Tài liệu STEALTH TECHNOLOGYSTEALTH TECHNOLOGY: A REVEALING ppt

STEALTH TECHNOLOGY:A REVEALING An investigative study on stealth technology... What is it?• RADAR to detect position of objects.. Radar Absorbing Materials RAM• RAMs often as paints used

STEALTH TECHNOLOGY:

A REVEALING

An investigative study on stealth technology.

What is it?

• RADAR to detect position of objects

• Counter measures 1 ECM ( e.g chaff

cartridges) 2 Non ECM

• Avoiding detection and innovating deception

• RCS reductions, acoustics, thermal and other

EM emissions

• Smooth edges maximum radio

• Mainly plan form alignment

• The leading edges of wing and tail surfaces set at same angles.

Vehicle structure (contd )

• Use of re-entrant triangles behind skin.

• Distinctive serrations used in

external airframes.

• Propulsion subsystem shaping.

• Now in research is fluidic nozzles for thrust vectoring.

Vehicle structure (contd )

Radar Absorbing Materials (RAM)

• RAMs often as paints used to

absorb RADAR signals.

• Iron ball paint, ferrite in polymer

matrix used.

• The cockpit canopy coated with

thin layer of indium tin oxide

• Small cell foams painted or loaded with absorbing ink.

Other fields

• Reducing RCS alone not enough.

• More difficulty is reducing the IR signature.

• Interest is near IR region (shorter than 10 µm)

• Major IR emission sources.

1 Tailpipe region

2 Turbojets have EGT’s of 1000oC

3 Exhaust gas plume

4 Hot engine parts

5 Aircraft skin (frictional heating)

6 Reflected and reemitted sunlight

IR Emission

IR Reduction

• Using surface paints

• Non circular tail pipe

• Emissions from hot parts screened by airframe

• The plume mixed with cool air.

• IR best transmitted 2.5, 4 and 10 micron bands.

• IR outside window absorbed by CO2

• Passive IR target acquisition

systems more used.

IR Reduction (contd…)

Electromagnetic emissions

• EM emissions other than IR

• The greatest source is RADAR itself.

• Shutting down RADAR a solution having negative effects

• Radio /radar altimeters and Doppler

navigation systems

• Use of inertial navigation , laser or millimetric wave

system

1 Radio communication

2 ECM exploited (passive listening)

3 Composite materials radiating switching transients

communication, inertial navigation are used.

EM emissions (contd…)

• Most important for submarine & ground vehicles

• Rubber mountings, AIP system, slow

turning propellers etc

Visibility

• Matte paint, gray paint in disruptive

schemes , yehudi lights ( active

camouflage)

• Uninterrupted radio waves from stars mapped.

• Failure or fainter image suggests

probability of stealthy craft

• Advantages of using lethal SAM’s and remain undetected

• Low frequency radar nullifies stealth from shape

Stealth counter (contd….)

• Disadvantages of LFR

1 Wavelength unavailability

2 Inaccuracy

3 Size

2 Using reflections from civilian radio transmitters.

gives better detection.

Stealth counter (contd….)

• Stealth technology developed a lot

• Investment needed is very high

• High chance of low cost gain

• A lot learned about signature reduction and absorption

• Useful for other projects.

• Success yet to be proved extensively.

For the time spared