Stealth Seminar

7/30/2019 Stealth Seminar

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Ranjith JoY 1NT06ME037


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Stealth Technology? Stealth means Secret proce dure or manner.

Stealth Technology covers arange of techniques used with aircrafts, ships and missiles,in order to make them lessvisible (ideally invisible)to radar and other detectionmethods. It allows a Machine tobe partially invisible to any

means of detection. All it does is


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In Second World War allied aircrafts used tinand aluminum in huge amount to confuse German

RADARS.

First ever working Stealth Aircraft wasdeveloped by Lockheed Martin in 1983 called the

F- 117A nicknamed as the Nighthawk.

First Stealth Ship was develope d by Defense

Advanced Research Project Agenc y, US Navy and Lockheed combined in 1985 called the SeaShadow(IX- 529).

History of Stealth Technology


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SignatureSignature - Any unique indicator of the presence of

certain materiel or troops; especially the characteristicelectronic emissions given off by a certain type of vehicle,radar, radio, or unit.


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Radio Signature Radar waves are beamed at a target, and a certainamount are reflected back. This accounts for the radio

signature.

Radar Signature can be reduced by


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Infrared Signature Infrared radiations commonly called infrared (IR) is generated by the vibration and rotation of atoms and molecules within any material whose temperature isabove 0K.

Radiation emitted (e)= T 4 ,where = Stefan Boltzmann's constant= 5.67*10 -8W/m2

= Emissivity of the bodyT= Temperature of the body


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Visual Signature

The visibility of the vehicle by any means : naked eyes,cameras or Night vision etc.

Its said to be the most difficult one to eliminate

Its the most easily and widely adapted Stealth measure

for land units.


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Acoustic Signature Acoustic stealth plays a primary role in

submarine stealth as well as for ground vehicles

Submarines have extensive usage of rubber mountings to isolate and avoid mechanical noisesthat could reveal locations to underwater passive

sonar arrays.

The vibrations of the hull need be reduced and pumps, fans mounted in such a way that they have

their natural vibrations damped.


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Magnetic Signature Vessel's traveling on water or under water causedisturbance in earth's magnetic field.

Reduced by counter magnetic field of suitable strength and direction based on prior knowledge of the vessel.

Vessel's material or hull should be made of non-magnetic material


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Radar Cross-Section Radar cross section (RCS) is a measure of howdetectable an object is with a radar. A larger RCS indicatesthat an object is more easily detected.


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Reducing RCS By Reflection


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It contains tiny spheres coated with carbonyl iron or ferrite The iron particles in the paint are obtained by decompositionof iron pentacarbonyl and maycontain traces of carbon, oxygenand nitrogen Radar waves induce molecular oscillations from the alternating magnetic field in this paint,which leads to conversion of theradar energy into heat. The heat is then transferred to the aircraft and dissipated.


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Foam absorber is used as lining of anechoic chambers for ele ctromagneticradiation measurements

This material typically c onsists of a fireproofed urethane foam l oaded withcarbon black, and cut into l ong pyramids .

The length from base to tip of the pyramid structure is chosen based on thelowest expected frequency and the amount of absorption required.


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Jaumann layer was first introduced in1943

It consisted of two equally-spaced

reflective surfaces and a conductive ground plane similar to Salisbury screen.

It uses a series of dielectric surfacesthat separate conductive sheets.

It is a resonant absorber


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Disadvantages


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Conclusion and Future


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Stealth Seminar

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