Drone "looking for traffic", how exactly?

[Kerosene Kraut]

Last week, while being on the frequency of Joshua Approach (greater LA area close to Edwards), I monitored a conservation between ATC and two aircraft, one being a UAV, on conflicting courses. After the first guy, a biz jet, said he would be looking for traffic the drone announced to do the same.

My question is: How do they do it? Do they just monitor a networked mil radar, TCAS or can the drone actually use a movable video camera ore something similar?

Cheers, Kraut

[Spitoon]

Some do it with a camera downlinked to the pilot, other use various sensing systems.