I happened to pass by high-speed railway station's mobile phone and received a service message: How do you know my number?

The local area network of the mobile phone will recognize where you are, and you can locate it as long as you turn it on.

Mobile phone positioning system refers to the technology or service that obtains the location information (latitude and longitude coordinates) of mobile phones or end users through specific positioning technology, and marks the location of the located objects on the electronic map. Mobile phone positioning system is not necessarily mobile phone GPS positioning. First of all, talk about positioning technology.

There are two kinds of positioning technologies, one is based on GPS, and the other is based on the positioning of base stations in mobile operating networks. The positioning method based on GPS is to use the GPS positioning module on the mobile phone to send its own position signal to the positioning background to realize the positioning of the mobile phone. Base station positioning is to determine the location of the mobile phone by measuring the distance between the base station and the mobile phone. The latter does not need the mobile phone to have GPS positioning ability, but the accuracy depends largely on the distribution and coverage of base stations, and sometimes the error will exceed one kilometer. The former has high positioning accuracy, but the penetration ability of GPS satellite signal is weak, so it can not be used indoors, and the power consumption is high. In addition, there are also methods of using Wifi for small-scale positioning.