XM-1156 Precision Guidance Kit (PGK) for 155mm HE projectiles

[HAZORD]

A bullet with your address on it!

Recently, while doing some research I collected some information about a new GPS guidance device and fuze currently being employed by the U.S. in the Middle East. Unlike the Excalibur precision guided projectile, the PGK replaces the fuze in one of the three standard U.S. 155mm HE projectiles. It is programmed to hit a specific GPS location and will hit with a CEP of 50 meters or less, no matter the range, out to 30 Km., and the thing only costs about $3,000.00 per copy.

The attached chart of attainable accuracies shows that the further you fire a RAP M549 projectile, the greater the error in coming close to the target. The XM-982 Excalibur has the greatest accuracy, but costs a fortune and is a high tech munition. The PGK is simply a guidance unit/fuze combination that will screw into any deep fuzewell currently for 155mm HE projectiles. That is the phase I application. Phase II is designed to refine the PGK to also work on 105mm Howitzer projectiles and increase the accuracy. Phase III is to increase its usage for all of the 155mm projectiles.

These units are currently in use in the Middle East using the phase I model. Due to the small file size limits of the BOCN file posting guidelines I can't post pdfs, but much information is available using google and searching "Precision guidance kit"

If anyone comes up with a spare, I need one for the fuze collection (lol).

Info:

http://www.globalsecurity.org/military/systems/munitions/m1156.htm

http://www.dtic.mil/ndia/2010fuze/IVAPergolizzi.pdf

http://www.atk.com/products/documents/pgk - precision guidance kit.pdf

http://www.dote.osd.mil/pub/reports/FY2010/pdf/army/2010pgk.pdf

 

[AMMOTECHXT]

As a bit of an update on this see https://en.wikipedia.org/wiki/M1156_precision_guidance_kit . I was researching whether allied forces in WW2 used 8 inch self propelled howitzers (yes but not many), having seen what looked like an 8 inch howitzer that had just landed at Anzio in the Italian campaign (from THe World At War), eventually leading to the post-war M110. A link about that led to this. The XM1156 was adopted for military service (if I remember correctly the X meant it was experimental) and became the M1156. Long story short the use of this fuze in a standard 155 mm shell is the cheaper alternative to the purpose made precision guided M982 shell. The trade-off is a decrease in accuracy from 10 m to 50 m over whatever range the shells are fired. The fins are powered by an alternator to generate power in flight so that course corrections can be made via GPS. Therefore there is no need for a thermal battery. Since it is reliant on GPS availability, protection in space for military satellites is essential. I read that the acronym CEP relates to greater than 50 % of the shells landing within the designated radius of the target, i.e. 50 m using this fuze. Maximum range with a rocket assisted projectile is up to 70 km / 43 miles. I also read that BAe was one of the two firms that tendered to make these fuzes but lost out to their US rival. All very interesting stuff!