Which statement describes a Semi-Active weapon guidance system?

• A. Missile Illumination Is Supplied By A Component Carried In The Missile.
• B. Missile Illumination Is Supplied By An External Source, Such As A Transmitter Carried In Launching Aircraft.
• C. Directing Intelligence Is Received From The Target.
• D. Ground-Based Guidance Directs The Missile.

Answer: (B)

Semi-active guidance relies on external illumination of the target. The missile carries a passive seeker that detects energy reflected off the target, while the energy used to illuminate the target comes from another source, typically the launching aircraft’s radar or a ground-based transmitter. This external light source is what the seeker homes in on, not energy emitted by the missile itself. That’s why the statement describing illumination supplied by an external source, such as a transmitter in the launching aircraft, best fits semi-active guidance. The other scenarios describe different guidance modes: one where the missile itself emits illumination (active guidance), another implying the target provides directing intelligence or emissions for tracking (not about how illumination occurs), and another where guidance is provided by ground-based commands rather than reflection from external illumination.