A mooted plan for the US to buy S-400 SAM systems from Turkey could prompt a ELINT bonanza.
Senator John Thune, a Republican Senator from South Dakota has proposed that the US purchase the Almaz-Antey S-400 (NATO reporting name SA-21 Growler) long-range/high-altitude Surface-to-Air Missile (SAM) systems that Turkey procured from Russia.
In 2017 Turkey procured two S-400 systems, a total of four battalions, for $2.4 billion with deliveries commencing in 2019. This threw a spanner in the works of plans by the Türk Hava Kuvvetleri (THK/Turkish Air Force) to acquire Lockheed Martin F-35A Lightning-II combat aircraft.
A total of 120 aircraft were expected to be acquired before the acquisition was cancelled by the administration of President Donald Trump in July 2019. The administration was concerned that the S-400’s sensors, principally its ground-based air defence and fire control radars, could collect sensitive information regarding the F-35A’s radar cross section and electromagnetic emissions.
The cancellation of the acquisition resulted in the four THK F-35As delivered to Luke airbase, Arizona, being rerolled to furnish the US Air Force.
Nyet from Moscow
Mr. Thune suggested that the US acquisition of both S-400 systems would remove them from Turkey and hence THK control allowing F-35A deliveries to continue. Russian lawmakers protested the proposal with Leonid Slutsky, chair of the Russian Duma (parliament) committee on international affairs, condemning Mr. Thune’s proposal as “unprincipled and cynical.”
It seems unlikely that such a purchase will occur in the near term. Such a move by Ankara would make Moscow hopping mad. Yet such a purchase by the US would offer serious benefits.
Aside from resuming F-35A deliveries to Turkey, it would give the United States Air Force, and US armed forces in general, once of the world’s most advanced air defence systems to pour over at their leisure.
The US Department of Defence already possesses a smorgasbord of Soviet-era SAMs and ground-based air surveillance and fire control/ground-controlled interception radars. These have been sourced from a myriad of ex-Warsaw Pact countries. They are routinely used to provide realistic threats during US-based international air exercises like Red Flag.
The US Navy and USAF are both overhauling their Suppression/Destruction of Enemy Air Defence (S/DEAD) postures. The US Navy is deploying the Boeing EA-18G Growler electronic warfare and S/DEAD aircraft, along with Northrop Grumman’s AGM-88E Advanced Anti-Radar Guided Missile, a variant of the venerable AGM-88 HARM (High Speed Anti-Radar Missile) family. The US Air Force is optimising the F-35A to perform S/DEAD using Northrop Grumman’s AGM-88F HCS (HARM Control System) AGM-88 variant.
US and allied aircraft operating over Syria have flown in airspace thought to be protected by the S-400. Russia has deployed two systems to the northwest of the country since 2015.
However, there is doubt in some quarters of the NATO electronic warfare community as to whether either system has been activated in full for fear that Electronic Intelligence (ELINT) regarding their 91N6 (NATO reporting name Big Bird) S-band (2.3 gigahertz/GHz to 2.5GHz/2.7GHz to 3.7GHz) and 96L6E (NATO reporting name Cheese Board) C-band (5.25GHz to 5.925GHz) early warning and target acquisition radar could be hoovered up by US and NATO ELINT aircraft.
For all intents and purposes much of the S-400’s design and capabilities remain a mystery. No wonder Moscow is nervous about NATO getting its hands on a couple.
The Republic of Korea Air Force (ROKAF) could spend up to $725 million on new SIGINT aircraft between now and 2026.
Plans were approved by Republic of Korea’s Defence Project Promotion Committee (DPPC) on 26th June to acquire new Signals Intelligence (SIGINT) platforms for the ROKAF with a budget of $725 million.
The ROKAF uses two Dassault Falcon-2000S and four BAE Systems Hawker RC-800 SIGINT gathering aircraft. The Falcon-2000S jets were delivered in 2017. The RC-800 aircraft are slightly older, entering service in the early 2000s. DPPC plans call for four of the RC-800s to be replaced with the new SIGINT acquisition.
Both the Falcon-2000S and RC-800s are believed to gather Communications Intelligence (COMINT) and Electronic Intelligence (ELINT) at the operational, and possibly strategic, levels. To this end, they are thought to collect COMINT/ELINT across 500 megahertz to 40 gigahertz wavebands. This intelligence maybe analysed onboard by electronic warfare specialists and/or transmitted across air-to-ground datalinks.
It is reasonable to assume that the ROKAF may choose to procure at least four new aircraft to replace the same number of RC-800s. The force could spend up to $175 million on each aircraft with a residual $25 million covering training and other ancillary costs. Local reports state that the first new SIGINT aircraft could enter service in 2026.
The People’s Republic of China has made grandiose claims for the performance of its JY-27A ground-based air surveillance radar. They should be treated with caution.
An article published in the Global Times, an offshoot of the
People’s Daily, itself a mouthpiece for the People’s Republic of China’s ruling
Communist Party, claimed on 28 May that the country’s new CETC JY-27A Very High
Frequency (VHF: 30 megahertz/MHz to 300MHz) can detect aircraft with a low
Radar Cross Section (RCS). The article said that, not only can the radar detect
such aircraft, but can “guide missiles to destroy them.”
Low frequency radars detecting low
RCS aircraft is not a new claim. This principle has been known for decades and
has already been exploited in radars like Russia’s NNIIRT 1L119 Nebo-SVU VHF system. The
long wavelength signals transmitted by VHF radars have meant that while low-RCS
aircraft maybe detectable, they may not be detectable with the sharp precision
required to guide an Air-to-Air Missile (AAM) or Surface-to-Air Missile (SAM)
to its target. Put simply, this is why many fighter radars, ground- and
ship-based fire control radars and missile radar seekers transmit in
frequencies from X-band (8.5 gigahertz/GHz to 10.68GHz) and above. What these
radars lose in detection range, compared to lower frequency radars, they make
up for in precision. The Global Times article
claimed that Chinese radar engineers have solved this precision deficit by
networking together several radars positioned a known distance from one
another, looking at the same patch of sky in different directions to determine an
aircraft’s location. Once detected it could be possible to guide “long-range
anti-aircraft missiles” to perform precision strikes on these targets.
Distributed, networked radars to
counter stealth is an established concept. The electronic warfare and radar
expert Dr. Carlo Kopp discussed this approach in his seminal 2012 article in Defence Today entitled ‘Advancing
Counter-Stealth Radar Technology’. He asserted that “Defeating stealth targets
using networking and data fusion presupposes that some radars can see the
target some of the time, also that the target’s stealth is considerably poorer
in some directions compared to others, and finally that the target is visible
to radars from varying aspects.” Basically, a low RCS aircraft may have a low
radar signature when viewed from head on, of from a particular angle but not an
equally low signature in all directions. By scattering and networking several
antennas across a wide area, one of the antennas may get a lucky glimpse of
part of the aircraft which is not so stealthy and thus detect it. Dr. Kopp adds
that for this to be effective, the non-stealthy part of the aircraft needs to
be visible to that particular radar for some time. An aircraft flying into hostile
airspace is unlikely to hang around and may be travelling at very high speeds,
thus only exposing itself to the radar for a very short time. To further
complicate matters, aircraft such as the US Air Force’s Northrop Grumman B-2A
Spirit strategic bomber and Lockheed Martin F/A-22A Raptor air superiority
fighter use ‘all-aspect’ RCS reduction techniques. This means that they are
stealthy regardless of the angle from which they are viewed by radar. Future US aircraft, such as the forthcoming
Northrop Grumman B-21 Raider strategic bomber are likely to have even better RCS
reduction design configurations.
Dr. Kopp concedes that “a networked
data fusion system (fusing data from several distributed radars) is thus not a
panacea, but is potentially quite effective against stealth designs that do not
have genuine ‘all aspect’ stealth capability.” There is an additional problem.
Airframe limitations mean that low-RCS aircraft cannot be designed to defeat
all radar transmission wavelengths. Instead, airframes are optimised to defeat
the radar systems most likely to be used for the precision detection of such a
target and for fire control. This typically includes radars transmitting in
S-band (2.3GHz to 2.5GHz/2.7GHz to 3.7GHz) and above. To summarise, a network
of VHF radars maybe capable of detecting an aircraft with a low RCS but lacking
all-aspect stealth, yet weapons still have to be guided with precision to the
target. This is where a fighter aircraft’s X-band radar would come into play,
or the guidance radars and radar seekers used by AAMs or SAMs transmitting in
X-band and above. These are precisely the frequencies that low-RCS aircraft are
designed to defeat. Networked VHF radars may give you a good fix on where the
aircraft is in the sky, but the missile’s end game still depends on higher
frequency radars which stealth aircraft are designed to outfox.
Arguably this could be overcome by a
salvo launch of SAMs and AAMs into the area of sky where the aircraft is
thought to be. This might not be done with too much precision, but a load of
missiles could be launched ballistically with the hope of scoring a lucky hit. It
could prove an expensive tactic as it would potentially waste missiles at an early
stage of a conflict, the moment when low-RCS aircraft are most likely to be
Moreover, these VHF radars, and fire
control radars operating in higher wavebands would almost certainly be
subjected to heavy electronic attack at the outset of a conflict. Aircraft such
as the F/A-22A, B-2A, B-21 or Lockheed Martin’s F-35A/B/C Lightning-II fighters
would be accompanied by jamming platforms like the US Navy’s E/A-18G Growler
aircraft as they fly into contested airspace. The Block-2 Low Band Jammer (LBJ)
segment of the latter aircraft’s Next Generation Jammer, which replaces its
current Harris AN/ALQ-99 tactical jamming system, is thought to cover a
waveband of 100 megahertz to two gigahertz. The US Navy is currently selecting
a vendor for the Block-2 LBJ with a team comprising Northrop Grumman and
Harris, and L3 vying for selection. While VHF radars like the JY-27A maybe
trying to detect low RCS aircraft, they will be a prime target for both escort
and stand-off jamming for aircraft like the E/A-18G. They will also be high
priority targets for kinetic weapons. Given the frequencies they use, VHF
radars tend to be big. In the case of the JY-27A PRC officials have hinted that
several radars are required to detect low RCS aircraft. Such targets could show
up well on aerial reconnaissance imagery. They also need to transmit, and once
transmitting, will reveal their position to ELINT (Electronic Intelligence)
gathering assets such as the US Air Force’s Boeing RC-135U Combat Sent
aircraft. Once their position is betrayed, electronic and kinetic attack can be
brought to bear.
The PRC maybe feeling emboldened by the development of the JY-27A and its touted capabilities. The death of low RCS airframe design has been predicted umpteen times since the B-2A and Lockheed Martin F-117A Nighthawk ground attack aircraft debuted in service in 1997 and 1983 respectively. The possible shortcomings of such radars are no excuse to be complacent, and such systems should be high priority electronic and kinetic targets at the start of any conflict. The JY-27A’s attributes may be accompanied with a healthy serving of hyperbole, but that is no excuse for complacency.
The growing provision of private-sector signals intelligence gathering will take an important step forward with the launch of the UK’s IOD-3 AMBER CubeSat in 2020.
IOD-3 AMBER will be the first of a constellation of satellites providing a
global Signals Intelligence (SIGINT) footprint to enhance maritime security for
the British government. While the exact number of satellites that will
eventually be launched has not been revealed, it is expected to include less
than ten spacecraft.
satellites will possess both an L-band (1.3 gigahertz/GHz to 1.7GHz) and
Automatic Identification System (AIS: 161.975 megahertz/MHz to 162.025MHz) SIGINT
packages. This is derived from Horizon Technologies’ FlyingFish
COMINT-gathering system. FlyingFish routinely equips aircraft particularly
maritime surveillance, maritime patrol and signals intelligence-gathering
platforms. These furnish several NATO (North Atlantic Treaty Organisation)
navies, coastguards and border protection agencies. The L-band equipment will
detect Satellite Communications (COMINT) from vessels across a waveband of one
gigahertz to two gigahertz. AIS is mandated by the International Maritime
Organisation for all vessels displacing in excess of 300 tonnes.
transponders equipping vessels transmit an array of regarding a vessel’s
voyage, identity and location. By correlating the AIS and the source of the
L-band SATCOM it becomes possible to cross reference both sets of transmissions
and match them to a vessel’s location. X-band (7.9-8.4GHz to 7.25GHz/7.75GHz)
downlink and S-band (two to four gigahertz) SATCOM COMINT receivers will also
be carried. Interestingly the concept of operations used for the constellation
does not require a number of satellites to receive transmissions and then
triangulate the position of a vessel, based upon signal’s time difference of
arrival at each satellite. Instead, the IOD-3 uses “a new proprietary
geolocation technology which does not include groups of satellites ‘flying in
formation’” to perform direction-finding, notes John Beckner, chief executive
officer of Horizon Technologies.
such technology needed? The high seas are home to criminal activities whether
that be narcotics or people smuggling, illegal fishing or environmental damage.
Sometimes such activities are betrayed by a vessel switching off its AIS
transponder, or altering its transmissions. This can have the effect of making
the vessel appear in a different location, or to be moving at speeds not routinely
associated with marine traffic. Should AIS transmissions be spotted from a
vessel that seems to be in two locations, the simultaneous collection of SATCOM
COMINT will indicate the likely real location of the ship: SATCOM transmissions
will not, for example, also be coming from the false position. The version of
the Flying Fish COMINT system equipping the satellite can also demodulate
L-band SATCOM transmissions. This means that users can directly listen to these
communications. This is important for gathering intelligence on what the
targeted vessel maybe doing. Secondly, AIS can be switched off by a vessel.
Should this happen and then SATCOM be initiated, this could reveal that the
vessel is engaged in suspect, or illegal activity. From a humanitarian perspective
monitoring L-band SATCOM can enable the user to instantly receive distress
calls and to immediately organise assistance given that the vessel’s location
can be determined through its SATCOM and AIS transmissions. For example,
satellite phones using the Thuraya (1.525GHz to 1.661GHz) network are routinely
used by people smugglers in the Mediterranean. The phones
are often the only means of communications with the outside world that boats
carrying refugees have. In this context, aircraft equipped with the Flying Fish
payload have helped saved numerous lives by intercepting distress calls from
these craft when they run into trouble.
IOD-3 Amber satellite will transmit its SIGINT to the Goonhilly teleport in
There, the data will be analysed using Horizon Technologies’ AMBER Ground
Exploitation System. The IOD-3 will be launched from the International Space
Station (ISS) in 2020. The satellite bus has been developed by AAC Clyde Space.
Several undisclosed UK government agencies will receive the SIGINT collected by
the satellites. The capability is being procured via a public-private
partnership: Horizon Technologies and AAC Clyde has joined forces with the UK’s
Satellite Applications Catapult technology incubator and Nanoracks which is
organising the launch from the ISS. Meanwhile, the British government is
funding the initiative and will be the customer for the intelligence.