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Location monitoring technologies track the location of a target through device or network based methods. Device methods use software that logs and reports the device location using GPS or Wifi positioning data. Network methods locate the device by performing calculations on radio signals transmitted to and from the device. After the location is determined, the coordinates are transferred to a mobile or computer interface that can present visualisations of current, past and predicted locations, in addition to various features such as fenced tracking, paired satellite imagery and proximity alerts. Location monitoring is often used without the target’s consent and is an effective tool for determining daily activities, deviations from routine and interpersonal interactions.
The signal strength displayed on mobile phones corresponds to the approximate distance of the device to the nearest base station tower. Similarly, the base station subsystem, the network of interconnected towers, calculates and logs where the device is located using a method called multilateration. Mobile phones constantly send signals to the base station subsystem to remain connected to the network. The base station towers near the device will receive the signal, which travells at the speed of light, at slightly different times. By using the known locations of the towers and the time difference between each tower receiving the signal, the location of the phone can be predicted within a certain accuracy. This accuracy improves significantly when more towers are present, as is the case in urban areas. Location data is logged whenever an action is taken by the device (making a call, receiving a message, using data) and periodically as the device moves throughout the network. Anyone accessing location data can determine the location of individual mobile device users through unique identification numbers.
Two unique numbers identify mobile devices: the International Mobile Subscriber Identity (IMSI) and the International Mobile Station Equipment Identity (IMEI). Each SIM card has an IMSI number and each mobile device has an IMEI number. Both numbers are routinely communicated to network providers. Certain location monitoring technologies identify activity corresponding to these two numbers that the monitoring body may see as suspicious, such as SIM card swapping (the IMSI number would remain the same but the IMEI number changes frequently). IMSI Catchers, monitoring devices that transmit a strong wireless signal that entices nearby phones to connect, can be retrofitted with location monitoring technologies that determine the location of a target to within one metre.
Device based location monitoring technologies are either dedicated tracking devices that can be attached to the target or applications installed on the target’s mobile device. Tracking devices are GPS receivers that can calculate their own position to within one metre. Over 24 satellites are constantly orbiting the earth at an altitude of approximately 20,000 kilometres. These satellites transmit their location and precise time to the tracking device through radio waves. The distance between the satellite and the tracking device can be computed and in the presence of three more satellites a precise and accurate location is found. The location is then transmitted to the monitoring body through the mobile network. Tracking devices can be as small as coins and are easily affixed to a target’s car or effects for constant tracking.
Once location data is collected through network or device based methods, it is transferred to a software platform for analysis. Based on tracking records, this software can generate a report of the target’s daily commuting trends, areas of interest and predicted travel routes. Location data is often retained allowing investigators to see every location visited over years. Location monitoring software can create a “geo-fence”: a predetermined virtual border that transmits a notification when the target approaches or crosses the border. Similarly, notifications can be sent to the monitoring body when two targets meet. Depending on the resources available, the location monitoring software can be linked to satellite or drone imagery for enhanced surveillance. Mobile devices are ubiquitous in modern day life and separating yourself from the mobile world– from emergency, personal and business communications– has become impractical, further increasing the inability to not be tracked.