ShackTac ArmA2 TTP2 Guide/Combined Arms/Working with Artillery

Artillery is long-range fire support that can act as a massive force-multiplier to the troops it is supporting on the ground. An infantry platoon supported by a battery of 155mm Howitzers has far, far more firepower at its fingertips than a Company (four platoons) of enemy infantry without artillery support.

Pros & Cons of Artillery in the Combined Arms Fight

Pros

Powerful terminal effects. Artillery rounds come in a variety of types and sizes, but the general rule is that they offer powerful blast effects and are effective at putting a great deal of hurt on enemy forces, particularly soft-skinned vehicles, light armor, and infantry. Specialized rounds are also effective at dealing with hardened or armored targets.
Can cover areas that cannot be reached or observed by infantry, complementing any infantry defense. Due to their flight characteristics, artillery can rain down on areas that the infantry may not be able to effectively cover. This can be used, particularly in the defense, to reinforce the overall defense by forcing the enemy to either face the direct fires of the defending infantry, or come under the indirect fires of the supporting artillery.
Long reach. Artillery starts at several kilometers of range, and goes up significantly with each increase in artillery type. They are able to sling rounds all over Chernarus with relative ease.
Can screen with smoke or illuminate the night with flares. Smoke rounds are available to provide either a defensive or offensive smoke screen in most weather conditions, while flares can be used to illuminate targets and terrain at night.
Variety of ammo types and fuze types for maximum effects. Arty comes with a huge variety of ammunition and fuzing types, described later in this section. Whether working against infantry or armor, there is a fuze and round combination for pretty much every eventuality.
Can be directed by a single person without giving their position away. A forward observer can call in and adjust artillery fire from a concealed location without ever giving themselves away. One good forward observer in a good position, with the support of an artillery battery, can be a major thorn in the enemy's side.

Cons

Delay between calling for it and getting effects on the ground. The time-of-flight of artillery rounds will vary based on whether they are fired as high-angle or low-angle fire (note that mortars are high-angle only), as well as the distance from the target. This delay can be up to a minute just for the time-of-flight. Add onto that the fact that the artillery battery must plot the target, align their guns to it, and load the ammo before ever firing the first shot, and you may have to wait several minutes before the first shot impacts.
Requires skilled FO to call effectively. A bad forward observer can easily call artillery down onto empty ground, or worse, friendly positions.

"An artillery battery in the middle of carrying out a fire mission"

Artillery Realism

There are several aspects of realistic artillery support that are not seen in games with more casual action-based artillery (ie BF2) or mods/scripts that don't model it ballistically (ie the typical "map click" scripts for OFP/ArmA). Some of these elements are as follows.

It takes time for the artillery crew to dial in the information from the Forward Observer and get their battery ready to fire. Artillery support can be quick, but it is not instantaneous as in some unrealistic models of it.
Artillery rounds fly a ballistic path from the guns to the target. There are many factors that can influence the accuracy of the rounds, and several measures that the enemy can take to help to lessen their effects. Guns may fire high-angle, low-angle, from close or long range, with any combination of sheafs and such, and all of this combines to dictate how much of an effect any given strike will have on the target. The terrain they are used in, and the terrain at the target, also factors into it.
It takes time for the artillery to impact after it has begun firing. There is a significant amount of "lead" or pre-planning that must be factored into the use of an artillery asset. Finding chokepoints, natural rally points, and other likely enemy routes and pre-planning fires on them can help to make the artillery responsive and able to engage such targets effectively. Waiting until the last second and trying to call in a strike on a moving enemy will be far less effective than planning ahead and anticipating their movements and attack routes.

The Forward Observer

The Forward Observer is the platoon's direct link to artillery support. He is tasked with calling for fire in accordance with the Platoon Commander's direction, adjusting fire, and generally being all things artillery.

The proper use of artillery requires that the person calling it in is knowledgeable on the previously-listed aspects (and more) and is competent as a "Forward Observer". Artillery in the hands of a skilled FO is a huge asset, whereas without that skill the artillery will only end up churning dirt and making loud but ineffective noises.

Forward Observer Tips

Get a good perspective. Calling for accurate fire oftentimes (but not always) requires you to see what you're trying to hit. Adjusting fire requires that you can not only see the impact area, but can also view it from a perspective where you can accurately gauge depth. This usually means that you will need to be at a higher elevation than whatever you're directing fire on.
Don't pick an obvious observation point. There were very few church steeples that survived World War II in western Europe. While such a position gives you a commanding view of the terrain, it also sticks out like a sore thumb and tends to attract all manner of enemy fire, particularly of the high-explosive variety. The use of tall structures must be considered carefully - the benefit is observation, the downside being an obvious target to the enemy.
Try to predict where the enemy will go, where they might halt to regroup, and what lanes they'll attack through when in the defense. Pre-plotting targets in these areas will allow for you to be more responsive with your artillery fire. Establishing reference targets also allows for friendly forces to more easily call for quick-reaction artillery strikes on pre-established locations.
Know your round types, fuze types, gun/battery types, sheaf options, and fire options, and take advantage of them. A good FO will know how best to utilize his artillery assets to maximize their effects on the enemy.
Coordinate closely with infantry units at all times. Pay particular attention to coordination when suppressing the enemy while friendly forces move up to assault. You want to maintain artillery fire on the enemy unit the maneuvering friendly elements are close enough to the objective to assault it immediately after the artillery fire is lifted. Failure to do this can result in heavy casualties for an assault force, as the enemy potentially will be able to recover in time to attempt to repel the assault.
Know the different types of artillery and how to employ them effectively. Mortars, howitzers, and MLRS systems all have distinct characteristics and uses.
Know how to adjust fire. Be familiar with concepts like "Bracketing", firing spot rounds, calling in adjustments to human players, and so on.

Forward Observer & Artillery Terms

Term	Meaning
Shot	This is sent from the firing unit once the first rounds are fired. The FO at that point knows that rounds are on the way. The FO can use this term to communicate to his platoon that a friendly artillery unit has begun firing.
Splash	This is sent from the firing unit five seconds before the first rounds impact. The FO at this point should observe the impact area to watch the effects of the artillery. Adjustments will be called if necessary to get the rounds on target. When Splash is called, all friendly units within "danger close" distance of the target should ensure that they are in good cover in case the rounds are off.
Rounds Complete	Firing unit has fired all rounds for the fire mission. Depending on the number of rounds and the trajectory used, "Rounds Complete" can sometimes come before the first round ever hits.

Artillery Rounds & Fuzing 101

The following table of artillery round types and their effects is taken from the Chain of Command's "Artillery Module" manual for VBS1. If you would like to read more about CoC's Unified Artillery mod for Operation Flashpoint (along with videos of it in action), you can find my old beta preview of it here.

Round Types

Round Type	Description
High Explosive	HE is usually TNT or Composition B, and takes a PD (QUICK), VT, delay or Mechanical Time fuze. Effective against personnel, vehicles, and structures. HE/VT is also effective against stationary armored vehicles. HE/Delay is good for targets under vegetation, and for flipping vehicles.
White Phosphorous (Willy Pete)	Bursts on impact, or in the air (with fuze time). On bursting, the shell spreads burning white phosphorus, for marking, screening, obscuring and incendiary effects. It is useful against vehicles, ammunition, POL and enemy observers.
Illumination	A base-ejecting projectile that expels a burning illuminant and a small projectile. The parachute drifts over the area, and provides illumination for maneuver or adjusting fire (with continuous and coordinated illumination). It can also be used to mark targets.
Smoke	The Artillery Module models improved smoke effects, that is, felt wedges impregnated with WP, which can provide 5-10 minutes of smoke over a large area.
Remote Anti-Armor Mines (RAAMS)	The 155mm howitzer can fire Remote Antiarmor Mines (RAAMS); Part of the Family of Scatterable Mines (FASCAM), RAAMS typically spread over a 400m area, arm shortly after impact, and will trigger when armored vehicles run over them.
Copperhead	Copperheads are special 155mm projectiles employed by later versions of the M109 series and the M198 howitzer. Approximately thirteen seconds before impact, the Copperhead's laser light sensor becomes active, and it uses fins to guide itself to the laser light source. It fuzes on impact with a shaped charge capable of destroying or disabling armored vehicles. Because of their relatively high cost, low volume (one platoon fires a single Copperhead every thirty seconds), and restrictive employment considerations, Copperheads are best used against enemy command vehicles and centers, and other high-value targets. Copperheads are ideally used in priority fire missions, and the reduced response time they bring.
Improved Conventional Munitions (ICM)	ICM is a base-ejection projectile with a MT fuze and a number of submunitions. APICM grenades saturate the target area with shrapnel, and are highly effective against personnel in the open. DPICM submunitions are capable of penetrating 2cm of armor, and have an antipersonnel effect as well. DPICM is highly effective against personnel in the open and soft vehicles. It is also effective against armor. ICM shells and sheaves assume a target with a 200m-radius. (instead of 100m for HE). ICM should never be fired High Angle.
Sense and Destroy Armor (SADARM)	Sense-and-Destroy Armor rounds are third-generation artillery shells carried by 155mm Howitzers. They deploy two sensor-fuzed munitions which parachute over the battlespace, and scan (using radar and infrared) for suitable armor targets. When they find such a target, they fire a penetrator to destroy or disable it. SADARMs are highly effective, and are called as any other round. If they do not find a suitable target, they self-destruct. The observer should ensure that no friendly units are in the area. SADARMs can be used effectively in CANNOT OBSERVE conditions, especially counter-battery fire.

"High-angle fire from a 105mm gun"

Fuze Types

Fuze Type	Description
Fuze Quick	Fuze quick is a point-detonating fuze, and is used with HE and WP projectiles. Fuze quick is effective against standing and prone personnel, armored and soft-skinned vehicles. Fuze quick is useful for adjusting fire and engaging targets on ridgelines; but it is not recommended against entrenched troops or those on uneven ground.
Fuze Delay	A fuze delay functions 0.05 seconds after impact. A fuze delay allows penetration of dense woods and light earthworks.
Fuze Time	Fuze time has a mechanical or electronic timing device that functions a set time after being fired. Fuze time, when used with HE and WP, should be adjusted to obtain an effective HOB; then these projectiles are useful against troops and vehicles in open and in trenches, as well as in rough terrain. Because of the variations between fuzes, fuze time should never be used for High Angle fire with these projectiles. Time fuzes are the only fuze used for Base-Ejecting projectiles (e.g., Illumination, ICM, SADARM) and smoke.
Fuze VT	VT (Variable Time) fuzes arm approximated 3.5 seconds before anticipated impact. They then use a radio signal to determine the shell's proximity to other objects (especially the ground). When they pass within a set distance of other objects (for example, 8 meters), the fuze functions. HE/VT is effective against all targets that Fuze Time is, except that it is not recommended for targets under canopy, such as those in woods.