DISCUSSION

Back To Discussion Page
Back To Main Page



           Cell Phone GSM Tracking

GSM tracking could either be network based or device based, while the former requires less or no operation from the mobile devices, the latter needs the mobile devices to install certain software and perform the calculating and locating operation and send the data to the location server via GPRS or Wi-Fi or 3G.

Typically, a GSM network consists of mobile stations, cell towers (or base stations), and the network systems.

1.)    Mobile stations are mobile devices like cell phones. It consists of a mobile terminal and a Subscriber Identify Module (SIM).

2.)    Base station consists of Base Transceiver Station (BTS) and Base Station Controller (BSC).

3.)    Network system consists of Mobile-Service Switching Center (MSC), Operation and Maintenance Center (OMC) and a few other devices.

Your cell phone is constantly connected to the nearest cell tower set up by the carriers, and some cell phones can switch to other cell tower which have better signal strength automatically, that’s why they have better call quality. Each cell tower has a unique Cell ID. But it’s not always the case, sometimes you can find a base station has three Cell IDs, each covers a third of that area (a 120° sector).

The working range of a cell tower/base stations is determined by a few actors, like the frequency, the transmitter’s rated power and size, as well as weather conditions. Generally, cell towers are grouped in areas of high population density because each base station is limited by its capacity. In inhabited areas, base stations are commonly spaced 1-2 miles apart and in dense urban areas, cell towers s may be as close as 200 hundred meters apart or even less, that is, each base station covers an area of a circle with a diameter of 200 meters or less.

That is why we can use base stations to roughly locate a cell phone. Here are the five types of GSM cell tower based cell phone tracking:

i.)                  TA or CellID+TA

ii.)                AOA (Angle of Arrival)

iii.)              TOA (Time of Arrival)

iv.)              TDOA (Time Difference of Arrival)

v.)                E-OTD (Enhanced-Observed Time Difference)