AoA is an algorithm that enables us to calculate and output the direction of the target

cellular phones in real time.

The algorithm is based on the received phase difference between two antennas connected to the USRP:

 

 

 

 

 

 

 

 

 

 

 

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Two antennas separated by a distance d, with a wave front incident at an angle theta,

then the extra path the signal must travel between Antenna 1 and Antenna 2 results in a phase difference, 

delta phi, between the two antennas.

 

This algorithm is implemented in GNURadio, the process of the direction finding is described in this block diagram:

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The GRC (GNURadio file) can be downloaded here.

In order to perform Direction Finding test (and Distance estimation is included) just open the file in GNURadio,

and hit Play.

Remember to change parameters according to your frequency activity.