Stealth Presentation Ver.2

November 20, 2017 | Author: Waqas Haider | Category: Aviation, Aeronautics, Military Technology, Military Science, Aircraft
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2nd Int'l Conf. on Applications of Mathematics and Informatics in Military Sciences (AMIMS), Hellenic Military Academy, April 11-12, 2013, Vari, Athens

Low Observable Principles, Stealth Aircraft and Anti-Stealth Technologies Konstantinos Zikidis (Major, HAF), Ph.D. Alexios Skondras (2nd Lieutenant, HAF) Charisios Tokas (2nd Lieutenant, HAF)

Department of Aeronautical Sciences, Hellenic Air Force Academy Dekelia Attica, Greece

An impressive aircraft, with stealth characteristics...

Anyone knows the aircraft type ?

MiG-31 Firefox, a fictional aircraft from the 1982 movie “Firefox” “a Soviet interceptor aircraft, capable of Mach 6, invisible to radar, carrying weapons controlled by thought...” Despite such interesting features, it seems that reality had already surpassed the filmmakers' imagination... At the same time, a real stealth aircraft had already been developed...

Lockheed F-117 Nighthawk (US) attack aircraft First flight: 1981, IOC: 1983, revealed to public: 1988

Took part in:

Operation Just Cause, Panama (1989), Operation Desert Storm, Persian Gulf War (1991), Operation Desert Thunder, Iraq (1997-8)...

...Kosovo (1999), Afghanistan (2001), Iraq (2003)...

Subsonic, no AB, no radar, Link16 or countermeasures system... However, thousands of successful missions, only one combat loss... was retired in 2008

First aircraft types exhibiting low observable features, most possibly not deliberately... Horten Ho 229 (Germany, 1945): reported to make use of graphite (absorbing) paint, remained at prototype stage

Avro Vulcan (UK, prod.: 1956 – 65): sometimes disappeared from the radar screen

Early attempts by the US towards stealth in the 50s and 60s, mainly relying on absorbing paints, more or less unsuccessful... U-2 Dragon Lady (1957 - ...) SR-71 Blackbird (1964 - 1998)

A-12 (1963-1968)

First real steps towards radar signature reduction, with the (unintentional) help of USSR... •1964, Moscow: “Method of Edge Waves in the Physical Theory of Diffraction” by Pyotr Ufimtsev: radar return is related to the edge configuration of an object, not its size • Ufimtsev's work later translated and studied by the US

Have Blue technology demonstrator

•1970s: advances in computers and software allows computer simulation and fly-by-wire systems •1976: Lockheed Skunk Works "Have Blue" project: 2 planes built, both lost during successful demonstration program •1978: US decides to develop F-117 •1981: first flight of YF-117A

Radar Cross Section – RCS: a measure of the radar signature or radar return of an object RCS of a target: the cross section of a metal sphere (in m²), yielding the same radar return as the target Depends on many parameters, such as: relative size (size versus wavelength), target material /painting, shape / orientation...

RCS reduction techniques Purpose shaping: – Surface faceting – No external loads (weapons, tanks) – No propellers – Hidden engine blades – No parallel surfaces – No corner reflectors – Tilted tail fins (or no fins at all) – AESA radar (or no radar at all) Radar Absorbent Materials (RAM) Passive cancellation Active cancellation


RCS (m2)

Destroyer (200 m)


Β-52 Stratofortress


RCS (m2)

F-18 E/F Super Hornet








Radar (ΙΕΕΕ Band)

Possible anti-stealth techniques: Multistatic radars separate transmitter and receiver antennae Reported to provide certain detection capabilities, even for stealth targets. Requires a network of nodes, while the target is expected to be “between” transmitter and receiver nodes.

Passive radars (passive coherent location – PCL): no transmitter – various receivers, exploiting disturbance on existing RF transmissions (TV, FM, GSM, HDTV...) Pros: no transmission, use of low frequency bands (better stealth detection), detection even at very low altitude, cannot be detected and targeted... Cons: uncontrolled RF transmissions, no detection at high altitudes, 2D tracking Lockheed Martin Silent Sentry 1999

Passive radars (passive coherent location – PCL)

Homeland Alerter 100 (Thales, France)

Transportable passive radar by Cassidian (EADS, Germany) CELLDAR – CELL PHONE RADAR (BAE Systems – Roke, UK) AULOS Passive Covert Location Radar (Selex Sist. Int., Italy) Hellenic Multi-target Passive System – HEMPAS or CCIAS (“Thessaloniki Team”, Greece): multistatic PCL – ESM system

Electronic Support Measures (ESM) Systems a system of 3 or 4 receivers, detecting and tracking targets using their own emissions Not very useful against aircraft which will not use IFF, Link16, V/UHF etc. Kolchuga

(Topaz, Ukraine)

Vera-NG (ERA, Czech Republic)

Low frequency band radars e.g., VHF-band or L-band Stealth designs are optimized for medium to high freq. bands  Wavelength is comparable to aircraft parts (wings, stabilators)  Scattering enters Mie or resonance region (max RCS)  RAM less effective at low frequencies  VHF radars cannot be detected by HARM-like weapons 

Transportable, 3D AESA VHF Radar 1L119 NEBO SVU (Rosoboronexport, Russia)

Low frequency band radars transportable, digital design, modern semiconductor technology, designed for low RCS targets 2D VHF Radar VOSTOK E (Agat/KB Radar, Belarus)

3D L-Band Radar 67Ν6Ε Gamma-DE (VNIIRT, Russia)

Multi-band radars Transportable 3D Radar system 55Zh6M Nebo M (NNIIRT/Almaz-Antey, Russia) Comprises Nebo SVU (VHF-Band), Protivnik G (L-Band) and Gamma S1 (S/X-Band), linked to a central command station

Over-The-Horizon Radars HF (3-30 MHz), utilization of sky waves Extreme range (800 – 4000 km) but low accuracy See targets “from above” - prohibitively high min range

InfraRed (IR) Systems Stealth aircraft employ techniques for IR signature reduction, as well. However, it never disappears... IRST: IR Search and Track  Missile seekers (e.g., MICA IIR, IRIS-T)  The combustion chamber of the F135 has the highest temperature (>2200°C) among fighter aircraft engines 

EADS Eurofighter: PIRATE (Passive Infra Red Airborne Tracking Equipment) by EUROFIRST. Comprises FLIR and IRST (up to 200 targets at 50 – 90 km)

InfraRed (IR) Systems Dassault Rafale OSF (Optronique Secteur Frontal) by Thales Optronique – SAGEM An F-22 in the HUD and OSF of a Rafale, during ATLC 2009 (6 dogfights Rafale vs F-22: 5 draws and 1 win for the Raptor)

InfraRed (IR) Systems Lockheed Martin SpectIR: long range IRST

F-18 E/F: in the front part of a fuel tank

F-16: in a pod

InfraRed (IR) Systems The Russians have been using IRST systems as standard equipment in most fighters from the '80s... Sukhoi Su-35E, with IRST OLS-35


Stealth technology has become sine qua non: all military aircraft, tanks, ships etc, are designed or redesigned according to low observable techniques  Stealthiness is not panacea: stealth aircraft are not invincible. This applies to the F-35, as well...  It seems not possible to confront stealth aircraft employing only one radar / sensor technology  A promising approach relies on the following:  Low freq. radars for med-high altitude surveillance  Passive radars for low-med altitude surveillance  Data fusion of all sensors through networking  Aircraft guidance and track designation via data link  Onboard IR systems for detection and tracking 

quote from Dr. W. Edwards Deming (1900 – 1993), American author, statistician, professor, lecturer and consultant:

“It is not necessary to change. Survival is not mandatory.” mandatory.”

ANY QUESTIONS ??? K. C. Zikidis, Al. Skondras, C. Tokas: "Low Observable Principles, Stealth Aircraft and Anti-Stealth Technologies", 2nd Int'l Conf. on Applications of Mathematics and Informatics in Military Sciences (AMIMS), Hellenic Military Academy, April 11-12, 2013, Vari, Athens

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