Which guidance term describes using energy reflected off the target by energy from another source to guide the munition?

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

Answer: (B)

Semi-active guidance uses energy from an external source to illuminate the target, and the munition’s seeker detects the energy reflected off the target to steer toward it. In this setup, another platform (like a radar or laser designator) provides the energy, and the missile only needs to sense the reflected signal to guide itself. This differs from active guidance, where the munition itself emits energy to illuminate and locate the target, and from passive guidance, which relies on energy emitted by the target or environment rather than a separate illumination source. Homing is a general term for a seeker-based approach, but the specific mechanism described—external illumination with reflection detected by the missile—is best described as semi-active guidance.