Airborne electronic warfare (EW) systems are becoming an increasingly important part of the electronic systems in fighter aircraft. Moreover, the functionality of many airborne EW designs are no longer just limited to being a self-protection system. One of the secondary—but growing in importance—features of this technology is to be able to record all the signals and electronic emissions that the aircraft is either subjected to or in range of during its mission.
Russia’s designers refer to the recording function of an EW system, or what they call “REB” (a Russian acronym meaning Radio-Electronic Combat), as radarnaya razvedka, or “radar signals intelligence.” Each time an aircraft is able to intercept and record a new adversary radar emission, EW jamming signal, or other electronic transmission that data can then be downloaded and becomes part of the database or “threat library” that is constantly being updated and then uploaded into other databases across the fleet of combat aircraft operating with EW suites on board.
At present, the main Russian EW design and manufacturing enterprises fall under the Radio-Electronic Technologies Concern, or KRET, in its Russian acronym. One of the most well-known and active of the KRET companies responsible for the design of many of the current-day Russian airborne EW systems is the Kaluga Scientific-Research Institute for Radio Engineering (KNIRTI).
KNIRTI produces an entire line of EW systems that are all derived from a basic design that is produced in several variants that are adapted to specific platforms. Russian writings on the development of this current generation of EW systems discuss the process by which it was designed and the current-day capabilities of the L-175 family of EW designs, which have the nickname of Khibiny.
Russian experts describe the system as “a magical piece of kit”—the history of the developmental work on the system traces its roots to the Soviet period. “Work on the system was carried out from 1977 to 1990,” according to one of the country’s most prominent military systems databases. “In 1995 the first cycle of testing was carried out and then in 1997 a second series. Only in 2014 was the system officially accepted into service as part of the equipment set for the Sukhoi Su-34, which was the platform the system it was originally designed for.”
At present there are several variants of the system designed for specific platform applications:
• KC418E—Sukhoi Su-24MK/MK2 export variant
• L-175М10-35—Sukhoi Su-35
• L-175V Khibiny-10V—Sukhoi Su-34
•L-265 Khibiny-10M/L-26510M—Sukhoi Su-35S (installed in wingtip pods rather than underwing containers)
• Khibiny-U—Sukhoi Su-30SM
The L175 series of designs is described in one of the Russian documents outlining its specifications as “being capable of acting as an individual or group of aircraft against detected threat signals by emitting active radar jamming pulses across a wide range of frequency bands and against up to four separate targets simultaneously, launching anti-radiation missiles against emitting targets, and also transmitting passive jamming by creating false thermal images and dipole reflectors.”
Observers in Ukraine and Belarus say these while Russian systems are powerful jammers and can create enough interference to adequately blind adversary radars and other sensors, “the overall objective that the Russian systems are designed to achieve is for their adversaries to lose situational awareness—at least long enough for the Russian aircraft to be able to carry out its mission,” according to one Ukrainian EW design engineer.
The Russian methodology for EW has shortcomings, however, say both Belarus and Ukraine EW designers—all of which will only become more pronounced over time.
One is the continued Russian reliance on Digital Radio Frequency Memory (DRFM) as the basis for the signals generated by these jamming pods. This is a system by which the threat library of an EW system recognizes the radar signal that it is receiving and parrots back the signal so that the radar system appears to have contacted nothing. This method depends on the pulses from adversaries to be on a constant frequency and at a standard, regular interval.
“This is no longer the case with more modern radar systems,” said the same Ukrainian designer. “Today’s radars are often ‘frequency-hopping’ and also the pulse width varies and with no repetitive pattern—therefore making it impossible for many jammers to mimic the incoming signal in such a way as to adequately conceal the aircraft.”
A second issue is the power levels of Russian jamming systems. The strength of Russian EW signals is at times overpowering, Ukrainian EW specialists tell AIN, but that signal is also so strong that it is also like a beacon. For any enemy’s anti-radiation weapon that has a “home on jam” mode, it literally makes the Russian aircraft a target.
Thirdly, both Ukraine and Belarus engineers state that smaller, lower power, and quieter EW systems can be built that use commercially available components—reducing costs—which are not based on DRFM technology and require none of the many hours of collecting and analyzing signals needed to build threat libraries. They instead create false targets that shift position regularly. This causes a missile or other weapon’s homing system to be diverted away from the real target, but without generating a powerful signal that also gives away an aircraft’s position.
Designs of this type are included in a series of developments in off-the-shelf technology that makes it possible for a much larger number of nations to build effective EW systems. The analogy that some of the Ukrainian and other non-Russian designers use is that this change is not unlike the availability today of commercial satellite imagery.
EW, they observe, is like some other categories of modern weaponry. Once the monopoly of only a handful of nations with large budgets and technologically sophisticated defense industrial bases, the ability to create jammers and other EW systems is now present in nations where it could not have been thought of as possible a decade ago.