Guided Mortar Systems APRIL 2015
uided mortar systems are guided mortars from other types of artillery. Finally, NUMBER 51 • NUMBER 51 weapons intended to provide increased the increased accuracy of guided mortar sys- Gfiring accuracy and reduced ammu- tems has increased the utility of the mortar as nition consumption over their conventional an anti-tank weapon, allowing for the more
counterparts. Mortars typically fire projec- accurate engagement of moving targets. The tiles intended for use against personnel, light advantages of guided mortar systems have armoured vehicles, and structures. They are made them increasingly popular weapons and normally smooth-bore, muzzle-loading, indirect- they are now in service with several militaries fire support weapons that allow the operators around the world.3 to engage targets that may not be within their Guided mortar systems first entered line of sight. Conventional mortars do not have development more than thirty years ago.
WEAPONS WEAPONS & MARKETS recoil mechanisms, with the main recoil force Early attempts to develop guided mortar sys- being transmitted directly to the ground via tems were limited by the comparatively small the baseplate. Additionally, most mortars are size of mortar projectiles and fuzes compared restricted in elevation, only capable of firing to larger guided missiles and guided artillery at high-angle trajectories (above 45°), meaning projectiles. Advances in microelectronics have that they cannot be used in the direct-fire sup- allowed for the development of effective guid- port role (Ryan, 1982).1 Mortars are limited in ance packages and fuze assemblies within the range and accuracy when compared to many size constraints of mortar projectiles (Weber, other artillery systems. 2014). Guided mortar projectiles are consid- Guided mortar systems allow for precision ered precision guided munitions (PGMs), and targeting and increased first-round hit prob- are often part of a broader battlefield command ability, and greatly reduce the potential for network that may include target-designation collateral damage. The ATK XM395 120 mm systems, fire-control computers, and commu- Precision Mortar, currently in service with the nications devices. US Army under the Accelerated Precision In most cases guided mortar projectiles Mortar Initiative, and the General Dynamics have been developed so that no modifications Ordnance and Tactical Systems 81 mm and need to be made to the mortar tube itself, allow- 120 mm Roll Controlled Guided Mortar (RCGM)2 ing new munitions to be used with in-service projectiles all have a circular error probable weapons. Guided mortar projectiles are often (CEP) of less than ten metres, making them compatible with all smooth-bore mortars of more than seven times as accurate as unguided the same calibre. Both smooth-bore and rifled mortar projectiles in the US Army inventory guided mortar projectiles have been developed. (Calloway, 2011; Habash, 2012). Conventional Guided mortar projectiles differ from un- mortar systems typically require two or more guided mortar projectiles by their inclusion of rounds to be fired in order to stabilize the firing a guidance and navigation unit (GNU)4 and a platform and make corrections for weather method of adjusting the munitions’ trajectory in effects, if the latter have not been calculated in flight. Some guided mortar projectiles are pur- the firing solution, before being capable of accu- pose-built, while others use existing (typically rately delivering fire on target. Some guided in-service) mortar projectile bodies modified mortar systems minimize or obviate this by the addition of a guidance assembly and a requirement and allow for much lower ammu- tail assembly. This ‘bolt-on’ approach is similar nition consumption. An especially desirable to the conversion of a general-purpose air- advantage is that this allows for greater mobil- craft bomb into a PGM by the addition of a ity, one of the characteristics that distinguish guidance kit. In-flight trajectory adjustments
General Dynamics Ordnance and Tactical Systems 120 mm Roll Controlled Guided Mortar (RCGM) projectile, an example of a ‘bolt on’-type conversion kit that allows for the use of in-service components such as the projectile body (warhead), ignition cartridge, propellant, and fuze. Research Notes
Small Arms Survey Research Notes • Number 51 • April 2015 1 can be accomplished by a variety of also been developed and offered for methods, including fins, motor-control sale by manufacturers from other coun- options, and special pyrotechnic rota- tries, including China, Germany, and tion charges (Weber, 2014). Guided mor- Israel (Weber, 2014). To date, guided About the tar projectiles may also offer multiple mortar systems have not been docu- Small Arms Survey fuzing options to the firer, including mented in the hands of non-state The Small Arms Survey is a global centre impact (point-detonating), time-delay, armed groups; however, their increas- of excellence whose mandate is to generate and proximity modes. Many guided ing prevalence on the battlefield may impartial, evidence-based, and policy- mortar projectiles are fitted with a see this situation change in the future relevant knowledge on all aspects of self-destruct mechanism to minimize (Berman, Gobinet, and Leff, 2011). small arms and armed violence. It is the the risk of collateral damage from muni- Despite this risk, guided mortar sys- principal international source of exper- tions that fail to function. tems require a certain level of training tise, information, and analysis on small Two common methods of guidance and technical capability to be prop- arms and armed violence issues, and acts are used in conjunction with these sys- erly employed, and are most effective as a resource for governments, policy- tems: semi-active laser (SAL) guidance when supported by a wider battlefield makers, researchers, and civil society. and satellite (typically GPS) guidance. command network. It is located in Geneva, Switzerland, at The use of laser-designation technol- the Graduate Institute of International ogy provides a high level of accuracy, and Development Studies. but requires a clear line-of-sight from Notes The Survey has an international staff with expertise in security studies, politi- the laser target designator to the tar- 1 Not to be confused with direct aiming at cal science, law, economics, development get. Satellite guidance offers slightly visible targets via an optical sight, which is one of the two conventional options for studies, sociology, and criminology, and reduced accuracy, but removes the aiming mortars, the other being forward collaborates with a network of researchers, need for an observer to ensure that the observer(s) and a fire controller. partner institutions, non-governmental munition remains on target. While 2 Also referred to in the manufacturer’s litera- organizations, and governments in more ture as the ‘Roll-Controlled Guided Mortar’ laser guidance remains the global than 50 countries. standard for PGMs, the use of satellite and the ‘Roll Control Guided Mortar’. 3 See Calloway (2011), Dutoit and Zahnd guidance, sometimes combined with Publication date: April 2015 (1997), Grau (2005), and Lewin (2006). other guidance methods, is becoming 4 Sometimes referred to as a ‘computer increasingly commonplace (Weber, control group’ (CCG) or a ‘guidance, 2014). Other forms of guidance are navigation, and control unit’ (GNCU). Credits used by some guided mortar systems, Author: N. R. Jenzen-Jones including millimetre-wave radar and infrared imaging. References Contributors: Michael Horn, John Ismay, Graeme Rice, Michael Smallwood, and While most modern guided mortar Berman, Eric G., Pierre Gobinet, and Jonah Michael E. Weber projectiles are of the high-explosive Leff. 2011. ‘Mortars.’ Research Note No. 2. or high-explosive fragmentation type, Geneva: Small Arms Survey. Copy-editing: Alex Potter Calloway, Audra. 2011. ‘Picatinny Fields First optimized for use against personnel, ([email protected]) Precision-guided Mortars to Troops in Proofreading: Donald Strachan light armoured vehicles, and struc- Afghanistan.’ US Army Press Release. tures, early guided mortar projectiles 29 March.
2 Small Arms Survey Research Notes • Number 51 • April 2015