The UAV is fully implemented as standard. The easiest way is to play the the Marine Recon FAC (FOB Condor) e the carries the correct radio to allow FAC access through the action menu.

From a previous post:-

Quote Originally Posted by [b
Quote[/b] ]Regarding UAV's, the Reaper UAV is tied into the FAC Console. Either play as the Recon Marine FAC (FOB Condor) or just pick up a VHF radio from the rucksack crate to access the FAC Console.

You will see a button in there with "RC" on it, that will call in the UAV. On the bottom right of that screen you will also see a "Target Area" box, if you click on "RC ON" you will be taken to the UAV view. (I will take a few minutes for the UAV to get over the target area.)
Hope that helps.