Saab and Anduril Upgrade GLSDB for Better Accuracy and Range: What’s New and Why It Matters

GLSDB

The Ground-Launched Small Diameter Bomb (GLSDB), a collaborative innovation by Saab and Boeing, was once heralded as a cost-effective, long-range strike solution. However, its real-world performance particularly in Ukraine fell short of expectations. Now, a promising partnership with U.S.-based Anduril Industries may be the key to unlocking the GLSDB’s full potential.

The Promise and Pitfalls of the GLSDB

Originally conceived in 2014, the GLSDB merges a Boeing GBU-39/B Small Diameter Bomb with an M26 rocket motor, offering a range of up to 150 kilometers. Its design allows for 360-degree targeting and precision strikes, making it an attractive option for militaries seeking affordable alternatives to high-end missile systems.

Yet, in combat scenarios especially in Ukraine the GLSDB struggled. Its reliance on satellite guidance made it vulnerable to electronic warfare (EW) interference, which significantly degraded its accuracy. Reports indicated that deviations of 30 to 50 meters were not uncommon, a critical flaw for a munition designed to strike within a few meters of its target.

Enter Anduril: A New Engine for a New Era

Recognizing the need for a technological overhaul, Saab turned to Anduril Rocket Motor Systems, a subsidiary of the defense tech disruptor Anduril Industries. The goal: replace the aging M26 rocket motor with a modern, high-performance alternative that could be produced quickly, affordably, and at scale.

Anduril’s solution is more than just a new engine. It represents a shift in how defense manufacturing is approached. By leveraging advanced automation, novel manufacturing techniques, and a robust supply chain, Anduril aims to deliver rocket motors that are not only more efficient but also significantly cheaper than those of traditional competitors.

The engines will be produced at a new $75 million facility in McHenry, Mississippi, operated by Adranos—a company acquired by Anduril in 2023. Once operational, the plant is expected to produce up to 6,000 solid rocket motors annually, bolstering the U.S. and allied nations’ munitions supply chains.

Testing, Modernization, and the Road Ahead

The revamped GLSDB has already undergone a new round of testing. In March 2025, 19 upgraded units were trialed to assess improvements in reliability and performance. Enhancements included reinforced internal connections and better resistance to EW interference. While full-scale production is slated for 2026, the early results suggest that Saab and Anduril may have finally addressed the system’s most pressing flaws.

This development is particularly significant for Ukraine, currently the only confirmed operator of the GLSDB. With the updated engines, the country could receive more reliable and effective long-range strike capabilities—an essential asset in its ongoing defense efforts.

Strategic Implications

Beyond the technical upgrades, this partnership signals a broader trend in defense innovation. Saab’s decision to collaborate with a relatively new player like Anduril reflects a growing appetite for agility and innovation in an industry often dominated by legacy contractors. It also underscores the importance of transatlantic cooperation in strengthening NATO’s collective defense posture.

Moreover, the move aligns with Saab’s broader strategy to expand its U.S. footprint. The company is building a new production facility in Grayling, Michigan, where it plans to manufacture GLSDB systems domestically. This not only enhances supply chain resilience but also positions Saab as a more integrated player in the U.S. defense ecosystem.

The GLSDB’s journey from underperforming prototype to revitalized precision weapon is a testament to the power of innovation and collaboration. With Anduril’s cutting-edge rocket motors and Saab’s commitment to modernization, the system is poised for a second act—one that could redefine the role of affordable precision munitions in 21st-century warfare.

As full-rate production looms on the horizon, all eyes will be on how the upgraded GLSDB performs in the field. If successful, it could mark a turning point not just for the weapon itself, but for the future of agile, tech-driven defense manufacturing.

From Innovation to Integration: Operationalizing the Upgraded GLSDB

As Saab and Anduril transition from developmental testing to operational deployment, several key questions shape the trajectory of the GLSDB’s future: How will these revamped munitions integrate into existing command structures? Will logistical chains and fire-control systems require adjustment? And how rapidly can full-scale production ramp up to meet global demand?

The logistical versatility of the GLSDB—being compatible with standard M270 MLRS and HIMARS launchers—already gives it an edge. However, modernization introduces new layers of complexity. Software updates, additional training modules, and integration with situational awareness platforms may be necessary to fully exploit the new capabilities. The enhanced resistance to electronic warfare and upgraded propulsion systems mean recalibrated tactics, especially in joint operations or contested zones.

Expanding the Global Footprint

While Ukraine remains the sole known operator, interest is mounting across NATO and allied nations. The combination of precision, affordability, and adaptability makes the GLSDB a compelling option for countries seeking to bolster deterrence without overextending defense budgets. Saab’s Michigan-based production line—combined with Anduril’s streamlined motor manufacturing in Mississippi—creates a supply chain blueprint that can be replicated or scaled to suit international orders.

Moreover, as global tensions evolve and asymmetric threats grow, demand for long-range precision weapons is expected to rise. The revitalized GLSDB could fill a unique niche between short-range artillery and strategic missile systems, offering rapid-response capabilities with reduced collateral damage.

A Shift in the Defense Paradigm

Beyond the battlefield implications, the GLSDB modernization underscores a broader evolution in defense philosophy. Rather than relying solely on legacy systems and long procurement cycles, defense industries are embracing a more agile, innovation-driven approach—mirroring startup ecosystems in the civilian tech world.

Anduril’s rise exemplifies this shift. Founded by Silicon Valley entrepreneurs, the company blends rapid prototyping, vertical integration, and AI-driven manufacturing processes to reduce cost and lead times. Its collaboration with Saab not only rejuvenates the GLSDB but serves as a case study in how non-traditional defense players can reshape the industry.

As 2026 approaches, full-rate production of the upgraded GLSDB is within reach. Whether the system becomes a mainstay of modern arsenals will depend not just on its technical specs, but also on real-world results, timely delivery, and adaptability to emerging threats. If successful, the project could redefine how nations think about smart munitions—bridging the gap between affordability and precision in an increasingly complex security environment.

The GLSDB’s second act, driven by Saab’s engineering and Anduril’s disruptive ingenuity, is more than a retrofit—it’s a reinvention. And in a world where strategic agility and readiness are no longer optional, that reinvention couldn’t come at a better time.

Combat Debut in Ukraine

The Ground-Launched Small Diameter Bomb (GLSDB) has had a relatively short but eventful operational history, with its most notable deployment occurring in Ukraine. While initially hailed as a game-changing precision weapon, its real-world performance revealed several critical challenges.

The GLSDB made its combat debut in Ukraine as part of Western military aid aimed at bolstering the country’s long-range strike capabilities. With a range of up to 150 km and compatibility with HIMARS and MLRS launchers, it was expected to provide Ukrainian forces with a cost-effective alternative to more expensive systems like ATACMS.

However, battlefield reports quickly highlighted significant shortcomings. Chief among them was the weapon’s vulnerability to Russian electronic warfare (EW). The GLSDB relies heavily on GPS for guidance, and Russian forces employed GPS spoofing and jamming to disrupt its navigation systems. This interference caused the bombs to miss their targets by 30 to 50 meters, a substantial deviation for a munition designed to strike with near-meter accuracy.

Technical and Tactical Limitations

The problems weren’t limited to EW interference. Analysts also pointed to doctrinal and tactical mismatches. The GLSDB’s relatively small warhead—about 36 kg of explosive in the GBU-39/B variant—meant that even minor targeting errors could render a strike ineffective. Unlike larger munitions, the GLSDB doesn’t have the blast radius to compensate for imprecision.

Moreover, the system’s inertial navigation backup—designed to maintain course when GPS is jammed—proved insufficient in high-interference environments. While it prevented total mission failure, it couldn’t maintain the tight accuracy needed for high-value or hardened targets.

Operational Pause and Reassessment

Due to these issues, Ukrainian forces reportedly paused the use of GLSDBs for several months. This operational stand-down allowed Saab and its partners to reassess the system’s vulnerabilities and explore upgrades. The recent collaboration with Anduril Industries, which introduced a new rocket motor and improved internal components, is a direct response to these early setbacks.

Lessons Learned

The GLSDB’s troubled debut underscores the evolving nature of modern warfare, where electronic and cyber capabilities can neutralize even the most advanced kinetic weapons. It also highlights the importance of adaptive design and rapid iteration—qualities that Saab and Anduril are now embracing as they prepare for full-scale production of the upgraded system.

GLSDB Technical Specifications

Feature	Details
Range	Up to 150 km (93 miles)
Minimum Range	Approximately 70 km (with maneuvering)
Warhead Type	Multipurpose, penetrating blast-fragmentation
Warhead Weight	~93 kg total, with ~16–57.6 kg of explosive fill depending on variant
Launch Weight	~272 kg (600 lb)
Length	3.91 meters (12 ft 10 in)
Diameter	24.1 cm (9.5 in)
Wingspan	1.61 meters (5 ft 3.3 in)
Guidance System	GPS-aided Inertial Navigation System (INS), with anti-jam capabilities
Accuracy (CEP)	Within 1 meter (3 ft 3 in)
Launch Platforms	M270 MLRS, M142 HIMARS, or containerized launchers
Engine	Originally M26 rocket motor; now upgraded with Anduril’s modern variant

These specs highlight the GLSDB’s unique blend of precision, flexibility, and affordability. Its ability to engage targets from any angle—even behind the launch point—makes it a standout in the realm of long-range precision munitions.