Because the location record of the travel card is located in real time according to the itinerary, it can't be located after shutdown. Travel code is the code of communication big data travel card, which is also equivalent to health code. China Institute of Information and Communication, together with China Telecom, China Mobile and China Unicom, used mobile phones to receive data, which was obtained through the location of the base station where the users' mobile phones were located, providing free inquiry service for the 654.38+06 billion mobile phone users nationwide.
All mobile phones can be located through the base station. The principle is to determine the location of the mobile phone by measuring the distance between the mobile phone and the base station. The accuracy of this positioning method depends largely on the distribution of base stations and the size of coverage. The more surrounding base stations, the higher the positioning accuracy.
Mobile phone positioning knowledge
First, in order to increase the appreciation and suspense, some film and television works mistakenly describe the positioning of mobile phones as having to talk for a certain period of time before they can be successfully positioned. In fact, you only need to turn on the located mobile phone, and you can locate it without talking at all.
Second, the phone is turned off. Because there is no signal transmission, the base station can't capture the signal of the located mobile phone and can't locate it.
Third, mobile phone positioning is to locate the mobile phone card, not the mobile phone. As long as the located mobile phone number is turned on, no matter how to change any mobile phone, it can be located normally, but the serial number of the original mobile phone body cannot be located.
Fourth, set call forwarding on the located mobile phone number, which is equivalent to turning off the mobile phone and making calls by transferring to other numbers. This situation is also impossible to locate.