Stealth Seminar 5z5m1h

Ranjith JoY 1NT06ME037

Stealth Technology? † Stealth means Secret procedure or manner.

† Stealth Technology covers a range of techniques used with aircrafts, ships and missiles, in order to make them less visible (ideally invisible) to radar and other detection methods. It allows a Machine to be partially invisible to any means of detection. All it does is

History of Stealth Technology †In Second World War allied aircrafts used tin and aluminum in huge amount to confuse German RADARS. †First ever working Stealth Aircraft was developed by Lockheed Martin in 1983 called the F-117A nicknamed as the “Nighthawk”. †First Stealth Ship was developed by Defense Advanced Research Project Agency, US Navy and Lockheed combined in 1985 called the “Sea Shadow(IX-529)”.

Signature †Signature - Any unique indicator of the presence of certain materiel or troops; especially the characteristic electronic emissions given off by a certain type of vehicle, radar, radio, or unit.

Radio Signature Radar waves are beamed at a target, and a certain amount are reflected back. This s for the radio signature. Radar Signature can be reduced by

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

†Radiation emitted (e)= εσT4 ,

where σ= Stefan Boltzmann's constant= 5.67*10-8W/m2K ε= Emissivity of the body T= Temperature of the body

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.

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 noises that could reveal locations to underwater ive 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.

Magnetic Signature † Vessel's traveling on water or under water cause disturbance 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 nonmagnetic material

Radar Cross-Section

† Radar cross section (RCS) is a measure of how detectable an object is with a radar. A larger RCS indicates that an object is more easily detected.

Reducing RCS – By Reflection

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

† Foam absorber is used as lining of anechoic chambers for electromagnetic radiation measurements † This material typically consists of a fireproofed urethane foam loaded with carbon black, and cut into long pyramids. † The length from base to tip of the pyramid structure is chosen based on the lowest expected frequency and the amount of absorption required.

† Jaumann layer was first introduced in 1943 † It consisted of two equally-spaced reflective surfaces and a conductive ground plane similar to Salisbury screen. † It uses a series of dielectric surfaces that separate conductive sheets.

† It is a resonant absorber

Disadvantages

Conclusion and Future