Monday, July 12, 2010

Underground Airfields: The DPRK


During the Cold War, NATO and Warsaw Pact nations erected numerous hardened aircraft shelters (HASs) to protect their multi-million dollar combat aircraft during wartime. Over time, this practice spread throughout the world's conflict zones, with similar structures being found in many Middle Eastern and Asian nations. Some nations, however, took this practice one step further: they began building full underground facilities (UGFs) to store aircraft.

UGFs are commonly used in many nations to store and protect military hardware, but only a few nations have used them to protect their combat aircraft. These nations include the DPRK, China, and Taiwan in Asia, and Albania, the FRY, Sweden, and Switzerland in Europe. In this feature, the facilities used by the DPRK will be examined.


Twenty major airfields in the DPRK feature significant UGFs for storing combat aircraft. In addition, two locations feature unique runway layouts incorporating UGFs, and seven airfields feature no UGF storage facilities. The locations of these facilities can be seen in the image below. The airbases incorporating UGFs are marked in red, those lacking UGFs are marked in blue/white, and those incorporating hardened airfields are marked in yellow.

There are two basic UGF layouts employed by the DPRK to protect and house combat aircraft. These facilities are either positioned close to the main runway, facilitating ease of movement between the UGF and the operations area, or further afield, suggesting their use primarily for long-term storage. In addition, they are connected to their assigned facilities using two different taxiway styles. Some UGFs are connected by simple taxiways which wind their way through bulidings and terrain to reach the runways, while others appear to have a more interesting purpose, that of a backup launching strip for concealed assets. This information, combined with an analysis of the types stationed at each location, can give an indication as to the employment strategy or readiness level of aircraft contained within. Three airbases will be examined in detail to provide an overview of the DPRK's UGF design, layout, and potential use.

Sunchon AB

Sunchon AB is arguably the DPRK AF's most important installation. Situated approximately 40 kilometers northeast of Pyongyang, it is home to the most advanced combat aircraft in the DPRK. Sunchon AB is home to the DPRK's MiG-29 (FULCRUM) and Su-25 (FROGFOOT) fleets. The MiG-29 represents the DPRK's only true modern, 4th generation fighter aircraft. The Su-25 is likewise the only true survivable, modern ground attack aircraft in the DPRK. Sunchon's MiG-29 unit also makes up roughly half of the BVR-capable combat aircraft in the DPRK, with Pukchang's MiG-23 (FLOGGER) unit being the only other BVR shooters in the AF's inventory. Despite widely published claims to the contrary (including a thoroughly ludicrous Wikipedia article), whereby the MiG-29 fleet is believed to be based at a host of other locations, Sunchon is the only facility where the MiG-29 has been imaged inside of the DPRK.

An overview of Sunchon AB is provided in the image below, with significant facilities or features annotated:
Sunchon's UGF is situated in close proximity to the airfield itself. There are three main entrances, with two entrances likely leading to the storage area for operational aircraft. The third entrance may be for long-term storage of derelict or obsolete aircraft, or for entrance into a dedicated maintenance or GSE storage area. Sunchon's UGF is connected by a series of taxiways to the main apron area.

An overview of the UGF at Sunchon AB can be seen in the image below:
Sunchon AB has ramp space for roughly 34 combat aircraft, with HASs for four more aircraft. There is also an alert or arming/dearming pad at the north end of the runway which can easily park two aircraft. Open ramp space is therefore provided for at least 38 aircraft. 66 modern aircraft, discounting possible attrition since delivery, are based at Sunchon AB, indicating that at least half of them are stored in the UGF at any point in time. 36 Su-25s and 24 MiG-29s were delivered from the USSR, including 4 UB/UBK training versions of each type, as well as 6 MiG-29S (FULCRUM-C) SKD kits assembled in the DPRK. It was the MiG-29S that was used to intercept a USAF RC-135 in 2003.

Analysis of imagery of Sunchon AB provides insight into a number of factors. First, while between 19 and 29 Su-25s are visible depending on the date, only 5 to 9 MiG-29s are visible. This may indicate a much lower readiness level in the far more technologically complicated MiG-29 fleet. Second, it would appear that aircraft are moved from the UGF to the parking ramps for operations, before being re-stored. The image below depicts an open UGF, and an Su-25 being towed from the apron back to its underground hangar:
Furthermore, analyzing the layout of Sunchon AB in relation to the UGF illustrates an interesting feature. A 1350 meter taxiway extends from the UGF to a point beyond the main parking aprons. This taxiway may in fact be an auxiliary runway, allowing aircraft to be prepared for flight while concealed within the UGF and then launched with little or no warning for a strike against the ROK. While the MiG-29 would likely be employed to defend the skies above Pyongyang, the Su-25 is certainly a credible platform for use in this capacity given its relative survivability (compared to other available air to ground platforms in the inventory) and its high payload. Alternatively, this may facilitate the storage of armed, combat-ready MiG-29s in an alert status, protecting them from the elements while other airframes are removed for training flights as needed.

Sunan AB

Sunan AB, situated just north of Pyongyang, is the primary home to the DPRK AF's air transport assets. Assigned aircraft include the DPRK's Il-76 (CANDID) fleet. It also serves as the major international air terminal for the DPRK.

An overview of Sunan AB is provided in the image below, with significant facilities or features annotated:
There are no identified combat aircraft at Sunan AB, but the UGF can be used to illustrate a different layout than that of Sunchon AB. In the case of Sunan AB, the UGF is situated a much greater distance from the main operating area, likely indicating that aircraft stored therein are not operational or are being held in storage. Also, the UGF is not connected by a taxiway suitable for use as an auxiliary runway, reducing the chance that assets contained in the UGF are suitable for rapid deployment.

An overview of the UGF at Sunan AB can be seen in the image below:
Hwangju AB

Hwangju AB, approximately 40 kilometers south of Pyongyang, is home to a DPRK AF MiG-21 (FISHBED) unit.

An overview of Hwangju AB is provided in the image below, with significant facilities or features annotated:
Hwangju's overall layout is similar in many respects to that of Sunchon AB. Hwangju features three ramp areas and four HASs for housing its assigned aircraft. It also features a UGF complex for storing MiG-21s, which is connected to the main facility by an auxiliary runway similar to that found at Sunchon AB. The primary difference in the two facilities is the distance. Sunchon AB features a UGF in relatively close proximity to the main airfield, suggesting that combat aircraft may be stored there on a regular basis. Analysis of the available imagery would seem to validate this theory. In contrast, the UGF complex at Hwangju AB is much further removed from the main airbase. Imagery indicates that a consistent number of MiG-21s, around 20, is parked on the main ramp space of the airfield. This suggests that the UGF is not used for primary storage of aircraft, as it appears to be for Sunchon AB's MiG-29 fleet. This illustrates the relationship between UGF location and storage activity in the DPRK AF.

An overview of the UGF at Hwangju AB can be seen in the image below:

As operational fighter bases, both Sunchon AB and Hwangju AB possess four HASs in close proximity to the main runway. These facilities are likely employed for alert aircraft, enabling them to be protected to a degree from a preemptive strike. While aircraft parked on open ramp areas are soft targets, those contained in HASs would potentially be available for airbase defense or counterstrike sorties in cooperation with aircraft retained within the UGFs.


Onchon airbase in the west and Kang Da Ri airfield in the east feature unique hardened facilities. These airbases incorporate large UGFs for storage, maintenance, and operations work, with runway surfaces exiting the UGFs in multiple directions. No information is available as to the purpose for, use of, or units assigned to these facilities. The most probable use for these unique airbases is as dispersal sites for combat aircraft. They represent very survivable hardened structures, and could potentially house a significant number of aircraft. The only drawback is that deploying a significant number of aircraft to each facility would be a potential identifiable indicator of forthcoming hostile action. To mask such activity, the DPRK would likely establish routine training deployments to each location.

An alternative use for the hardened airbases has nothing to do with aircraft and at this time represents pure speculation. Given that air activity at either location has never been publicly disclosed or identified in imagery, an interesting concept would be to employ the facilities as hardened SSM bases. The facilities resemble airfields in their layout, but a concrete SSM launch pad is little different from a runway surface. Ergo, the DPRK could stockpile SSMs in these facilities, using the "runways" as mass launching areas. In this scenario, transporting SSMs to the facilities would be far easier to mask than the deployment of combat aircraft. The facilities could represent logical storage and mating points for nuclear or chemical warheads, allowing them to remain protected prior to use. Furthermore, what better way to hide an SSM base than by designing it as an airfield? The only serious additional expense would be the additional concrete used to create a "runway" rather than a number of SSM launch pads. In this vein, given the security and survivability of these facilities, they could also represent launch points for UAVs or drone conversions of obsolete aircraft armed with nuclear warheads. At this point in time, however, the facilities are assumed to be exactly what they appear to be: hardened airfields.

Onchon AB

Onchon AB is unique in the DPRK as it possesses both a traditionally designed airfield and a separate hardened airbase facility. The airfield itself is home to a number of old, outdated combat aircraft including the MiG-19/J-6 (FARMER).

An overview of Onchon AB depicting its location relative to the hardened airbase can be seen in the image below:
The hardened airbase at Onchon consists of a single massive UGF with multiple entrances, and three runway surfaces. The facility was noted as being complete in January of 2004. The two primary runway surfaces lead directly into the massive UGF. A third surface useable as an auxiliary runway is connected to the main facility through a taxiway leading to one of the primary runways and to two secondary, secured UGF entrances. These secured entrances may lack the clearance for combat aircraft to use them to gain access to the UGF, but may provide entrance and exit points for GSE or other necessary equipment. A small exterior parking ramp is also provided, possibly for alert aircraft.

Details of the Onchon AB hardened airfield can be seen in the image below:
Kang Da Ri AB

As of 2007, Kang Da Ri AB was still under construction. It is a hardened airbase similar in concept to that found at Onchon. Kang Da Ri AB consists of a large UGF with two separate entrances leading directly to runway surfaces. There is a separate external runway surface, but unlike Onchon it does not lead directly to a UGF portal. Instead, it leads to one of the main runway surfaces via a taxiway still under construction in the latest imagery.

Details of the Kang Da Ri hardened airfield can be seen in the image below:

Employing UGFs to store aircraft does not necessarily mean they will remain viable combat assets. There are numerous options available for negating the impact of these facilities. While penetrating weapons may not be able to access the UGFs themselves from above, PGMs could be used in an attempt to destroy the access doors to the facilities, collapsing the entrances and sealing the aircraft inside for a period of time. Taxiways and auxiliary runways could also be cratered and seeded with bomblets from cluster munitions. The value of the UGFs therefore depends on the ability of DPRK personnel to clear and repair runway and taxiway surfaces and gain access to the facilities to allow the assets held within to be deployed.


The DPRK employs a number of UGFs throughout the nation to house various types of military equipment. The DPRK's Air Force is no exception, and the employment of UGFs will ensure that a portion of the air element remains viable after a first series of strikes by the ROK or USA.


-Satellite imagery provided courtesy of Google Earth

Saturday, July 10, 2010

Slight Schedule Change

This month I'll post an updated Russian SAM Network overview. I was going to do China, but as China is about two and a half years old, it's taking a lot longer to basically completely rewrite the entire thing. Russia is almost two years old, but the layout of the original article made it way easier to update. China will therefore be moved to August, and will be a ridiculous improvement over what is available now.

Now stop reading this and go see Predators.

Friday, July 9, 2010

If It Bleeds, We Can Map It


Overhead imagery can be useful for all sorts of analysis work, but it can also be used for purely amusing pursuits. Earlier today I went and saw Predators, the new movie featuring everyone's favorite chameleonic aliens. The movie, which was awesome, got me thinking: I know Predator (the 1987 original) was shot in Mexico, I wonder if I can find the sets in Google Earth?

Guerilla Base

The easiest site to locate is the guerilla base that Schwarzenegger and his commandos obliterate. It turns out that the old set has been largely retained and is now a museum and restaurant dedicated to the movie. As far as I'm concerned, this means that everyone on the planet now has a reason to go visit Mexico! The site is located south of Puerto Vallarta on Mexico's western coastline, a few miles into the jungle near Mismaloya, and can be seen in the image below:

Two different waterfalls were used in the movie. One of them, Misol-Ha, depicted where Schwarzenegger (ok, his stunt double, who actually messed up his leg doing the scene) fell off of the cliff into the water trying to get away from the Predator. The other one, Agua Azul, was where the Governator fell over a few small falls and crawled out of the water covered in mud. Both sites are located near Palenque in eastern Mexico. They aren't visible in high resolution in Google Earth, so a general overview is provided in the image below:
Wait, where?

The last location isn't a set, but it is related to the movie. This is one of the fun things that Blu-Ray lets you figure out when you have way too much time on your hands. In the opening scene of the movie, Schwarzenegger, Carl Weathers, and R.G. Armstrong are discussing where the helicopter was shot down carrying the guys Schwarzenegger's commandos are being sent in to rescue. Armstrong points to a map of the location, and if you pause the movie on Blu-Ray you can make out what the map says. It turns out that it's actually a real navigation chart...but it's pointing to a location in Brazil, one that's not even close to any border the helo was supposed to have crossed! Check out the image below to see what's actually at the coordinates indicated on the map, and notice the total lack of jungle foliage in the area:
This amusing exercise just goes to show how much fun you can have when you stop being serious with Google Earth. SAM sites? Bah. Finding the set locations of the greatest movie of all time is way more entertaining! Check out the location of the Predator set near Puerto Vallarta in Google Earth and bring up the Panoramio Photos of the area to see some of the fun leftovers from the film. There are a ton of good Panoramio Photos showing the waterfalls as well.

-Overhead imagery courtesy of Google Earth

The South Korean SAM Network


With cross-border tensions between the two Koreas seeming to increase daily, the Republic of Korea's (ROK) SAM network is a significant element in protecting its citizens and infrastructure from hostile forces. Currently undergoing a deep modernization, the ROK's SAM network represents a significant facet of the nation's defense against air and missile attack.


The ROK's SAM force is operated by the Air Defense Artillery Command. The Air Defense Artillery Command became part of the ROK Air Force in 1991, previously being subordinate to the ROK Army. The ROK Air Force also controls the EW radar facilities throughout the nation. EW radars report information to the ROK Air Force's Master Control Reporting Center, which is responsible for managing the airspace above and around the peninsula.Additional SAM assets available to defend ROK airspace are operated by the US Army.


Early warning coverage of the ROK is provided by seventeen identified EW sites. Five of these sites are positioned along the DMZ, with a further three positioned on the islands of Baegryeong-do to the west, Ullung-do to the east, and Cheju-do to the south. EW coverage will be bolstered in the near future with the introduction of four Boeing 737 PEACE EYE AEW&C platforms, the first of which was handed over to KAI at Sacheon in February 2010 for radar integration.

The locations of the ROK's EW sites can be seen in the image below:

The most numerous SAM system employed in the ROK is the MIM-23 HAWK. The 40 kilometer range missile system is deployed at twenty three locations spread throughout the peninsula. While the HAWK is technically a mobile, tactical SAM system, it is employed in a strategic capacity by the ROK, being emplaced at fixed, hardened locations containing both the missile launchers and the guidance radars.

The locations and coverage zones of the ROK's HAWK batteries can be seen in the image below:

The primary long-range strategic SAM system employed by the ROK is the Nike-Hercules. Six sites remain operational in available imagery, primarily situated in the northern third of the nation. Nike-Hercules batteries are each split between two locations, one hosting the guidance radars and another hosting the actual missile battery.

An example of the Nike-Hercules split site layout can be seen in the image below, which depicts a Nike-Hercules location near Yeoju, southeast of Seoul:
The locations and coverage zones of the ROK's Nike-Hercules batteries can be seen in the image below:
While the Nike-Hercules boasts a range of 155 kilometers, an impressive number, its effectiveness is in doubt. Recent incidents have suggested that the missile may no longer be a viable weapon system, causing the ROK to pursue other options. In fact, due to the varied dates of imagery available to analyze the individual battery locations, some (or all) of them may already have been withdrawn from use. However, as no reporting has been located to suggest that the Nike-Hercules has been fully withdrawn by the ROK, those sites which remain active in available imagery are noted here.

Nike-Hercules may remain a significant weapon in the ROK's arsenal following retirement from the air defense role. Two SSM variants have been developed, with ranges of 150 and 180-250 kilometers. These systems are referred to as Hyunmoo I and Hyunmoo II, and may be sited at existing Nike-Hercules facilities as they can employ the same launch systems. Interestingly, the northwestern Nike-Hercules site west of Inchon is 180 kilometers from P'yongyang, and does not appear to have a guidance radar facility nearby necessary for surface-to-air operations. This facility may represent an operational Hyunmoo SSM base, and was apparently constructed between 2004 and 2008. It is unlikely that the ROK would construct such a significant facility merely to support a SAM that was already overdue for replacement.

The Inchon Nike-Hercules site can be seen in the image below:

To bolster the air defense of the ROK, the US Army began deploying Patriot strategic SAM batteries to the peninsula in the 1990's. US Army Patriot batteries began to be upgraded in 2003 with the addition of the PAC-3 missile, optimized for the ATBM role. The PAC-2 missile has a range of 160 kilometers, with the PAC-3 having a range of approximately 30 kilometers due to its significantly smaller airframe.

There are currently eight Patriot batteries assigned to the ROK, with active batteries located at Osan (two), Suwon (two), and Kunsan (one) airbases. A sixth active battery was briefly located at Gwangju airbase in October of 2004, but was relocated by December of 2006. Despite the protests from anti-American elements when the battery was sited at the Korean airbase, the US Army had never intended the relocation to be permanent. It relocated to Camp Carroll near Daegu, where it remains garrisoned with the other two batteries assigned to the ROK for future deployment when required. Each Patriot battery is typically deployed with eight TELs and a guidance radar.

A representative Patriot deployment at Osan AB can be seen in the iamge below:
The locations and coverage zones of US Army Patriot batteries deployed in the ROK can be seen in the image below. The Camp Carroll garrison facility is also annotated.
The ROK began to investigate purchasing its own Patriot missile systems in the 1990s. The SAM-X program was initiated in 1990 to find a successor to the Nike-Hercules. Due to financial and political reasons, the program did not bear fruit until 2007, when a decision was made to purchase second-hand German PAC-2 batteries. The first ex-German Patriots were delivered in 2008. They will serve in a trials capacity before being operationally deployed in 2012.

A SAM training facility southeast of Daegu was expanded between 2003 and 2007. The timing is significant as this was when the ROK government was still investigating its options for SAM-X, and by this stage had decided to focus on a variant of the Patriot system. This facility, which likely trains ROK SAM operators as evidenced by the presence of Nike-Hercules equipment, was hosting Patriot equipment in January of 2009. This likely represents the first sighting of ROK-operated Patriot equipment in imagery.

The ROK SAM training facility can be seen in the image below:
Unconfirmed reporting suggests that the ex-German Patriot systems have been deployed near Seosan, Suwon, Incheon, and Gangneung. This report first appeared in September of 2008, coinciding with the first deliveries of Patriots to the ROK. Sighting ROK Patriot equipment at the training facility near Daegu suggests that it was not deployed directly after delivery as the report suggests. With the exception of Suwon, these locations all feature Nike-Hercules batteries. While Patriot deployment has not been confirmed at these locations, they do represent logical deployment sites in the future once crews have been trained and the sites have been reconfigured to support Patriot batteries.


On paper the ROK's SAM network appears to be relatively robust. Sites are organized in a logical fashion, often enjoying overlapping fields of fire. Terrain concerns, particularly in the areas closest to the DMZ, are largely alleviated by placing many of the sites at high altitude atop mountain ranges. The bulk of the ROK-operated sites are consolidated in the heavily populated northwestern sector.

The coverage zones of ROK-controlled SAM batteries can be seen in the image below:
US-operated Patriot batteries provide additional defense against both aircraft and ballistic missiles over a large portion of the nation. This added coverage can be seen in the image below, which adds range rings for PAC-2 missiles to those of the ROK's HAWK and Nike-Hercules batteries:
The main problem facing the ROK's SAM network is one of quality. Nike-Hercules and HAWK systems are both legacy systems better suited for museum display than battlefield use at this juncture. HAWK missile batteries likely retain a degree of effectiveness thanks to numerous upgrades being available during their service lives, but they lack the range to effectively protect the peninsula. Cognizant of the deficiencies of the HAWK system in the 21st Century, original plans called for the replacement of ROK HAWK batteries by 2010, a deadline which will not be reached. By 2012, Nike-Hercules batteries should be withdrawn in place of Patriot batteries, providing a significant upgrade to the ROK SAM network in terms of overall capability.


In the future, the ROK's SAM network will see significant changes. First and foremost, the ROK will no longer rely on the ineffective Nike-Hercules for long-range air defense, with Patriot batteries replacing these systems in 2012. Whether the withdrawl of Nike-Hercules SAM batteries will affect the Hyunmoo programs is not known at this time.

A replacement for the HAWK is being co-developed with the Russian Almaz design bureau, and is slated to complete development in 2011. This system, codenamed KM-SAM or Cheolmae-II, will employ a modified Fakel 9M96 active radar homing SAM along with a modern phased array radar. KM-SAM batteries will consist of a radar vehicle, a command post vehicle, and up to eight TELs, all mounted on wheeled vehicles for high mobility. Each TEL will carry eight cold-launch missile canisters. The modified 9M96 dispenses with the original Russian design's canard foreplanes, but retains the nose-mounted reaction control thrusters. It will also employ a directional warhead, and has an advertised range capability of over 40 kilometers.

The ROK also plans to create a missile defense network called KAMD, incorporating the Elta EL/M-2080 Green Pine BMEW radar, Patriot systems, and KDX-III AEGIS destroyers. Mention has also been made of an improved Cheolmae-II called K-THAAD forming part of this network. Creation of such a system is ironic given that protests over potential PAC-3 purchases were due in part to a feeling that the ROK would be drawn into a US-led anti-missile network.


The ROK currently fields a SAM network that would have been state of the art in the 1960s, and effective into the early 1980s. The modernization programs underway will correct many of its deficiencies and shortcomings, allowing the network to achieve technological parity with other nations in the region and provide capable and effective defense well into the 21st Century. Hopefully the ROK's citizens will find their government's desire to defend them acceptable.


-Satellite imagery provided courtesy of Google Earth

Patriot moves to Camp Carroll
PEACE EYE Delivered
PAC-3 Deployed to Korea
German Patriots Delivered
Seoul Begins Deploying Patriot Missile Interceptors
Air Defense Artillery Command
Hyunmoo Ballistic Missiles
Korean Missile Defense