YDG-65

YDG-65
Type	Anti-ballistic missile
Place of origin	Menghe
Service history
In service	2013-present
Used by	Menghe
Production history
Manufacturer	Buksŏng Industries Group
Specifications
Weight	5400 kg
Length	9.68 m (overall)
Diameter	104 cm (overall)
Warhead	150 kg directed high-explosive fragmentation
Detonation mechanism	Radar proximity fuze
Engine	solid fuel rocket
Operational range	180 km
Flight ceiling	45 km
Speed	2600 m/s
Guidance system	Semi-active radar homing

The YDG-65 is a type of anti-ballistic missile developed in Menghe for the Menghean Army. It is designed to provide missile defense against short-range and medium-range ballistic missiles with ranges of up to 3,000 kilometers, and specializes in intercepting the threat in its terminal or re-entry stage, though it has some mid-course intercept capability against missiles within its engagement ceiling. It is the heaviest surface-to-air missile ever developed for the Menghean armed forces.

When deployed as part of the Chŏlgung air defense system, the YDG-65 is carried on a tracked hull and used to defend mobile high-value targets such as large unit headquarters and logistics hubs. When deployed as part of the Changgung air defense system, it is carried on a trailer and used to defend fixed strategic targets such as bridges, airfields, rail yards, and cities. Because the missile is too large for the canisters in the Mark 41 Vertical Launching System, it is not used by any Menghean Navy warship.

Design

The YDG-65 missile was developed to defend against tactical and medium-range ballistic missiles operated by Maverica and the former Innominada. Prior to its introduction, Menghe did not operate any surface-to-air missiles with true ABM capability. Hypersonic cruise missiles were not considered as possible targets during the development phase, as none of Menghe's likely adversaries had such missiles in service.

The YDG-65 is a two-stage solid-fuel missile with a total mass of 5,400 kilograms. Until launch, the missile is carried in a cylindrical canister with a spring-loaded lid.

When a launch command is issued, the canister's lid opens and a spherical cold launch gas generator in the base of the missile activates. Once the missile is propelled free of the tube, the large base stage activates, rapidly accelerating it to full speed and high altitude. This stage is steered by a thrust vectoring system inside the thrust cone, which operates by channeling high-pressure exhaust from the combustion chamber to one of four ports around the interior of the cone. After about five seconds, all fuel in the first stage is exhausted and a pyrotechnic charge separates it from the 1,150-kilogram second stage.

The second stage then fires its own solid-fuel sustainer motor to close with the target. Of the eight conventional tail fins arranged around the base of this stage, four are fixed fins for stabilization and four are actuator-driven control surfaces which steer the missile. After climbing to a peak altitude, the final stage then descends toward an intercept point with the target, relying on inertial navigation and command guidance from the battery command post. In the terminal stage, the battery guidance radar illuminates the target and the YDG-65 homes in using its semi-active nose antenna. This semi-active seeker can reportedly acquire a re-entry vehicle with a radar cross-section of 0.05 m² from a range of 30 kilometers, and the guidance radar can reportedly distinguish between missile warheads and decoys, then send command signals to keep the missile locked on the correct target. At this intercept point, the missile's velocity is in the Mach 3-4 range, and it is reportedly able to conduct 30-G maneuvers to intercept maneuvering targets.

As the YDG-65's second stage nears the target, it performs a roll maneuver to align the warhead with the intercept course. When the target is at the correct point, an onboard radio proximity fuse detonates a 150-kilogram directed fragmentation warhead. The size of the warhead and the use of a directed fragmentation charge both maximize the concentration of shrapnel in the target's direction, increasing the kill probability against a ballistic target. A seeker algorithm accounts for the relative velocities and bearings of the target and the interceptor missile when firing the directed fragmentation charge, thus ensuring a high probability of direct impact with the target's warhead at all intercept angles. The warhead also has a command-fired self-destruct mode, which can be activated if the target is destroyed by another system.

Although it was developed to defeat short- and medium-range ballistic missiles in their terminal phase, the YDG-65's rapid acceleration and directional warhead also make it effective against medium-altitude supersonic cruise missiles, large artillery rockets, and missiles following quasi-ballistic trajectories. Theoretically, it can also engage fixed-wing aircraft, medium-altitude subsonic cruise missiles, and helicopters, though its poor low-altitude performance and SARH guidance make it ineffective against low-level targets. Menghean Army training documents explicitly discourage using the YDG-65 against non-ballistic targets, due to the missile's size and cost and the small number of missiles per battery.

Because of the doctrinal prohibition against engaging non-ballistic targets, and because of the YDG-65's long minimum range and high minimum altitude, it is standard practice to position a YDG-65 launch battery inside the coverage of a medium- or short-range surface-to-air missile system. This also allows the YDG-65 launch battery to share targeting information with a broader air defense network. When the YDG-65 is deployed as part of the Changgung air defense system, the protected target installation usually has medium- and short-range SAM defenses as well; within the Chŏlgung air defense system, YDG-66 batteries would be attached to Chŏlgung-DT batteries as needed.

Detailed specifications (YDG-65G)

Dimensional characteristics

Characteristic	Canister	First stage	Second stage
Length	--	4880 mm	1680 mm
Diameter	--	1040 mm	680 mm
Mass	--	4250 kg	1150 kg

Performance characteristics

Maximum range	180 km
Minumum range	15 km
Maximum altitude of the target	45 km
Minimum altitude of the target	1 km
Terminal maximum load factor	30 G
Terminal peak velocity	Mach 3-4
Kill probability (non-maneuvering aircraft)	0.85 to 0.95
Kill probability (non-maneuvering SRBM)	0.8 to 0.9
Kill probability (maneuvering aircraft)	0.7 to 0.9
Kill probability (maneuvering SRBM)	0.6 to 0.8
Kill probability (supersonic cruise missile)	0.5 to 0.7
Kill probability (MRBM)	0.4 to 0.6

Chŏlgung-DT battery

The Chŏlgung air defense system is a family of surface-to-air missile batteries deployed on the IMCh-J Koppulso heavy tracked utility chassis. It is used by the Menghean Army for Division- and Corps-level air and missile defense. Chŏlgung-DT (Dae-Tandotan, anti-ballistic missile) is the family of vehicles which support the YDG-65 missile, including the missile launch vehicle, the guidance radars, and the command post.

A typical Chŏlgung-DT battalion is organized as follows:

• 1 battalion command post
• 1 battalion staff post
• 1 long-range air search radar vehicle
• 4 Chŏlgung-DT batteries (24 missiles total)
  • 1 guidance radar and command post vehicle
  • 1 medium-range air search radar vehicle
  • 3 TELTs (2 missiles each)
• 4 Chŏlgung-DT transport platoons (24 missiles total)
  • 1 staff and command vehicle
  • 3 transport trucks (2 missiles each)
• 1 maintenance vehicle
• 1 field kitchen and life support vehicle
• 4 general logistics vehicles

The command posts, search radar vehicles, guidance radar vehicles, and TELTs (transporter-erector-launcher-transloader) all use the IMCh-J Koppulso chassis, which can operate offroad more effectively than wheeled vehicles. This allows Chŏlgung-DT batteries to accompany Army units in areas with poor transportation infrastructure and reposition regularly to avoid detection. The transport trucks and logistics vehicles use the Taekchŏn T512 heavy 8x8 utility truck, which has good but inferior offroad capability, especially when the summer monsoon season floods rice paddies and reduces dirt roads to mud. As such, batteries which exhaust their missiles would be expected to rendezvous with missile transport platoons at points near a paved road.

Chŏlgung-DT batteries use a TELT derived from the YB-60Ch, also part of the Chŏlgung air defense system. This vehicle carries two missile canisters on individually elevating arms, and has a six-ton-capacity crane which folds flat over the chassis when not in use. Using this crane, the TELT can individually reload each of its missile canister arms individually by elevating the other canister arm to create working space. Because the TELT incorporates its own crane, there is no need to rendezvous with a dedicated transloader or crane truck; instead, the TELT can directly reload itself from a flatbed truck, a trailer, a railcar, or a pallet of missiles.

The TELT of the Chŏlgung-DT system can transition from a road march to a firing position in 5 minutes. Once deployed, it can prepare for an engagement in 30 seconds; once engagement-ready, it can fire a missile 15 seconds after receiving a fire order. This reaction time gives the Chŏlgung-DT system good "shoot-and-scoot" capability, allowing firing batteries to reposition at short notice while minimizing downtime. As on other Chŏlgung-family systems, the individual battery vehicles can communicate targeting information with VHF radio, SHF radio, or direct cables between TELTs and guidance radar vehicles, with each communication mode providing increased resistance to communications jamming and fewer radio signals to enemy passive antennas.

Changgung-DT battery

The Changgung air defense system is a family of surface-to-air missile batteries which the Menghean Armed Forces use to defend stationary strategic targets on land. The Changgung-DT system is the terminal anti-ballistic-missile component of the Changgung air defense system, and should not be confused with Changgung-DTW, a mid-course anti-ballistic missile system developed for the YDG-68. Changgung-DT places two YDG-65 cold-launch canisters on a towed trailer which can be parked in the open and commanded from a battery command post, also towed. The use of an unmanned trailer was partially a response to the missile tube's length, and partly a safety measure to distance the crew from the launch position.

While Chŏlgung-DT batteries are a Corps-level asset and accompany the Menghean Army's advance and retreat, Changgung-DT batteries are grouped into an Army-level Ballistic Missile Defense Brigade and would be posted near stationary strategic targets, such as airfields, bridges, rail yards, port facilities, and major cities. Changgung-DT systems have also been spotted at airfields and port facilities run by the Menghean Navy in the Republic of Innominada.

Upgrades and variants

YDG-65G

This is the designation given to the semi-active radar homing variant which was first introduced to service in 2013.

YDG-65N

The YDG-65N is a variant with a dual-mode active and semi-active radar homing seeker. The active radar homing mode allows a single battery to conduct a larger number of simultaneous missile intercepts. It also allows the missile to intercept threats which are below the radar horizon, and to intercept threats which are tracked by air search radars without activating the battery-level guidance radar. In addition to its active radar mode, the YDG-65N retains a semi-active radar homing mode, which can be used against targets with small radar cross-sections, targets in a jamming-intensive environment, or targets which deploy decoys in flight.

YDG-65D

YDG-65D is the speculative designation given to a special variant of the YDG-65 missile rumored to be in development as of 2021. In place of a semi-active radar homing seeker, it incorporates an advanced imaging infrared seeker for terminal-stage interception. This variant is reportedly being developed in an effort to counter hypersonic cruise missiles, which have a very small radar signature because they are cloaked in radio-absorbent plasma during their cruise phase. The Menghean Ministry of National Defense has stated that existing radar-guided variants of the YDG-65 missile can intercept plasma-cloaked hypersonics "with high confidence," and has not provided formal evidence for the existence of the rumored YDG-65D program.