Field artillery
Field artillery is a category of mobile artillery used to support armies in the field. These weapons are specialized for mobility, tactical proficiency, short range, long range, and extremely long range target engagement.
Until the early 20th century, field artillery were also known as foot artillery, for while the guns were pulled by beasts of burden, the gun crews would usually march on foot, thus providing fire support mainly to the infantry. This was in contrast to horse artillery, whose emphasis on speed while supporting cavalry units necessitated lighter guns and crews riding on horseback.
Whereas horse artillery has been superseded by self-propelled artillery, field artillery has survived to this day both in name and mission, albeit with motor vehicles towing the guns, carrying the crews and transporting the ammunition. Modern artillery has also advanced to rapidly deployable wheeled and tracked vehicles and precision delivered munitions capable of striking targets at ranges between 15 and 30 kilometers.
Types
- Field guns – capable of long range fire
- Gun howitzers – capable of high or low angle fire with a long barrel
- Howitzers – capable of high angle fire
- Infantry support guns – directly support infantry units
- Gun mortars – breech-loaded mortars capable of high or low angle fire.
- Mortars – weapons that fire projectiles at an angle of over 45 degrees to the horizontal, modern versions being lightweight with fin-stabilized explosive ammunition
- Mountain guns – lightweight weapons that can be moved through difficult terrain
- Multiple rocket launchers – mobile rocket artillery launchers
History
Early modern era
Early artillery was unsuited to the battlefield, as the extremely massive pieces could not be moved except in areas that were already controlled by the combatant. Thus, their role was limited to such functions as breaking sieges. Following the beginning of the gunpowder era, the first field artillery came into being as metallurgy allowed thinner cannon barrels to withstand the explosive forces without bursting. However, there was still a serious risk of the constant changes of the battlefield conspiring to leave behind slow-moving artillery units – either on the advance, or more dangerously, in retreat. Artillery units were particularly vulnerable to assault by light cavalry, which were frequently used in this role. Only with a number of further inventions, did the concept of field artillery really take off.The medieval Ming dynasty Chinese invented mobile battlefield artillery during the early part of the fourteenth century at the time when gunpowder and the primordial cannon were first being adopted in the West. One of the earliest documented uses of field artillery is found in the 14th-century Ming Dynasty treatise Huolongjing. The text describes a Chinese cannon called a "thousand ball thunder cannon", manufactured of bronze and fastened with wheels. The book also describes another mobile form of artillery called a "barbarian attacking cannon" consisting of a cannon attached to a two-wheel carriage.
20th century
Before field artillery batteries generally fired directly at visible targets measured in distances of meters and yards. Today, modern field batteries measure targets in kilometers and miles and often do not directly engage the enemy with observed direct fire. The hundredfold increase in the range of artillery guns in the 20th century has been the result of development of rifled cannons, improvements in propellants, better communications between observer and gunner, and technical improvements in gunnery computational abilities.Most field artillery situations require indirect fire due to weather, terrain, night-time conditions, distance, or other obstacles. These gunners can also rely upon a trained artillery observer, also called a forward observer, who sees the target and relays the coordinates of the target to their fire direction center, which in turn translates those coordinates into: a left-right aiming direction; an elevation angle; a calculated number of bags of propellant; and finally a fuze with a determined waiting time before exploding to be set, which is then mated to the artillery projectile now ready to be fired.
US field artillery team
Modern field artillery has three distinct sections: All batteries have a Fire Support Man, Fire Direction Control, and Cannoners.The FOs are forward with the infantry where they can see the targets and Call For Fire 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. 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. 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, 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 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 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 FO and the battery iteratively "walk" the fire onto the target. The Fire Direction Center 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". 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.