More information comes to light concerning the communications systems used at the Russian Aerospace Force’s Arctic Trefoil air defence facility.
In March Armada examined the communications systems used by the Russian Aerospace Force’s (RASF) Arctic Trefoil Aviation Guidance Point (AGP) located at the RASF’s Nagurskoye airbase on Alexandra Land in the Arctic Ocean’s Franz Josef archipelago. AGPs are ground-based air defence facilities tasked with tactical Command and Control (C2) of combat aircraft. C2 is performed in support of the Integrated Air Defence Systems (IADSs) furnishing each of Russia’s five Military Districts (MDs). The AGP at Nagurskoye airbase is part of the Leningrad MD. Each aviation guidance point uses aircraft tracks generated by adjacent ground-based air surveillance radars and fire control/ground-controlled intercept radars. Radars deployed at the Arctic Trefoil include 12A6 Sopka-2 S-band (2.7 gigahertz/GHz to 2.85GHz), 1RL131 Terek (North Atlantic Treaty Organisation reporting name Spoon Rest-D) Very High Frequency (VHF: 133 megahertz/MHz to 144MHz/216MHz to 225MHz) ground-based air surveillance radars and PRV-13 (Odd Pair) S-band height-finding radars.
The AGP produces its Recognised Air Picture (RAP) by consolidating and converging each radar’s RAP into a tactical RAP which is then shared upwards to other echelons within the MD’s IADS. The air defence of each military district is the preserve of its organic Air Force and Air Defence Forces Army (AFADFA). The AFADFA is the operational/strategic command for all air forces and air defence forces within that military district. It is highly likely that the RAPs produced by the radars equipping each AGP are sent upwards from the MD to the strategic level to provide a detailed, nationwide view of Russian airspace and air approaches.
EW Analytics LLC produces unrivalled, exhaustive analysis of Russia’s IADS and general air defence and electronic warfare capabilities. The company has graciously shared its expertise with Armada in recent years, providing regular updates on Russia’s capabilities in these, and other, areas. In mid-May, EW Analytics LLC shared its latest analysis of the Arctic Trefoil facility focusing on the Radian-8 radio relay communications systems deployed there.
Radian-8
EW Analytics LLC has previously identified that the Nagurskoye airbase AGP is equipped with at least one R-441 Liven vehicle-mounted Satellite Communications (SATCOM) system. The company has recently identified at least four Radian-8 systems also deployed at the base which are likely used to carry voice and data traffic, including telephone communications. By examining official Russian language documents, the company has concluded that the Radian-8 stations provide links on frequencies between 7.9GHz and 8.4GHz. The Radian-8 link uses the Quadrature Amplitude Modulation-4 (QAM-4) protocol. QAM-4 carries data by modulating the amplitude and timing of the carrier wave. As EW Analytics LLC notes, QAM-4 provides high data rates over restricted bandwidths while boasting good resistance to naturally occurring, or deliberate, interference. It appears that the mast-mounted Radian-8 stations are primarily used for intra-base communications between the facilities’ constituent components. Moreover, given the AGP’s Arctic location digging up ice-covered hard ground to lay cables may be impractical and/or costly. Adversaries wishing to jam the links provided by the Radian-8 stations would also have to be within a line-of-sight range to have any hope of success. Given the AGP’s location in the Arctic Ocean, the jammers would most likely have to be mounted on warships making them vulnerable to Russian Navy and RASF engagement.
It is noteworthy that, alongside the R-441 Liven SATCOM vehicle and the Radian-8 stations, the Arctic Trefoil facility uses RPDRUM-1/5 High Frequency (HF: three megahertz to 30MHz) radios. These latter systems have fallen under EW Analytics LLC’s gaze in the past, as noted in this article. While the limited bandwidths offered by HF maybe insufficient to share the AGP’s RAP they maybe sufficient to share radar target track information in written form, along with limited voice communications.
In summary, EW Analytics LLC has identified three distinct communications systems used for intra- and inter-base communications; chiefly the R-441 Liven SATCOM system, RPDRUM-1/5 radios and the Radian-8 ensembles. Knowing these links, and their accompanying protocols, might enable electronic warfare planners to determine potential weaknesses which could be exploited either to gather communications intelligence and/or to perform communications jamming. Those keen to learn more about the Russian military’s electromagnetic capabilities should visit EW Analytics LLC’s website.
by Dr. Thomas Withington
