The Oerlikon GDF or Oerlikon 35mm twin cannon is a towed anti-aircraft gun made by Oerlikon Contraves (renamed as Rheinmetall Air Defence AG following the merger with Rheinmetall in 2009). The system was originally designated 2 ZLA/353 ML but this was later changed to GDF-001. It was developed in the late 1950s and is used by around 30 countries.
The system traces its origins to a post-war effort to develop a series of related autocannon classified by the calibre; 20mm weapons became the KA series, 25mm the KB, 30mm KC, and 35mm KD. As the first model in the 35mm line, the gun itself is known as the Oerlikon KDA. Although single-gun systems have been used, the twin-gun mount became almost universal, and the KDA naming fell from use.
Design and development
The system uses twin autocannons, firing 35×228mm NATO-standard ammunition. It was originally designated 353 MK and is now designated as the KD series. The same KD series 35mm cannons are used in the Leopard 1 based Gepard and Type 74 tank based Type 87 SPAAG and Marksmanself-propelled anti-aircraft guns (SPAAG). The system could be paired with the off-gun (remote) Super Fledermaus fire control radar, which in the late 1970s was upgraded to the Skyguard system. The weapons were aimed either directly, by way of an advanced sighting system, or automatically, by locking onto the target with radar. Early models carried 112 rounds ready to fire, and an additional 126 stored on the chassis as reloads. Later versions with automated reloading carry 280 rounds total. A typical engagement burst is 28 rounds.
In 1980 an upgraded model, the GDF-002 was produced, which featured an improved sight, and the ability to be directed by an off-gun digital control system. A few years later a third version of the system was being produced, the GDF-003, which was broadly similar to the GDF-002, but included some enhancements like self-lubricating weapons and integrated protective covers.
A self-propelled concept, the GDF-001 Escorter 35 existed.
In 1985 a further upgraded model was produced, the GDF-005, which was introduced, featuring the Gunking 3D computer-controlled sight with an integrated laser range-finder and digital control system. The GDF-005 also introduced an automated ammunition-handling system, which eliminated the need for the two reloaders, reducing the crew from 3 to 1.
The guns are usually transported by a 5-tonne 6×6 truck.
KD series cannons
An Austrian GDF-005 (FIAK85) gun system. Note the muzzle velocity measuring device on the muzzle of each gun
Development of the KD series cannon began around 1952 soon after Oerlikon calculated that 35mm was the optimum calibre for an anti-aircraft gun. The KD series cannons were a design adapted from the post-war 20mm KAA 204 Gk cannon. Several designs were developed, including a water-cooled design, designated Mk 352, which was tested by the U.S. Navy.
The final design was the Mk 323, which was developed in two variants, a belt-fed version the KDA, and a linkless version the KDC, fed by seven-round clips. Both designs are gas-operated, with a propped-lock locking system.
The Super Fledermaus fire control system was designed and built by the then separate Contraves company. It consists of a four-wheeled towed trailer with an E/F band pulse dopplersearch radar with a range of around 15km and a pulse doppler tracking radar operating in the J band, also with a range of 15km. It was also used as the fire control system on the Gepard SPAAG.
An Oerlikon Contraves Skyguard Radar of the Austrian Air ForceFour-tube Aspide/Sparrow missile launcher closeupSkyguard System Set Display in Chengkungling, Taiwan
The Skyguard is a fire control system developed by Contraves and introduced in the 1977 to replace the Contraves Super Fledermaus system in the Swiss Air Force. It is produced by Oerlikon-Buehrle (now Rheinmetall Air Defence). Updated versions were fielded in 1975, 1995 and 2010. It is an all weather low- to medium-altitude (up to 3,000m) air defence system with the maximum effective distance of 4,000m.
The Skyguard fire control system performs air surveillance, target acquisition, calculation of the derivative-action values and control of the twin 35mm guns or missiles. Pulse doppler search radar, pulse doppler tracking radar and co-axial television camera are mounted on the roof of the towed trailer. Skyguard is operated by four people. The radar is deployed quickly through the use of hydraulic systems for antenna erection. The trailer houses the crew of two and a small power generator.
A typical fire unit consists of two twin 35mm gun platforms with a single Skyguard fire control radar. Skyguard systems can also incorporate an optional SAM module based on the GDF's mount and radar system but with the guns replaced by four missile canisters. It can be armed with either AIM-7 Sparrow, RIM-7 Sea Sparrow or Aspide missiles.
The Skyguard radar system was used in the German Air Force for surveillance of low-altitude flight zones. In Taiwanese service, the system includes the Sky Sentinel radar, two 35mm Oerlikon twin gun and an AIM-7 Sparrow Missile Launcher. Greek service the Skyguard system with RIM-7M is known as the VELOS. In Spanish service, Toledo is a Skyguard system with Aspide launchers where the fire control unit has been replaced with Skydor from Navantia.
A total of 468 systems were built through 1994 and major users were Italy (84 systems), Spain (64 systems) and Pakistan (32 systems).
Ammunition
NATO designation
HE-T/HEI-T
HE/HEI
HEI(BF)
SAPHEI/SAPHEI-T
APDS/FAPDS
TP-T/TP
AHEAD
ATOM 35mm
Projectile weight
535g (18.9oz)
550g (19oz)
550g (19oz)
550g (19oz)
375g (13.2oz)
550g (19oz)
750g (26oz)
n/a
Explosive
98g (3.5oz)
112g (4.0oz)
70g (2.5oz)
22g (0.78oz)
n/a
n/a
n/a
n/a
Propellant
330g (12oz)
n/a
Complete round
1,565g (55.2oz)
1,580g (56oz)
1,580g (56oz)
1,552g (54.7oz)
1,440g (51oz)
1,580g (56oz)
1,780g (63oz)
1,750g (62oz)
Muzzle velocity
1,175m/s (3,850ft/s)
1,175m/s (3,850ft/s)
1,175m/s (3,850ft/s)
1,175m/s (3,850ft/s)
1,440m/s (4,700ft/s)
1,175m/s (3,850ft/s)
1,050m/s (3,400ft/s)
1,020m/s (3,300ft/s)
Romanian soldiers firing TP rounds.
Designation:
HEI: High Explosive Incendiary (-T—Tracer)
SAPHEI: Semi-Armour Piercing High Explosive Incendiary
Fuze: Time-programmable base fuze with electronic selfdestruct function
Effective range: 4000 m
Maximum range: 12500 m
Norwegian Nammo, in addition to Oerlikon, supplies at least some variants of this ammunition. Norwegian ammunition was supplied to Ukraine in 2022 for use in the GDF guns in its Flakpanzer Gepard anti-aircraft systems, but it was found not to be compatible, requiring modification.
Versions
A Japanese built version of the gun in travelling positionUnder tow, an Oerlikon 35mm twin cannon of the Republic of Singapore Air ForceJapanese Type 87 SPAAGFinnish ITPSV 90Finnish ITPSV Leopard 2 MarksmanThe PZA Loara-A anti-aircraft vehicleSamavat near Natanz Nuclear Facility
GDF-001 / 2 ZLA/353 MK: XABA sight
GDF-002: Introduced in 1980. Improved Ferranti sight and digital data bus. The gun has 112 rounds ready and 126 in reserve (238 rounds total)
GDF-003: Minor enhancements including protective covers and automatic weapon lubrication.
GDF-005: Introduced in 1985. Fitted with Gunking 3D computer-controlled sight with a laser range finder and digital fire control system. Integrated power supply and diagnostics. 280 rounds on the gun and an automatic re-loading system.
GDF-006: GDF-001/002/003 upgraded with AHEAD system.
GDF-007: GDF-005 upgraded with AHEAD system.
GDF-009: Unveiled at IDEF 2015, held in May 2015 in Istanbul. To date, its exterior significantly changed, although the installation has retained the design of the original serial versions of the systems. Unlike other variants, this one relies on an internal power source. The GDF-009 model is based on a four-wheeled carriage, and is raised off the ground by three stabilisers when deployed in the firing position. It also features an automatic levelling system that can compensate for a maximum tilt angle of up to 7°. Mounted on the forward part of the carriage is the integrated battery, which functions as the gun's power supply unit and can be recharged from an external source if required.
AHEAD: An upgrade for the GDF series guns built around a special projectile which explodes at a pre-calculated point in front of the target, sending a cone of 152 tungsten sub-projectiles at the target. Used by Canada, Pakistan, Greece, Oman, Spain, Taiwan, and Chile (unconfirmed).
MKE/Aselsan GDF-003B Modernized: MKE GDF-003B system modernized by another Turkish company Aselsan. MKE made 35mm guns linked with an Aselsan made Fire and Command Control System. The system has similarities with Skyguard system. The Fire and Command Control System consists of Aselsan made 3D search radar, fire control radar, electro-optical (E/O) sensors and other electronics. Each weapons system can fire up to 1100 rpm (2 x 550rpm) to an effective range of 4km. The upgradation enables the system to fire Aselsan ATOM 35mmairburst round which explodes at a pre-calculated point in front of the target, sending a cone of tungsten pellets at the target. The gun can also fire HEI and TP-T ammunitions. The concept of ATOM 35mm air burst ammunition came up in order to increase the efficiency of the gun systems against modern targets including fixed/rotary wing aircraft, cruise missiles, air-to-ground missiles and unmanned aerial vehicles and other precision guided weapons. Aselsan Fire and Command Control system can also incorporate a low altitude air defense SAM along with 35mm gun platform. Like the GDF-009 each gun platform equipped with the integrated battery, which functions as the gun's power supply unit and can be recharged from an external source if required.
KORKUT: Turkish Self-propelled (SPAAG) variant designed by Aselsan. The system developed from modernized GDF-003B and based around the amphibious capableFNSS ACV-30. KDC-02 cannon of the system manufactured under licence by MKE. Each Korkut system comprises a command-and-control vehicle and three weapons platform vehicles. The command-and-control vehicle has the 3D search radar with an effective radar range of 70km. Each weapon platform vehicle carries enclosed twin 35mm cannons, fire control radar and electro-optical (E/O) sensors.
Gepard: Self-propelled (SPAAG) version of the system based around the Leopard 1.
Marksman: Self-propelled version of the system based around the Marksman turret, which could be fitted on numerous tank chassis. The only model that went into production was a version based on the T-55AM chassis for Finland, seven systems of the ITPSV 90 Marksman were produced. After having been moved to reserve storage since 2010, the Marksman turrets had their electronics modernized and were transferred over to Leopard 2 chassis in 2015, creating the ITPSV Leopard 2 Marksman.
Type 90 (PG99): Chinese licensed copy of GDF-002. The PG99 is a towed anti-aircraft gun suitable for point and coastal air defence. It is usually deployed near military bases, airfields, tunnels, islands, and along the coast to defend Sea Land of Communication (SLOC), ports, bridges and other important assets.
MAA-01: Myanmar's locally made variant using Chinese GDF guns.Similar to Type-90.
CS/SA1: Chinese upgrade of GDF-002. Mounted on the 6×6 SX2190 truck, the PG99 (CS/SA1) is a self-propelled variant of the Type 90 35mm AA system, previously available only as a towed AA piece.
Type 09 SPAAA: Self-propelled version of the system based around the Type 90. First appeared in 2015 China Victory Day Parade.
Samavat: Iranian version of these guns with night vision sight and used with Skyguard & Super Fledermaus FC radars.
Amoun: Egyptian version of Skyguard & Sparrow SAM.
Operators
A deployed Swiss GDF-005
Argentina: 38 GDF-002 Army with Skyguard, 6 GDF-001 Air Force with Super Fledermaus FC radar.
Austria: 74 GDF-005 Army, Air Force 18 GDF-005 with 37 Skyguard FC radar
Bahrain: 12 GDF-005 units, used with Skyguard FC radar.
Bangladesh: 4-8 Oerlikon GDF-009 anti aircraft gun systems have been ordered with Skyguard 3 fire control radar.[verification needed] In 2019, the gun systems have been tested at Cox's Bazar.
Brazil: 38 GDF-001, being gradually phased out in favor of the EMADSas of 2026[update].
Japan: some 70 GDF-001 units, used with updated Super Fledermaus FC radars. Made under a joint venture with Japan Steel Works for the 35mm gun and Mitsubishi Electric Corporation for the rest of the system 52 On the Type 87 (self-propelled anti-aircraft gun)
South Korea: 36 GDF-003 units, used with Skyguard FC radar.
Kuwait: 12 GDF-005 (Amoun) units, used with Skyguard and Sparrow SAM
Malaysia: 28 GDF-005 units, used with Skyguard FC radar.
Myanmar: unknown number of locally made MAA-01 (Type 90) in service.
South Africa: 102 GDF-002 (100 Mk1 GDF-002 units in 2004 were sold for $500 000) + 48 modified GDF-005 units. Upgrading to the Skyshield system, GDF-006 AHEAD and GDF-007 AHEAD standard by 2017. Some 169 Oerlikon GDF-00? were acquired by the SADF along with 75 Super Fledermaus FC radars.
Spain: 92 GDF-007 upgraded from GDF-005 between 2003 and 2006. With 27 Skydor and 18 Skyguard FC radars.
Switzerland: Some 24 GDF-005 modified units (from a total of 264 GDF-001/002 units) used with Skyguard FC Radar.
Taiwan: 24 Skyguard "Sky Sentinel" fire control radars linked to some 50 GDF-003 35mm twin guns. Upgraded to GDF-006 to fire AHEAD rounds since 2009.
Thailand: 8 GDF-007, used with 4x Skyguard 3 FC radar units.
Turkey: 35mm Oerlikon gun produced under licence by MKE. 120 GDF-003 units, Turkish version known as MKE GDF-003B. Multiple gun systems upgraded to GDF-003B Modernized with Aselsan Fire and Command Control System by Aselsan.
United Kingdom: 15 GDF-002 35mm twin guns were captured during the Falklands War along with six Skyguard and one Super Fledermaus FC Radars. Currently four of these Skyguard fire control systems are being used to detect UK military aircraft exceeding flight restrictions over residential areas. GDF-002 guns now in storage and in a few military museums in the UK.
The system was used in a direct fire role during the Battle of Goose Green, killing two, wounding 11. and at Wireless Ridge shortly before the Argentine surrender.
The weapons were involved in two friendly fire incidents. On 1 May 1982, a GADA 601 battery shot down a combat-damaged Argentine Mirage III (I-019) near Stanley Airfield, killing its pilot, Captain Gustavo Cuerva. The second occurred on 24 May 1982, when a Douglas A-4 Skyhawk (C-244) entered a restricted zone over Goose Green and was shot down, killing the pilot, Lieutenant Gavazzi.
Skyguard radars were targeted by the RAF during Operation Black Buck on 31 May and 3 June. One radar was destroyed by Shrike missile shrapnel, killing four operators.
British forces captured 15 guns and six Skyguard units, later refurbished in "Operation Skyguard". BMARC restored the GDF-002 AA guns at Grantham, while Rheinmetall/Oerlikon refurbished four radars in Germany. Twelve guns and four radars entered RAF service with 1339 Wing Royal Auxiliary Air Force, operated by 2729 and 2890 Squadrons at RAF Waddington. Two more Skyguard units were procured. Budget cuts and maintenance costs eventually forced their retirement. One gun is on display at the RAF Regiment Heritage Centre, RAF Honington. The Skyguard system is still used by the RAF to monitor low-level flights.
12 October 2007: A malfunctioning GDF-005 killed nine and injured 14 SANDF soldiers during an exercise at Lohatla, Northern Cape. The gun jammed, then entered automatic mode and fired a burst while traversing uncontrollably. A 2008 SANDF report blamed a sheared spring pin, while others cited poor training.
↑Anti-Aircraft Gun, Oerlikon GDF 009 (14 October 2019). "Oerlikon Radar Controlled Gun". The Financial Express. Archived from the original on 17 October 2019. Retrieved 17 October 2019.{{cite web}}: CS1 maint: bot: original URL status unknown (link) CS1 maint: numeric names: authors list (link)
