Reducing collateral damage, simplifying logistics, and reducing the time it takes to strike a target are just three of the many benefits of guided munitions.
If we add a long range here, then it is clear how valuable this type of projectile is for gunners and commanders. The main disadvantage is the cost of guided ammunition compared to unguided ammunition. However, it is not entirely correct to make a comparative assessment of individual shells. It is necessary to calculate the total cost of impact on the target, since in some situations it may be necessary to fire significantly more shots with standard projectiles, not to mention the fact that the firing task may, in principle, not be feasible with unguided projectiles or shorter-range projectiles.
Increasing accuracy
Currently, the main consumer of guided munitions is the US military. In combat operations, the army shot thousands of such shells, in turn, the fleet also seeks to obtain such opportunities. Although some programs were closed due to cost problems, for example, the 155-mm LRLAP (Long Range Land Attack Projectile) projectile, designed specifically for firing from the Mk51 AGS (Advanced Gun System) gun mount, installed on the DDG 1000 destroyer of the Zumwalt class, the American fleet, nevertheless, did not give up trying to find a guided projectile for the AGS itself, as well as for its 127-mm Mk45 cannons.
The United States Marine Corps is ready to begin the Moving Target Artillery Round (MTAR) program, which may begin in 2019 with the aim of deploying ammunition capable of hitting moving targets in the absence of a GPS signal at ranges from 65 to 95 km. In the future, the extended-range guided projectiles will also remain in the sphere of interests of the US Army, which is starting the ERCA (Extended Range Cannon Artillery) program to replace 39-caliber barrels in existing systems with 52-caliber barrels, which, in combination with extended-range projectiles, will double their current range.
Meanwhile, Europe is also following these trends, and while numerous companies are developing guided and extended-range projectiles, European armies are eyeing these ammunition with interest, and some expect to adopt them in the near future.
It would be correct to start with the most widespread 155-mm Excalibur projectile, as more than 14,000 of them were shot in combat. According to Raytheon, the Excalibur IB, currently in series production, retained the characteristics of the original projectile while reducing the number of components and cost and showed reliability over 96%, even in difficult urban conditions, providing an accuracy of 4 meters at maximum ranges of almost 40 km when firing from guns with a length of 39 calibers. In the 2019 budget, the army requested money to purchase 1,150 Excalibur rounds.
Dual-mode seeker
Although the current version is a bestseller, Raytheon is far from resting on its laurels. By improving its systems, the company is close to identifying new solutions that can cope with more complex scenarios and new threats. Jamming of the GPS signal was tested in several directions, resulting in a new version of the projectile with improved anti-jamming capabilities and dual-mode guidance. The new Excalibur S ammunition will be guided both by GPS signals and using a homing head (GOS) with laser semi-active homing. The company is discussing its final configuration with potential customers, but no specific dates have yet been announced.
Another dual-mode option is being developed with guidance at the end of the trajectory. It does not yet have a name, however, according to Raytheon, in terms of development, it is not far behind the "S" variant. An option with a multi-mode seeker is also being considered. Guidance is not the only component that can evolve. The army has set itself the goal of dramatically increasing the range of its barrel artillery, in connection with which Raytheon is working on advanced propulsion systems, including bottom gas generators; in addition, new combat units, for example, anti-tank units, are on the agenda. This could be a response to the already mentioned project of the MTAR Marine Corps. As for the US Navy, in the summer of 2018, another demonstration firing was carried out with a 127-mm version of the Excalibur N5, compatible with the Mk45 gun. The fleet requires a range of 26 nautical miles (48 km), but the company is confident that it can achieve or even exceed this figure.
Raytheon is looking at the export market with interest, although the potential orders here will be significantly less than in the United States. The Excalibur is currently being tested with several 155mm artillery systems: PzH200, Arthur, G6, M109L47 and K9. In addition, Raytheon is working on its compatibility with the Caesar and Krab ACS.
There is no available data on the number of 155-mm ammunition equipped with the M1156 PGK (Precision Guidance Kit) developed by Orbital ATK (currently Northrop Grumman) and used in combat. Although the first production batch was produced in February of this year, over 25,000 of these GPS-guided screw-on systems have been manufactured. Two months later, the Department of Defense awarded Orbital ATK a $ 146 million contract for the completion of the projectiles, which allows PGK production to be extended until April 2021.
The PGK is screwed onto the projectile instead of the standard fuse, a GPS antenna (SAASM - Selectively Available Anti-Spoofing Module) is built into the nose, four small fixed inclined bow stabilizers are installed behind it and a remote fuse behind them. Programming is done using a manual fuse installer EPIAFS (Enhanced Portable Inductive Artillery Fuse-Setter), the same device is connected to a computer when programming the Excalibur projectile.
The shells are bigger and better
Based on its experience with the PGK kit, Orbital ATK is currently developing a 127 mm projectile aimed at the fleet's guided munitions program for the Mk45 gun. The company proactively wants to demonstrate to the fleet the capabilities of the new PKG-Aft projectile in terms of accuracy and range.
Few details are known about this device, but the name, for example, suggests that it is installed not in the nose, but in the tail (aft-tail) of the projectile, while the technology for overcoming overloads in the gun barrel is taken directly from the PGK system. This solution with a tail guidance device is based on a study carried out by ATK in conjunction with the DARPA Administration for the 12.7 x 99 mm EXASTO cartridge (Extreme Accuracy Tasked Ordnance - the ultimate accuracy cartridge). The tail element will also have a rocket engine, which will increase the range to the required 26 nautical miles, and the target-guided seeker will provide an accuracy of less than one meter. There is no information on the type of seeker, but the company said that "PGK-Aft supports various advanced seeker and fire missions of direct and indirect fire with all calibers without major modifications to the gun system." The new projectile is also equipped with an advanced warhead with ready-made striking elements. In December 2017, Orbital ATK conducted successful live firing of 155 mm PGK-Aft prototypes and is currently developing a 127 mm high-precision projectile with the PGK-Aft kit.
BAE Systems is working on the PGK-M (Precision Guidance Kit-Modernized), aiming to improve maneuverability while improving anti-interference capabilities. The latter is achieved through GPS-based navigation in combination with a rotationally stabilized guidance unit and antenna system. According to the company, the circular probable deviation (CEP) is less than 10 meters, the projectile can hit targets at high angles of attack. After over 200 tests have been completed, the projectile is at the stage of subsystem development. In January 2018, BAE Systems received a contract to refine this kit to a production sample. The PGK-M kit is fully compatible with 155 mm M795 and M549A1 ammunition and M109A7 and M777A2 artillery systems.
Aboard American cruisers
After the decision to close the project on the LRLAP (Long Range Land Attack Projectile) projectile, created for the 155-mm AGS (Advanced Gun System) gun mount, it turned out that not a single projectile was suitable for this gun without modification. In June 2017, BAE Systems and Leonardo announced cooperation in the field of new high-precision systems based on new modifications of the Vulcano family for various weapon systems, including the AGS and Mk45 naval guns. The Memorandum of Understanding between the two companies provides for the development of all artillery systems, but each under a separate agreement. At the moment, an agreement has been signed on two naval guns, but in the future, ground systems, for example, M109 and M777, may become part of the agreement. The BAE-Leonardo group fired the Mk45 gun with a Vulcano GLR GPS / IMU projectile this summer in order to demonstrate their compatibility. The US Navy has a need for high-precision ammunition and is very interested in extended-range projectiles, and the Vulcano family of projectiles satisfy both of these requirements.
The Vulcano family is close to completing a qualification process being carried out in parallel for ship and ground ammunition, respectively 127 mm and 155 mm caliber. In accordance with the intergovernmental agreement between Germany and Italy on the controlled option and the decision on the integration of a semi-active laser seeker from Diehl Defense, the qualification process for the GLR (Guided Long Range) option is funded equally by two companies, while the unmanaged BER (Ballistic Extended Range) option is funded entirely by Italy. All operational tests have been successfully completed and the Vulcano ammunition is currently undergoing safety testing, which should be completed by the end of 2018. Meanwhile, Leonardo has begun production of a pilot batch, which will prepare for serial production and accept the final configuration of the shells. Full-scale production is scheduled to start in early 2019.
In 2017, live firing of a 127-mm Vulcano GLR projectile from a modified 127/54 gun was carried out on board the Italian ship; and at the beginning of 2018, the shell was fired from the new 127/64 LW gun mounted on the FREMM frigate. For the first time, this projectile was fed into a gun mount from a ship's magazine of a revolver type, programmed by an induction coil built into the gun, to which data were fed from the ship's battle control system; thus, complete system integration was demonstrated. As for the ground version, these shells were fired from a PzH2000 self-propelled howitzer, programming was carried out using a portable unit. At the moment, Germany is not seeking to integrate this system into the PzH2000 howitzer, since some refinement of the semi-automatic loading system will be required. In Italy, the shells were also tested with the FH-70 155/39 towed howitzer.
The increase in the range of Vulcano projectiles is realized due to the sub-caliber solution, a pallet was used to seal the projectile in the barrel. The fuse can be set in four modes: shock, delayed, temporary and air blast. BER shells can be fired at a range of more than 60 km, while GLR shells can fly 85 km when fired from a 127 mm cannon and 70 km when fired from 155 mm / 52 caliber guns (55 km from 155/39). A fuse is installed in the bow of the GLR projectile, then four steering surfaces that correct the trajectory of the projectile, and behind them the GPS / IMU unit. Shells for naval guns can be equipped with an infrared seeker, while shells fired at ground targets can be equipped with a semi-active laser seeker. These heads slightly increase aerodynamic drag, minimizing the range. Although at the moment the configuration is actually accepted and the tests have confirmed the predicted range and accuracy, Leonardo is working on reducing the KBO of the laser-guided version under an additional contract and is confident that it will cope with the new requirements. This revision will be adopted for all Vulcano projectiles; the company expects to produce one version of the projectile with a semi-active seeker.
In addition to Italy and Germany, the Netherlands has observer status in the Vulcano family of projectiles, and the possibility of purchasing them is also being considered by several other potential customers, including South Korea and Australia. Recently, the Slovak company Konstrukta-Defense signed a cooperation agreement with Leonardo to promote Vulcano ammunition and integrate them with its artillery systems, for example, the Zuzana 2 155/52.
Nexter goes into 3D world
Nexter Ammunition has embarked on an evolutionary 155mm ammunition program that includes the development of 3D printed ammunition elements. The first step was the Bonus high-precision projectile. The Spacido trajectory correction kit was the next step. In the summer of this year, the company announced that all the shooting was successful, the qualification was completed and it remained to issue the certification documents.
Spacido, screwed on instead of a fuse, is an aerodynamic brake that reduces range error. A small Doppler radar checks the initial speed and monitors the first part of the trajectory, the radio frequency channel provides data transmission to Spacido, whose computer decides when the brake should turn, reducing the dispersion by three times. In fact, while the anti-jamming device Spacido costs twice as much, it can significantly reduce the consumption of projectiles and fire at targets in the immediate vicinity of its forces.
At Eurosatory 2018, Nexter announced a new family of high-precision 155mm long-range artillery shells called the Katana. The development of new projectiles was carried out as part of the Menhir program, which was announced in June 2016. It was launched in response to the needs of customers for increased accuracy and range. Above all, the French army needs precision for what it calls "urban artillery." The projectile, designated Katana Mk1, has four rigidly fixed wings in the bow, followed by four corrective rudders connected to the IMU-GPS guidance unit. All wings, including tail rudders, unfold after the projectile leaves the barrel. The projectile is currently at the stage of technological development. The first shootings were carried out under the supervision of the Office of Defense Purchases. The purpose of this program is to provide the army with a guided projectile with a CEP of less than 10 meters and a range of 30 km when fired from a 52 caliber barrel. According to the schedule, the Katana Mk1 projectile should appear on the market in two years. The second step will be to increase the range to 60 km, this will be achieved by adding a set of foldable wings, the location of which could be seen on the layout displayed at Eurosatory. They will provide lift in the descent phase, which will double the flight range. Nexter intends to surpass the capabilities of other competitors' projectiles in terms of the combination of range and warhead, but at a lower cost, set at 60 thousand euros. The shell, designated Katana Mk2a, will be available around 2022. In two years, if the need arises, Nexter will be able to develop a 155-mm laser-guided Katana Mk2b projectile with a meter KVO.
Nexter is also working on warhead technology using 3D printing and an aluminate material consisting of nylon filled with aluminum dust. This will allow you to control the radius of destruction in case of shelling a target in the immediate vicinity of your forces. The company today started researching opto-pyrotechnic technologies in order to control the initiation of an explosion by means of optical fiber; all of these studies are still at an early stage and will not be included in the Katana projectile program.
Israel Aerospace Industries is ready to complete the development of its TopGun artillery fuse. The screw-on system, which performs trajectory correction in two coordinates, reduces the CEP of a conventional projectile to less than 20 meters. The range with such a fuse is 40 km when firing from a gun with a barrel length of 52 caliber, guidance is carried out by the INS-GPS unit. The program is currently at the qualification stage.
On the Norwegian side
The Norwegian company Nammo recently awarded the first contract for its 155mm long-range artillery ammunition. Based on their rich experience, a special module-bottom gas generator was developed there. At the same time, processes for the production of small-caliber high-precision ammunition were used in order to minimize material and shape deviations, which, as a result, entails minimizing changes in air flow and mass distribution.
The program was partially funded by the Norwegian Directorate of Defense Property, but Finland was the first customer, which signed a contract in August 2017, the result of which will be firing tests scheduled for 2019. Compared to standard 155-mm projectiles, the low-sensitivity high-explosive fragmentation projectile with an increased range can fly 40 km when fired from a 52-caliber barrel. Nammo is awaiting an order from the Norwegian army.
Nammo decided to use a radical new technology by integrating a ramjet engine into a 155-mm Extreme Range projectile. A ramjet engine, or ramjet engine, is the simplest air jet engine because it uses forward motion to compress the incoming air without using an axial or centrifugal compressor, there are no moving parts in this engine. The required minimum muzzle velocity is Mach 2.5-2.6, and a standard 155mm projectile exits a 52 caliber barrel at approximately Mach 3. A ramjet engine is by nature a self-regulating engine, maintaining a constant speed regardless of flight altitude. The speed of Mach 3 is maintained for about 50 seconds, while the thrust is provided by the fuel НТР3 (concentrated hydrogen peroxide) with additives. Thus, the range of a projectile with a ramjet is increased to more than 100 km, which turns the artillery gun into a much more flexible and versatile system. Nammo plans to conduct the first ballistic tests in late 2019 and early 2020. Since the consequence of the increase in the range is an increase in the CEP by 10 times, the Nammo company, together with a partner company, is working in parallel on a guidance system for this projectile based on the GPS / INS module. In this case, no GOS can be installed in the bow, the principle of operation of a ramjet engine is aerodynamic and, therefore, an air intake device is simply necessary for its operation. The projectile is compatible with the JBMOU L52 155-mm projectile protocol (Joint Ballistic Memorandum of Understanding). It defines a typical air intake in the bow with a central cone, four front stabilizers and four curved tail wings that deploy when the projectile leaves the barrel. The warhead of the projectile is high-explosive, the amount of explosives will be reduced compared to the standard 155-mm projectile. The company Nammo said that the mass of the explosive "will be about the same as in the 120-mm projectile." The projectile will be used against stationary targets, air defense ground targets, radars, command posts, etc., the flight time will be on the order of several minutes. In accordance with the requirements of the Norwegian Armed Forces, Nammo plans to begin mass production of this projectile in 2024-2025.
At the Eurosatory exhibition, Expal Systems confirmed the signing of an agreement for the supply of 155-mm extended-range ammunition. The 155-mm ER02A1 projectile can be equipped with either a module with a tapering tail section or a bottom gas generator, which provide a flight range of 30 and 40 km, respectively, when fired from a 52-caliber barrel. The high-explosive fragmentation variant, developed in conjunction with the Spanish army, was qualified, in contrast to the lighting and smoke variants, which still have to go through this process. The agreement also includes the newly developed EC-102 electronic fuse with three modes: shock, timer and delay. In accordance with the operational needs of the Spanish army, Expal will supply new shells and fuses for them in the next five years.
