Complex sentence: The USAF describes the Predator as a "Tier II" medium-altitude, long-endurance unmanned aircraft system, which consists of four aircraft or "air vehicles" with sensors, a ground control station, and a primary satellite link communication suite.
Split into simpler sentences: The USAF describes the Predator as a "Tier II" MALE UAS (medium-altitude, long-endurance unmanned aircraft system). The UAS consists of four aircraft or "air vehicles" with sensors, a ground control station (GCS), and a primary satellite link communication suite.