First of all, the new portable radar is called a SAT COM. Second of all, its not UAC, its UAV.
Heres how the system goes:
1: Reveals enemies within any teammate's line of sight
2: Regular UAV
3; UAV but with faster ping speed
4: Advanced UAV
And we'll have to see if they expire. As they're placed on the ground like Portable Radar, i would assume that they will last until destroyed. And you can just toss in a grenade to kill the campers XD
Since the site has released official info about the Sat-Com, you are correct, however the device will auto shutdown after 30 seconds time. < http://community.callofduty.com/community/call_of_duty/english/ghosts/blog/2013/ 09/25/prepare-for-call-of-duty-ghosts-sat-com#.UmeqRfkcSM8