The US Army is pushing to get precision mortars developed and deployed to the field in Afghanistan as soon as possible. Mortars are lighter and can be towed by a HMMWV or MRAP, or carried and fired from inside M113 or Stryker APCs, making them easier to deploy than heavier cannon artillery.
When indirect fire support is needed against enemies who are dug in along mountain ridgelines and other high positions, or in an urban area where which building you hit matters a great deal, getting the job done requires precision artillery. That capability has already come to MLRS rockets (M30/31 GMLRS, ATACMS), and 155mm artillery shells (Excalibur), and has been deployed to great effect on the front lines by American forces and their allies. Now it is coming to the USA’s 120mm mortars as well.
The Accelerated Precision Mortar Initiative (APMI)
The US army has been experimenting with guided mortar development efforts since the 1980s, but the technologies required have only recently become small enough and reliable enough for use. An effort to field a laser-guided mortar began in earnest in 2004, but eventually the Army decided to change its guidance focus.
The Army’s Operational Needs Statement from Afghanistan (ONS-09-7722) specifies a GPS-guided 120mm mortar, with a circular error probable (CEP) of 16.4 feet or less and a 4.3 mile range, said Maj. Jeffrey Hilt, the APMI program lead for the Army, in an interview with Greg Grant of DoD Buzz. The mortar must also be compatible with existing fire control systems, such as the Lightweight Hand-held Mortar Ballistic Computer, work with Soltam’s M120/M121 fin-stabilized smoothbore mortar, and have the same multi-option fuze as the current M734A1 fuze.
Maj. Hilt told DoD Buzz that GPS guidance is preferable to laser guidance because insurgents in Afghanistan frequently duck down behind ridges and rock outcroppings; laser guidance would require a laser marker almost on top of them, buts a soldier on the ground can accurately target a GPS round against an enemy taking cover behind obstacles, or in dead ground.
Three companies were competing to develop a 120mm precision mortar compatible with the M120 system under the Accelerated Precision Mortar Initiative (APMI): Raytheon, General Dynamics, and Alliant Techsystems (ATK). The 3 companies tested GPS guided versions of the precision mortar in May 2009. The first phase would conclude with flight tests and a competitive “shoot off” amongst industry designs in January 2010, after which the Army would select the winning design.
In April 2010, ATK’s design won. An initial contract for the M9933/M9934 120mm mortar body’s attached guidance and flight kits followed in June 2010.
ATK explains that its Mortar Guidance Kit (MGK) converts mortar bodies into precision mortar rounds by replacing standard fuzes in the mortar’s fuze well with a guidance kit that includes fins, guidance, and fuze. That multi-functional fuze allows the round to be programmed to explode in the air, once it hits a hard surface, or after it penetrates a target. Operators input mission and GPS data from a fire control computer into the round using the Precision Lightweight Universal Mortar Setter Systems (PLUMSS), which combine the GPS and mission data, and loads coordinates and fuzing into the APMI XM395 round. Once fired, APMI’s front fins provide guidance, and folding fins in the tail provide additional stability.
The design owes much to the Precision Guidance Kit for 155mm artillery. APMI’s MGK has more than 90% commonality with the PGK GPS-guidance fuze, developed under US Army PEO Ammunition’s previous Excalibur 155m artillery shell program. On the back end, US Army Armament Research Development and Engineering Center (ARDEC) helped to modify the Army’s Lightweight Hand-held Mortar Ballistic Computer and Dismounted 120mm Mortar Fire Control System for the APMI.
ATK’s MGK has demonstrated its ability to accurately and reliably guide a 120mm mortar to within 10 meter CEP (Circular Error Probable) at ranges in excess of 6.5 km. Peter Burke, PEO Ammunition’s deputy product manager, Guided Precision Munitions and Mortar Systems, says that APMI is actually under the 10m CEP accuracy goal; he won’t give specific figures, but ONS-09-7722 requirements translate into 5m CEP. As a point of comparison, the average for unguided 120mm mortar rounds is 136m CEP, or 76m with precision mortar pointing systems.
ATK’s MGK/XM395 offering will join a growing list of global 120mm mortar competitors, including the Russian Gran system, and Raytheon/ Israeli Military Industries’ 120GM DAGGER. When combined with similar advances for 155mm and 105mm artillery, and for longer-range 227mm+ rockets, the net effect is to make precision firepower widely available, even when aircraft or UAVs aren’t nearby. If successful, precision mortars in particular would be a “70% solution” that leverages weapons present in every battalion – severely undercutting the rationale for “missiles in a box” projects like the NETFIRES NLOS-LS. It’s no coincidence that NLOS-LS was canceled by the US Army in 2010 – after the 155mm Excalibur shell and 227mm GMLRS rocket had proven out similar snap-in GPS solutions, and just as APMI passed testing and declared a winner.
As of March 2011, US Army PEO Ammunition’s Peter Burke said there is no requirement for precision 81mm and 60mm mortars, as fitting all of the electronics into smaller rounds that can be fired from land-based mortars is seen as “beyond today’s technology.” He adds that the 120mm mortar also has the advantage of packing enough of a punch to justify the extra expense of the guidance system.
Contracts & Key Events
DID is aware that XM395 also refers to a separate laser-guided 120mm mortar project, begun in 2004. For whatever reason, the Pentagon has begun referring to the GPS-guided shells as APMI XM395 rounds, and it’s those weapons that we’re covering here.
March 16/17: The US Defense Security Cooperation Agency (DCSA) has cleared the possible sale of 2,000 XM395 precision mortar rounds to the government of Singapore. Built by Orbital ATK, the value of the sale is estimated to reach $66 million and will include support equipment and services. Singapore intends to use the mortar rounds to defend against current and future threats in addition to bolstering homeland defenses.
Feb 3/11: ATK in Plymouth, MN receives a $50 million contract for the material release production of XM395 high explosive, guided 120mm mortars under APMI . Work will be performed in Plymouth, MN, with an estimated completion date still to be determined. One bid was solicited with one bid received by the U.S. Army Contracting Command in Picatinny, NJ (W15QKN-10-C-0059).