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Last Updated: Mon Jan 27 11:18:09 UTC 2014 | ||||||||||||||||||||||
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Surviving the Modern Integrated Air Defence System |
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The only US combat aircraft design to be in production before 2020 with the capability to penetrate and survive in modern Integrated Air Defence Systems is the F-22 Raptor. The depicted aircraft is dropping a GBU-32 JDAM guided bomb (US Air Force image). |
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Defense Policy Agenda Statement, |
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Disclaimer:
No classified materials needed to be used, nor were classified
materials used in the preparation
of this analysis. |
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The stunning successes achieved in US
led air
campaigns since 1991 have been owed more than anything to the US
technological
and operational capabilities to penetrate and suppress opposing
Integrated Air
Defence Systems (IADS). Ongoing
technological evolution of IADS capabilities
since 1991, and a failure by the US to further evolve its once
formidable
relative capabilities, now present the prospect of the US being unable
to
achieve a decisive advantage in an air campaign, either quickly or with
low
expenditures in aircraft and aircrew losses. At this
point in time the US has firm commitments for only 183 F-22A
Raptor aircraft, and an operational fleet of only 20 B-2A Spirit
stealth
bombers. Yet these are the only aircraft capable of surviving in the
kind of
IADS environment we now see emerging globally. |
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IADS EvolutionThe subject of
technological strategies
and countering
technological adaptations for penetrating IADS has been recently
detailed in [1], [2], [3], [4] and [5]. However,
to date we have yet to see a
more comprehensive analysis of the ongoing trends in this evolution. Until the
advent of the F-117A during
the mid 1980s,
tasked in a large part with crippling key command posts in an opposing
IADS,
Western defence penetration and IADS suppression strategies were
essentially a
sophisticated but linear evolution of techniques first pioneered during
the
1940s Combined Bomber Offensive over Germany. During that
period the RAF and USAAF
first employed
standoff jamming and escort jamming aircraft, but also employed low
altitude
penetration below radar coverage on numerous critical bombing raids.
The
British pioneered the model of Suppression/Destruction of Enemy Air
Defences
(SEAD/DEAD) flying rocket and gun armed Typhoon fighters against
Luftwaffe
search and acquisition radars. It is also significant that the Germans
pioneered the Surface to Air Missile (SAM) with their Wasserfall ands
Rheintochter designs, neither of which achieved operational status, but
both of
which provided the technological jumpstart for US, British and Soviet
developments post-war [6], [7]. The protracted
Vietnam conflict provided
the next
important stage in this evolution, as the Soviets deployed the
S-75/SA-2
Guideline SAM en masse to defend
North Vietnam, and the US developed and deployed specialised EB-66,
EA-6A/B and
EKA-3B tactical jamming and anti-radiation missile firing EF-100F,
A-6B, F-105G
and EF-4C SEAD aircraft to cripple this IADS. In parallel the US
deployed the
F-111A which used automatic terrain following to evade SAM acquisition
and
engagement radars [8],
[9], [10],
[11]. While opinions
and assessments often
differ widely on
the success of the US SEAD/DEAD campaign in Vietnam, what is abundantly
clear
is that the combination of jamming and lethal attacks against missile
batteries
and supporting radars worked, to the extent that sustainable loss rates
in
penetrating bombers were achieved. In this respect the combination of
jamming
and lethal attacks must be considered to be the winner, as the IADS
strategic
aim of achieving unsustainable bomber loss rates was simply not
achieved.
Against the tens of thousands of sorties flown, the success rate of the
SAMs
was not good enough to deter penetration. The 1973 Yom
Kippur conflict presented a
mixed
outcome. Initially the highly mobile Soviet supplied 2K12 ZRK Kub /
SA-6
Gainful and static S-125 Neva / SA-3 Goa inflicted significant loss
rates on
Israeli fighter aircraft, but innovative low level flying tactics and
use of
land manoeuvre forces swung the final outcome in favour of the Israelis
[12],
[13]. The US further
refined its technological
capabilities
during the late 1970s, developing the very capable F-4G Wild Weasel IV
and
EF-111A Raven, both of which set long term benchmarks for these
respective
capabilities. The rather simple AGM-45 Shrike anti-radiation missile
was
replaced by the sophisticated digital AGM-88 HARM [14]. The Soviet
reaction to the IADS debacle
in Vietnam,
and the not entirely convincing performance during the Yom Kippur
conflict, and
the subsequent Syrian debacle in 1982, was to develop a new generation
of SAMs
and radars, with more range, better jam resistance, and importantly
much better
mobility [15]. These weapons
were the S-300P / SA-10A
Grumble
semi-mobile strategic air defence missile, with its semi-mobile 5N63
Flap Lid
engagement radar, modelled on the US MPQ-53 Patriot radar, and the
sibling
Soviet Army high mobility weapon, the S-300V / SA-12A/B Giant/Gladiator
[16],
[17]. By the early
1980s Soviet Voyska PVO
units were
receiving the self propelled S-300PS / SA-10B, soon followed by the
digital
S-300PM / SA-10C, a true analogue to the MIM-104 Patriot, but with
better
battery mobility. Concurrently, the medium range Army 2K12 / SA-6 was
being
replaced with the more capable 9M38 / SA-11 Gadfly [18]. The
distinguishing features of this late
Cold War
generation of IADS systems were in very high mobility, all three of
these
systems being capable of firing five minutes after coming to a halt,
and being
capable of departing a location within 5 minutes of completing a
missile
engagement. The S-300PS/PM and
S-300V both employed high power, and for that period, exceptionally
long
ranging phased array engagement radars, much more difficult to jam than
the
engagement radars in the SA-2, SA-3 and SA-6 deployed and used during
the 1960s
and 1970s, and much more difficult to target with anti-radiation
missiles.
Importantly, the SA-10, SA-11 and SA-12 employed radio frequency
datalinks,
which allowed the battery command posts, engagement radars and missile
launch
vehicles considerable flexibility in how the battery was deployed
geographically [19], [20]. When Saddam
invaded Kuwait, the US
possessed a robust
conventional SEAD/DEAD capability in its fleets of HARM firing F-4G
Wild Weasel
and F/A-18 Hornet fighters, and a robust tactical jamming capability in
the
mixed fleet of EF-111A Ravens and EA-6B Prowlers. Less visible was the
37th
Tactical Fighter Wing equipped with 60 F-117A Nighthawk stealth
fighters. The
overwhelming and indeed crushing
defeat of
Saddam’s Soviet and French supplied IADS in 1991 was the result of a
concentrated, coordinated and sustained effort using aerial decoys,
SEAD/DEAD
assets, jammers against IADS radars, and the F-117A against key
hardened
command posts [21],
[22]. There are
several key observations,
which must be made
about this campaign. The first is
that it was representative
of the NATO vs.
Warpac scenarios of that period – while the Soviets had good numbers of
SA-10, SA-11 and some SA-12 deployed, these were mostly committed to
protecting
strategic targets inside Soviet territory, leaving much of the IADS
capability
in Central Europe to Warsaw Pact allies equipped with a mix of SA-2,
SA-3,
SA-4, SA-5 and SA-6 batteries. While these systems were better
maintained,
often of better subtypes, and more competently operated than Iraqi
systems,
they also had to cope with the full capabilities of NATO and the US,
not just
the forces deployed during Desert Shield. The second
observation is a corollary of
the first, in
that the new highly mobile SA-10, SA-11 and SA-12 were not deployed in
Iraq.
Indeed, Iraqi deployment doctrine of that period paid little attention
to
mobility, with SAM batteries nearly always fixed in location. To achieve the
intended effect against
this legacy
IADS, the US expended hundreds of drones, and importantly, around 2,000
AGM-88
HARM anti-radiation missiles, to which must be added the complete but
smaller
warstock of British ALARM anti-radiation missiles. The Desert
Storm campaign remains a key
historical
benchmark, but unfortunately it has also created quite unrealistic
expectations
of what can be achieved over the longer term. The next
significant air campaign was
the 1999
Operation Allied Force effort against Serbia. While it has been
considered a
success due to the low aggregate loss rates of Coalition aircraft, the
success
of the SEAD/DEAD effort was much less convincing. While the Coalition
did
successfully destroy most of the static SA-2 and SA-3 batteries, they
only
managed to destroy 3 out of 25 mobile SA-6 batteries, or 12% percent of
that
total, despite the large number of HARMs launched. Disciplined “shoot
and
scoot” tactics by the Serbian defenders, intended to keep missile
batteries
alive, resulted in a persistent threat of sniping attacks which kept
much of
the NATO force of F-16CJs, EA-6Bs and Tornado ECRs occupied chasing SAM
systems, largely to no avail. The Serbians did execute one particularly
successful ambush, killing an F-117A stealth fighter using a legacy
SA-3
missile battery [23]. The Allied
force campaign happened a
decade ago, since
then there have been no significant air campaigns in which an IADS was
employed
to deny access to attacking aircraft. What the Desert
Storm and Allied Force
campaigns did
achieve was to provide both a focus and an imperative for further
evolutionary
growth in IADS capabilities, doctrine and technological strategy. In the decade
that has elapsed since
Allied Force, we
have seen a commercially and strategically driven flurry of
developmental
activity in the Russian and Chinese defence industries, reacting to the
lessons
of the 1990s, but also exploiting the globalised market for high
technology,
especially computer technology, commodified high performance
microprocessor
chips, and Gallium Arsenide microwave chips. Perhaps the only silver
lining in
this situation is that the global Internet provides Western observers
with a
much clearer picture of technological evolution in Russia, less so in
China,
than during the late Cold War and early 1990s [24]. We can now identify a number of key trends in IADS evolution, which are well established, and will define the basic features of well constructed near future air defences, such technology being globally marketed by Russia, former Soviet Republics, and China. High Mobility:All Russian SAM
systems designed over
the last decade
can “shoot and scoot” in 5 minutes, with all key components self
propelled, now
mostly on all terrain wheeled vehicles with high road mobility. The
most
recently
developed SAM system acquisition radars can redeploy inside 15 minutes.
Chinese
developed radars and SAM systems are following a similar pattern, with
an
increasing change to self-propelled designs [i]. A concurrent
trend has been to market
self-propelled
mobility upgrades for legacy SA-2 and SA-3 systems, leaving only the
legacy
SA-5 as an inherently static system [25]. High
Resistance to Jamming:
Most recent
Russian engagement and
acquisition radars
are automatic pseudorandom frequency hoppers, many in fact “fast”
frequency
hoppers with pulse-to-pulse hopping capability. A similar trend is now
being
observed in Chinese radar designs. Such radars will exhibit similar jam
resistance to Western frequency hopping technology used in radar and
digital
networks. Importantly,
frequency hopping
technology is now
appearing in upgrade packages for legacy radars, with at least one
SNR-125 Low
Blow upgrade including this capability [26],
[27],
[28], [29]. Phased
Array
Antenna
Technology:
An increasing
proportion of Russian
engagement and now
also acquisition radars are phased arrays, with at least two designs
being active
arrays with solid state transmitter modules (AESA). These provide agile
beam
steering, adaptive jammer nulling, adaptive allocation of transmit
power, in
addition to very low sidelobe emissions to frustrate emitter locating
systems
and anti-radiation missile seekers. All of the three recent Chinese
engagement
radars disclosed are phased arrays [30],
[31],
[32]. An important
advantage in all phased
arrays is they
permit angle jam resistant high precision angle tracking by fast
sequential
lobbing, emulating monopulse techniques. They also permit high update
rate
angle and range tracking of multiple targets. This not only increases
the
potency of SAM engagement radars, but also blurs traditional
distinctions
between engagement radars and acquisition radars. If an outbound SAM is
receiving midcourse trajectory updates produced by a VHF-band phased
array
“acquisition” radar networked with the SAM’s X-band “engagement” radar,
both
might as well be considered to be battery “engagement” radars. The inevitable
long-term trend is that
Russian
designers will move to active arrays (AESA) once manufacturing
obstacles are
overcome, resulting in further improved peak power performance. Increasing
Missile Range and Radar Power:
The trend in
Russian missiles has been
unequivocally
toward increasing range, and concurrent increases in radar
power-aperture
product as a result. The improvements in missile range are partly due
to more
energetic solid propellants, but also due to “smart” trajectory control
laws in
the digital guidance systems employed. The longest ranging Russian
SAMs, the
48N6E2/E3 and 40N6E, all fly ballistic trajectories against distant
targets,
achieving respectively ranges of 250 km and 400 km. Smart trajectory
control in
at least one digital upgrade to the SA-3 doubled its kinematic range [33],
[34]. The increases
in radar peak power
required to support
the increases in kinematic range provide useful counter-stealth
capabilities,
effectively neutralising stealth designs in the -20 dBSM performance
class [35], [ii]. Lower
Band
Operating Frequencies:
The late Cold
War preference for compact
antennas and
S-band operation has been supplanted by a preference for designs
operating in
the L-band and VHF-band. Of the six recent Russian acquisition radar
designs,
only one may operate in the S-band, the remainder being beyond any
question
L-band or VHF-band designs. The preference
for lower bands is
intended to defeat
stealth shaping and coatings optimised for S-band and X-band threats,
but also
electronic warfare self protection systems most of which cannot jam
below the
S-band due to antenna size limitations [36], [iii]. Pervasive
Use of Digital COTS Processing:
The globalised
market for computing
hardware and open
source software has seen all recent Russian radar and missile system
designs
built around COTS computing hardware and more that often open source
software,
especially the Linux operating system, and C/C++ programming language.
This
trend encompasses signal processing, track data processing, display
graphical
interface processing, networking, and command post processing [37], [38]. The
availability of advanced yet
commodity high
performance computer hardware suitable for embedded applications has
removed
one of the single greatest technological advantages held by the Western
world
over the Soviets throughout the Cold War period. Advanced Digital Signal and Data Processing:The
availability of COTS digital
hardware and open
source software has been a fundamental enabler for the introduction of
a range
of advanced processing algorithms and techniques until recently
exclusive to
Western radar designs. Non Cooperative
Target Recognition
(NCTR) techniques
based on target return fine structure are now appearing in Russian
radar
designs [39]. Space Time
Adaptive Processing (STAP)
techniques,
which adaptively reject surface clutter and chaff, are also now
appearing in
Russian radar designs [40]. Track fusion
algorithms, which are the
basis of the US
Navy Cooperative Engagement Capability (CEC) system, are now available
in at
least one Russian design, the Salyut Poima E [41]. Defensive
Counter Measures and Emitting Decoys:
Radio frequency
emitting decoys intended
to seduce
anti-radiation missiles are now being offered for most Russian radars,
many of
which include integration features to synchronise radar emissions with
multiple
decoys [42]. Inflatable
visual decoys are on offer
for some Russian
equipment items, including the S-300PMU/S-400 series TELs. At least one
Russian radar is being
offered with a
comprehensive countermeasures suite, including a smoke generator to
defeat
laser and television guided smart weapons, a flare dispenser to defeat
infrared
and imaging infrared guided smart weapons, and a chaff dispenser
intended to
defeat millimetre wave (MMWI) band radar seeker guided weapons [43]. Russian GPS
jamming equipment has been
available for
at least a decade in the global market. Active
Interception of Smart Weapons:
A trend which
emerged during the
nineties and has been
reinforced by recent design optimisations in the Tor M2E / SA-15 and
Pantsir S
/ SA-22 SAM systems, is the use of these short range point defence
missile or
missile / gun systems to shoot down smart munitions targeting SAM
battery
acquisition and engagement radars. The cited intent is to kill
anti-radiation
missiles, cruise missiles, or any other guided munitions being used by
SEAD/DEAD aircraft against the missile battery [43],
[44]. This is more
than marketing, in that
both the SA-15
and SA-22 have been re-equipped with agile beam phased array engagement
radars
designed to concurrently track many targets and engage same with
missiles. Alternative Missile Seekers:Cold War era
Soviet medium and long
range SAMs
employed primarily command link guidance and semi-active radar homing
guidance,
later supplemented by Track Via Missile guidance similar to that in the
US
MIM-104 Patriot. SAM designers did not espouse the philosophy of AAM
designers,
who would equip like missile airframes with alternative radar,
infrared, and
most recently, X-band anti-radiation homing seekers. Since the end
of the Cold War we have
seen Serbia and
Iraq experiment with the retrofit of infrared homing seekers to legacy
Soviet
SAM types. Agat in Russia have developed derivatives of their active
radar AAM
seekers for use in the SA-6/8/11/17 SAM rounds. China developed an
anti-radiation seeker for use in their FT-2000 SAM, claimed to be a
variant of the
HQ-9. The expectation
that SAM rounds will be
equipped only
with a single seeker type belies the pressures to provide diversity in
seeker
types to overcome defensive jamming. Pervasive
Use of Digital Datalinks/Networks:
The Soviets
were heavy users of digital
datalinks and
this propensity has expanded in more recent designs for SAM systems and
supporting IADS elements, as commodified Gallium Arsenide chips have
reduced
the cost of development and production, and widely available software
design
tools have accelerated the development tempo. Many
contemporary equipment designs are
designed
around networks to provide wireless connectivity between self propelled
components, and COTS networking to provide connectivity inside
equipment. Unlike the
Western preoccupation with
providing
generalised “Metcalf-like” connectivity, Russian designers have been
more
disciplined and tend to use wireless connectivity for more specific
functions. Low
Probability
of
Intercept
Techniques:
Low Probability
of Intercept (LPI)
techniques involve
the use of exceptional frequency agility, noise-like waveforms, and
controlled
emission patterns, to make the interception of radar or datalink
transmissions
exceptionally difficult. To date there
have been no significant open source
disclosures on
the use of these techniques in Russian datalinks or radars. However, most
if not all of the
prerequisite
technologies needed to implement LPI have been mastered by Russian
industry.
The assumption that LPI will not be introduced and employed in IADS
components
is simply not supportable even in the near term [iv]. Integration
of Emitter Locating Systems with SAM Batteries:
A feature long
expected and recently
announced as part
of the S-400/SA-21 SAM system is the provision of interfaces to permit
the battery
to accept targeting track data from 85V6 and 1L222 series mobile
passive
emitter locating systems [45],
[46],
[47]. Such emitter
locating systems have
proven very
effective at three-dimensional tracking of aircraft, using their
JTIDS/Link-16
network terminal, IFF, or TACAN emissions. Emitting ISR platforms are
especially
vulnerable to tracking by such systems. If used in
concert with a SAM system
engagement radar,
where the radar will “tease” emissions from defensive jammers in an
aircraft to
facilitate tracking, the emitter locating system may effectively
nullify the
benefit of having a jammer. Most recent
Russian radar designs
include capabilities
for angle tracking of opposing jammers. Hybridisation
of
SAM
Systems:
Hybridisation
of SAM systems, where
legacy missiles
and launchers are supported by
newer technology engagement radars, has a well established history in
the
Soviet IADS environment, but mostly in the provision of “backward
compatibility” in evolving families of weapons. The two best examples
are the
SA-6 and SA-11 family of weapons, where transitional subtypes could
control
Fire Dome engagement radars on TELARs, and the SA-10/20 family of
weapons,
where later 30N6 Tomb Stone radars can guide SA-10 5V55 series missile
rounds. A more recent
trend has been the
hybridisation of
dissimilar systems, where a modern agile beam phased array engagement
radar
gains the capability to guide legacy missiles associated with an
entirely
different SAM system design. The best example is the SA-20/21 family of
systems
acquiring the ability to control the SA-5 Square Pair illuminator
radar, and
emerging evidence of likely Chinese integration of the legacy SA-2/HQ-2
missiles with the new H-200 phased array engagement radar developed for
the new
HQ-12/KS-1A SAM [48]. Hybridisation
is especially concerning
for two
reasons. The first is that it completely obsoletes all extant
electronic
warfare techniques and equipment developed against the legacy radar –
and
it may be difficult to determine its presence a priori.
The
second
is that a new phased array radar will expand
the lethality of the system providing many capabilities absent in the
legacy
radar. What
is
abundantly
clear
at the close of the first decade of the 21st century
is that
almost two decades after the fall of the Soviet regime, the former
Soviet
defence industry has remade itself and successfully assimilated much of
the
digital and microwave technology base available in the global market. With the
exception of a handful of
technologies, such
as advanced low observables, high density chip design, and X-band
active phased
array (AESA) modules, Russian industry has closed the gap in most key
areas of
IADS related technology. This should be
neither surprising nor
unexpected, but
given repeated statements, and related policy decisions, by numerous
senior
Western DoD bureaucrats in recent times, it is evident that this “new
reality”
is either not understood, or there is complete indifference to its
existence. To appreciate
the specific impacts
produced by
evolving IADS technologies and doctrine, it is well worth testing the
primary
Western tools used to defeat IADS, against the new reality. |
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Effectiveness of Established Technology vs. Modern IADSThe US
and its Allies have relied in recent decades
upon a small number of pivotal technologies and techniques to defeat
IADS and
gain access to hostile airspace. These
include precision emitter locating systems, the
anti-radiation missile, guided bombs and cruise missiles, Electronic
Warfare
Self Protection equipment carried by penetrating aircraft, high power
support
jamming aircraft, and most importantly, stealth. To a greater or lesser
extent,
all of these technologies are now being challenged. Precision
Emitter
Locating
Systems:
Modern
Russian doctrine is to directly attack airborne
ISR assets using very long range SAMs and AAMs [49]. Where
the ISR system is not so threatened, it will
have to contend with low sidelobe antennas and smart/agile scan
patterns, the by-product
of a move to phased array designs. Further challenges will arise from
a well
proven doctrine of carefully controlling emissions, using passive
sensors, and
the exploitation of the high mobility of modern IADS components [50]. The
conclusion is that future IADS elements will be
much more difficult to locate and track. Penetrating ISR assets with
high
stealth performance will be required. Anti
Radiation
Missiles:
The
defeat of Anti-Radiation Missiles (ARM) has
absorbed considerable intellectual effort in Russia, which is now
yielding
dividends. An ARM
will have to overcome synchronised, smart
emitting decoys, which are likely to employ extant Russian DRFM
(Digital RF
Memory) technology and thus be extremely difficult to distinguish from
the
target emitter. In addition, emitters will generate low side and
backlobes and
may exploit agile electronic beam steering to evade interception. The
pervasive
use of self-propelled radars will exacerbate the problems observed in
the OAF
campaign of 1999. If the
ARM can overcome these impediments, it has to
survive interception by short range weapons tasked with interception of
the
ARM. Unless
the ARM is hypersonic, or exceptionally
stealthy, or both, it is likely to fall victim to the terminal defences
deployed in the IADS. While
recent developments such as ramjet propulsion to
improve kinematics, and multimode seekers to attack non-emitting
targets, will
improve anti-radiation missile effectiveness against high mobility
threats,
they cannot address the active use of countermeasures against the
missile
seeker, and the use of defensive fire against the missile itself. Guided
Bombs
and
Cruise Missiles:
Guided
bombs have been used increasingly for the DEAD
role. Like ARMs, they will have to contend with countermeasures and
decoys, and
jamming of the GPS carrier signals. They will also have to survive
terminal short-range
missile and gun defences. A
consideration for glide weapons like the JSOW, winged JDAM and SDB, as
well as
cruise missiles, is that self-propelled IADS components may no longer
be at the
DMPI when the weapon arrives. Time of
flight is therefore an issue in its own right
and for standoff attacks with cruise missiles such as the Tomahawk,
CALCM and
JASSM, the basic operating cycle of a mobile battery may be enough to
defeat
the weapon. While datalinks offer potential for retargeting a cruise
missile in
flight, they increase the vulnerability of the weapon, and will be
jammed by
the defending side, while the availability of penetrating ISR
capability to
support such retargeting remains problematic. Stealthy
cruise missiles such as the JASSM/JASSM-ER
offer the best potential for surviving enroute to the target, but their
endgame
survivability in the last three miles of flight remains questionable,
given
existing and emerging capabilities in “counter-PGM” optimised point
defence
weapons. Eight SDBs targeting a single aimpoint are more likely to be
successful than one or two cruise missiles, simply due to the
saturation of the
missile batteries involved. Weapons
with terminal seekers will have to overcome
countermeasures deployed by a target system, if the weapon can arrive
before
the target has redeployed itself, and is not shot down as it approaches
the
target. Electronic
Warfare
Self
Protection
and Support Jamming:
EWSP
equipment has been critical to the survivability
of Western combat aircraft subjected to SAM attacks. The advent of DRFM
based
jammers during the 1990s provided much greater potency compared to
earlier
analogue jammers. In a
modern IADS environment jamming will have to
overcome robust Electronic Counter Counter Measures (ECCM/EPM)
capabilities in
radars and SAM seekers. Russian design philosophy stresses
countermeasures
resistance, and modern designs employ monopulse angle tracking
techniques,
frequency hopping, jammer nulling and other techniques. The advent of
track
fusion techniques will further enhance jam resistance. No less
importantly, most modern Russian radars employ
jammer angle tracking techniques, which combined with pervasive
networking,
will provide missile batteries with an organic capability to target
SAMs
against jamming aircraft. The potential for alternate SAM seeker types
increases this risk. The
integration of passive Emitter Locating Systems
into SAM batteries provides at a minimum an ability to overcome
jamming, and at
worst an organic targeting capability exploiting emissions from the
jammer. Support
jamming aircraft have been a priority target
since the Soviet era, and the S-300V/SA-12 system had specific angle
tracking
capabilities designed in for this very purpose during the 1980s.
Current
Russian thinking is to employ very long range SAMs to kill support
jamming
aircraft in their standoff orbits. By extending SAM kinematic range
past 120
nautical miles, the Russians have driven aircraft using the extant
ALQ-99
Tactical Jamming System (EA-6B/EA-18G) outside of the power-aperture
envelope
where this system performs most effectively [51], [52],
[53]. The Next
Generation Jammer, if at all implemented,
will need to be designed around the realities of long range missile
attacks
against standoff jamming aircraft. Very
Low
Observable
Performance
(Stealth):
Stealth
remains the ace in the US deck of cards for
defeating modern IADS. Unfortunately a belief has developed in parts of
the US
defence community that “any stealth is good enough”, as evidenced by
the
ongoing debate surrounding the viability of the Joint Strike Fighter.
Unfortunately what might have been true in the world of the 1980s is
not true
today, as Western aircraft must confront much more powerful and longer
ranging radar
technology. Analysis
of available performance data for a wide
range of modern Russian and Chinese acquisition and engagement radars
indicates
that at a minimum to survive in a modern IADS a combat aircraft will
require an
“all aspect” Radar Cross Section in the -35 dBSM to -45 dBSM class,
from the
L-band through to the Ku-band [54]. Such
performance is demonstrably delivered by only two
existing designs, the B-2A Spirit and the F-22A Raptor. The X-47B UCAS
and
planned New Generation Bomber (“QDR Bomber” or “2018 Bomber”) will, if
well
designed, fall comfortably within this performance envelope. The
Joint Strike Fighter is not in this class and
without a deep, time consuming and very expensive redesign, cannot be [55]. This
should not be surprising as it is a design built
to earn export dollars rather than deliver credible and survivable
capabilities
in the long term. Benefits for the US and other industrial complexes,
ahead of
capability, may well be politically attractive, but have no place in a
world
where potential threats have been allowed to outweigh, and increasingly
so, the
deterrent capabilities meant to keep the world in balance. |
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The B-2A Spirit is the only operational type in the US inventory, other than the F-22, which can survive in a modern IADS. Only twenty were built due to the post Cold War budgetary collapse. |
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Strategic Impact of IADS EvolutionThe United States and its Allies have
relied since the
end of the Cold War upon the ability to quickly overwhelm an opposing
IADS, and
the ability to then deliver massed precision firepower from the air, as
the
weapon of choice in resolving nation state conflicts. The reality of evolving IADS technology
and its global
proliferation is that most of the US Air Force combat aircraft fleet,
and all
of the US Navy combat aircraft fleet, will be largely impotent against
an IADS
constructed from the technology available today from Russian and,
increasingly
so, Chinese manufacturers. If flown against such an IADS, US legacy
fighters
from the F-15 through to the current production F/A-18E/F would suffer
prohibitive combat losses attempting to penetrate, suppress or destroy
such an
IADS. The IADS technology in question is
currently being
deployed by China, Iran, Venezuela, and other nations, most of which
have poor
relationships with the Western alliance. Until the US Air Force deploys
significant numbers of
the intended New Generation Bomber post 2020, only aircraft types in
the US
arsenal will be capable of penetrating, suppressing and destroying such
an IADS
– the B-2A Spirit and the F-22A Raptor. Cruise missile bombardment from standoff
ranges is
often presented as an alternative to crewed combat aircraft delivering
precision bombs. The difficulty, identified earlier, with cruise
missile
bombardment is that it is most effective against fixed targets, and
improving
point defence capabilities present a genuine risk that a sizeable
proportion of
cruise missiles sortied will be shot down as they close on their
targets.
Another consideration is the aggregate cost of such bombardment, since
cruise
missiles are still at least an order of magnitude more expensive than
guided
bombs, making the sustained delivery of thousands of rounds difficult
to
sustain by production, and fiscally [56]. Stealthy Uninhabited Combat Aerial
Systems (UCAS/UCAV)
have also been proposed, specifically for SEAD/DEAD and fixed target
strike
operations. This technology presents as a better choice than cruise
missiles,
for economic reasons and the potential for a UCAV to saturate terminal
defences
with multiple SDBs. While a credible airframe with adequate stealth
performance
is feasible in the near term, the X-47B presenting as a good example,
the
remaining components required for a credible capability remain
immature, risky
and in many respects, problematic. The required range and loiter
endurance will
require an aerial refuelling capability for the uncrewed system.
Satellite
downlinks from the vehicle, and line of sight datalinks, will be jammed
by an
opponent, forcing heavy reliance on autonomous onboard artificial
intelligence,
and organic ISR capabilities on the vehicle itself, if anything beyond
fixed
infrastructure targets are to be attacked [57]. The only low risk technological strategy
available to
the US in the 2010 – 2020 timeframe is exploitation of existing stealth
technology designs, which are as noted earlier, only the F-22A Raptor
and B-2A
Spirit [58], [59], [v]. There are only twenty B-2As in existence
and retooling
to manufacture a B-2C is an expensive approach given the commitment to
the New
Generation Bomber [60]. The United States therefore has only one
remaining strategic
choice at this time. That strategic choice is to manufacture a
sufficient
number of F-22A Raptors to provide a credible capability to conduct a
substantial air campaign using only the B-2A and F-22A fleets. The expectation that the US can get by
with a small
“golden bullet” fleet of stealth aircraft to carve holes in IADS to
permit
legacy aircraft to attack is no longer credible. The difficulty in
locating and
killing the new generation of self propelled and highly survivable IADS
radars
and launchers presents the prospect of a replay of the 1999 OAF
campaign, with
highly lethal SAM systems waiting in ambush, and mostly evading
SEAD/DEAD
attacks. The F-22A Raptor will therefore have to
perform the
full spectrum of penetrating roles, starting with counter-air, and
encompassing
SEAD/DEAD, penetrating ISR and precision strike against strategic and
tactical
targets. The B-2A fleet can robustly bolster capabilities, but the
small number
of these superb aircraft available will result inevitably in very
selective
use. How many
F-22A Raptors is enough to meet this capability benchmark? If we assume
an
aircraft configuration reflecting the planned F-22A Block 40
configuration, and
we assume a contingency of similar magnitude to Desert Storm, then the
required
number of F-22A aircraft to cover the spectrum of penetrating roles is
of the
order of 500 to 600 aircraft [61], [62]. This is making assumptions such that few
F-22A
aircraft will need to be retained for other duties in other theatres,
and that
a significant air threat does not exist and thus few F-22A aircraft
need to be
committed to Defensive Counter Air operations. From a different perspective, a block
replacement of
the ~600 strong F-15A-E Eagle / Strike Eagle fleet one for one with
F-22A
Raptors would provide the proper fleet size. The United States no longer has any real
choices in
this matter, if it wishes to retain its secure global strategic
position in the
2010 – 2020 time window. Any other force structure model will result in
a
nett loss of strategic potential, and produce strategic risks, which
neither
the US nor its Allies can afford.
Endnotes:[i]
There are
some indications that the Russians intend to wholly standardise on
wheeled vehicles for all of their IADS components. This makes sense
insofar as wheeled vehicles are more affordable to buy and
maintain, provide higher road speed than tracked equivalents, and
produce a less challenging vibration environment for electronic
equipment. The Cold War imperative to provide organic air defence for
tank armies operating off road has vanished, while the imperative of
mobility has increased.
[ii] An
argument which sometimes energes in the radar observables engineering
community is that power aperture alone is not enough to detect and
track targets with an RCS below -20 dBSM, due to impairments such as
receiver channel noise floor, master oscillator coherency and phase
noise, and limitations in receiver analogue/digital converter
linearity, and quantisation performance / dynamic range. While these
impairments may well compromise detection performance against very low
signature targets, these impairments are also readily reduced by block
upgrades to key radar components, block upgrades which are typically
much cheaper than transmitter design changes to increase power-aperture
performance. Power-aperture performance thus sets the outer bound
on the performance of the radar in question, and it is strategically
unsafe to assume that over the operational life of such a radar
receiver and oscillator upgrades will not be inserted to drive actual
detection performance to this physics constrained bound.
[iii] A wider consideration here is that most Western threat warning receivers and aircraft self protection systems do not have coverage extending into the L-band, indeed many systems cut off at around 2 GHz. Much the same is true of anti-radiation missiles. The technological problem is that of the antenna dimensions required to produce useful gain. [iv] The PLA is known to have experimented with LPI techniques for at least 25 years. They have employed Frequency Modulated Continuous Wave (FMCW) modulations, Frequency Modulated Interrupted Continuous Wave (FMICW) modulations, forms of Pulse Code Modulation, and pseudonoise modulations. The author is indebted to John Wise for his advice in this area. [v] The B-2A has the radar low observables performance to defeat all of the threat radars in question. However if unescorted it will be limited to night only operations, due to the risk of hostile fighters and weapons with electro-optical guidance regimes, under clear sky conditions. With an adequate number of F-22s available, such that OCA/DCA/SEAD/DEAD escorts can be attached to the B-2A, the aircraft can then be safely flown day or night. Subject to basing distances and turnaround times, this could double the sortie rates achievable by the limited number of B-2As in service. |
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Imagery
Sources: Author; www.jsf.mil, US DoD.
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Air Power Australia Analyses ISSN 1832-2433 |
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