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New
Delhi, 06 November 2005
With
the Air Exercise COPE INDIA 2005 slated to start from Monday, Sayan
Majumdar has sent in this piece about the E-3C ‘Sentry’ AWACS
aircraft, which is to take part in the Exercise. He suggests that
the IAF will gain invaluable experience about the effectiveness of
airborne early warning and control by operating with this type of
aircraft.
The
E-3 Sentry is an airborne warning and control system (AWACS)
aircraft. It is a modified Boeing 707 commercial airframe with a
rotating radar dome. The dome is 30 feet in diameter and six feet
thick, mounted 11 feet above the fuselage. It contains a radar
subsystem that permits surveillance from the Earth's surface, over
land or water. The radar has a range of more than 200 miles for
low-flying targets and farther for aerospace vehicles flying at
medium to high altitudes.
It
can look down to detect, identify and track enemy and friendly low
flying aircraft by eliminating ground clutter returns that confuse
other radar systems. Position and tracking information on enemy
aircraft and ships, and location and status of friendly aircraft,
naval vessels and ground troops can be sent to major command and
control centres in rear areas or aboard ships instantly, and, in
time of crisis, forwarded to the national command authorities. In
support of air-to-ground operations, the E-3 Sentry can provide
direct information needed for interdiction, reconnaissance, airlift
and close air support for friendly ground forces. It can also
provide information for commanders of air operations to gain and
maintain control of the air battle.
As
an air defence system, the E-3 can detect, identify and track
airborne enemy forces far from own boundaries, and can direct
fighter-interceptor aircraft to these enemy targets. Experience has
proven that the E-3 Sentry can respond quickly and effectively to a
crisis and support worldwide military deployment operations. It is a
jam-resistant system that has performed missions while experiencing
heavy electronic countermeasures.
The
E-3 Sentry has an endurance of 11 hours without refuelling. Its
range and on-station time can be increased through use of in flight
refuelling and an on-board crew rest area.
Sentry
Watch
By
Sayan Majumdar
Indo-United
States Air Exercise Cope India 2005 appears to be rather well
planned event. Preparations were initiated months before as six
Indian Air Force (IAF) staff visited Misawa from August 21 to 27,
2005 as part of a bilateral exchange program. The 13th Fighter
Squadron and 610th Air Control Flight at Misawa each hosted two
pilots, two controllers and two safety officers from various units
in India. They toured base facilities and worksites, and learned
about day-to-day military operations at the Base, including flight
operations, maintenance, air traffic control and crash recovery. In
the same week in August Misawa and Kadena each sent one airman who
will participate in the exercise to familiarise with the
Russian-made IAF operated Sukhoi-30 air dominance fighter.
Misawa
and Kadena Air Base stationed on Japanese island of Okinawa are well
geared up to send about 256 military personnel from the 35th
Operations Group and 961st Airborne Warning and Control Systems,
respectively, to Cope India 2005, to be held from November 7 to 19
to be held at Kalaikunda Air Force Base (AFB) near Kolkata
(Calcutta). In preparation for the exercise, the AFB has been
brought up to international standards. An initial planning
conference, between IAF and United States Air Force (USAF), was held
in May 2005 and a final planning conference was held in September
2005 at Kalaikunda. From United States Air Force (USAF) side twelve
F-16CJ ‘Fighting Falcons’ from Misawa AFB are to take part, as
is an E-3 ‘Sentry’ Airborne Warning & Control System (AWACS)
aircraft from Kadena AFB. The ‘Sentry’ platform appears to be
the star attraction of the show as this particular USAF type was
indeed evaluated by the IAF and found to be well at par, if not
better than the Israeli PHALCON AWACS platform that the IAF
ultimately chose.
AWACS
platforms have emerged as the central pillar of modern air defence
systems and the most effective means by which a nation can avert the
catastrophe of a surprise air attack. Surface-based radars, which
rely on short wavelengths for detection, are limited to
line-of-sight observations and oblivious to aircraft Beyond The
Horizon (BTH). Even with careful positioning of the surface radar on
mountaintops, the time between a fast enemy aircraft/missile being
sighted and weapons being released is too little for effective
countermeasures, assuming that correct identification of the enemy
was instantaneous. On the other hand owing to its elevation the
AWACS has the advantage of a greater radar horizon compared to
ground-based radar, which translates to surveillance of a larger
chunk of airspace.
A
single AWACS of the E-3C class, on patrol at an altitude of say
nine-km, could have the capability to provide surveillance up to a
range of 400-km at low level and detect up to 600 targets. It
incorporates technology sophisticated enough to direct up to 30
interceptions simultaneously. In addition the AWACS has a data link
facility to pass target information to ground-based radar and the
air defence network. An AWACS would also possess inherent Electronic
Counter Measures (ECM) capability making it a difficult proposition
for a hostile air force to electronically interfere with its
operations. As far as its endurance is concerned, the E-3C has a
patrol time of 11-hours on station and may be increased through
in-flight refuelling. The radar on E-3 has a low-level coverage of
400-km. With this AWACS flying 150-km inside one's own territory,
the lateral coverage along the border would be 750-km for each
aircraft. Therefore, it could fly a racecourse pattern and still
cover a 600-km long segment inside enemy territory for at least
8-hours. To cite a parallel During the Gulf War I, the Russian A-50
“Mainstay” operating over the Southern Black Sea and Caucasus
area, were observed flying sorties to monitor 'Coalition Forces' air
operations in Turkey and Northern Iraq. Air patrol operations were
reported as normally conducted at 10-km and flying “figure of
eight” [8] flight patterns, with up to 100-km between orbit
centres.
The
AWACS radar of the USAF E-3C is of pulse-Doppler type like the
Westinghouse AN/APY-1/2 mounted on the rear fuselage and performs
multi-mode operations to maximise detection possibilities. Mounted
on the back of the aerial within the same saucer-shaped envelope is
the complementary antenna of TADIL-C IFF (Identification Friend or
Foe) and data-link fighter-control, plus secondary surveillance
radar. The pulse-Doppler radar permits AWACS platforms to locate
targets flying close to the ground, filtering out “clutter” by
Doppler shift induced in reflected signal pulses. By using a sharp
beam and narrow Doppler filter, very low-level intruders can be
tracked with accuracy in the Pulse-Doppler Non-Elevation Scan (PDNES)
mode. If target elevation is required, the returning signal is
electronically scanned in the vertical plane to elicit the data,
this being known as Pulse-Doppler Elevation Scan (PDES) mode.
For
targets beyond the horizon, there is Beyond The Horizon (BTH) scan
available using the pulse radar without the Doppler option because
ground clutter is in the shadow of the horizon. The AN/APY-1 or
upgraded AN/APY-2 of Boeing E-3 Sentry radar operated within the
rotodome rotates at a rate of 6-rpm, giving a scan every 10-seconds.
Operation frequency is in the 10-cm wavelength, with seven operating
modes, including a PDES, PDNES, BTH, a short-pulsed maritime mode,
passive, and a test/maintenance and standby modes. However AWACS is
mainly designed for detection of low level targets and its ability
to pick up targets above its own level is limited.
For
maritime operations, a very short pulse is employed to reduce the
sea clutter and so reveal the moving and stationary vessels. Maps of
coastal areas stored in the aircraft's computer automatically remove
shoreline returns from the screen. Not only can the AWACS provide
air battle management at sea, but also guide own aircraft to carry
out anti-ship strikes. In addition it can make available data for
Over-The-Horizon (OTH) targeting of ships by own missiles. Finally
there is the passive mode in which the radar is silent and only the
Electronic Support Measures (ESM) equipment is listening for signs
of radar and radio transmissions from other airborne platforms and
ships. Again it is possible to “go passive” only in selected
segments of the compass and interleave radar modes in each scan. ESM
equipment and IFF provides important complements to the radar.
Data
received by all sensors is processed by an on-board computer like
the IBM 4PiCC-1 onboard the E-3 Sentry, filtered for extraneous
signals and presented to the tactical crew inside. The avionics
automatically opens a file on each new plot, tracks its progress and
correlates radar ESM and IFF returns. In the fourteen command &
control display screens, clear computer-generated pictures appear in
which each target is annotated with its vital characteristics. Under
leadership of a tactical-controller the tactical crew manage target
tracks and handle communications with airborne and ground units. In
this context the E-3 employs the Link16 JTIDS (Joint Tactical
Information Distribution System) Class II and posses “Have
Quick” secure voice communications. Boeing, with the Electronic
Sensors and Systems Division of Northrop Grumman as subcontractor,
have carried out an E-3 AWACS Radar System Improvement Programme (RSIP)
which upgrades the capability of the AN/APY-1/2 against threats from
small radar cross section targets, cruise missiles and electronic
countermeasures.
During
Exercise Garuda II held during June 2005, both the IAF and French
Armee de L’Air (AdlA) performed highly complex operations under
the control of an AdlA operated E-3F/SDA ‘Sentry’ platform. In
these exercises the IAF displayed a remarkable knowledge of North
Atlantic Treaty Organisation/Organisation du traite de
l’Atlantique Nord (NATO/OTAN) tactics and procedures, indicative
of potentially smoother absorption of USAF AWACS tactics in Cope
India 2005. As reported the practice missions of Cope India 2005
will include dissimilar Air Combat Manoeuvring (ACM) and Large Force
Engagement (LFE) in the Beyond Visual Range (BVR) regime.
Yet
the prominent “J” suffix of guest USAF F-16CJ platforms are well
indicative of their primary Suppression of Enemy Air Defence (SEAD)
role, having inherited the responsibility from retiring F-4J “Wild
Weasel Phantoms”. The USAF F-16CJs tend to operate closely with
United States Navy (USN) EA-6B ‘Prowler’ electronic warfare
platforms but as it appears the IAF is reluctant to allow such a
potent foreign electronic warfare platform within its airspace. IAF
Mirage 2000s may well be tasked to fulfil this particular role.
The
IAF has a lot to learn from USAF in these spheres of operations as
the USAF by now has gained considerable experience in these roles
over Iraq and in Kosovo in particular where as much 80
radar/surface-to-air missile installations were decimated within
first 24-hours in combination of SEAD and Tomahawk cruise missile
strikes. In one of the rare instances the USAF appears to be
contributing the “lo-component” in hi-lo-mix during joint
operations, with the IAF being honoured to provide the
“hi-component” the Su-30. The “secure and jam resistant”
digital JTIDS is sure to play a vital part in the exercise and it is
high time for the Indian Armed Forces to initiate negotiations to
secure the JTIDS (Link-16) technology from United States. The
potential success of Cope India 2005 may well provide IAF the
“prestigious ticket” to United States Red Flag Exercises held at
high-profile Nellis AFB at Nevada from 2006.
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