How do telecoms trace my location?
Telecom companies and mobile network operators use several methods to trace the location of a mobile phone, even when location services are turned off. Here are the key methods:
Mobile Signal Tracking from Cell Towers
When your phone is powered on and connected to a cellular network, it continuously communicates with nearby cell towers. This communication involves sending and receiving radio signals, which can be used to determine your location. The process, known as trilateration or multilateration, involves measuring the signal strengths and timing differences between signals received from multiple cell towers to estimate your location. This method can pinpoint your location to within a few hundred meters to a kilometer, depending on the density of cell towers in the area35.
Cell Identification and Signal Strength
Your phone's location can be determined by identifying the cell tower it is connected to and the signal strengths of the home and neighboring cells. This information is continuously sent to the carrier, allowing them to approximate your location5.
GPS and Assisted GPS (A-GPS)
While GPS is typically associated with location services, it is not the only method used by telecoms. Even if GPS is turned off, A-GPS can still be used to determine your location. A-GPS uses a combination of GPS signals and data from cell towers or Wi-Fi networks to provide location information. This method is particularly useful in areas where GPS signals are weak, such as indoors or in urban areas24.
Wi-Fi and Bluetooth Tracking
When Wi-Fi is enabled on your phone, it scans for nearby Wi-Fi access points and measures their signal strengths. This information can be used to estimate your location by matching it against a database of known Wi-Fi access points. Similarly, Bluetooth signals can be used to track your location, although modern devices often randomize MAC addresses to make this type of tracking more difficult23.
Cell Site Simulators (IMSI Catchers)
These are portable devices that mimic cell towers to capture the IMSI (International Mobile Subscriber Identity) of nearby phones. While primarily used by law enforcement, these devices can also be used by other entities to track phone locations3.
Emergency Services Requirement
Even if you turn off location services on your phone, the cellular system must still know your location for emergency services. This means your phone continues to communicate with nearby cell towers, allowing your provider to pinpoint your location in case of an emergency. This historical location data is recorded and stored by the service providers4.
In summary, telecom companies can trace your location through a combination of cellular signal tracking, GPS and A-GPS, Wi-Fi and Bluetooth signals, and the necessity of maintaining connectivity for emergency services, even when you have turned off location services on your device.