Final answer:
The JHCU uses the IR tracker sensor in helmet-mounted systems to lock onto and track targets, enhancing situational awareness and reaction times for pilots.
Step-by-step explanation:
The JHCU (Joint Helmet Mounted Cueing System Unit) acquires and then tracks targets of interest using the IR tracker sensor in the helmet-mounted system. This advanced technology allows pilots to lock onto targets by simply looking at them, increasing situational awareness and reaction times in combat situations. The IR tracker sensor is a critical component that enhances operational capability by allowing high-off-boresight target acquisition and tracking.