If yes how? If no, why not?
In: Technology
Sure, especially if the user is moving. Watch which cell towers handle and then hand off the call. That’ll tell the area where the caller is located.
It’s possible to track a mobile phone without GPS and without you making a phone call.
Even when not making a call, your phone is still talking to the towers.
You often here people talking about “triangulating” someones position, this works with phones.
Say you got a map of a city. On this map, you can see every cell tower, and you are trying to locate a phone user as they connect to the towers in the city.
If you can see which towers are talking to the phone, this gives you a rough idea of where the person is. If 2 or 3 towers connect at once, you can generally say the phone is somewhere between them.
But you can take it further, the towers cannot tell which DIRECTION the phone is in, however they have a pretty good idea how FAR the phone is from them.
If the phone connects to one tower, and you know it is about 500m away, you can draw a circle with a radius of 500m from the tower and know the phone is somewhere on that line.
If the phone then connects to a second tower and you know it is about 700m away, you can draw a circle around that tower as well.
Now, you have only 2 possible locations (the 2 places where the 2 circles cross each other)
With a third tower though, you have a 3rd circle and where all 3 circles cross is the phones location.
The need for 3 points to locate a signal is why it is called “triangulation”
If you’re the police and want to know the location of a mobile phone, you can just call the network operator. They know which of their towers had the strongest signal and therefore probably was closest to the phone. That gives you at least a rough location.
I’ve heard that nowadays they can narrow it down further by correlating the signal strengths of various towers in the vicinity. The accuracy of this is probably still limited compared to the phones GPS.
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