Sunday, November 28, 2010

Cellids and mobile locating

Your mobile is constantly communicating with the service provider through the mobile tower which is giving  the strongest signal in your location. There are multiple towers near you but your mobile is connected to only one of them. Amost always there are three antennas pointing at three directions, 120 degrees apart,  on a single tower. They are usually indicated with cellids whose last digit is either 1,2 or 3. Example 6881,6882,6883. The directions are 0,120,240 or 30,150,270 clockwise from north.

When you are at home, your mobile may connect to different towers at different times depending on your mobile's location. In  one room it may show 6881 in another it may show 10121. But rarely 6881 and 6882 or 10121 and 10122. because the direction of signal cannot coincide  from  different antennas  on the same tower. So if you get two different tower locations it is easier to estimate your approximate location.

Most mobiles does not show the cellid to the user but the service provider keeps a record of your calls and the cellids at the beginning and end of the call.

There are applications like PhoneNetInfo and Celltrack which work on specific handset models which can provide network information including cellids. PhoneNetInfo is downloadable from net and works with S40 and S60 phones.

The call data records contain the called number, duration, time of call, first cellid, last cellid and IMEI number of your handset.

This is the information that the police requests for a specific period for a specific IMEI or mobile number. If you want to trace your stolen mobile you better have  it's  IMEI number handy when you file your police complaint.

Mobile service providers are also  required to provide their tower list and addresses of the towers along with the cellids periodically to the Police.

After installing 'celltrack' or 'PhoneNetIOnfo' on your phone  you can visit the location indicated in the call records  and when you see the cellid displayed on your phone is same as the one you are seeking,  you have some idea of your target's location.

Since you are looking at past data you can't be sure if the target is still in the area. For that you need to study the the call records more closely and try to estimate target's location of residence or work.

Our police are not trained to do this type of work -- apart from increasing the work load of the service provider mostly nothing is achieved by this. They try to locate the target either by calling him directly or calling his contacts  --- which is a sure way to warn him. Very often when you get a criminal's call record all his contacts are also equally shady, equally difficult to trace and equally alert.

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