Trip code generation principle: the first one is through the base station. When the mobile phone is turned on, it will automatically search the surrounding base stations and choose the access with the best signal. The location of the mobile phone can be determined by detecting the received signal parameters, such as signaling data and billing data, as well as the arrival time and signal strength of the signal. If you stay for more than four hours, the base station will record your itinerary information, and the operator can clearly know our itinerary through this information. Then upload these data to the trip code system. You only need to scan the code to see where everyone has been in the last 14 days. Then the second one is via Wi-Fi. Every Wi-Fi router has a unique and unique MAC address. If the wireless function of our mobile phone is turned on, the Wi-Fi antenna will always detect the power and MAC address of the surrounding wireless hotspots and provide them to a special location service provider. In this way, the service provider can obtain the specific positioning of the individual. The third is through satellite positioning. Satellites constantly send navigation signals to the ground in space. Once the mobile phone receives multiple satellite signals, it can calculate the position of the mobile phone from the distance and angle between the mobile phone and each satellite. All the above three require the mobile phone to be turned on, and the related functions must be turned on to track the trip.