Even though the big guns are expected to fire ‘intelligently,’ shells fly through the air. Turbulences, humidity and sudden gusts of air can alter the trajectory of the shells. They might have been aimed and fired perfectly, but because of these environmental factors they may fail to hit the target. The only way out is to make the shells ‘intelligent’ too. When shells are fired from the guns, the pressure developed inside the barrels exceeds several bars. The electronic and electromechanical systems in the shells must withstand this extreme physical condition and work effectively. This challenge of fabricating high-endurance electronic components and integrating them with the shells has recently been met with success. This has resulted in various types of smart shells for both tanks and SPGs.
Smart shells for tanks
The distance of engagement is shorter in tanks, and it occurs generally in the line of sight. Also, the speed of shells is very fast. Therefore there is not much need for smart shells. Yet, there can be situations where a tank is used to spot another tank (using shells) outside its range of engagement. Since battles are full of ‘now or never’ moments, to engage such targets way beyond the engagement range, gun-launched anti-tank missiles are used. These are launched through the gun of the tank itself.
Gun-fired anti-tank missiles
These missiles are generally laser-guided, and the laser illumination is carried out by the tank commander—using his sight (a traversing periscope) that contains an integrated laser designator. If the commander spots an enemy tank situated outside his tank’s engagement range, he orders an anti-tank missile to be fired. While it is fired, he keeps that target tank in the crosshairs of his sight. Some famous gun-launched laser-guided missiles are the USSR/Russian ‘9M119 Svir’ and ‘9M119M Reflek’, and the Israeli ‘Lahat’.
Smart shells for SPG
If a war is fought in an urban terrain, enemy forces are likely to be alongside the civilian population. Thus, if the artillery support is called in, it may lead to very high civilian casualties. Similarly, even if the shells are fired in the MRSI mode, due to heavy crosswinds, all shells may land at the same time but not on the target. However, the entry of smart shells has revolutionised the scenario. Today, with smart shells, artillery guns have become an economical long-range precision strike weapon system.
Semi-active laser-guided shells
These shells use a semi-active laser-guidance system, which is not entirely autonomous and needs human assistance. The lines of operation of these shells are similar to the laser-guided missiles explained earlier. Such shells typically have a range of around 20 kilometres. Each shell has a laser seeker and a high performance microprocessor-centric guidance system. A set of movable wings and fins are present in a folded position and get deployed after the shell reaches the maximum height. Until then the shell is ballistic in flight. These wings and fins move in accordance to the commands provided by the guidance system to alter the trajectory of a shell. The artillery troops embedded with the front-line troops have to flash an infrared laser beam on targets with their laser designator. The shell has a nose-mounted laser seeker with an enormous footprint. When the shell is at the maximum height of its parabolic trajectory, it can lock on a target even from several kilometres. Once the target is visible, the guidance system guides the shell towards the target by correspondingly actuating its fins and wings.
Though considered to be smart, these shells are not entirely smart. The success of the hit entirely depends on the troops’ laser-illuminating the target. Cloud cover can also hinder the performance of these shells. Russian ‘Krasnopol’ and American ‘Copperhead’ are well-known examples, and the former is in service with the Indian Army.
Typically, these shells have a maximum range of 35 kilometres. The shell’s guidance system is centred on a mission computer that continuously derives the GPS coordinates from a shell-embedded GPS receiver. As in the laser-guided shells, fins are present in this shell also. Before firing a shell, the target’s GPS coordinates are loaded into the shell’s mission computer by a trooper known as ‘fuse setter.’ When the shell is fired, the embedded GPS receiver constantly feeds current GPS coordinates to the mission computer, which compares them with the pre-loaded coordinates. It, then, calculates the required trajectory and guides the shell in that trajectory.
The advantage of this is that, even if the shell is shot off-target, it automatically glides toward the target. When fired in MRSI mode, these shells can raze a single building to the ground without any damage to neighbouring buildings. The American ‘Excalibur (M982),’ a product of Raytheon Missile Systems, and ‘Bofors’ of BAE Systems, are the only known examples. Typically, the estimated cost of a single shell is around US$ 50,000!
Sensor-fused tank killer shells
Meant to take out enemy tanks, these shells act as carriers and deploy smaller, standalone, smart anti-tank munitions that take out tanks. Each smart submunition contains a flight computer, radar and an explosive detonating mechanism. When the shell reaches the target area, submunition are ejected out and slowly descend through a parachute and spin. While spinning, the submunition’s radar is activated. The radar maintains a spiral-scanning pattern during descent. When the flight computer recognises the radar echoes of a tank, the computer simply jettisons the parachute. This allows the submunition to fall over the target. An explosive detonating mechanism detonates the explosive. The result is an explosively-formed penetrator (EFP), a molten-copper jet travelling at hypersonic speeds. This jet penetrates the tank’s weakest place—its top. In case the submunition is not able to find any tank, it automatically explodes and destructs itself. The American ‘SADARM M898,’ German ‘Suchzünder Munition für die Artillerie 155’ (meaning ‘sensor-fused munition for 155mm artillery’) and ‘BONUS’ of BAE systems are the presently operational shells.
An entire armoured offensive of the enemy could be blunted by batteries of howitzers firing such sensor-fused shells.
These shells are of a different genre. They consist of a high-powered radio frequency (RF) jammer that jettisons through a parachute and lands in the target area. After impacting the ground, it starts emitting high-power noise in a particular RF band. This turns all communication systems that use that particular band in the target area ‘deaf and dumb.’ Less than a dozen of these rounds, jamming various bands, can completely choke all communication systems for a definite period. The military application of this system is vast and spreads over various doctrines. So far, such shells are said to be available with the Russian forces in limited scale.
Command and control systems
Each combat leader in the echelon gets his orders from his superior based on ground situation, delegates a task to his subordinate units and reports back the result to his superior. This process is called command and control (C2) and is based on robust communication systems. The C2 is to be maintained from the top to the bottom level forces—be it a 4-6 member team or 40,000-50,000 strong strike corps. The performance of a fighting force is directly influenced by the efficacy of C2. Tanks and SPGs, crucial to a battle, are highly communication-intensive systems.
Communication systems for tanks
With improvements in communication technology, a better C2 has become possible, from intra-tank communication to inter-tank communication. Due to the immense noise associated with the tanks, direct voice communication is not even possible between the tank crew seated next to each other. Helmet-mounted headphone intercoms are used for intra-tank voice communication. These are plugged into a wired two-way communication system. With the inter-tank communication mode selected, the tank commander can communicate with other tank commanders in the formation or his superiors using a wireless radio transceiver. The warning from the active protection system (APS) is coupled with the intercom system. The commander hears a warning tone if his tank is targeted—an eventual sign of an impending missile attack. A specially-designated tank with a better communication facility, called command tank, is also used. This tank hosts the formation commander, who commands the tank commanders of the formation. He or she also communicates with the higher echelons.
Due to the changing geopolitics, combined infantry-armour operations are required inside the cities. This requires the infantry to move in close proximity with the tanks. To facilitate better infantry vs tank communication, telephones are being progressively installed in the rear of the tanks. The associated commander can directly communicate with the tank’s commander through these phones.
With the development of communication technology, tanks are better able to share information. In modern tanks, the commander has a touch-screen interactive display that shows the map of the terrain he is operating in. This is frequently updated by satellites, which helps the tank commander to view the graphical disposition of his own and known enemy troops in the battlefield. He also gets on-field intelligence through unmanned aerial vehicles that transmit live video or image feeds to the tanks. The tank forces—the main strike forces—are slowly switching towards network-enabled capabilities. Through this they share information, designate targets and neutralise them very effectively in close cohesion.
Communication systems for SPG
When front-line troops encounter strong resistance from the enemy, they call for an artillery strike. A trooper, known as the forward observer (FO), is present among the front line troops. The FO generates that request through a radio to the fire direction centre (FDC), the overall command centre for SPGs throughout the battlefield. Six to eight guns are grouped to form what is known as a battery, which is commanded by a battery command centre (BCC). Firing commands from the FDC are issued to the appropriate BCC. The FO, FDC and the SPGs are all situated far away from each other.
In a typical mission, the FO generates the request for an artillery strike to the FDC. He intimates his precise location on the map and the target’s location with respect to his location. The FDC determines which battery would be able to engage the target most effectively and communicates the same to the BCC. It also determines which shell type has to be used, the required numbers, the elevation and orientation of the gun, etc. In the BCC, guns are directed accordingly to load, align and fire. As the firing is initiated, the FO actively reports to the FDC information, like impact of the shell, side to which the target shell landed and its distance. From these reports, the FDC deduces the coordinates and communicates the updates to the BCC. Trained FOs can direct the artillery fire even on specific targets, like stationary tanks. In an artillery barrage, they move the shell’s point of impact progressively. This is known as walking the fire to the target or a rolling barrage.
The process of receiving artillery-fire-support requests from various units operating at various sectors in the battlefield, categorising and prioritising them, allocating targets to the BCC, getting targets bombarded, collecting feedback through FOs, and giving correction orders, is called artillery C2. In the past, this was based on wireless radios and all calculations were done manually using slides and maps. these are carried out through rigorous training.
The FDC and BCC are slated to get closely integrated through computerised C2 systems. The FCS of the SPGs requires specific alignment to be entered, so it gets the SPG aligned easily. The FDC typically has a huge computer screen on which a detailed map of the battlefield is displayed. It is marked with positions of known enemy and friendly units, target sizes and locations, safety regions, available ammunitions at various batteries, etc. The FOs provided with imagers can send live videos by hooking their imagers to the radio. Through this, the FDC can see the result of the bombardment for themselves. Some of the functions the FDC can execute in a go are:
1. Taking account of the available munitions at the BCC
2. Identifying the required number of guns for a mission
3. Selecting the mode of bombardment and the required shell impact distribution, according to the type of target
4. Synchronising the firings
5. Simultaneously controlling several fire missions, where certain number of guns in a battery are used for bombarding targets of a different mission
The BCC for these SPGs are also mobile vehicles that follow these guns. All FCSs of the individual SPGs are connected with a radio data link to the BCC, which sends the target’s coordinates, required shell type and numbers through the radiolink to the FCS of the SPG. These parameters are displayed separately. The gunner enters these values into the FCS, which in turn aligns the gun. On receiving the fire command through the radio, these SPGs fire. This method of C2 is being tested and is expected to be deployed soon.
Some more systems
Automatic fire extinguishing system. A tank or an SPG contains live ammunition inside it. If it catches fire either due to enemy firing or by accident, the result can be catastrophic. The resulting explosion can destroy a turret weighing around 20 metric tonnes!
The automatic fire suppression system has sensors in the ammunition and engine compartments. These sensors detect fumes that rise before a fire and trigger a gas canister that contains halon (halogenated hydrocarbon) gas. This fire-retardant gas is released in milliseconds. The crew has to escape from the vehicle in a few seconds to save themselves. This system is effective only against accidental fires or meagre hits from enemy fire.
Close-range protection system. A tank or an SPG is a deadly monster, but only when the enemy is away from these machines—the striking range of these machines has a minimum distance below which they cannot engage the enemy. For shorter distances, machine guns are fitted in these systems. During a battle, these guns can be fired from under the protection of armour. But, to load these guns, operators have to come out of the armour.
To tackle this, remote-controlled weapon stations (RWSs) are being introduced. These are situated on the top of the turret and have a high-power machine gun. The way a target is engaged is similar to the target engagement through the main gun since inside these RWS there is a mini FCS similar to that of a tank’s. A joystick is used to control the movement of the machine gun. There is a camera and display for aiming and monitoring. With these RWSs, close-range infantry threats can also be dealt with, without exposing the shooter to the enemy.
In the past, guns were the primary armament of combat naval. These guns could even determine the size of the ships. These were used to fire at enemy vessels and on-shore installations, that too in both direct and indirect fire modes. Anti-ship cruise missiles that were introduced in the early sixties defanged these big guns and took their place. Due to this, today these guns have diminished in both size and power. The modern-day shipboard gun’s FCS uses a radar to derive the coordinates of the enemy vessel. These guns are autoloaded.
For direct firing modes, the FCS functions like a tank’s. But, for indirect firing support, it works like the FCS of an SPG. A naval gun’s FCS has to also take care of the wave factor because while firing there is a strong possibility of the wave heaving the ship upwards, and shifting the point where the shells will land. So, the FCS incorporates the gun stabilisation feature too for the indirect firing mode, unlike their land-based SPGs. These guns can shoot shells even faster than the tanks or SPGs.
In the future, high-powered laser beam firing weapon platforms will replace big guns.
Until then, these big guns driven by electronic systems will rule the battlefield.
The author is working in BrahMos Aerospace and is pursuing a doctorate in military technology. He has contributed various articles in the past