I am trying to understand the concept of direction finder (DF), for mobile GSM devices.
I have found the following description:
It seems to describe the following configuration:
<IMSI catacher>-------- <additional handset (mobile)> | |-------- <target mobile device>
According to web site description, it is composed of IMSI catcher (probably), i.e. active base station, which force the target mobile to transmit, and probably the attacker base station (SDR radio) can detect the exact direction/signal strength of the attacked device.
I am not sure how it works, but this is what I think:
The base station (which is also a receiver) force the target mobile to keep transmission (by sending silent sms which force the mobile to transmit ack).
The additional handset is actually a second receiver.
So we get 2 receivers (handset and base stations) , each can find the signal strength.
We can draw a map, with 2 circles, and the merge points will point us to the correct direction.
Do you think this is how it works ? any comment is appreciated.
EDIT: Can someone please give a description how it is done and what is the purpose of the handset ? Is it a reciever of just an antenna ?