Team Geared Up

talking about outdoor adventure…

Jan
3
2006

How to triangulate a mobile phone location

Written by admin

I’ve been in discussion with people before interested in how Robert Holohan’s body was found in west Cork by his mobile phone (cellphone). Well here’s a run down of how it’s done, but may not be the exact method used in this case as I have talked to no-one who was involved.

A mobile phone uses antenna arranged in a hexagonal pattern like a honey comb structure. Your phone tries to be in contact to more than one at any time, and transmits to the one that has the strongest signal at the time. You can change between masts, during a call with any glitches (called a handover) and so while flying down a motorway the RNC (Radio Network Controller) is busy receiving mast signal strength values from your phone and deciding which way to route the signal to your mobile handset.

The next part works just like GPS (although not with satellites, but with phone masts). If you know the signal strength, you have a fair idea of the distance from the mast in question, but are not sure of in which direction. Add another mast’s signal strength to your handset. Aha! now you know the location is somewhere within the two overlapping spheres and, at ground level (most likely!), so you now have an ellipse with pointy ends shape (is there a proper name for that shape?) patch on the ground. Add the signal strength from a third antenna and where the 3 spheres cross, cha ching, thats your spot. It’s called triangulation and is a fairly simple process. See the image below.

Triangulate cell phone

This is how they would have got the location of the last communications from Robert’s phone to the network (this data is stored for up to 3 years! Or longer? Ask DRI!) Now, the issue was that his phone had run out of battery, so how do you find a phone with no battery. This is apparently how, but I’m not 100% on that this method was used… A phone sitting with no power in the brush has it’s aerial which is a coil of metal, nothing fancy. When an electric current is passed through a coil a field is created which will give a bounce back on a scanner, or so I’m told. Hence with directional scanners they set about looking for this phone in the off position in the last known location of it just like with longer range metal detectors that will only pick up aerials. This process is called ‘pinging’.

Latest Comments (19):

excelent description… This is exactly the process of a triangulation… Nice Job

who loves sony-ericsson… call me! (212)6971519

“so basically what you are telling us is that each AERIAL would be uniquely identified rather than the phone?” - no re-read it.

They knew the body was in the area with a phone in his pocket. Therefore they threw electrical signals across the field. When electricity passes through a coil of metal it creates a magnetic field, right?

So they then scanned/pinged for magnetic fields in the brush.

Makes sense to me.

can you tell me exactly what resources need to be used for this, what type of antenna, and GPS system etc?

Comment by TheRedeemer | 6:55 pm February 3, 2008

This is crap! Yeah, that is the way it works, but the ping stuff…come on!
I work at the Secret Services in my country, if you want to see how it really works, call me.My number is +40743582183. Maybe i’ll help you track some mobile phones! And i’ll tell you how to do it fast and safe! Just call…

Comment by Luigi | 11:39 am May 1, 2008

first of all…how do you find out where the phone masts near you are? Also, you said “Add another mast’s signal strength to your handset.” How exactly do you change…like your signal to another phone mast?

Comment by Wilko1664 | 4:51 am June 30, 2008

You cannot ping a phone whilst it is switched off period.
The phone will have been pinged retrospectively as the phone data is stored for some considerable time.

AS the phone moves from place to place it automatically locks on to the nearest mast in the area to achieve the strongest signal, when it does so it sends a ping to the mast which in turn sends out a pong (just like your PC) whilst this electronic data is being sent it gets recorded by the network providers. As a result of the phone constantly searching for a strong signal. By doing this a triangulation search can be carried out to locate the phone, simple geometry not rocket science, nothing to do with the coil on the aerial or gps.

The accuracy of the search depends on how far apart the phone mast are, better results are achieved in built up areas as the masts are nearer together and more of them . When the mast are out in the country it makes it more difficult, but not impossible to search for .

You can ping a phone. You are pinging the metal coil in the aerial. Any metal coil would respond - it just happens that the aerial is made from one.

Comment by Daryl | 2:43 am November 19, 2008

In phone triangulation u can find a phone. for me I’ve lost my phone and been every where i can think it could be. how and where would u go to do a phone triangulation? how bout if the phone is dead?

You pack of idiots. Yes it can be done. Just like metal detectors detect the difference between iron and brass. OK this is how it goes. The antenna in the phone is a very efficient antenna, and thus needs very little power to put out a good signal. You want to get the longest life out of the battery, right? And a very efficient antenna is very good at absorbing the signal it is intended to receive, as it is at transmitting it out. So if you’re looking for a dead mobile phone out in the bush, use a low-powered transmitter that will put out a signal on the exact frequency that the mobile phone (all mobile phones) is made for. You then wander around until something starts absorbing the signal. The more your signal is being absorbed by the ‘object’, the closer you are. The antenna will absorb the energy that it is designed to absorb whether the phone has power or not. Now this would only work out in the scrub, where there are not likely to be any other metal objects that are going to ‘resonate’, and they would also have to turn off the local phone towers so that there is not any ‘competeting/interfering’ signal. There.

plz mind telling about the how to mast phone and find location of a stolen mobile.also kindly arrange some relevant software or map .

Comment by Securis | 10:59 pm March 9, 2009

Yeah there is really some confusion here. The aerial does nothing to identify or triangulate the actual phone. First through triangulation you would find the last known location of the phone. Then from there if the phone is still close enough, guessing that it has not moved since the battery died. As in the case of locating a body. Then from that location you can use the methods described above to try and locate the phone. As said, like a metal detector, you can determine if there is an aerial nearby. Of course this is hit or miss, but if you have triangulated the last known location of a cell phone that may be in some brush somewhere with a body, then your chances of using this method successfully are pretty good.

Comment by CHRISTIAN | 4:15 pm April 2, 2009

HI THERE
I WOULD LIKE TO FIND OUT HOW I CAN TRACE A MOBILE PHONE AND WHICH AREA IT IS IN, HOW MUCH WILL THIS COST ME?
THANKS CHRISTIAN

Comment by EVA | 12:00 pm April 9, 2009

It’s really important for me and my family to locate the area of a specific mobile (but i think there is a problem, because the specific number seems to be ringing at other numbers - that thing was prooved from me twice , because it was answered for sure by people who didn’t know anything about anything i told them ). So i don’t know if it’s the right word “it was pushed to elsewhere”. Maybe it’s something that the man who owns it does it regularly so that he can’t be revealed. Please mail to me if someone can help !
THANKS EVA

Comment by simpsonX | 9:24 am June 27, 2009

what exactly do u need to triangulate a phone?? can it be done by your local phone operators..just watching 24 got me thinking..

Comment by Rick | 10:51 am November 9, 2009

Wow, you’re ALL pretty much dense.

The only way it works is with the phone on and actively associating with a cell tower. The cell towers themselves are broken up into (usually) 3 transmit sectors of 120 degrees each. By determining which towers a stationary phone is connecting to you can determine an area of overlap within which that phone -must- be.

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