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GPS-guided precision mortar rounds on way to Afghanistan


March 1, 2011

Illustration depicting an XM395 Accelerated Precision Mortar Initiative round closing in on a target (Image: U.S. Army)

Illustration depicting an XM395 Accelerated Precision Mortar Initiative round closing in on a target (Image: U.S. Army)

Mortars have existed for hundreds of years, proving extremely useful in World War I where the high angle of flight of the shells made them an ideal weapon for the muddy trenches of the Western Front. The weapon's simplicity coupled with the ease with which it can be transported and operated means mortars are still in common use today but, although methods of calculating azimuth and elevation angles for targeting have improved, their greatest weakness still remains their lack of accuracy. Mortars are now moving into the 21st Century with U.S. Soldiers in Afghanistan set to receive a first-of-its-kind, GPS-guided 120mm mortar munition that can pinpoint targets at ranges of up to 6,300 m (20,669 ft).

The new mortar rounds, which the U.S. Army will deliver to soldiers in Afghanistan early this month, are the result of the Accelerated Precision Mortar Initiative (APMI) program that commenced after an urgent request from the field commander in Afghanistan in Feb. 2009 looking to pinpoint targets more accurately. GPS guidance was preferred over laser guidance as it would allow soldiers on the ground to more accurately target insurgents hidden behind ridges and rock outcroppings.

Current conventional mortar rounds used by the army only have an accuracy of about a 136 meter (446 ft) Circular Area Probable (CEP). This means that 50 percent of rounds will land within 136 m of the target, 43 percent will land between 136 m and 272 m, 7 percent between 272 m and 408 m and the proportion of rounds that land further than this is less than 0.2 percent.

The new 120 mm APMI precision rounds, which have been undergoing testing since late last year, have been able to demonstrate a CEP of less than 10 m at ranges in excess of 6,500 m to greatly improve accuracy and reduce the risk of collateral damage. This equates to 50 percent falling within 10 m of the target, 43 percent between 10 m and 20 m and 7 percent within 20 m to 30 m.

"This is designed for a precision capability such as against a sniper in a building, or enemies in a bunker or trench. If you were to engage with a conventional mortar round, you would have to fire 8-to-10 rounds to kill or suppress the target. With APMI, you will probably be able to do the same thing with one or two rounds," said Bruce Kay, Department of the Army Systems Coordinator, Mortar Systems.

ATK was awarded the contract to deliver the APMI rounds after a "shoot off" against two other competing companies early in 2010. Its Mortar Guidance Kit (MGK) design converts M934 mortar bodies into precision mortar rounds by replacing standard fuzes in the mortar's fuze well and adding GPS guidance and navigation capability

The APMI rounds won't completely replace the conventional rounds in the field, which will still be required for area and suppressive fires. The U.S. Army plans to deliver a total of 5,480 APMI rounds to Afghanistan and they could be expanded beyond Afghanistan once they have successfully been demonstrated in combat.

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

This will save lives on both sides but give the winning edge to our boys. A GPS mortar that\'s accurate to 10m and can take down an enemy unit in two shots will discourage many attacks. However if both sides have it casualty numbers could soar particularly if commanders don\'t update their tactics quickly.

Wesley Bruce

@Wesley Bruce: You know what\'s still better at saving lives? Avoiding war in the first place. Then you can move on to building an education system that doesn\'t require your \"boys\" to risk their lives in Iraq or Afghanistan to be able to afford going to college.

Although I agree: building heavy ordnance might be less brainpower-consuming, and more fun when it goes \"ka-boom!\"

Gavrilo Bozovic

Wish we could avoid war but just because you don\'t want one doesn\'t mean there isn\'t somebody out there that\'s not going to try and subdue you just because they don\'t like you for not being one of them! Hitler comes comes to mind. This looks like a good idea. :-)


Not that i dont think youre both right or wrong, if you wish to win just over power the opponent, why launch 1 or 2 accurate mortars, launch a cruise missile instead with a 100meter radius of destruction.

Youll soon find out how long they like hiding when theres nowhere left to hide.

Either you fight to win, or dont bother fighting. There is no such thing as a kind war. The WAR is won or lost. One principle survives and the other dies.

Faffing around with small fights is pointless, war = wipe the lot of them out or dont bother and use diplomacy.


It\'s not surprising to get better accuracy with weapons. Killing each other over rocky useless ground seems to be the hallmark of humans.


@GavriloBozovic - Gavrilo we all said the same thing in our teens. But life teaches you to stand up against bad people or else they win. Fortunately NATO stood up against the Serbs and that was a good thing for everybody...no?

Todd Dunning

Dear folks,

As a history teacher I feel compelled to point out that... The bloody trenches of the western front were not of World War II, as the article points out but from World War I. Hitler\'s Blitzkrieg was designed to avert trench warfare. On a more positive note putting rounds on the target is better than just being \"close\" to the target.

Mr. Mac

@Todd Dunning: it\'s been a long time since I was last mistaken for a teenager, thanks for that!

War is a staple of mankind, and I don\'t think it will be completely suppressed anytime soon. Don\'t misunderstand me: I\'m not a misinformed utopian, more of a realist.

My point merely is that: people get excited about new weapons technologies, as they go fast and make loud bangs. However, other, less exciting measures, make the usage of warfare unnecessary. Take the example of Somalia, for instance: you hear weekly how NATO is going to put more warships in the area, be firmer with the pirats, etc, etc.

But seriously, people in Somalia spent the last 20 years in civil war, don\'t have a stable government and no way to make a decent living. What do you expect them to do, when given the opportunity to make some extra cash?

In the end, it all comes back to the first book of the Utopia, by Thomas More, when he describes the situation of 17th century England: when people have no choice, they will do what they have to do to survive, and repression is not going to solve the problem. People dont attack each other with AK-47 in Switzerland (that\'s where I live) not because they have some superior morality, but because there are better ways to make a living here.

What baffles me is that everyone agrees that the WTC would still be standing if the US didn\'t mess things up THAT MUCH in Afghanistan in the first place, but the people insist on messing stuff up elsewhere, claiming that \"this time it\'s not the same\".

Gavrilo Bozovic

@ Gavrilo Bozovic. Your myopic idea that avoiding war altogether is a better option. Is a sad delusion, as it totally denies the truth of the world we live in.

Peace through superior firepower.


To G Bozovic: Helvetia is fortunate in that its neutrality is supported by other countries, which allows it, rather than shoot off AK-47s, to sit back and make money from their conflicts without helping to stop the domination of other cultures, [in particular women] by the evil religious maniacs in the Taliban. Ian Colley.


@Bozovic, Two things: USA has been a long-term supporter of Israel and as such, we are considered one and the same by her enemies. I personally am flattered but the point is, we are the main enemy of radical Muslims the world over. The second thing is, when their \'bible\' tells them to kill all infidels, we got a problem. The twin towers were just the latest in a string of attacks big and small by radical terrorists. I know we are not the only ones they are attacking but is they who initiate war! @mg, When you talk about launching a cruise missle instead of a gps mortar, I\'m sure you are just trying to make a point but there is such a thing as economics. Cruse missles cost a bunch. Even if we have superior fire power, I still pray for our men. Fighting to the death is not something any civilized human being loves to do but it will be necessary where ever there are those who\'s sole goal it is to kill you

Will, the tink
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