Ground-directed bombing (GDB) is a military tactic for

airstrike An airstrike, air strike or air raid is an offensive operation carried out by aircraft. Air strikes are delivered from aircraft such as blimps, balloons, fighters, heavy bombers, ground attack aircraft, attack helicopters and drones. The off ...

s by

ground-attack aircraft An attack aircraft, strike aircraft, or attack bomber is a tactical military aircraft that has a primary role of carrying out airstrikes with greater precision than bombers, and is prepared to encounter strong low-level air defenses while pres ...

strategic bombers A strategic bomber is a medium- to long-range penetration bomber aircraft designed to drop large amounts of air-to-ground weaponry onto a distant target for the purposes of debilitating the enemy's capacity to wage war. Unlike tactical bomber ...

, and other equipped air vehicles under

command guidance Command guidance is a type of missile guidance in which a ground station or aircraft relay signals to a guided missile via radio control or through a wire connecting the missile to the launcher and tell the missile where to steer to intercept it ...

from aviation ground support equipment and/or ground personnel (e.g., ground observers). Often used in poor weather and at night (75% of all

Vietnam War The Vietnam War (also known by #Names, other names) was a conflict in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. It was the second of the Indochina Wars and was officially fought between North Vie ...

bombings "were done with GDB"), the tactic was superseded by an airborne computer predicting unguided bomb impact from data provided by precision avionics (e.g.,

GPS The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite sy ...

GPS/INS GPS/INS is the use of GPS satellite signals to correct or calibrate a solution from an inertial navigation system (INS). The method is applicable for any GNSS/INS system. Overview GPS/INS method The GPS gives an absolute drift-free position val ...

, etc.) Equipment for radar GDB generally included a combination ground radar/computer/communication system ("Q" system) and aircraft avionics for processing radioed commands. A 21st century variant of ground-directed bombing is the radio

for armed

unmanned aerial vehicle An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board. UAVs are a component of an unmanned aircraft system (UAS), which includes adding a ground-based controlle ...

s to effect ground-directed release of ordnance (e.g.,

precision-guided munition A precision-guided munition (PGM, smart weapon, smart munition, smart bomb) is a guided munition intended to precisely hit a specific target, to minimize collateral damage and increase lethality against intended targets. During the First Gu ...

s for bombing such as the AGM-114 Hellfire).

World War II

In early 1945, ground-directed bombing was invented by Lt Col Reginald Clizbe, deputy commander of the

47th Bombardment Group 47th may refer to: Chicago Transit Authority stations * 47th station (CTA Green Line), on the Green Line * 47th station (CTA Red Line) 47th is a station on the Chicago Transit Authority's 'L' system, serving the Red Line. The station is loca ...

(Light), using automatic tracking radar in Northern Italy for A-26C missions (e.g., in the

Po Valley The Po Valley, Po Plain, Plain of the Po, or Padan Plain ( it, Pianura Padana , or ''Val Padana'') is a major geographical feature of Northern Italy. It extends approximately in an east-west direction, with an area of including its Venetic e ...

). Development was by a team that included Donald H. Falkingham (who was awarded the Air Meda

that modified radar plotting to transmit control commands to the pilot direction indicator (bomb release was eventually automated from the ground radar). NOTE: "bombing by radar-control" is identified in a "19 February 1945" listing of the Combat Chronolog

/ref> Similar to the ground training configuration in the US for bombardiers with the

Norden bombsight The Norden Mk. XV, known as the Norden M series in U.S. Army service, is a bombsight that was used by the United States Army Air Forces (USAAF) and the United States Navy during World War II, and the United States Air Force in the Korean an ...

, in a tent near the SCR-284 radar a bombsight was automatically positioned over a large map by the plotting signals converted from the radar track's spherical coordinates from the SCR-284 ranging and antenna pointing circuits. The guidance signals output from the moving bombsight as it viewed the map were then relayed to the aircraft as if the bombsight were on board (e.g., to a 1945 AN/ARA-17 Release Point Indicator).

Post-war In Western usage, the phrase post-war era (or postwar era) usually refers to the time since the end of World War II. More broadly, a post-war period (or postwar period) is the interval immediately following the end of a war. A post-war period ...

, ground radar

was common for missiles designed to bombard ground targets, such as the AN/MSQ-1A with

alternating current Alternating current (AC) is an electric current which periodically reverses direction and changes its magnitude continuously with time in contrast to direct current (DC) which flows only in one direction. Alternating current is the form in which ...

analog computer initially used for guidance of the

MGM-1 Matador The Martin MGM-1 Matador was the first operational surface-to-surface cruise missile designed and built by the United States. It was developed after World War II, drawing upon their wartime experience with creating the Republic-Ford JB-2, a ...

(the Republic-Ford JB-2 Loon had used ground radar guidance in 1945, and a few V-2s bombarding England used radio control in 1944.)

Korean War

Korean War {{Infobox military conflict , conflict = Korean War , partof = the Cold War and the Korean conflict , image = Korean War Montage 2.png , image_size = 300px , caption = Clockwise from top: ...

GDB equipment of the

United States Marine Corps The United States Marine Corps (USMC), also referred to as the United States Marines, is the maritime land force service branch of the United States Armed Forces responsible for conducting expeditionary and amphibious operations through ...

included the AN/MPQ-14, and GBD in Korea "was first tried on November 28 950 when a detachment of the

3903d Radar Bomb Scoring Squadron 39 may refer to: * 39 (number), the natural number following 38 and preceding 40 * one of the years: ** 39 BC ** AD 39 ** 1939 ** 2039 * ''39'' (album), a 2000 studio album by Mikuni Shimokawa * " '39", a 1975 song by Queen * "Thirty Nine", a son ...

used truck-mounted AN/MPQ-2 radars erived from the World War II SCR-584 gun laying set">SCR-584.html" ;"title="erived from the World War II erived from the World War II SCR-584 gun laying setto guide Martin B-26 Marauder">B–26s against enemy positions in front of the 25th Infantry Division (United States)">25th Infantry Division." Three USAF RBS detachments (e.g., Det 5) commanded GDB until the 502nd Tactical Control Group "assumed control of the 3903's three MPQ-2 radar sets" in January 1951, 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." On February 23, 1951, the 1st

Boeing B-29 Superfortress The Boeing B-29 Superfortress is an American four-engined propeller-driven heavy bomber, designed by Boeing and flown primarily by the United States during World War II and the Korean War. Named in allusion to its predecessor, the B-17 F ...

mission controlled by an MPQ-2 was flown, and a new AN/MSQ-1 Close Support Control Set was at Yangu, Korea, by September 1951 ( AN/MPS-9 with OA-132 plotting computer & board). The similar AN/MSQ-2 Close Support Control Set also developed by Rome Air Development Center (MPS-9 radar & OA-215)http://webcache.googleusercontent.com/search?q=cache:_DNZybImKTIJ:groups.yahoo.com/group/combatevaluationgroup/message/23682+%22The+first+AN/MSQ-77+came+from+Richmond%22&hl=en&gl=us&prmd=imvns&strip=1 began arriving in 1951 (in October, one GDB detachment that hadn't been provided MSQ-2 Technical Orders mistakenly bombed itself by using MSQ-1 procedures.) Korea GDB operations of 2380 & 204 respective daylight & nighttime raids included 900 flown by USMC

Vought F4U Corsair The Vought F4U Corsair is an American fighter aircraft which saw service primarily in World War II and the Korean War. Designed and initially manufactured by Chance Vought, the Corsair was soon in great demand; additional production contract ...

Vietnam War

GDB equipment included the USMC AN/TPQ-10 "Course Directing Central" and the

United States Air Force The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army S ...

"Bomb Directing Centrals" with bomb ballistics computer by Reeves Instrument Corporation ( AN/MSQ-77, AN/TSQ-81, & AN/TSQ-96) for

Combat Skyspot Combat Skyspot was the ground-directed bombing (GDB) operation of the Vietnam War by the United States Air Force using Bomb Directing Centrals and by the United States Marine Corps using Course Directing Centrals (" MSQ-77 and TPQ-10 ground ra ...

. 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 (e.g., during the USMC "Operation Neutralize" bombing campaign against the North Vietnamese' siege of "Con Thien"). NOTE: Lake 2004, p. 48, mistakenly says the "normal limit (with two ''Skyspot'' beacons) was 3300 yards from friendly forces", but

TACAN A tactical air navigation system, commonly referred to by the acronym TACAN, is a navigation system used by military aircraft. It provides the user with bearing and distance (slant-range or hypotenuse) to a ground or ship-borne station. It is a mor ...

used multiple beacons, not Skyspot--which used only one radar even if a non-transmitting Skyspot backup receiving the A/C transponder returns tracked or later commanded the bomb run. In addition to Arc Light B-52 airstrikes, GDB during the war was used against Cambodia targets of

Operation Menu Operation Menu was a covert United States Strategic Air Command (SAC) tactical bombing campaign conducted in eastern Cambodia from 18 Ma