2. CONTENTS
•WHAT IS IFF ?
•HISTORY AND DEVELOPMENT OF IFF
•IFF SYSTEM PARTS
•IFF MODES
•HOW IFF SYSTEM WORKS?
•OTHER IFF APPLICATION
•CONCLUSION
3. WHAT IS IFF ?
Identification, friend or foe (IFF) is an
identification system designed for command and control.
It enables military and civilian air traffic control
interrogation systems to identify aircraft as friendly.
4. 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 in 1935
• This technology was later
used by Civil Aviation in
1950s.
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6. 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)
Mode 5-advanced mode of Mode S under processing
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10. 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
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