Which type of precision-guided munition (PGM) homes in on energy reflected off the target by another source?

• A. Semi-active
• B. Active
• C. Passive
• D. Homing

Answer: (A)

Semi-active guidance uses energy from an external source to illuminate the target, and the missile’s seeker only senses the energy reflected off the target to steer toward it. The aircraft or ground system provides the energy, such as a laser designator or radar illuminator, and the munition detects the reflected energy to guide itself. It does not emit its own illuminating energy. This is different from active guidance, where the weapon itself emits energy to illuminate the target and then tracks the reflection, and from passive guidance, which relies on energy emitted by the target itself. Homing is a general term, but the specific mechanism described—external illumination and reliance on reflected energy—defines semi-active guidance.