North Korea Claims “Autonomous” Guidance and Big Deployments of Its New Small Solid SRBM

North Korean media reported the use of a “new autonomous navigation system” on a May 17 test of a small solid-propellant short-range ballistic missile (SRBM) first flight-tested in April 2022. That system has apparently been designated as Hwasong-11D. Just two days earlier, media reports of Kim Jong Un inspecting a new defense production facility showed some 99 road-mobile Hwasong-11D launchers on display. Assuming the Democratic Republic of Korea’s (DPRK or North Korea) reporting is accurate, these recent activities are notable in at least four key respects.
- The missile flew 300 kilometers (KM) compared to the previous 110 km. However, this longer range probably was the result of a different flight profile that would reduce the missile’s accuracy.
- The nature of the new “autonomous” guidance system and its accuracy are unknown, but presumably it is intended to avoid reliance on global navigation satellite systems. Most options for a new guidance system would take up additional payload space and weight, requiring a reduction in explosive warhead weight within the same payload envelope. Sufficient accuracy improvement could offset such a warhead reduction, however.
- Very large deployments of the Hwasong-11D apparently are intended, especially since each launcher can carry four missiles, and North Korea probably intends to conduct multiple rounds of launches per vehicle. Although a large force underscores the potential availability of the system for export, its shorter range compared to the KN-23 and KN-24 may make it less desirable for export customers.
- The very large number of deployed Hwasong-11D missiles is consistent with an important conventional role for the system. The number of deployed SRBMs is much larger than the number of nuclear warheads North Korea is likely to allocate to SRBMs, especially given the numerous other types of weapons systems Pyongyang has linked with nuclear weapons. The war in Ukraine has underscored the importance of conventionally armed SRBMs in modern warfare, as well as the large numbers of such missiles that must be expended over long periods of time in order to have a meaningful battlefield and strategic impact.
The mid-May Hwasong-11D activity is fully consistent with the focus of North Korean missile activities on theater strike systems during the first four months of 2024. Spotlighting guidance improvements and impending large deployments of this SRBM underscores Pyongyang’s “long-range artillery” threat to South Korea, both nuclear and especially conventional.
Information to Date
According to North Korean media, Kim Jong Un visited an unnamed “defense industrial enterprise” on May 14 and “acquainted himself with the tactical missile weapon system” with which “the combined missile units of the Korean People’s Army (KPA) in charge of an important firing assignment” will be equipped. The report noted that “The firepower assault combined units of the KPA’s western operation group” will be equipped with “the missile launchers produced [at the enterprise] in the first half of the year.” Associated photographs depicted Kim in a large building with some 99 road-mobile transporter-erector-launchers (TELs) for the small solid-propellant short-range ballistic missile (SRBM) first flight tested in April 2022, which is apparently designated Hwasong-11D by the North.
On May 17, North Korea launched multiple probable SRBMs from Wonsan on its east coast to a range of about 300 km, according to the South Korean military. The next day, North Korean media announced that “a test fire of tactical ballistic missile, which employed a new autonomous navigation system” had occurred. Kim Jong Un reportedly oversaw the test, noting “the independent development and successful introduction of the autonomous navigation system.” Associated photos showed an apparent Hwasong-11D missile in the early launch phase and a video monitor next to Kim Jong Un displaying a Hwasong-11D TEL with the launcher erected and the aftermath of an explosion on an apparent target island.
Analysis and Implications
Assuming the North Korean reporting is accurate, these recent activities related to the Hwasong-11D SRBM system are notable in at least four key respects.
Longest system range to date. In two previous flights, both in April 2022, the Hwasong-11D reportedly demonstrated a range of 110 km and a maximum altitude (apogees) of 25 km; no such data was available for the four remaining previous flights, all in March 2023. At least the April 2022 missiles probably flew highly depressed trajectories entirely within the atmosphere, as has been the case for most flights of the contemporary North Korean KN-23/-24/-25 SRBMs, which allows the missiles to be guided during the entire flight and complicates interception by missile defenses—but at the expense of range.
The 300 km range reported for the May 2024 launches most likely means that the Hwasong-11Ds flew in a standard, “minimum energy” trajectory that maximizes range. No changes to the missile’s propulsion system would have been required, just the use of a different trajectory. If the latest flights used such a trajectory, the increased range would have come at the expense of accuracy, since the missile would not be able to perform guidance maneuvers throughout flight, only during boost phase and atmospheric reentry. That change also would increase the missile’s exposure to missile defenses in wartime due to its higher apogee and the reduced opportunities for the missile to maneuver.
Guidance system unknown. North Korea did not reveal the nature of the “new autonomous navigation system” reportedly employed on the latest Hwasong-11D tests. Most Western analysts presume that the original Hwasong-11D, along with the other current-generation North Korean SRBMs, probably uses modern inertial guidance updated by global navigation satellite systems.[1] The reference to “autonomous” suggests the objective of the new guidance system was to provide a guidance mode not reliant on inputs external to the missile, like satellite signals, that could be jammed. A new guidance system might also be intended to help restore the accuracy lost in shifting from the highly depressed trajectory used in at least April 2022 to a likely minimum-energy trajectory.
The missile photos released with the North Korean announcement of the launch did not reveal any differences from those released in April 2022, further complicating any assessment of the new guidance system. But the main possibilities are:
- An “autonomous” version of the Hwasong-11D relying solely on inertial navigation, the traditional ballistic missile guidance method using acceleration and orientation sensors within the missile. This would be immune from jamming, but would result in substantially lower accuracy, especially at longer range because inertial accuracy degrades as a function of flight time (and, thus, range).
- Terminal guidance using an optical seeker to replace the use of navigation satellites. This is a relatively less technically demanding form of terminal guidance, but often results in visible changes to the missile’s nose tip not seen in the North Korean photos.
- Passive radar homing, where the missile guides in on intercepted radar signals and destroys the emitting radar. This would also be less technically demanding, but would only be useful against emitting targets.
- Active radar homing, where the missile emits its own radar signal and uses it to navigate to the target. This would be the most technically demanding of these alternatives but potentially the most capable.
Except for inertial-only guidance, these new guidance systems also would take up additional payload space and weight, requiring a reduction in explosive warhead weight within the same payload envelope. Sufficient accuracy improvement could offset such a warhead reduction, but the potential accuracy of any new terminal homing system is unknown.
Large deployments expected. The display of 99 Hwasong-11D TELs indicates a very large deployment of this system is intended. Indeed, in 2021, North Korea had only deployed some 200 launchers for ballistic missiles of all types, according to the US Defense Intelligence Agency. The apparent Hwasong-11D force is especially impressive given that each TEL can launch four missiles, and North Korea probably intends to conduct multiple rounds of launches per TEL by using missile reloads. Moreover, the North’s May 15 announcement suggests these TELs are intended only for “the KPA’s western operation group,” and, thus, others have been or will be deployed elsewhere. Recent analysis also indicates that the TEL facility Kim Jong Un reportedly visited on May 14 was only brought online as of about December 2023, supplementing another facility building Hwasong-11D TELs that Kim reportedly visited in January 2023.
Although a large Hwasong-11D force suggests the potential availability of the system for export, there is as yet no evidence that this system has been used by Russia in Ukraine, or by any other potential customer. It may be that the system’s relatively short range compared to the KN-23 (up to 690 km demonstrated) or KN-24 (up to 410 km), which have been found on the battlefields in Ukraine, makes it less desirable for export customers. In particular, its range may be too short for the deep-strike missions Russia apparently has assigned to SRBMs in Ukraine—especially given the likely need to stand well back from the battlefront to avoid being attacked by Kyiv’s drones. It should be noted, however, that any loss in accuracy stemming from using the Hwasong-11D at the 300-km range probably would not be seen by Russia as a downside, given its indiscriminate use of SRBMs against Ukraine’s civilian population.
Conventional role underscored. The Hwasong-11D was the first SRBM North Korea directly associated with “tactical nukes.” It has also been associated, from its first introduction, with “drastically improving the firepower of the frontline long-range artillery units.” The very large number of launchers, and, thus, deployed missiles, indicated by the recent North Korea reporting, underscores the significant conventional role of the Hwasong-11D. That number of deployed missiles is much larger than the number of nuclear warheads North Korea is likely to allocate to SRBMs, especially given the numerous other types of weapons systems (including other SRBM types) Pyongyang has linked with nuclear weapons. Moreover, the war in Ukraine has underscored the importance of conventionally armed SRBMs in modern warfare, as well as the large numbers of such missiles that must be expended over long periods of time in order to have a meaningful battlefield and strategic impact.
Same Song, New Lyric
The mid-May Hwasong-11D activity is fully consistent with the focus of North Korean missile activities on theater strike systems during the first four months of 2024. Spotlighting guidance improvements and impending large deployments of this SRBM underscore Pyongyang’s “long-range artillery” threat to South Korea, both nuclear and especially conventional.
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For example, see Stéphane Delory, Antoine Bondaz, Christian Maire and GEO4i, North Korean Short Range Systems: Military consequences of the development of the KN-23, KN-24 and KN-25 (Paris: Fondation pour la Recherche Stratégique, 2023), 76-80, https://www.nonproliferation.eu/hcoc/wp-content/uploads/2023/01/NORTH-KOREAN-SHORT-RANGE-SYSTEMS-1.pdf.