APPLICATION OF SECONDARY

SURVEILLANCE RADAR(SSR) IN

MILITARY IDENTIFICATION-

FRIEND OR FOE(IFF) TECHNOLOGY

PREPARED BY-ADRIJA CHOWDHURY

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INTRODUCTION

Surveillance systems provide breakthrough performance in the Detection, Interrogation, Identification, Tracking & Data Extraction of targets in severe environments

Aim on Civil and Military air traffic control, battle management, efficient decision making in air defense system & keeping friendly forces out of harms way

Modern Methods of surveillance- IFF systems TCAS FLIR etc

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SURVEILLANCE IN DEFENSE SYSTEMS

SURVEILLANCE ~ A radar system used for locating the position of

both civilian as well military aircrafts & ships, or ground vehicles & most commonly in air traffic management

Used by ATC to indicate the position of aircraft while flying or on airport surface

Makes use of radio waves Also gives information like-speed, range, bearing,

altitude & direction of aircrafts Most Important function- Identifies the friendly

aircrafts & ships and distinguishes them from the hostile ones 3

OBJECTIVES OF SURVEILLANCE

For civil as well as air traffic control & management – safely directing traffic

For extracting various information regarding the targets

For defense mechanism• Identifying the friendly forces out of many &

keeping them out of harms way• Thus reducing the risk of enemy attack

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Also known as ‘INTERROGATOR’ A radar system used in ATC that

relies on a piece of equipment that is placed within the aircraft & is known as a 'transponder‘

For IFF system it is basically synchronized with the PSR on ground station

Gives additional information unlike PSR

Secondary Surveillance Radar (SSR)

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IFF is IDENTIFICATION-FRIEND OR FOE A system that distinguishes FRIENDS from FOES Based on the application of Secondary Surveillance

Radar Inception-1935, U.S. Initially was developed to identify

U.S aircrafts Mainly works on these major modes of operation- MODE 1 MODE 2 MODE 3/A MODE 4 MODE C MODE S newly developed

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IFF-A MODERN METHOD OF SURVEILLANCE

HISTORY AND DEVELOPMENT OF IFF

• The technology IFF was developed during WORLD WAR-II by British and American military

• Sir ROBERT WATSON WATT invented the first IFF transponder and SSR in 1935

• This technology was later used by Civil Aviation in 1950s.

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Detection And TrackingIdentificationInterrogationData ExtractionAir Traffic Control And ManagementEfficient decision making during battles and wars

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FEATURES OF IFF

HOW AN IFF SYSTEM WORKS

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WORKING PRINCIPLE OF IFF SYSTEM

Ground based transmitter known as interrogator that is the Secondary Surveillance radar synchronized with primary radar, transmits a radio signal(interrogating signal) to the aircraft’s transponder at 1030 Megahertz by selecting a unique transponder code

Transponder receives the signal and decodes it After decoding, the transponder replies back to the

interrogator for that particular transponder code Now the interrogator will decode the reply and report

back to ATC and thus we will get the display 10

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WORKING PRINCIPLE (Contd.)

RADAR DISPLAYWhat appear on radar

display?• Aircraft Identity.• Altitude• Speed• Direction• Example • MH092 FL280• 585• Meaning: Flight

Malaysian 092 cruising at 28’000ft with speed of 585knots

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• Transponder codes are four digit numbers transmitted by the transponder in an aircraft in response to an interrogation signal assisted by air traffic controllers in traffic separation. A discrete transponder code (often called a squawk code) is assigned by air traffic controllers to uniquely identify an aircraft.

• Squawk codes are four-digit octal numbers; the dials on a transponder read from zero to seven, inclusive. Thus the lowest possible squawk is 0000 and the highest is 7777. Four octal digits can represent up to 4096 different codes, which is why such transponders are often called "4096 code transponders” (ROUTINE & EMERGENGY CODES)

TRANSPONDER CODES (XPNDR CODES)

MODES OF OPERATION OF IFF SYSTEMS

Mode 1 is a non-secure method used to track aircrafts; codes manually set by pilot but assigned by ATC(military only)

Mode 2 is for identification; identifies the tail no.(military only) Mode 3/A is the standard system also used by civilian

aircrafts to relay their position to ground controllers throughout the world for ATC. Used in conjunction with MODE C(military & civilian)

Mode 4 is secure encrypted IFF(the only true method of determining friend or foe); only military

Mode "C" is the altitude encoder(military & civilian) Newly developed Mode S does selective interrogation; each aircraft

can be addressed using its unique 24 bit address(military & civilian) but not implemented yet

Mode 5-advanced mode of Mode S under processing 14

CHARACTERISTICS OF IFF MODES

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FRUITGARBLEFAILURE OF TRANSPONDERWRONG ENCRYPTION KEYSBATTLE DAMAGE

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PROBLEMS WITH IFF

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CONCLUSIONo IFF technology serves as one of the best methods of surveillanceo Multipurpose fulfilmento MODE S & MODE 5-GOOD FUTURE ASPECTS Less power required as Transmitter is typically more

efficient If the SSR interrogates selectively Mode S can reduce

power even more as it can replace both Mode 3/A & Mode C as together both modes would consume a lot of power

END OF THE PRESENTATION BUT NOT THE END OF THE

DEVELOPMENT

OF

IFF AND SSR

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THANK

YOU

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ANY QUESTIONS?????

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ACRONYMS• IFF~IDENTIFICATION-FRIEND OR FOE• TCAS~TRAFFIC COLLISION AVOIDANCE SYSTEM• FLIR~FORWARD LOOKING INFRARED RADAR• ATC~AIR TRAFFIC CONTROL• FAA~FEDERAL AVIATION AUTHORITY• SSR~SECONDARY SURVEILLANCE RADAR• PSR~PRIMARY SURVEILLANCE RADAR• FRUIT~FALSE REPLIES UNSYNCHRONISED WITH

INTERROGATOR TRANSMISSION or FALSE REPLIES UNSYNCHRONISED IN TIME

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