Northrop Grumman PGK E5 Adds Anti-Jamming to 155mm Artillery

PGK E5 Targets a Key Weakness in Precision Artillery

The Northrop Grumman PGK E5 is a next-generation Precision Guidance Kit designed to preserve the accuracy of 155mm artillery projectiles when GPS signals are degraded by electronic warfare. Northrop Grumman announced on September 9, 2026, that production of the upgraded system is underway at its Plymouth, Minnesota, facility, with first deliveries expected in early 2028.

The development addresses an increasingly important problem for modern artillery forces. GPS-guided munitions can provide substantial accuracy improvements over conventional ballistic rounds, but satellite navigation can become vulnerable when an adversary uses electronic warfare to interfere with or disrupt positioning signals.

The PGK E5 is intended to reduce that vulnerability without requiring a new artillery weapon, major changes to existing ammunition stocks, or extensive retraining. The approach is significant because it upgrades an established 155mm artillery capability rather than requiring armies to replace their existing guns and projectile inventories.

The U.S. Army’s acquisition documents identify the system as the M1156E5 PGK, with the E5 configuration adding GPS anti-jam capability for degraded GPS environments.

What Is the Northrop Grumman PGK E5?

The PGK E5 is the latest development of the U.S. Army’s M1156 Precision Guidance Kit family. It is not a new artillery shell or a new howitzer. Instead, it is a guidance and fuze assembly that is installed on compatible 155mm projectiles.

The basic concept is straightforward. A conventional artillery projectile is affected by numerous sources of ballistic error, including variations in firing conditions, projectile characteristics and atmospheric conditions. A precision guidance kit uses navigation information and aerodynamic control to correct part of that error during flight.

The U.S. Army describes the PGK as a course-correcting fuze that uses a GPS receiver and internal guidance and navigation computer. It provides point-detonating and proximity-fuzing functions while improving the accuracy of compatible 155mm high-explosive projectiles.

The PGK E5 retains that basic architecture while adding enhanced anti-jam capability.

Northrop Grumman says the E5 maintains the same form factor, reliability and user experience associated with the existing PGK, allowing it to be integrated into the current artillery ecosystem with limited changes.

PGK E5 Technical Capabilities

The key technical improvement is its ability to operate in a GPS-degraded environment.

GPS is an important component of modern precision fires, but a peer adversary can employ electronic warfare systems to interfere with satellite navigation signals. Jamming can reduce the availability or quality of navigation information received by a weapon.

The PGK E5 is designed to make the guidance kit more resilient to this threat.

Army documentation identifies the M1156E5 as the configuration that adds GPS anti-jam capability. The Army’s 2026 portfolio documentation also lists Northrop Grumman Defense Systems as the prime production partner and L3Harris as the GPS supplier.

Compatible 155mm Projectiles

Army program documentation identifies PGK compatibility with several 155mm projectile types, including:

• XM1113
• M1128
• M795
• M549A1

The same documentation identifies integration with the M109A6/A7 Paladin, M777A2 Lightweight Towed Howitzer and future next-generation howitzer configurations.

This compatibility is one of the most important aspects of the program.

Rather than creating a completely separate precision-fire system, the PGK approach allows existing artillery ammunition to gain a guidance capability by replacing the conventional fuze with the guidance kit.

The U.S. Army previously described the PGK concept as a way to convert conventional artillery stockpiles into near-precision munitions.

Accuracy and Guidance

Army program documentation lists the PGK family’s accuracy requirements at:

The figures above are program requirements rather than a claim that every operational round will achieve the same circular error probability under every battlefield condition. Actual accuracy depends on factors including the firing solution, environmental conditions, navigation signal quality and projectile characteristics.

Northrop Grumman states that recent PGK E5 testing in GPS-degraded environments exceeded both threshold and objective accuracy requirements.

The company also reports that the broader PGK family has achieved approximately 98% point reliability since 2013 and that nearly 145,000 kits have been delivered.

Why Anti-Jamming Matters for 155mm Artillery

The operational problem is larger than GPS alone.

Modern militaries increasingly assume that a peer conflict will involve intense electromagnetic warfare. Both sides can attempt to disrupt communications, navigation, radar systems and other electronic capabilities.

For artillery, GPS interference can affect weapons that depend on satellite navigation to correct their trajectories.

That creates an important distinction between:

Precision-capable artillery: A weapon can exploit accurate coordinates and navigation data to reduce delivery error.

GPS-resilient precision artillery: The weapon can retain useful performance when an adversary is actively attempting to disrupt its satellite-navigation inputs.

The PGK E5 moves the M1156 family toward the second category.

This does not mean that PGK E5 makes a projectile immune to electronic warfare. Instead, the anti-jam capability is intended to improve the guidance system’s ability to continue operating when GPS conditions are degraded.

That distinction is important when evaluating the system against sophisticated electronic warfare environments.

PGK E5 and the U.S. Army Precision Fires Architecture

The PGK E5 is part of a larger U.S. Army effort to improve the resilience of precision fires.

The Army has already introduced the M1156A1 PGK, which incorporates M-Code GPS capabilities and provides improved resilience against emerging threats. The Army reported that the M1156A1 achieved full materiel release in 2025.

The E5 represents another step in that progression.

The modernization sequence can broadly be understood as:

1. M1156: GPS-based course correction and fuze functions.
2. M1156A1: M-Code GPS and additional projectile compatibility.
3. M1156E5 / PGK E5: Enhanced GPS anti-jam capability.
4. Future PGK developments: Greater compatibility with future projectiles, navigation technologies and extended-range artillery systems.

The Army is also developing the XM1171/XM1172 Long Range Precision Guidance Kit, intended to modernize course-correcting fuze capabilities and support future projectiles and extended-range weapon platforms while retaining backward compatibility with current 155mm systems.

This indicates that precision guidance is being treated as an evolving ammunition architecture rather than a one-time upgrade.

A Low-Disruption Modernization Strategy

One of the strongest features of PGK E5 is its integration philosophy.

Northrop Grumman says the E5 maintains the existing fit, form and factor needed to integrate with 155mm artillery. The company also says the system is compatible with existing projectiles and fielded howitzers and requires minimal retraining or system changes.

That matters because artillery modernization is constrained by more than technical performance.

Armies also have to consider:

• Existing ammunition inventories
• Howitzer fleets
• Training pipelines
• Fire-control systems
• Logistics infrastructure
• Maintenance procedures
• Production capacity
• Interoperability with allied forces

A new munition that requires a new launcher, new fire-control architecture and extensive retraining can take years to field.

A fuze-level modernization can potentially move faster because much of the surrounding artillery architecture remains unchanged.

PGK E5 vs Conventional 155mm Artillery

The key advantage is not simply greater accuracy. It is the combination of precision, existing-platform compatibility and improved resilience to GPS interference.

PGK E5 vs Excalibur

The PGK E5 also needs to be distinguished from the Army’s M982 Excalibur precision-guided artillery projectile.

Excalibur is a purpose-built precision projectile with its own integrated guidance architecture. PGK takes a different approach by adding a guidance and fuze capability to compatible conventional 155mm ammunition.

This creates different tradeoffs.

PGK therefore occupies an important middle ground between conventional artillery ammunition and more sophisticated dedicated precision munitions.

Operational Impact in a GPS-Contested Battlefield

The significance of PGK E5 becomes clearer when viewed through the conditions expected in a high-intensity conflict.

A modern artillery unit could face a battlefield in which:

• GPS signals are intermittently disrupted.
• Communications networks are contested.
• Counter-battery sensors rapidly locate firing positions.
• Artillery positions must frequently displace.
• Ammunition consumption is extremely high.
• Targets can move or disappear quickly.
• Precision fires must be delivered with fewer rounds.

In that environment, the ability to use existing artillery ammunition while retaining precision under degraded navigation conditions can provide an operational advantage.

It can also reduce dependence on specialized precision rounds.

That does not eliminate the need for conventional artillery. Massed fires remain important because precision ammunition can be expensive and production capacity is finite.

Instead, PGK E5 provides commanders with another option between unguided mass fires and more expensive dedicated precision weapons.

Implications for U.S. and Allied Artillery

The PGK family has already been positioned for international use. Army material previously highlighted foreign military interest in the system because it can provide precision capability while maintaining compatibility with existing 155mm artillery architectures.

That compatibility is particularly relevant to NATO and other U.S.-aligned forces operating large fleets of 155mm artillery.

A number of allied militaries use weapons such as the M777 and other NATO-standard 155mm systems. A guidance kit that can integrate with established ammunition and artillery infrastructure can therefore offer a relatively practical route toward greater precision and GPS resilience.

The broader strategic value comes from interoperability.

If U.S. and allied artillery forces can operate compatible precision-guided ammunition within shared logistics and fire-support architectures, the technology can contribute to more integrated coalition fires.

China and Russia: The Electronic Warfare Challenge

The PGK E5 is also a response to the wider evolution of peer-level warfare.

Russia has demonstrated extensive use of electronic warfare in Ukraine, including efforts to interfere with satellite navigation and communications. China has invested heavily in electronic warfare, counter-space capabilities and systems designed to contest the electromagnetic spectrum.

For the U.S. Army, that creates a requirement to assume that satellite navigation will not always be continuously available or uncontested.

The PGK E5 should therefore be viewed as part of a broader assured positioning, navigation and timing strategy.

The Army has separately invested in M-Code GPS and other assured-PNT technologies for ground forces. Its modernization work includes systems designed to provide more reliable positioning and navigation when GPS is degraded or unavailable.

The artillery problem is one component of that larger challenge.

Production and Fielding Timeline

Northrop Grumman says production of PGK E5 is already underway at its Plymouth, Minnesota, facility, with first deliveries expected in early 2028.

Army acquisition documentation provides additional context.

The 2026 Army ammunition budget identifies Northrop Grumman in Plymouth as a PGK contractor and lists ongoing procurement activity for the PGK family.

The Army’s 2026 portfolio documentation identifies the M1156E5 configuration as adding GPS anti-jam capability and projects materiel release for the first quarter of fiscal year 2028.

This timeline is important because it shows that the anti-jam version is moving from development and testing toward formal fielding.

Cost and Production Considerations

Northrop Grumman has not publicly disclosed the value of the September 2026 PGK E5 production contract in the material examined for this report.

Army budget documents do, however, show that PGK procurement costs can vary considerably according to configuration, production year and contract structure. For example, the Army’s FY2026 ammunition justification lists different quantities and unit costs for PGK procurement lines. Those figures should not be treated as the specific PGK E5 contract price.

That distinction matters because defense procurement prices can include different combinations of hardware, engineering, qualification, support and production costs.

Limitations and Remaining Challenges

PGK E5 addresses a major vulnerability, but it does not eliminate all problems associated with precision artillery.

GPS Remains a Critical Element

The system remains fundamentally associated with GPS-based guidance. Enhanced anti-jam capability improves resilience but does not mean that satellite navigation can be treated as permanently available.

Future systems will likely need increasingly diverse navigation inputs, including alternative PNT technologies and complementary sensors.

Electronic Warfare Will Continue to Evolve

Anti-jamming technology is part of an ongoing competition.

As navigation systems become more resistant to interference, adversaries can develop new electronic attack techniques. The result is likely to be a continuing cycle of improvements rather than a permanent solution.

Artillery Survivability Remains Separate

PGK E5 improves the ammunition’s effectiveness, but it does not make the artillery platform itself less detectable.

In a high-intensity conflict, counter-battery radars, drones, electronic intelligence and other sensors can rapidly identify firing positions.

Precision ammunition therefore needs to operate alongside:

• Shoot-and-scoot tactics
• Counter-battery systems
• Unmanned aerial systems
• Electronic warfare
• Decoys
• Distributed fires
• Networked targeting

Production Capacity Matters

The value of precision artillery ultimately depends on the ability to manufacture sufficient quantities.

The wars of the 2020s have reinforced the importance of ammunition production capacity. A technically advanced guidance kit has limited strategic value if production cannot keep pace with wartime consumption.

Future Outlook: From GPS Guidance to Assured Precision Fires

The PGK E5 is likely to be one step in a longer evolution of artillery guidance.

The U.S. Army is already pursuing future precision-guidance technologies intended to work with new projectiles and extended-range artillery systems. Its Long Range PGK program specifically aims to modernize course-correcting fuze technology while retaining backward compatibility with current 155mm systems.

That points toward a future in which guidance kits become increasingly modular.

Instead of treating each artillery projectile as a completely separate precision weapon, militaries can potentially combine:

Common projectile + modular guidance + resilient navigation + networked targeting

Such an architecture could allow existing ammunition stocks to receive improved capabilities as technology evolves.

For the U.S. Army, that is particularly valuable because the 155mm artillery ecosystem is already extensive. Incremental modernization can provide new capability without waiting for a complete replacement of the artillery fleet.

Conclusion

The Northrop Grumman PGK E5 represents a focused upgrade to one of the U.S. Army’s established precision-artillery technologies.

Its most important feature is not simply improved accuracy. The central development is the addition of GPS anti-jam capability to a guidance kit that can remain compatible with existing 155mm projectiles and fielded artillery systems.

That gives the Army a way to address a growing problem in modern warfare: precision fires that must continue operating when an adversary actively contests the electromagnetic spectrum.

Northrop Grumman says production is already underway and first deliveries are expected in early 2028. Army documentation identifies the M1156E5 as the anti-jam configuration and places it within a wider effort to improve precision fires and assured positioning, navigation and timing.

The broader lesson is significant. Future artillery modernization will not be defined only by greater range or larger warheads. Navigation resilience, electronic warfare survivability, production scale and compatibility with existing weapons will increasingly determine whether precision fires remain effective on a contested battlefield.

PGK E5 is designed around that reality.