Forces that have shown the ability for their ‘guns’ (field artillery) to keep up with advancing infantry and cavalry combat forces have always had a decisive advantage. This is because the ground force as a whole is able to move forward, rather than one part risking outrunning another.

Unlike mechanized artillery, towed guns need to uncouple from their prime mover to fire and have limited off-road mobility. This means that they cannot be as responsive to the indirect fire demands of mechanized combat units particularly during the offensive, compared to their mechanized counterparts. It did not take long for armies to begin fitting artillery guns onto tracked and half-tracked platforms in an attempt to provide artillery the ability to keep closer to the fighting units, once the proliferation of tracked vehicles occurred en masse during the First World War. In the Second World War, mechanized artillery evolved further to provide indirect fires from vehicle-mounted howitzers as well as direct fire support by assault guns such as the Wehrmacht (Nazi Germany’s armed forces) Sturmgeschütz III tracked assault gun.

self-propelled artillery
For many years self-propelled artillery, though more mobile, was employed in the same manner as towed guns typically used in batteries of six to eight guns that moved into pre-surveyed positions. (US Army)

There are clear tactical advantages to Self-Propelled Artillery (SPA) beyond its capability to move with a mechanized force yet there are also drawbacks. As with all military equipment there is no ‘perfect solution’ but rather a trade-off between competing characteristics. The ‘right’ system is influenced by the mission, terrain, anticipated enemy and their capabilities, and the method of employment of the guns and the land force as a whole. Still there have been a number of design and equipment innovations and technologies in the last decades that have substantially multiplied the effectiveness of SPA. These in turn have influenced the way artillery is organized, employed and integrated into the larger combat force.

Advances and Innovations

Artillery’s role is to quickly delivery accurate and effective indirect fires against both enemy forward forces and to suppress or destroy opposing artillery’s ability to deliver similar fires on friendly units (referred to as counter-battery). Thus, artillery must be capable of attacking targets on demand but also avoid being destroyed by enemy attempts to find, engage and neutralize themselves. The prerequisites for effective lethal artillery fires are accurately knowing your position and that of the target, rapidly computing the fire control solution, applying it to the gun, and achieving maximum destructive effect by delivering with minimum or no warning multiple rounds directly on target spaced within seconds. Having completed the fire mission it can be expected, at least against an equally technically capable opponent, that the gun position has been detected and may be targeted in return by the enemy. To preclude being taken under fire the guns must now move to a new position and then be ready to respond to new calls for fire. A common term for this sequence is ‘shoot-and-scoot’.

SPA, unlike towed guns (see above), are most suited to this technique but accomplishing all the steps described is still challenging. However, a number of technologies have been introduced that give artillery a new dimension in its employment and effectiveness. These enhanced capabilities cover navigation and positioning, digitized integrated networked command and control, automatic loading, automated firing solution computation and gun laying, and improved ammunition.

Navigation and Positioning

The Global Positioning System (GPS) geolocation satellite network coupled with electronics miniaturization allows gunners to determine accurate location down to a personal or individual equipment level. Yet guns, particularly Self-Propelled Howitzers (SPHs), ideally require even higher accuracy as well as reliable access and responsiveness even while moving, perhaps more than GPS can often offer. When computing advances improved and lowered costs for Inertial Navigation Systems (INS), which uses computers and motion sensors to determine a vehicle’s position and speed, it provided a major advance in positioning information that can now be installed on every SPH. INS units like the Safran Defence Electronics (formerly Sagem) Sigma 30, the Kearfott LandNav and those produced by ASELSAN provide better than ten metre/m (32.8 feet/ft) position and up to one mil direction accuracy in any conditions including on the move, under trees or other cover. As a Safran design engineer pointed out to Armada, “this combination of INS and GPS eliminates any need for outside survey support and allows each gun to autonomously and precisely know its location at all times.”

Command and Control

The introduction of digital communications corresponding integrated data networks address what have been ever-present problems for artillery; chiefly how to pass target information from forward-positioned observers to the gunners, and how to coordinate the fires of batteries spread over the battlefield. Systems like Thales’ ATLAS artillery Command and Control (C2) system which is used by the Armée de Terre (French Army) solve this. It provides onboard terminals for communications and real-time firing management including fire-support requests and firing orders. Raytheon’s Advanced Field Artillery Tactical Data System (AFATDS) Fire Support C2 system is employed by the US Army and US Marine Corps. A Raytheon spokesperson explained that the AFATDS enhances artillery by “prioritizing targets and coordinating firing assets from battery to higher (echelons) to provide timely, accurate and managed fire support options.”

When these C2 systems are coupled with forward observer target locators like Vinghøg’s LP10TL Target Locator and FOI2000 Forward Observation System, Safran’s GonioLight or Instro Precision’s Thor Targeting System it is possible to achieve true observer to shooter synergy. With both the guns and observer having precise locations and exchanging raw target data directly, the fires can be delivered with unprecedented speed. The SPH can be in transit to its next position and yet receive a ‘call for fire’ from an observer and begin to compute and prepare a firing response. Literally in seconds a firing solution can be determined, guns laid, rounds loaded and fired. The Kraus Maffei-Wegmann (KMW) PzH2000, BAE Systems’ FH-77BW L52 Archer Artillery System and Samsung Techwin’s K-7 Thunder SPH can have rounds on the way within 30 to 60 seconds of halting. The advantages of these designs are reflected in their export success. The K-9 Thunder for example is the baseline (by license production) for the Turkish T-155 Firtina (Storm), and its 2015 selection by India as the K-9 Vajra which will be assembled in country by Larsen and Toubro. In addition, the K-9 chassis will be produced and to be integrated with Polish Huta Stalowa Wola AHS Krab, the rollout of which occurred in August 2015, with plans to deliver 120 to the Wojska Lądowe (Polish Army).

K-9 Thunder is the baseline design for the Turkish T155 Fintina
The K-9 Thunder is the baseline design for the Turkish T155 Fintina. K-9 was also evaluated for the Australian Army Self Propelled gun programme which was cancelled. (RoK Army)

Logistics

An axiom of combat is that the surprise multiplies combat effect; thus, the initial attack, before the target can react, always has the greatest impact. This is even truer of indirect fires. The ideal mission is where multiple guns or batteries are coordinated to all fire so as to impact on a target at the same time. The substitution of automated loading systems on SPHs for manual loading allows a single or ‘short’ battery of two or three guns to repeatedly achieve this goal. When coupled with computer-controlled gun aiming the auto-loader allows Multiple-Round Simultaneous-Impact (MRSI) engagements by even a single gun. The process has the computer changing the gun elevation for each round so as to have all rounds then impact at the same time on the target area. The FH77BW L52 has a rate-of-fire of three rounds in 15 seconds, the PzH2000 achieves twelve rounds in fewer than 60 seconds, and the US Army’s BAE Systems M-109A6 Paladin can fire three rounds in 16 seconds with a sustained rate of eight per minute. These capabilities exceed that which could be achieved by a full battery of six to eight guns only a few years ago.

PzH2000
The PzH2000 maximizes the use of automation in all aspects of the gun aiming, loading and firing process to both reduce the crew size and to allow the gun to undertake fire support missions as an independent unit. (KMW)

A consequence of the auto-loader’s introduction is that it requires configuring the ammunition storage in some version of a ‘magazine’ whereby the specific round and projectile type can be readily accessed. Approaches have included a ‘clip type’ on the gun as with the FH77BW L52; a separate protected ammunition compartment as in the M-109A6, K-9 and T-155. Christian Budd, a KMW spokesperson, reflected, “Our PzH2000 is optimized for autonomous operations. Auto-loading and rapid fire (‘burst fire’) capabilities are key, as well as the need to have larger amounts of on-board ammunition. In fact, the PzH2000 has a basic on-board load of over 60 projectiles.”

Replenishing ammunition for artillery has always been a challenge. With SPHs this is compounded by their ability to move quickly and off-road. Ammunition in trucks is inadequate as such vehicles cannot keep up with the advance and often have, in the past, no crew protection against enemy fires. The US Army was one of the first to address this in 1982 by introducing the BAE Systems’ M-992A2 FAASV (Field Artillery Ammunition Supply Vehicle). With the same chassis as the M-109A2, it has equivalent mobility and armour and can carry 96 conventional rounds (the M-109A2 itself has a basic load of 36). It has a powered ammunition handling system that assists the five-person crew in transferring rounds to the SPH. Other armies have followed suit, in fact, often referring to their combination of gun and resupply vehicle as a ‘system’ to be employed together. BAE Systems’ FH77BW L52 refers to a complete system which includes both the FH77BW L52 SPH itself and its ammunition resupply and support vehicles. The K9 Thunder SPH is employed with the K-10, a fully-automated re-supply vehicle with which it shares the chassis, power pack and suspension. It can transfer twelve rounds-per-minute. These purpose built ammunition resupply systems perform a critical role in assuring that continuous fire support can be reliably provided on a highly fluid battlefield. This is particularly true in combat where it may be essential for the guns to move often and where high ammunition expenditure is expected.

Automation

The presence of INS/GPS and digital computers provides almost seamless calculation of the gun firing solution for each target. Integrating this data into the gun traverse and elevation servos permits the gunner to direct their gun to the proper aim point with the push of a button. The process can be totally automated with even propellant charges determined, selected and prepared. This ‘hands-off’ process, coupled with the automatic loading, is the core to the Multiple-Round Simultaneous-Impact (MRSI) capability. Another benefit is the substantially reduced crew size required. Early SPHs required five to seven troops in the gun/vehicle crew. Current systems have reduced this by 50 to 75 percent. For example, the FH77BW LA2 can be fired by as few as three soldiers. They can carry out an entire fire mission and displace to a new position without ever touching the gun or leaving the protection of the armoured cab. This capability is of special interest to nations with smaller forces and limited numbers of soldiers and equipment. This was one of the motivations for the Armén (Swedish Army) on its FH77BW LA2 selection. Singurlaug Jonsdottir, a spokesperson for BAE Systems’ Bofors division which builds the product, confirmed that the Swedish army accepted its first unit in September 2015 with further deliveries in the first 24 unit order occurring in 2016.

FH77BW LA2
The FH77BW LA2 combines a number of innovations including use of a truck platform, automatic magazine loading, computerized fire control and gun laying. (BAE Systems)

Improved Ammunition

Advances in electronics miniaturization opened the door for taking the precision targeting technology being employed in air-to-ground munitions and applying it to artillery projectiles. One of the first was the US M712 Copperhead which used a laser seeker that homed into the target being ‘painted’ by a laser designator. Paul Daniels, a programme manager at Raytheon for PGMs (Precision-Guided Munitions) who used the M712 as an artillery officer, shared with Armada that “although it was a great idea the complexity of the firing process made it difficult to actually employ … current PGMs, like Raytheon’s Excalibur, are far simpler, cost less and are more reliable and accurate.” The Excalibur, which is fired from a 155mm gun, had a goal of a CEP (Circular Error of Probability: see How it Works box) of better than 20m (65ft). In fact the latest ‘1B’ version achieves five metres’ (16.4ft) even at 36 km (22.3 miles) range. The ‘S’ version adds a semi-active laser seeker that improves the CEP to one metre (nine feet). Further work has seen the introduction of GPS guided projectiles which can be offered in ‘kits’ that are fit to the standard 155mm projectiles. Orbital ATK’s PGK is a ‘course correction’ projectile provided as a kit that transforms a standard 155mm projectile into a PGM. The PGK, Precision Guidance Kit M1156, allows the gun crew to change the fuse and adds fins to the standard M549A1 and M795 155mm projectiles. Its CEP is six metres (19.6ft).

Stand Alone Box 

How it Works: Circular Error Probability

Traditional artillery target engagement often required firing of a number of shells to neutralize a target. This is a function of the inherent inaccuracy of the rounds and the impact of wind and other factors while the round is in flight. Accuracy is measured by what is called CEP (Circular Error Probability), essentially the measured diameter of a circle in which 50 percent of rounds will impact. The greater the engagement range the less accurate they will be and the larger the CEP will be. Firing more rounds at a specific target then increases the chances that sufficient rounds will impact sufficiently close to the desired target. A standard 155mm shell has a CEP of 200m to 300m (656ft to 984ft) at moderate range. Therefore, to achieve the desired effects on a target it would be necessary to fire multiple guns, or to have one gun firing multiple times, at the same target. Even with an auto-loader this lengthens the engagement time and increases the ammunition expended. The longer the engagement time the greater the possibility that the firing unit will be detected and receive incoming counter-battery fires. Likewise with limited on-board ammunition supplies, the more rounds fired on a single target the lower the number of engagements that are possible on other targets.

Raytheon’s Excalibur
Precision guided artillery projectiles like Raytheon’s Excalibur have the ability to strike targets with an accuracy of ten metres or less. When employed with a laser designator/rangefinder this can be increased to a pin-point strike. (US Army)

Transportability

A drawback of the SPH has been the difficulty in transporting it for far deployed operations. The weight and size of many self propelled guns limit their strategic movement to ship or heavy transport aircraft. Several companies have developed solutions that offer ground and air transport mobility by fitting the gun onto a tactical truck. The Nexter CAESAR and Soltom ATMOS 2000 are both 155mm howitzers mounted in the rear bed of a truck. The DONAR from KMW goes even further. It is a modular gun system that can be mounted on a wide range of either tracked or wheeled chassis depending on the user’s preference. These systems replicate the full complement of navigation and positioning, C2, digital fire control and fires management networking. A difference from the heavier SPH is that these are generally (with exception of DONAR) manually loaded although with mechanical assisted ammunition handling which allows the ATMOS to be served by a crew of only four, while the CAESAR uses six.

Moving Forward

The attributes provided by SRH are crucial to the ability to effectively deliver indirect fire support to manoeuvring armoured units. However, increased incidences of insurgency (witness Afghanistan and Iraq), though relatively conventional but at a lower scale of sophistication than high-tempo air-land battle, may well find the truck-mounted SPH as an adequate and even preferred option. The more substantial advances in self-propelled artillery may well be found in electronics and computing rather than in mechanics and hardware. These are likely to further facilitate the operational concept around which the KMW PzH2000 is designed. This is for a gun to operate as a self-contained firing unit that can operate autonomously while undertaking multiple fire missions in rapid succession. The time of battery fires may be coming to a close with a shift to single, or pair of guns, working independently but managed and directed via a network. Mobility of data is furthering the benefits of the mobility of the guns themselves.

The Artillery Gun Module
The Artillery Gun Module (DONAR) developed jointly by KMW and General Dynamics Land Systems, which is a 155mm howitzer, is a fully automatic, unmanned and autonomous artillery gun module that can be placed on tracked or wheeled platforms. (KMW)

by Stephen W. Miller

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