Identification of Friend and Foe

3. The deployment of modern, high precision weapon
systems and their effectiveness depend to a large
degree on a timely and accurate identification of all
targets both friendly and hostile. This presentation
introduces the basic concepts and operations of the
Identification Friend or Foe (IFF) systems currently
deployed in major US and NATO combatants. The
directly related commercial aircraft identification
equipment is the Air Traffic Control Radar Beacon
System (ATCRBS) or the Secondary Surveillance Radar
(SSR). These two systems share the same operating
philosophy, waveforms, and frequencies.

4. 1937, radio recognition identification friend-or-foe
(IFF) system, the Model XAE, which met an urgent
operational requirement to allow discrimination of
friendly units from enemy units.
1958, the FAA had established the Air Traffic Control
Radar Beacon System (ATCRBS), which is essentially
the civilian version of the Mark X. The International
Civil Air Organization later adopted the ATCRBS,
making the Mark X the basis of the world's air
traffic control system.
1960, It was the first IFF system to use cryptographic
techniques to prevent deception where an enemy
appears as a friend by using a captured
transponder.

5.  Identification, Friend or Foe (IFF):
is a cryptographic identification system
designed for command and control, that
enables military, and national interrogation
systems to distinguish friendly aircrafts,
vehicles or forces, and to determine their
bearing and range from the interrogator .

6. Modern IFF systems are basically Question/Answer systems.
 An interrogator system sends out a coded radio signal that
asks any number of queries, including: Who are you?
 The interrogator system is frequently associated with a
primary radar installation, but it may also be installed
aboard a ship or another airplane.
 The interrogation code or challenge is received by an
electronic system known as a transponder that is aboard
the target aircraft.
 If the transponder receives the proper electronic code from
an interrogator, it automatically transmits the requested
identification back to the interrogating radar.
 The IFF system is also known as secondary radar Because
it was developed and used as an adjunct to the primary
echo-type detection radar.

7. Each vehicle is provided with:
o a radiation transmitter
o a receiver with a detector to detect radiation transmitted by
other vehicles.
 Steps:
1. Each transmitter can transmit a first coded signal which can be
detected by the receivers in other vehicles.
2. The receivers provide an unblocking signal after the first coded
signal is correctly identified.
3. The unblocking signal clears a radiation transmission path in
the vehicle.
4. This path containing a reflector which reflects the received
signal back to the source of the transmission.
5. The reflector adds a further predetermined code to the signal
reflected from the reflector with each vehicle having another
detector for detecting a reflected signal and a device to identify
the further predetermined code.