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In telecommunications, identification, friend or foe (IFF) is a crypto identification system designed for command and control. A system that enables military, and national (civilian located ATC) interrogation systems to distinguish friendly aircraft, vehicles, or forces, and to determine their bearing and range from the interrogator. Telecommunication involves the transmission of signals over a distance for the purpose of communication. ...
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IFF was first developed during World War II. It's a bit of a misnomer, as the purpose of IFF is to identify friendly targets, and not replying to an IFF interrogation does not make one a foe. Combatants Allies: Poland, British Commonwealth, France/Free France, Soviet Union, United States, China, and others Axis Powers: Germany, Italy, Japan, and others Casualties Military dead: 17 million Civilian dead: 33 million Total dead: 50 million Military dead: 8 million Civilian dead: 4 million Total dead: 12 million World War II...
There are many reasons for not replying to IFF by friendly aircraft: battle damage, loss of crypto, wrong crypto, or equipment failure. Aircraft hugging terrain are very often poor candidates for microwave line-of-sight systems such as the IFF system. Microwaves can't see through mountains, and very often atmosphere effects (referred to as Anamalous Propagation - AP) cause timing, range, and azimuth issues.
Method of operation The IFF of WWII and Soviet era systems used coded radar signals (called Cross-Band Interrogation, or CBI) to automatically trigger the aircraft's transponder in an aircraft "painted" by the radar. Modern crypto IFF systems use a separate specialized transponder beacon which can operate without radar. They are referred to as cross-band beacon or transponders. Each IFF transponder also has a KIR or KIT crypto computer associated with it. The KIR (designed for interrogaters) and the KIT (designed for transponders) have an access port where the crypto codes are inserted. The military IFF system will not function without a valid code. No code means no IFF. Civilian SIF systems and Mode S do not require crypto codes. This long range radar antenna, known as ALTAIR, is used to detect and track space objects in conjunction with ABM testing at the Ronald Reagan Test Site on the Kwajalein atoll[1]. Radar is a system that uses radio waves to detect, determine the distance of, and map, objects such...
Signal Tower at Cobbs Hill, near New Market, Virginia, 1864. ...
An IFF transponder responds: In telecommunication, the term transponder (sometimes abbreviated to XPDR or TPDR) has the following meanings: An automatic device that receives, amplifies, and retransmits a signal on a different frequency (see also broadcast translator). ...
- in a military aircraft, vehicle, or unit by returning a coded reply signal only when the incoming interrogation is identified as part of the friendly forces network;
- if no IFF response is generated a civil (Selective Identification Feature - SIF) interrogation may then be generated and the aircraft, by returning various mode replies can then be identified or sorted.
In an IFF network both the interrogation and reply are verified as friendly.
An IFF transponder receives interrogation pulses at one frequency (1030 MHz), and sends the reply pulses at a different frequency (1090 MHz). Just the opposite of a non-crypto SIF interrogation format is used. In SIF, the interrogation is composed of two pulses spaced apart by a different amount for each mode, and a transponder replies with a long series of bits. In IFF, the interrogation is a long series of bits that contains the message and parity. The message is encrypted with a secret crypto key, and only IFF transponders with the same crypto key will decode the message. Once decoded, the IFF transponder will process the encoded message and send back a 3 pulse reply. The interrogator compares the reply to the challenge message and marks the target friendly, and determines the azimuth and range. A second possibility is the target being marked as a spoof target. That is, the target replied but failed to process the message correctly on a significant number of challenges. Targets marked as a spoof may be declared hostile and, inside a battle-space, are often destroyed when able.
Benefits Major military benefits of IFF include: There are no civilian uses of IFF. Civilian systems are all based on SIF and MODE S. Friendly fire (or non-hostile fire) is a term originally adopted by the United States military in reference to an attack on friendly forces by other friendly forces, which may be deliberate (e. ...
Fratricide (from the Latin word frater, meaning: brother) is the act of a person killing his or her brother. ...
IFF modes There are two military modes of operation designated for use by Allied forces: - Mode 4 is crypto-secure mode (the only currently fielded true method of determining friend)
- Mode 5 is a new crypto-secure mode (that is just beginning to be deployed)
See also In computer security, challenge-response authentication is a family of protocols in which one party presents a question (challenge) and another party must provide a valid answer (response) to be authenticated. ...
Look up Shibboleth in Wiktionary, the free dictionary. ...
In telecommunication, the term transponder (sometimes abbreviated to XPDR or TPDR) has the following meanings: An automatic device that receives, amplifies, and retransmits a signal on a different frequency (see also broadcast translator). ...
A Secondary Surveillance Radar (SSR) is a radar device installed in air traffic control facilities to allow the precise identification of aircraft. ...
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