Which subsystem is primarily responsible for tracking aircraft using high-power pulses?

The subsystem primarily responsible for tracking aircraft using high-power pulses is search radar. Search radar systems emit high-frequency microwave pulses that allow for the detection and tracking of aerial targets over significant distances. These radar systems send out pulses of energy and monitor the time it takes for the returns, or echoes, from objects like aircraft to return to the radar. By analyzing these echoes, the radar can determine the location, speed, and trajectory of the aircraft.

This capability is crucial for air defense, air traffic control, and military operations, where accurate tracking of aircraft is necessary to ensure safety and strategic effectiveness. Search radar's high power is essential for extending its range and improving resolution at long distances, which is why it plays a pivotal role in airspace surveillance.

The other options—communications, local control interface group, and IFF/SIF feature—serve different purposes. Communications facilitate information exchange, the local control interface group is related to managing and controlling systems, and the IFF/SIF feature is concerned with identifying friendly versus enemy aircraft rather than tracking them primarily.