U.S. approves $54 million sale of precision kits to Finland
The U.S. State Department has approved selling 5,500 M1156A1 Precision Guidance Kits (PGKs) to Finland. These kits will enable the conversion of regular artillery shells into guided weapons, similar to the M982 Excalibur rounds, at a much lower cost. Here is how this is achieved.
The U.S. agreement covers a contract amount of up to $54 million, but as is always the case with foreign military sales (FMS) transactions, the actual amount should be lower. In addition to the PGK modules, the contract will include compatibility tests with Finnish artillery ammunition, ballistic tables, technical assistance, and simulators for training purposes.
PGK modules present a very interesting alternative to M982 Excalibur rounds, which perform poorly in satellite navigation jamming environments, among other challenges, due to the reduced explosive charge compared to conventional shells. Meanwhile, the M1156A1 PGK modules, as described by Wirtualna Polska journalist Łukasz Michalik, conceptually resemble JDAM/-ER modules for aerial bombs, achieving similar performance at a much lower cost.
M1156A1 PGK — turns any shell into a guided weapon at an acceptable cost
Northrop Grumman has been mass-producing M1156A1 PGK modules since 2015, although their history dates back to the early 2000s, when they competed with M982 Excalibur rounds. Initially, PGK modules performed poorly, providing an accuracy of about 50 metres, but over time, they improved, and today, they allow hitting targets with an accuracy of 10 metres or less and a reliability exceeding 90%.
While this precision is still a bit lower than that of Excalibur, which can achieve around 4 metres in optimal conditions, the advantage is the very low price of PGK modules. While one Excalibur could cost up to £81,600, the price of one PGK module is below £11,400.
PGK modules have an inertial and satellite navigation module connected to a system that oversees control surfaces, correcting the flight path. Additionally, there is a small alternator inside that powers the onboard electronics during flight, and the whole system ends with a classic thread used in fuses screwed onto the tip of an artillery shell.
As a result, it gives the ability to convert basically any 155mm artillery shell into precision ammunition. In case, for instance, of the enemy employing electronic warfare systems to jam satellite navigation, there’s no need to waste very expensive rounds. It’s sufficient to just unscrew the PGK modules and use classic fuses or those detonating in the air over the target.
An additional advantage is that most standard 155mm artillery shells with a rear band, such as the DM121 or similar ones with a gas generator, have a full TNT load of up to 9 kilograms. At the same time, for Excalibur, it is about half. In such a case, missing by a few extra metres is no longer a big issue. PGK modules are also ideal candidates for filling the precision ammunition gap in Polish artillery.
