I dont know the exact procedure, but I do know they :

1. record the signal and run through algorithms to determine if its artificial or suspect rather than say a natural source.
2. move the receiver off at least 5 degrees (?) from the source and retest
(this is to help identify if its terrestrial or not)
3. return the receiver to the coordinates to verify its still there
4. send coordinates to other (far away) facilities for secondary verification of signal.


edit for atrocai atrosi atroshus atr-- bad spelling.