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This topic may not be complete but is enough for understanding IFF.
Identification Friend or Foe (IFF) is the system that ships,aircrfat and stations use to identify friendly aircraft and ships. Since hostile aircraft, with their fast speeds, pose a greater threat than ships, we will concentrate on aircraft IFF procedures. However, some of the IFF procedures also can be used for identifying ships.
Origin
Originated in WWII for just that purpose - a way for our secondary radars to identify U.S. aircraft from enemy aircraft by assigning a unique identifier code to U.S. aircraft transponders. The system is considered a secondary radar system since it operates completely differently and independently of the primary radar system that tracks aircraft skin returns only, although the same CRT display is frequently used for both. The system was initially intended to distinguish between enemy and friend but has evolved such that the term "IFF" commonly refers to all modes of operation, including civil and foreign aircraft use.
Working
Basically, the ship or station desiring to know whether an approaching aircraft is friendly sends out a special electronic signal in the direction of the aircraft. The signal triggers an electronic response from an IFF transmitter in friendly aircraft. This response signal, in turn, generates a coded symbol on the radar scope of the interrogating ship or station. This symbol, in addition to designating the contact as friendly, may provide such information as type of craft, squadron, side number, mission, course, and altitude. If the aircraft does not respond, it is classified as either “unknown” or “hostile”.
The term is a misnomer, as IFF can only positively identify friendly targets, not hostile ones. If an IFF interrogation receives no reply or an invalid reply, the object cannot be identified as friendly, but is not positively identified as foe. There are many reasons that friendly aircraft may not properly reply to IFF.
Modes
There are four major modes of operation currently in use by military aircraft plus one submode.
A cross-band beacon is used, which simply means that the interrogation pulses are at one frequency and the reply pulses are at a different frequency. 1030 MHz and 1090 MHz is a popular frequency pair used in the U.S.
The secondary radar transmits a series of selectable coded pulses. The aircraft transponder receives and decodes the interrogation pulses. If the interrogation code is correct, the aircraft transponder transmits a different series of coded pulses as a reply.
The advantage of the transponder is that the coded pulses "squawked" by the aircraft transponders after being interrogated might typically be transmitted at a 10 watt ERP, which is much stronger than the microwatt skin return to the primary radar. Input power levels may be on the order of several hundred watts.
The transponder antenna is low gain so that it can receive and reply to a radar from any direction.
An adjunct to the IFF beacon is the altitude encoding transponder known as mode C - all commercial and military aircraft have them, but a fair percentage of general aviation light aircraft do not because of cost. The number of transponder installations rises around many large metropolitan areas where they are required for safety (easier identification of aircraft radar tracks).
Air traffic control primary radars are similar to the two dimensional search radar (working in azimuth and range only) and cannot measure altitude.
The expanded display in figure 1 is typical of an air traffic control IFF response. The aircraft was told to squawk a four digit number such as "4732". The altitude encoded transponder provides the aircraft altitude readout to the ground controllers display along with the coded response identifying that particular aircraft.
Combat Identification (CID)
IFF is a tool within the broader military action of "Combat Identification (CID)", the process of attaining an accurate characterization of detected objects in the operational environment sufficient to support an engagement decision." The broadest characterization is that of friend, enemy, neutral, or unknown. CID not only can reduce fratricide, but also contributes to overall tactical decision-making.
Role in Air warfare
Using IFF a fighter in air knows about friendlies near, US and other NATO countries use single system known as Mark XII Britain developed a program for a compatible system known as successor IFF (SIFF).
IFF is so important in aerial warfare that after "Gaza flotilla raid" in 2010 Turkey started to change all of it's IFF systems onboard every Aircrfat,ship,SAM and submarine,According to Turkish sources reason for that move is
"The US system is comprised of lists of "friends" and "foes." The system's settings are designed to prevent pilot error as well, to an extent, disabling the ability to fire at "friendly" targets even by mistake. The US system identified Israel as a 'friend,' thus preventing Turkish fighter jets from firing at them automatically.
The new system, however, allows Turkey control the "friend or foe" list independently."
Report: Turkish warplanes now able to fire at Israeli targets - Israel News, Ynetnews
Videos
Identification friend or foe - YouTube
IFF & Combat ID Video - YouTube
@syedali73 @Windjammer @levina @Bratva @That Guy @waz @Dazzler @TankMan @Blue_Eyes @MilSpec @Sage @engineer saad @Akheilos @Gufi
Identification Friend or Foe (IFF) is the system that ships,aircrfat and stations use to identify friendly aircraft and ships. Since hostile aircraft, with their fast speeds, pose a greater threat than ships, we will concentrate on aircraft IFF procedures. However, some of the IFF procedures also can be used for identifying ships.
Origin
Originated in WWII for just that purpose - a way for our secondary radars to identify U.S. aircraft from enemy aircraft by assigning a unique identifier code to U.S. aircraft transponders. The system is considered a secondary radar system since it operates completely differently and independently of the primary radar system that tracks aircraft skin returns only, although the same CRT display is frequently used for both. The system was initially intended to distinguish between enemy and friend but has evolved such that the term "IFF" commonly refers to all modes of operation, including civil and foreign aircraft use.
Working
Basically, the ship or station desiring to know whether an approaching aircraft is friendly sends out a special electronic signal in the direction of the aircraft. The signal triggers an electronic response from an IFF transmitter in friendly aircraft. This response signal, in turn, generates a coded symbol on the radar scope of the interrogating ship or station. This symbol, in addition to designating the contact as friendly, may provide such information as type of craft, squadron, side number, mission, course, and altitude. If the aircraft does not respond, it is classified as either “unknown” or “hostile”.
The term is a misnomer, as IFF can only positively identify friendly targets, not hostile ones. If an IFF interrogation receives no reply or an invalid reply, the object cannot be identified as friendly, but is not positively identified as foe. There are many reasons that friendly aircraft may not properly reply to IFF.
Modes
There are four major modes of operation currently in use by military aircraft plus one submode.
- Mode 1 is a nonsecure low cost method used by ships to track aircraft and other ships.
- Mode 2 is used by aircraft to make carrier controlled approaches to ships during inclement weather.
- Mode 3 is the standard system also used by commercial aircraft to relay their position to ground controllers throughout the world for air traffic control (ATC).
- Mode 4 is secure encrypted IFF (the only true method of determining friend or foe)
- Mode "C" is the altitude encoder.
A cross-band beacon is used, which simply means that the interrogation pulses are at one frequency and the reply pulses are at a different frequency. 1030 MHz and 1090 MHz is a popular frequency pair used in the U.S.
The secondary radar transmits a series of selectable coded pulses. The aircraft transponder receives and decodes the interrogation pulses. If the interrogation code is correct, the aircraft transponder transmits a different series of coded pulses as a reply.
The advantage of the transponder is that the coded pulses "squawked" by the aircraft transponders after being interrogated might typically be transmitted at a 10 watt ERP, which is much stronger than the microwatt skin return to the primary radar. Input power levels may be on the order of several hundred watts.
The transponder antenna is low gain so that it can receive and reply to a radar from any direction.
An adjunct to the IFF beacon is the altitude encoding transponder known as mode C - all commercial and military aircraft have them, but a fair percentage of general aviation light aircraft do not because of cost. The number of transponder installations rises around many large metropolitan areas where they are required for safety (easier identification of aircraft radar tracks).
Air traffic control primary radars are similar to the two dimensional search radar (working in azimuth and range only) and cannot measure altitude.
The expanded display in figure 1 is typical of an air traffic control IFF response. The aircraft was told to squawk a four digit number such as "4732". The altitude encoded transponder provides the aircraft altitude readout to the ground controllers display along with the coded response identifying that particular aircraft.
Combat Identification (CID)
IFF is a tool within the broader military action of "Combat Identification (CID)", the process of attaining an accurate characterization of detected objects in the operational environment sufficient to support an engagement decision." The broadest characterization is that of friend, enemy, neutral, or unknown. CID not only can reduce fratricide, but also contributes to overall tactical decision-making.
Role in Air warfare
Using IFF a fighter in air knows about friendlies near, US and other NATO countries use single system known as Mark XII Britain developed a program for a compatible system known as successor IFF (SIFF).
IFF is so important in aerial warfare that after "Gaza flotilla raid" in 2010 Turkey started to change all of it's IFF systems onboard every Aircrfat,ship,SAM and submarine,According to Turkish sources reason for that move is
"The US system is comprised of lists of "friends" and "foes." The system's settings are designed to prevent pilot error as well, to an extent, disabling the ability to fire at "friendly" targets even by mistake. The US system identified Israel as a 'friend,' thus preventing Turkish fighter jets from firing at them automatically.
The new system, however, allows Turkey control the "friend or foe" list independently."
Report: Turkish warplanes now able to fire at Israeli targets - Israel News, Ynetnews
Videos
Identification friend or foe - YouTube
IFF & Combat ID Video - YouTube
@syedali73 @Windjammer @levina @Bratva @That Guy @waz @Dazzler @TankMan @Blue_Eyes @MilSpec @Sage @engineer saad @Akheilos @Gufi
