel card has been?

The travel card is located according to the signal communication between the mobile phone and the nearby base station.

1, base station positioning

When you use your mobile phone, whether you surf the Internet, send text messages or brush videos, you need to exchange information through the signals sent by the base station. The specific information, number, location and corresponding operator of each base station are clearly marked.

The signal on the trip code will be updated as you move, and the operator will collect the data information of the contact between the user's mobile phone and the nearby base station, and then upload it to the line code system. We click on the communication travel itinerary inquiry system, agree and authorize to inquire about the information I have been to within 14 days of the outbreak, and then my itinerary and places I have been to within 14 days will appear.

2. Wireless network positioning

When the mobile phone turns on the wireless network, it will automatically search the surrounding wireless networks. Once the mobile phone is connected to the wireless network, Big Data will instantly collect information according to the globally unique MAC address of the wireless network router, and then upload it to the run-length encoding system, so as to accurately locate the mobile phone users.

3.GPS and Beidou positioning

Domestic mobile phones are basically dual-mode chips compatible with GPS and Beidou. The built-in GPS of the mobile phone will constantly search for satellites in space orbit. Once connected, the satellite system can search the specific position of the user according to the signal phase difference, and the error is about15m. General mobile phones support a variety of satellite positioning systems, such as GPS, Beidou, GLONASS and Galileo. But Apple's mobile phone doesn't support Beidou satellite system.

An error occurred while recording the location of the travel card.

Travel itinerary is not recorded everywhere. For example, someone took the high-speed train through several cities, but the travel itinerary code didn't record all the cities. This is because the travel code will judge that you stayed in the local area for four hours, and the system with less than four hours will automatically judge that you are just passing by.

However, many friends have reported that they have never been to this city, but they have been recorded, or the itinerary code of a certain place has not changed. Sometimes such a mistake may not matter, but once the city it passes through is a risk area, it is "unexpected trouble" that is not worth the candle.

The reason for this may be that there are too many base stations, and the coverage can easily be extended to other cities. In this way, you go to a small city next to the city, or you may only record your trajectory in a big city. Another possibility is to go to the junction of the city. Although you didn't go to that city, it will be recorded as your trajectory because you are too close.