The precision guided mortar revelation
(Richard da Silva for Defence IQ)
The resurgence of US mortar systems appears to be hitting their zenith since the introduction of PGMs and so Defence IQ explores the first smart mortar on the battlefield.
In early November 2012, ATK completed the production and delivery of more than 4,000 precision mortar cartridges (XM395, 120mm mortars) to the US Army. This final delivery accomplished ATK’s contract in support of the Army’s Accelerated Precision Mortar Initiative (APMI) and establishes the baseline for future precision mortar programmes. “Our precision guidance fuze technology has proven that existing mortar and artillery munition inventories can quickly and reliably be transformed into precision weapons,” said Dan Olson, Vice President and General Manager for ATK’s Armament Systems Division. “While we’ve completed the work for APMI, we are currently producing Precision Guidance Kits (PGK) for 155mm artillery under a similar Army urgent material request and have been chosen by the Marine Corps to prove a design for a Precision Extended Range Mortar.”
Bring on the APMI
The Army sponsored APMI to meet operational needs for a precision, 120mm mortar capability for reliable response to enemy engagements and especially in mountainous terrain which is inaccessible to artillery. A precision guided mortar provides field commanders with indirect fire capability successfully to engage targets while mitigating collateral damage. Additionally, greater accuracy reduces the number of rounds required to successfully defeat targets while reducing in-theatre logistical requirements and also providing collateral effect mitigation.
APMI – XM395
ATK leveraged mature guidance technologies and weapon subsystems to rapidly transform the more than 4,000 standard M934 mortar bodies into precision mortar cartridges (mortar bombs in UK parlance) through the addition of a GPS guidance and navigation fuze that replaces conventional fusing in the mortar cartridge fuze well. The standard cartridge tailfin is also replaced with an ATK-designed tailfin which helps to create the conditions for precision flight. Operators enter data into the system from a fire control computer into the round using a setting device. Production was completed at ATK’s Minnesota-based Armament Systems Division production facilities.
XM395 (Prototype)
While this phase in the development of a precision mortar system is complete, the Army is working towards the creation of a programme of record and is currently finalising the programme objective memorandum which is an initial step in securing the necessary resources for the requirement that is known as the High Explosive Guided Mortar or HEGM.
“Our XM395 also successfully completed a Forward Operational Assessment with the Army in Afghanistan. The initial quantities provided battlefield commander with 10 metre accuracy,” said Olson. “Given the weapon’s battlefield success and our organisation’s ability to move the programme from development to initial fielding within a year, we are looking forwards to the Army’s decision to allow fielding across the force.”
APMI’s success was recently recognised by the US Army Research Development and Engineering Command (ARDEC), being named one of the Army’s greatest inventions. Recipients of the award are recognized for their inventiveness and contribution to Army capabilities. Award winners are chosen by a panel of non-commissioned officers with recent combat experience along with field-grade officers from the US Army Training and Doctrine Command (TRADOC).
ATK’s expertise in creating GPS guidance fuzes for indirect fire systems began with PGK (XM1156) which is a guidance fuze for artillery. The company is currently producing the kits to meet the Army’s urgent material request for precision guidance requirements for 155mm artillery projectiles that will be fielded for training and operational use. In parallel, ATK is nearing completion of a PGK development contract to produce the guidance fuzes under an ‘urgent material release’ for operational assessments in Afghanistan that includes training and tactical use. Additionally, ATK was recently awarded a Low Rate Initial Production contract with follow on options for full rate production which will begin Army-wide fielding in early 2014.
While proceeding on PGK, the company also is working towards proving that precision guidance is possible for the Marine Corps’ 120mm rifled mortar. In October 2012, ATK was awarded a $14.3 million contract to develop a solution to meet the Marine Corps’ requirement for a Precision Extended Range Mortar (PERM). The 24-month PERM development programme will demonstrate a precision mortar cartridge capable of reliably providing accuracy within 20 metres circular error probable (CEP) and can then be quickly transitioned to production and ultimately fielding.
Marching forwards
Lieutenant Colonel William McDonough, the US Army’s programme Officer for Mortars and PEO for Ammunition primarily credits the recent progress in mortar accuracy to the APMI and told Defence IQ that forces using the system had found it to be something of “a revelation”.
“It’s been in use in Afghanistan for a little more than two years and has seen good results, allowing for more accuracy and for commanders to have a better confidence level when engaging targets in urban areas. Accuracy is 10 metres CEP, so that is as accurate as I think we’re ever going to get at 120mm. It will provide all the effects you need.”
McDonough also highlighted the strong reliability and volume of sensors now available that can detect points of origin and extend situational awareness, which, when paired with the APMI, not only provides defensive coverage to forward operating bases but has also been useful in eliminating IED emplacers within a 6,250 metre circle around the position.
Other notable progress when it comes to the pace of mortar development has been seen on lightening of the soldiers’ load and the offer of more ammunition on the 60mm M224, and 81mm M252 sets, which has been well received in theatre. “We’ve taken about 9 pounds out of the 60mm mortar using the Inconel cannon (barrel in UK-speak), which is a more exotic metal [nickel-based] than standard steel, but maintains the same performance parameters and which is a good story in the hills and mountains of Afghanistan,” he said. “I would say we never beat the requirement demands from the operational community because we’re always playing catch up, but I think we are shortening the lead times and the time it takes to get products into the field.”
On this basis, target location is the one area in which focused training has been a key requirement, particularly for forward observers, because no matter how good the precision equipment becomes, the grid information must still be accurate first and foremost.
When it comes to accuracy, McDonough believes that the Army has peaked at the level it needs to and sees it to be an unnecessary investment to attempt to chase just a few more metres of accuracy, however, from a user’s experience, greater reach is always something that will be in demand. “The challenge is in knowing just how much range is needed, how much is too much, and how much is not enough.”
