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Ground-Launched SDB Gets Another Shot in Ukraine
Ukraine is set to receive an upgraded version of the Ground-Launched Small Diameter Bomb (GLSDB) from the United States, indicating a renewed attempt to bolster Kyiv’s long-range strike capabilities amid ongoing hostilities with Russia.
Reuters reports that the decision comes after previous GLSDB deployments in Ukraine faced significant challenges due to Russian electronic warfare (EW), which undermined their effectiveness.
Originally developed by Boeing and Saab, the GLSDB combines the air-launched GBU-39/B Small Diameter Bomb (SDB) with the rocket motor from an M26 artillery rocket.
This hybrid munition offers a cost-effective, precision-guided strike capability, capable of engaging targets at ranges up to 150 km. The GLSDB can be deployed from current launch platforms, such as the M270 Multiple Launch Rocket System (MLRS) and the M142 High Mobility Artillery Rocket System (HIMARS).
The GLSDB operates by initially using its rocket motor to achieve altitude and speed, following which it deploys wings and transitions into a guided glide phase. Its advanced guidance package includes GPS-aided inertial navigation, offering an accuracy of within just 1 m CEP. According to Saab, the GLSDB is capable of engaging targets from any angle – including reverse slope engagements – and can maneuver around terrain obstacles such as mountains.
However, despite these promising specifications, Ukraine’s military concluded that the GLSDB did not perform as well as they hoped. The Russian military’s use of electronic warfare (EW) is thought to have affected the GLSDB’s satellite navigation (GPS) connectivity, resulting in generally less accurate strikes. Subsequently, Ukraine withdrew the GLSDB from frontline use.
In response, Saab and Boeing have reportedly upgraded the GLSDB with enhanced anti-jamming features designed to counteract Russian electronic interference. Reportedly, 19 tests were carried out using the improved GLSDB to validate these improvements.
However, with Ukraine’s dwindling inventory of Army Tactical Missile Systems (ATACMS), it is likely that Kyiv is hoping that the GLSDB will help fill the growing gap in its stand-off range strike capabilities.
Notes and Comments
The introduction and subsequent upgrade of the GLSDB underscores a broader point: providing Ukraine with a credible land-based stand-off strike capability traditionally reserved for air-launched munitions.
Initially marketed as a cost-effective solution for ground forces lacking advanced air power, the GLSDB aimed to replicate air-strike precision from ground platforms. Yet, its vulnerability to EW has exposed a few key limitations when operating against sophisticated adversaries, like Russia, which can leverage such countermeasures at scale.
Indeed, Russia is proactively deploying EW technology and tactics as a means to degrade GPS-reliant munitions, from the GLSDB to Joint Direct Attack Munition (JDAM) precision-guided bombs (PGB), to new guided artillery shells, like the Excalibur.
A growing number of countries are taking both Ukraine and Russia’s experiences as lessons for their own long-term planning. Pakistan, for example, sharply increased its investment in EW systems to interfere or mitigate enemy radars, communications, and satellite navigation as well as communications links.
Thus, there will likely be an industry-wide shift towards autonomous or ‘smart’ munitions that can operate in denser EW environments. These new munitions could leverage techniques like artificial intelligence and machine learning (AI/ML) for independent target acquisition, swarming maneuvers, and other actions without relying as much, if at all, upon a data-link or GPS connectivity (as reflected in Pakistan’s efforts with the AZB-81LR, for example).
