Northrop starts building an anti-jam 155mm guidance kit that fits howitzers already in the field

The crew's part of this is fitting the kit to the front of a compatible 155 mm projectile, which then guides itself with GPS in flight ^[5]. Northrop says the E5 turns existing high-explosive stock into precision rounds without major changes to the ammunition or to the artillery firing it ^[10]. A force can field it without waiting for a new artillery weapon or changes to its existing infrastructure, the company says ^[15].

The buyer here is the one that already has the guns. Northrop says the upgrade is meant to let US Army and allied forces keep using GPS-guided artillery in places where electronic warfare disrupts satellite navigation ^[14].

The company's case for precision runs through the crew as much as the target. Greater accuracy can cut the number of rounds needed to engage a target and reduce the time crews stay exposed to enemy counter-fire, according to Northrop ^[6]. With the guidance degraded, a battery spends more rounds and more minutes in the same position for the same effect ^[12].

"Today's threat environment demands speed and innovation and we're working closely with the US Army to ensure the PGK E5 keeps maneuver forces ready to win in GPS degraded environments," said Dave Fine, vice president of armament systems at Northrop Grumman ^[9].

The Army has both a threshold and an objective accuracy figure for shooting in degraded GPS at all ^[4]. Jam resistance is a written requirement.

A retrofit like this turns on what the change touches. On Northrop's account the E5 touches only the consumable, keeping the same fit, form and user experience as the kit crews already handle ^[3]. It also turns on whether the buyer can measure the vendor's claim with equipment it already owns. That one stays with the government: the threshold and objective figures are not public, and the degraded-GPS testing described is the company's own ^[13].