Artillery

:For the thrash metal band, see Artillery (band)

Modern artillery operations

Depending on the calibre of the weapons, artillery is used in a variety of roles. Mortars fire relatively short range and small- to medium-calibre (up to about 120 mm) projectiles. Modern mortars, because of their lighter weight and simpler, more transportable design, are usually organic to infantry and armor units, allowing greater responsiveness and negating their shorter range.

Related Topics:
Infantry - Armor

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Howitzers are generally used in direct support of infantry and armor, where the guns of a battery or even a battalion will be massed to fire simultaneously onto a single point or area target. Howitzers are usually between about 105 mm and 155 mm in calibre.

Related Topics:
Battery - Battalion

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Counter-battery fire

Attacks aimed at enemy artillery rather than infantry or fortifications are known as counter battery fire.

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Radar coupled to computers can accurately track a projectile in flight back to its firing point. This can be used as targeting information for an enemy artillery site.

Related Topics:
Radar - Computers

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When artillery fire is directed via radio by a forward observer (FO), the location of FO's transmitter can be calculated and attacked with artillery as well. If successful, this counter-attack will limit the effectiveness of the FO's artillery fire. Radar also improves the all-weather flexibility of modern artillery.

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The rise in counter-battery abilities has driven field artillery to adopt "shoot-and-scoot" tactics emphasizing constant maneuver within a designated position area, usually from hide point to firing point and back again. This has required reliance on sometimes temperamental technology and increased the cost of modern field artillery systems.

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The field artillery team

Modern field artillery (Post-World War I) has three distinct parts: the forward observer (or FO), the fire direction center (FDC) and the actual guns themselves.

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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 range finders and designators and call back fire missions on his radio. This position can be anywhere from a few thousand meters to 20-30 km distant from the guns.

Related Topics:
Indirect fire - Binoculars - Laser range finders

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Using a standardized format, the FO sends either an exact target location or the position relative to his own location or a common map point, 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 metres of the target, requiring extra precision from the guns). Once firing begins, if the rounds are not accurate the FO will issue instructions to adjust fire and then call "fire for effect."

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The FO does not talk to the guns directly - he deals solely with the FDC. The forward observer can also be airborne and in fact one of the original roles of aircraft in the military was airborne artillery spotting.

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Typically, there is one FDC for a battery of six guns. 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.

Related Topics:
Battery - Earth

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The final piece of the puzzle is the "gun line" itself. The FDC will transmit the fire order to the guns, specifying the number of volleys, a particular shell and fuze combination, the specific charge, a deflection (horizontal direction) and quadrant elevation (vertical direction) both specified in milliradians (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 tube to the required point, using either hand cranks (usually on towed guns) or hydraulics (on self-propelled models).

Related Topics:
Mils - Hydraulics

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Technology Impact

It is possible for modern computer-controlled artillery to fire more than one volley at a target and have all the shells arrive simultaneously, which is called MRSI (Multiple Rounds Simultaneous Impact). This is because there is more than one trajectory for the rounds to fly to any given target - typically one is below 45 degrees from horizontal and the other is above it, and if you can vary the amount of propellant with each shell, you can create more trajectories. Because the higher trajectories cause the shells to arc higher into the air, they take longer to reach the target and so if the shells are fired on these trajectories for the first volleys (starting with the shell with the most propellant and working down) and then after the correct pause more volleys are fired on the lower trajectories, the shells will all arrive at the same time. This is useful because many more shells can land on the target with no warning. With traditional volleys along the same trajectory, anybody at the target point will have a certain amount of time (however long it takes to reload and re-fire the guns) to run away or take cover between volleys. In addition, if guns in more than one location are firing on one target, with careful timing it can be arranged for all their shells to land at the same time for the same reason.

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Examples of MRSI guns are South Africa's Denel G6-52 (which can land six rounds simultaneously at targets at least 25 km away) and Germany's Panzer Haubitze 2000 (which can land five rounds simultaneously at targets at least 17 km away). The United States Crusader programme (now cancelled) was slated to have MRSI capability.

Related Topics:
South Africa - Denel G6 - Germany - Panzer Haubitze 2000 - United States - Crusader

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When an effect similar to that of MRSI is achieved using separate batteries of traditional artillery, using varying fuses to account for the variant distances or trajectories to cause all shells to detonate on the target at the same time, it is called TOT (Time On Target). The logic behind this practice is the same as that for MRSI: to surprise the enemy and to sow confusion when guns heard to be firing at different times nonetheless result in deadly explosions in the same instant.

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An additional wrinkle can be added when some or all of the shells are set for airburst, meaning they explode in the air above the target instead of upon impact. This is a very effective tactic against infantry and light vehicles because it scatters the shrapnel over a larger area and prevents the blast shockwave from being blocked by terrain, but usually proves ineffective against troops or equipment protected by even rudimentary fortifications. However, airbursts are probably more likely to impact units protected by trenches and revetments, since the shrapnel can enter them from above, while a ground-burst nearby would simply cause the shrapnel to impact the walls or fly overhead.

Related Topics:
Shrapnel - Shockwave - Fortifications - Trench - Revetment

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