New GPS-guided mortar fires first round in Afghanistan

U.S. Army troops have begun using a Global Positioning System-guided mortar with seven times more accuracy than previous models.

Company C, 1-506th Infantry, 4th Brigade Combat Team, 101st Airborne Division, fired its first round in Afghanistan late in March, the Army reported on the Army.mil website. The Army plans to roll out the technology to the seven other Infantry Brigade Combat Teams within six months. 

"APMI (Accelerated Precision Mortar Initiative) is a 120mm GPS-guided mortar cartridge that provides the infantry commander precision-strike capability, which he has never had before," said Peter Burke, Program Executive Office-Ammunition's deputy product manager for Guided Precision Munitions and Mortar Systems.

The 120mm cartridge, also known as Precision Guided Mortar Munitions (PGMM), hit within four meters of its target. It is the first mortar with an on-board guidance system.

"Our soldiers on the ground have capabilities that were unimaginable when the war on terror started," said Lt. Col. David Womack, commander of the 1st Battalion, 506th Infantry.

Mortars are an indirect weapons system for infantrymen at the battalion-level for immediate firing. Unlike regular mortar rounds, the 120 PGMM can hit a within 10 meters of its target – what’s called the Circular Error Probable, or CEP – 50 percent of the time, Burke said. Current mortars have a 136-meter CEP at maximum range, although mortars with the most advanced features, such as precision position and pointing systems, can achieve 76 meters.

With the new technology, troops will be able to fire at insurgents and enemy locations in more populated areas or near friendly forces from a distance without accidentally harming civilians or damaging non-enemy property. "Sometimes, if the risk of collateral damage is too high, you might not be able to fire [a standard 120mm] at all," Burke said of enemy engagements. "In that case, instead of firing a mortar from a protected position, you would have to send troops in to engage with direct-fire weapons, exposing them to more risk."

The new mortars also reduce the amount of ammunition troops need to carry. "Typically mortars are fired in volleys against an area target because of their inherent inaccuracy, but with APMI, you have the potential to destroy a target with only one or two rounds," Burke said.

APMI will not replace standard 120mm mortars; soldiers will carry a mix of the two cartridges. Currently there are no plans to install the technology in 81mm and 60mm mortars, Burke said.

"The 120 gives you a lot more room to work with," he said. "To fit all the electronics into smaller cartridges, with today's technology, is not feasible. Plus, you're getting the lethality of a 120, which is leaps and bounds above what a 60mm [High-Explosive] round can do."

The APMI XM395 cartridge uses a standard M934 high-explosive 120mm projectile body with a GPS receiver in the nose. The cartridge can be programmed to explode in the air, on a hard surface, or once it penetrates a target. Operators enter data into the system from a fire control computer into the round using a setting device.