Wiktionary
targeter
n. A person who selects targets (typically for a remote weapons system)
Usage examples of "targeter".
The old man cut out the targeter, cautiously shifted position once more, and the bird was clearly revealed in the camera's view-finder: a chunky black creature 20 cents long, seeming to stare fiercely at him from its perch on the scraggly lehua tree.
The automatic targeters must have made the mistake of picking up some floating tree trunks.