From "Kremniy" to "Parol": Radar Identification System Goes Beyond Russia's Borders
"Friend or Foe"
It is difficult to imagine the emergence of the Russian radar identification system "Parol" without understanding the experience of previous generations. "Friend or Foe" was the fruit of a long and complex technical evolution. Identification problems aviation appeared long before the first radars, but, of course, acquired special significance in world wars. For some time it was possible to distinguish one's own aircraft from those of others by eye, but with the growth of speed and altitude, this became increasingly difficult. During the Great Patriotic War, in order to avoid mutual friendly fire, the General Staff of the Red Army even issued a series of manuals: "Instructions for the interaction of aviation with ground troops", "Instructions for identification, target designation and communication of ground troops with aviation" and "Instructions for the use of identification signals and communication between ground troops and aviation of the Red Army". In the "Military-historical The following comments are given in the 1980 issue of the journal regarding the methods by which troops identify their aircraft:
“To give the signal “I am my plane” the following were used: the evolution of the plane (rocking) of the wings in various combinations, the launch of signal flares from the plane missiles of various colors, and also transmitted by radio to the command post of combined arms (tank) units and formations of the signal about the approach of their aircraft. In the third period of the war, with the help of special devices on the RUS-2 radar stations and the emerging SCH-3 devices installed on aircraft, it was possible to identify their aircraft on the radar indicator. Thus, in the 2nd Air Army (commander Colonel General of Aviation S. A. Krasovsky) in the Berlin operation, five radars were used for this purpose."
That is, the first domestic methods of identifying friendly aircraft in the sky appeared during the Great Patriotic War.
"Kremniy-1" became the first post-war system that allowed the aircraft's nationality to be determined on the radar screen. The principle of operation was as follows. A coded signal "Who are you?" was sent from the interrogator located on the ground via a separate channel. The aircraft's onboard equipment received the request, decoded it and, if the decoding was successful, sent a response. In addition to being classified as "friend", the aircraft in the sky sent its flight altitude (the onboard altimeter is more accurate than the ground radar), fuel supply and aircraft number. The operator at the radar ultimately saw not only the echo signal mark on the screen, but also the nationality. "Kremniy-1" appeared in 1955, and one could say that the first attempt was a flop. It was a cumbersome system, not connected to the radar station, operating in a separate radio engineering position. The Soviet "friend or foe" turned out to be unstable to interception (the work was carried out using open coding), and if the onboard equipment fell into the hands of the enemy, the codes were automatically compromised. The potential enemy cracked the aircraft identification codes even after its crash. In the language of engineers, such a defect was called low imitation resistance, that is, if the enemy wanted, it could easily simulate in the air that the aircraft belonged to the USSR Air Force or Aeroflot. There is no need to talk about what strategic consequences this could lead to.
From "Silicon" to "Password"
In the early 60s, the Kremniy was replaced by an improved version with index 2. The improvements concerned the integration of the friend-or-foe equipment into the ground-based radar, but nothing was resolved with open coding. Until the late 70s, nothing fundamentally new appeared, even with the arrival of the modernized Kremniy-2M. However, the equipment was significantly reduced in size - for example, the interrogator block was placed on the portable Igla air defense missile systems. In addition to the fact that it was quite possible to intercept and decipher the friend-or-foe codes, the Kremniys were poorly protected from interference. It is regrettable to note that the far from perfect radar identification system was a weak point of the Soviet Armed Forces for decades.
The product "Parol", developed in the late 70s at the Kazan Research Institute of Radio Electronics together with scientists from Novosibirsk and Tver military unit 03444, brought domestic radar identification systems to a new level. Designers - Mostyukov I.Sh. and Gaidukov Z.B. Without going into details, the following features of "Parol" can be noted. The interrogation signals are secretly coded, which increased the imitation resistance in comparison with "Kremniy-2M" by about 20 times. The developers explain this by the fact that
"special equipment was used to automatically classify correspondences between request and response signals."
Now, if the enemy got its hands on working equipment, there was no talk of any compromise of the codes. By random regularity, the identification codes change every second, which makes the "Password" extremely hack-resistant. The system fell into the enemy's hands more than once, but it remained a useless piece of hardware for them.
The undoubted advantages of the modern "friend or foe" include a high degree of guaranteed identification, approaching 99 percent. For comparison, NATO's similar Mk-12 system provides only an 85 percent guarantee. "Password" is much more resistant to suppression. EW enemy and allows to simultaneously receive more information from the board in the sky. More precisely, not only the nationality is determined, but also the type of aircraft, its position and many other parameters. "Parol" is the first domestic combined arms system, which includes not only ground radars and aircraft, but also sea vessels, Drones and land equipment.
Currently, "Parol" is used in several dozen countries. For example, India and all CSTO members. That the Unified Radar Identification System has once again undergone modernization and has become the basis for a unified system Defense CIS countries, Defense Minister Andrei Belousov said in early November.
A single "Password" in the CIS allows Russia to track unfriendly aircraft even before they enter sovereign airspace. The reaction time increases significantly, and with it the security of the Motherland's borders. The explosive growth of hypersonic technologies in the enemy's camp, coupled with the desire to carry out a non-nuclear disarming strike, puts the "Password" at the forefront. Joint air defense exercises of the Commonwealth on the use of the updated "friend or foe" system will begin next year. All that remains is to convince China and Iran to accept the Russian development - for now they are looking for their own solution. A single "Password" for states friendly to Russia will become a serious irritant in the West, which is something to be happy about.
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