[3] In early 1945, ground-directed bombing was invented by Lt Col Reginald Clizbe, deputy commander of the 47th Bombardment Group (Light), using automatic tracking radar in Northern Italy for A-26C missions (e.g., in the Po Valley).
Korean War GDB equipment of the United States Marine Corps included the AN/MPQ-14, and GBD in Korea "was first tried on November 28 [1950], when a detachment of the 3903d Radar Bomb Scoring Squadron used truck-mounted AN/MPQ-2 radars [derived from the World War II SCR-584 gun laying set][10] to guide B–26s against enemy positions in front of the 25th Infantry Division.
"[11] Three USAF RBS detachments (e.g., Det 5)[12] commanded GDB until the 502nd Tactical Control Group "assumed control of the 3903's three MPQ-2 radar sets" in January 1951,[13] and the radar sites "became full-scale tactical air-direction posts called Tadpoles [code]-named Hillbilly, Beverage, and Chestnut,…about ten miles behind the front lines near the command posts of the I, IX, and X Corps.
From 1966-1971, ASRTs controlled more than 38,010 AN/TPQ-10 missions, directing more than 121,000 tons of ordnance on 56,753 targets[20] (e.g., during the USMC "Operation Neutralize" bombing campaign against the North Vietnamese' siege of "Con Thien").
Post-Vietnam War GDB Strategic Air Command missions were occasionally used for training/readiness, e.g., to maintain proficiency of aircrews and SAC's GDB-qualified technicians at 1st Combat Evaluation Group RBS sites.