Which GBU adds an optional precision laser guidance set in addition to its GPS/INS guidance system?

• A. GBU-39
• B. GBU-54
• C. GBU-31
• D. GBU-53

Answer: (B)

The concept being tested is adding a laser guidance option to a GPS/INS-guided bomb. The GBU-54 is the Laser JDAM: it keeps the standard GPS/INS guidance but adds a semi-active laser guidance set, allowing the weapon to home in on a target designated by laser illumination. If no laser is used, it still flies using GPS/INS, but when a laser designator is employed, the laser energy reflected from the target guides the bomb more precisely. The other bombs either rely on GPS/INS alone, use a different seeker system, or don’t use a laser guidance kit as an optional add-on, so they don’t fit the description as well.