On January 15, South Korea’s Defense Acquisition Program Administration (DAPA) held a kickoff meeting for the combat system development as part of the upgrade program (performance improvement program or PIP) for the Chungmugong Yi Sun-sin-class destroyers (KDX-II).
DAPA plans to significantly enhance the operational capabilities of the Chungmugong Yi Sun-sin-class destroyers by replacing their major onboard equipment with latest systems. Hanwha Systems was awarded the PIP (Performance Improvement Program) contract worth 135.93 million USD (197.1 billion KRW) in December last year and is expected to leverage its latest combat system technologies and utilize its prior experience of upgrading the KDX-I Gwanggaeto the Great-class destroyers.
As part of the upgrade, outdated combat systems will be replaced with a domestically developed system featuring advanced software, significantly improving target processing and information handling speeds. The existing towed array sonar system will be replaced with the latest version, which is also deployed on FFX Batch-III Chungnam-class frigates, while the missile illuminators for SM-2 surface-to-air missiles will be upgraded. This will greatly enhance anti-air and anti-submarine capabilities. This PIP is the first upgrade program for South Korean naval vessels equipped with the SM-2, integrating the missile with the combat system using advanced domestic technologies.
Additionally, the U.S. Department of Defense’s Defense Security Cooperation Agency (DSCA) announced in December 2024 that the U.S. State Department has approved a Foreign Military Sale (FMS) requested by the South Korean government for $300 million (approximately 430 billion KRW) in support of the KDX-II upgrade project. This includes technical support, software, and the MK 99 fire-control system to address aging issues of the KDX-II destroyers.
Following the KDX-I Gwanggaeto the Great-class destroyers, the KDX-II destroyers became the first in the Republic of Korea Navy to adopt SM-2 missiles, establishing themselves as a cornerstone of the ROK Navy’s fleet. The lead ship of the class, Chungmugong Yi Sun-sin, was built by Daewoo Shipbuilding & Marine Engineering (now Hanwha Ocean) and commissioned in December 2003. With the first ship now exceeding 22 years of service, the need for performance upgrades has become increasingly critical. KDX-II has experienced multiple instances of combat system malfunctions, emphasizing the urgency of modernization efforts to ensure operational reliability and maintain mission readiness.
A notable incident highlighting these challenges occurred during the U.S.-led multinational maritime exercise, RIMPAC in July 2022. During the exercise, the ROK Navy’s Munmu the Great fired an SM-2 missile, which failed to intercept its target and instead self-destructed mid-air. The investigation, conducted by the U.S. Navy and communicated to the ROK Navy, revealed that the failure was caused by a software error in the missile’s weapon control system. The incident underscored the critical need for comprehensive upgrades to both the software and hardware of the KDX-II class destroyers to address such vulnerabilities and ensure the reliability of the ROK Navy fleet’s air defense capabilities.
There was anticipation regarding whether the KDX-II would have its MW-08 air-surface radar replaced with an indigenously developed 3D AESA radar such as the SPS-560K, or the SPY-7 radar proposed by Lockheed Martin during MADEX 2021. However, the radar replacement was not included in the current performance improvement program.
DDH-II Chungmugong Yi Sun-sin-class destroyers
The Chungmugong Yi Sun-sin-class destroyers (KDX-II) have paved the way for the Republic of Korea Navy to transition into a blue-water navy. As a core asset of the Maritime Task Flotilla Seven, they are regularly deployed as part of the Escort Task Group in the Gulf of Aden, ensuring the safe navigation of both South Korean and civilian vessels against maritime crimes. Research to develop a successor to the Chungmugong Yi Sun-sin-class destroyers is currently underway, with completion targeted for the 2030s. At MADEX 2023, Hanwha Ocean proposed the KDDX-S concept, which features increased displacement and reduced personnel requirements through automation and unmanned systems.
Specifications
Displacement: 5,500t (full-load)
Length: 150 meters
Beam: 17.4 meters
Draft: 7.3 meters
Propulsion: GE LM2500 gas-turbine engine x 2, MTU diesel engine x 2 (CODOG) two-shafts
Speed: Top speed up to 30 knots
Range: 5,500nm at a speed of 20 knots
Approx. 230 personnel
SYQ-500K mod.II KDCOM2 (CMS)
Armaments
5-inch Mk 45 gun x 1
30 mm Goalkeeper CIWS x 1
RGM-84D Harpoon or SSM-700K C-Star anti-ship missiles x 8
RIM-116 Rolling Airframe Missile (RAM) x 1
32-cell Mk41 VLS for SM-2 Block IIIA
24-cell K-VLS for C-Star-II surface to land cruise missile and Red Shark K-ASROC
Triple 324 mm torpedo tubes for K745 Blue Shark torpedo x 2
Sensors
RTX AN/SPS-49(V)5 2D long-range radar
Thales Nederland MW08 3D radar
Thales Nederland STIR 240 fire-control radar
Sonar
Atlas Elektronik DSQS-21BZ hull-mounted sonar
SQR-220K towed array sonar system
Softkill/ECM
SLQ-261K TACM
K-DAGAIE Mk 2 decoy system
SLQ-200(V)K SONATA ECM
Aircraft
Mk 99 Super Lynx x 2
