Agreed. Emergency calls can be made without a SIM card. In fact, as soon as the phone is turned on, it will search the surrounding base station, so that the base station locates the phone, and then it will do further operations according to the information of the SIM card. Taking out the SIM card can not be located directly through the mobile phone number, but as long as you trace the mobile phone ID that has been associated with the mobile phone number, you can locate where your mobile phone has been turned on.
When the mobile phone turns on the wireless network, it scans the surrounding wifi signal, and then uploads the wifi information and mobile phone location information to the background server, forming a huge WiFi location database. In turn, when the phone is enabled with Wi-Fi, the server queries the location information of the wifi hotspot scanned by the phone, and then calculates the specific location of the phone according to the strength of the signal.
When the card is removed, there's no movement trace. Because the action trail is based on the location of cell towers in your area to determine where you are.
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When you remove your phone card, the cell tower will not be able to communicate with the phone, so it will not be able to recognize your movement.