Modern field artillery (i.e. post-
World War I) has three distinct sections: All batteries have a Fire Support Man (Forward Observer), Fire Direction Control (FDC), and
Cannoners (Gunner). The FOs are forward with the infantry (in support role) where they can see the targets and Call For Fire (CFF) upon them. They call the FDC on the radio and transmit a request for fire in the format of CFF. The FDC calculates the CFF and send a
deflection and
elevation to the gun line. The gun line cranks the specified elevation and deflection on the howitzers, punch the artillery shell followed by the bag (powder). Depending on the CFF, the gunline will fire the
round when they are ready or when the FO calls and tells them to fire. The FO spots the round and sends a correction back to the FDC and the process starts all over again until it's done. The batteries are many kilometres behind the
FLOT (Forward Line of Troops). They plan a location where they can be Fire Capability for some certain amount of time and do multiple fire missions before needing to displace. In normal operations the FOs locate targets and transmits the CFF to the FDCs. They can also calculate "defensive fire" tasks. These are pre‑planned missions, typically just in front of or upon one's own positions, designed with the intention of either suppressing potential attacks (where fire is dropped just in front of a friendly position), or in dropping fire on a recently abandoned or overrun position to prevent the enemy from consolidating there. Because the calculations have already been done, the fire can be called down very quickly when it is needed.
Reconnaissance and advance party The advance party consists of the battery commander, his driver, first sergeant, gunnery sergeant, FDC guide, gun guides, and communications representatives. Initially the Party looks to find suitable positions for an artillery unit to perform fire missions from. Then they perform what is known as route reconnaissance. The primary purpose of this reconnaissance is to determine the suitability of the route of the unit's movement. Items to be analyzed include possible alternate routes, cover, concealment, location of obstacles, likely ambush sites, contaminated areas, route marking requirements, and the time and distance required to traverse the route. Several factors are taken into consideration. Once a location is determined and having arrived at the new position the advance party conducts a security sweep and prepares the position for occupation. The purpose of the advance party security with METT-T and the absence of enemy troops, mines, booby traps, NBC hazards, and so on. If these threats or conditions are present in the proposed position area, the advance party breaks contact with any enemy forces or marks minefield and hazards and moves on to find another position area. The battery commander can coordinate for additional assets, or augment the advance party with internal assets, to provide the additional ability to clear areas of small enemy forces, obstacles, and minefields. Natural cover must be used to the maximum. Security is continuous throughout advance party operations. Once a location is determined to be safe the advance party prepares the position for eventual howitzer emplacement. This consists of several procedures such as escorting each howitzer to its prepared position, setting up communications, providing the unit with its initial azimuth of fire, and providing each gun with an initial deflection. In the case of the U.S. Army, this entire process is covered in U.S. Army Field Manual 6-50 Chapter 2.
Forward observer Because artillery is an
indirect fire weapon, the
forward observer (FO) must take up a position where he can observe the target using tools such as
binoculars and
laser rangefinders and call back fire missions on his radio or telephone. The FO usually establishes a covered and concealed
observation post (OP) on the ground, from which he can see the enemy. However, he may also be airborne—this was one of the first uses of
aircraft in World War I. He must take great care not to be observed by the enemy, especially if in a static position. Discovery of an FO does not only jeopardize his personal safety; it also hampers the ability of the battery to lay fire. Using a standardized format, the FO sends map references and bearing to target, a brief target description, a recommended munition to use, and any special instructions such as "danger close" (the warning that friendly troops are within 600 meters of the target when using artillery, requiring extra precision from the guns). The FO and the battery iteratively "walk" the fire onto the target. The Fire Direction Center (FDC) signals the FO that they have fired and the FO knows to observe fall of shot. He then signals corrections. These are normally of the form of left/right of the bearing line and distance along it, for example "right 50 add 100" (distance in meters). When the fire is good enough the FO signals "target on, fire for effect". If the mission requires a walking
barrage, he may continue sending correction orders. The FO may be called upon to direct fire for
close air support and/or
naval artillery in addition to field artillery based
howitzer and infantry-embedded
mortar units. The U.S. Army Field Manual describing the duties and responsibilities is FM 6‑30,
Tactics, Techniques, and Procedures for Observed Fire. but not to the soldiers manning the guns, themselves
Fire direction center Typically, there is one FDC for a
battery of six guns, in a light division. In a typical heavy division configuration, there exist two FDC elements capable of operating two four-gun sections, also known as a split battery. The FDC computes firing data—fire direction—for the guns. The process consists of determining the precise target location based on the observer's location if needed, then computing range and direction to the target from the guns' location. These data can be computed manually, using special protractors and slide rules with precomputed firing data. Corrections can be added for conditions such as a difference between target and howitzer altitudes, propellant temperature, atmospheric conditions, and even the curvature and rotation of the
Earth. In most cases, some corrections are omitted, sacrificing accuracy for speed. In recent decades, FDCs have become computerized, allowing for much faster and more accurate computation of firing data. The FDC at the battalion level is responsible for recording friendly and enemy positions, tracking available battery munitions, and determining the optimal response for engaging a target identified by the FO.
Command post In most Artillery Batteries the Command Post (CP) controls the firing of the guns. It is usually located at the battery center so as to be able to communicate easily with the guns. The CP should be well camouflaged, but the CPO (Command Post Officer) should be able to see all the guns with ease. Gun markers are sometimes placed in front of the CP to remind the CPO which gun is in which position. The CPO is assisted by two "Acks"—i.e., assistants—who operate the fire data computers. The GPO (Gun Position Officer) and CPO work at the plotter to ensure that the data calculated by the Acks is accurate and safe. The CP signaller is contact with the OP, or Observation Post, where the Forward Observer Officer (FOO), works with the OP team to identify targets and call-back fire data. In recent years headset radios have become common for communication between the CPO and gun detachment commanders.
Firing unit The final piece of the puzzle is the firing unit itself. The FDC will transmit a warning order to the guns, followed by orders specifying the type of ammunition and fuze setting, bearing, elevation, and the method of adjustment or orders for fire for effect (FFE). Elevation (vertical direction) and bearing orders are specified in
mils, and any special instructions, such as to wait for the observer's command to fire relayed through the FDC. The crews load the howitzers and traverse and elevate the barrel to the required point, using either hand cranks (usually on towed guns) or
hydraulics (on self-propelled models). == Counter-battery fire ==