GBU-38 JDAM

The GBU-38 is a guidance kit that converts unguided gravity bombs into all-weather precision-guided munitions. Development originated from a 1992 requirement for an adverse-weather precision weapon following the Persian Gulf War, where atmospheric conditions such as smoke, dust, and cloud cover frequently degraded the performance of laser-guided systems. Initial testing occurred at Eglin Air Force Base, leading to the first successful release of a GPS-guided weapon in February 1993. The system entered operational service in the late 1990s as a successor to the interim GPS Aided Munition.

The system comprises a tail section with aerodynamic control surfaces, a body strake kit, and a combined inertial guidance system (INS) coupled with a Global Positioning System (GPS) receiver. The GBU-38 designation applies to the 500-pound nominal weight class, utilizing warheads such as the Mark 82, BLU-111, BLU-126/B, or BLU-129/B. Guidance is autonomous following release; the weapon navigates to coordinates loaded prior to takeoff, manually entered by aircrew, or provided via datalink from targeting pods. This configuration enables fire-and-forget capability and an expanded launch acceptance region, allowing for off-axis releases. Flight trajectories can be programmed to dictate specific impact angles and headings to maximize warhead effectiveness or penetration. Variants include the Laser JDAM, which incorporates a nose-mounted laser seeker for engaging moving targets, and the JDAM-ER, which utilizes a wing kit to increase standoff distance. A specialized "Quicksink" variant is also employed for anti-ship operations, utilizing a target detection device to detonate near maritime vessels.

The weapon is widely deployed and has been exported to numerous countries, including Australia, Israel, Germany, South Korea, Italy, and Ukraine. It made its combat debut during Operation Allied Force in 1999, where it was employed by B-2 Spirit aircraft. Subsequent use occurred during operations in Afghanistan and Iraq. In 2001, a friendly fire incident occurred in Afghanistan when a technical error involving a battery change in a GPS receiver led to the weapon striking the operator's own coordinates. More recently, the system has been utilized in the Russian invasion of Ukraine and by Israeli forces in strikes in Gaza and Lebanon. Operational reports from Ukraine indicate that the system is susceptible to electronic warfare, specifically GPS jamming. To counter these disruptions, versions have been developed with encrypted M-code signaling and Home-on-Jam seekers designed to track and strike electronic warfare sources.