April 6, 2017:
Singapore has ordered 2,000 APMI GPS guided 120mm mortar shells. These will cost $33,000 each. Singapore needs these GPS guided mortar rounds because most of Singapore is heavily built up and you need something like guided mortar rounds to minimize collateral damage to structures and civilians, especially if dealing with possible Islamic terrorist acticity.
Singapore believed it needed all the military advantages it could muster because it is one of the smallest nations in the world, being a tiny (633 square kilometers) island city state. Defense spending is only about $12 billion a year for a population of 5.2 million. The armed forces consists of 71,000 active duty troops, of which 55 percent are conscripts. But on a per-capita basis, Singapore spends more on the military and has more people in uniform than the United States. The troops are highly trained, not easily replaced and the obvious solution is better weapons and equipment.
The United States thinks the same way but has had to take the lead in developing many of the high-tech weapons. This can be costly and time consuming and GPS guided mortar shells are a good example. This in 2010 after years of searching (and procrastinating), the U.S. Army finally selected a GPS guided 120mm mortar shell. This was the resulf of competive testing of three such systems (two American and one Israeli) in which the American ATK system won. In development since 2006, ATK uses a guidance system that replaces the fuze (which is screwed into the front of the shell) with a larger unit containing the GPS and little wings that move to put the 120mm mortar shell closer to the target. Thus all you need to convert existing 120mm mortar shells to GPS guidance is the ATK fuzes (which handle the usual fuze functions, as in setting off the explosives in the shell, as well as the guidance functions.)
To use the ATK GPS system, you place each fuse into a device that transfers the target GPS coordinates, then screw the fuze into the shell, and fire the shell. It would also be possible to program each fuze once it is screwed into the shell, via a metal probe that would go into a hole in the fuze, transfer the data, and signal that that the transfer was accurately made. The GPS guided fuze will put the shell within six meters (20 feet, and usually much less) of the coordinates entered.
Because of the GPS fuze, 120mm shells just got a lot cheaper and easier to use. This is particularly crucial for 120mm mortars, which are used by units close to the front lines, where not a lot of ammo can be carried, and resupply is riskier since the enemy is so close. Thus a guided 120mm shell means fewer shells getting fired to get the job done.
It’s about time, because the army has been working on a guided 120mm mortar shell for a long time. The initial effort used laser guidance. The XM395 Precision Guided Mortar Munition had been in development for twelve years, and was almost cancelled at least once because of the delays. The first version of the 17.3 kg (38 pound) XM395 round has a range of 7.5 kilometers, and could land within a meter (three feet) of where the laser is pointed. This high accuracy is achieved because the XM395 uses laser guidance in addition to GPS. But this was more complex, expensive and difficult to use than the army required. What was needed was a mortar round that just provided consistent GPS accuracy (landing within 10 meters of the aiming point). So the laser guidance was dropped.
Unguided mortar shells cannot put the first round very close to the target, and require firing several rounds, and adjusting aim, before you get one on the target. A guided mortar round is very useful in urban warfare, where a miss will often kill civilians. The 120mm mortar round has about 2.2 kg (five pounds) of explosives, compared to 6.6 kg (15) pounds in a 155mm shell. The smaller explosive charges limits collateral damage to civilians. The XM395 was tested in Iraq and Afghanistan in 2009 year, but since it required someone nearby to use a laser designator, it was considered to have limited usefulness. But when it worked the troops found it very useful. Thus the push to get a GPS guided shell into service. Normally, an unguided 120mm shell will land anywhere within a 136 meter circle (on the first shot). The laser guided round will land within a one meter circle, and the GPS guided one with a ten meter circle. The GPS round is deemed the most useful, especially since the troops are satisfied with that degree of accuracy in GPS guided 155mm artillery shells, 227mm rockets and JDAM bombs.
Most U.S. infantry battalions are equipped with 120mm mortars. The army would like to get the GPS shell system into service by the end of the year. But the other two GPS shell manufacturers can challenge the results of the competition, and demand another opportunity to win. This can go on for a while. In Singapore police and paramilitary organizations will also be trained to use the guided 120mm shells as well as a growing number of other small guided munitions.