The
FGM-148 Javelin is an American-made
man-portable anti-tank guided
missile fielded to replace the Dragon antitank
missile.
Overview
Javelin is a
fire-and-forget missile
with lock-on before launch and automatic self-guidance. The system
takes a
top-attack flight profile against
armored vehicles (attacking the top armor which is generally
thinner) but can also take a direct-attack mode for use against
buildings or fortifications. This missile also has the ability to
engage helicopters in the direct attack mode. The missile reaches a
peak altitude of 150m (492 ft.) in top attack mode and 50m ( 164
ft.) in direct fire mode. The missile is equipped with an
imaging infrared seeker. The
tandem warhead is fitted with two
shaped charges: a precursor warhead to
detonate any explosive
reactive armor
and a primary warhead to penetrate base armor. The Javelin was used
in the
2003 Invasion of Iraq ,
with devastating effects on the
Iraqi version of T-72 and
Type 69 tanks.
The missile is ejected from the launcher so that it reaches a safe
distance from the operator before the main
rocket motors ignite; a "
soft launch arrangement". This makes it harder
to identify the launcher and allows it to be fired from within
buildings; however, back-blast from the launch tube still poses a
hazard to nearby personnel. Thanks to this "fire and forget"
system, the firing team may move on as soon as the missile has been
launched.
The missile system is carried most often by a two man team
consisting of a gunner and an ammo bearer, although it can be fired
with just one person if necessary. While the gunner aims and fires
the missile, the ammo bearer scans for prospective targets and
watches for threats such as enemy vehicles and troops.
Development
In 1983, the
United States Army
introduced its AAWS-M (Advanced Anti-Tank Weapon System - Medium)
requirement, and in 1985, the AAWS-M was approved for development.
In August 1986, the Proof-of-Principle (POP) phase of the
development began, with three competitors designing prototypes such
as the SC440-AT.
In late 1988, the POP phase ended, and in
June 1989, the full-scale development contract was awarded to a
joint venture of Texas Instruments and Martin Marietta
(now Raytheon and Lockheed-Martin). The AAWS-M received
the designation of FGM-148.
In April 1991, the first test-flight of the Javelin succeeded, and
in March 1993, the first test-firing from the launcher succeeded.
In 1994, low levels of production were authorized, and in 1996 the
first Javelins were deployed with US Army units.
Test and evaluation
Development Test and Evaluation (DT&E) is conducted to
demonstrate that the engineering design and development process is
complete. It is used to reduce risk, validate and qualify the
design, and ensure that the product is ready for government
acceptance. The DT&E results are evaluated to ensure that
design risks have been minimized and the system will meet
specifications. The results are also used to estimate the system’s
military utility when it is introduced into service. DT&E
serves a critical purpose in reducing the risks of development by
testing selected high-risk components or subsystems. DT&E is
the government developing agency tool used to confirm that the
system performs as technically specified and that the system is
ready for field testing.
DT&E is an iterative process of designing, building, testing,
identifying deficiencies, fixing, retesting, and repeating. It is
performed in the factory, laboratory, and on the proving ground by
the contractors and the government. Contractor and government
testing is combined into one integrated test program and conducted
to determine if the performance requirements have been met and to
provide data to the decision authority.
The General Accounting Office (GAO) published a report questioning
the adequacy of Javelin testing. The report, called “Army
Acquisition – Javelin Is Not Ready for Multiyear
Procurement”,
[40146] opposed entering into full-rate production in
1997 and expressed the need for further operational testing due to
the many redesigns undergone.
Previously in 1995 the Secretary of Defense, William Perry, had set
forth five new operational test initiatives. These included: 1)
getting operational testers involved early in development; 2) use
of modeling and simulation; 3) integrating development and
operational testing; 4) combining testing and training; and 5)
applying concepts to demos and acquisitions.
The late-phase development of the Javelin retroactively benefited
from the then new operational test initiatives set forth by the
Secretary of Defense, as well as further test conducted as a
consequence of the Army’s response to the GAO report. Before the
Milestone III decision and before fielding to 3rd Battalion 75th
Ranger Regiment at Fort Benning (also Army Rangers, Special Forces,
airborne, air assault, and light infantry), the Javelin was
subjected to limited parts of the five operational test and
evaluation initiatives, as well as a portability operational test
program (an additional test phase of the so-called Product
Verification Test
[40147]) which included live firings with the
full-rate configuration weapon.
Per initiatives and as a DT&E function, the
Institute for Defense
Analyses (IDA)
[40148] and the Defense Department’s Director of
Operational Test and Evaluation (DOT&E)
[40149] became
involved in three development test activities, including: 1)
reviewing initial operational test and evaluation plans; 2)
monitoring initial operational test and evaluation; and 3)
structuring follow-on test and evaluation activities. The results
of these efforts detected problems (training included) and
corrected significant problems which led to modified test plans,
savings in test costs, and GAO satisfaction.
Qualification testing
The Javelin Environmental Test System (JETS) is a mobile test set
for Javelin All-Up-Round (AUR) and the Command Launch Unit (CLU).
It can be configured to functionally test the AUR or the CLU
individually or both units in a mated tactical mode. This mobile
unit may be repositioned at the various environmental testing
facilities. The mobile system is used for all phases of Javelin
qualification testing. There is also a non-mobile JETS used for
stand-alone CLU testing. This system is equipped with an
environmental chamber and is primarily used for Product
Verification Testing (PRVT). Capabilities include: Javelin CLU
testing; Javelin AUR testing; Javelin Mated Mode testing; Javelin
testing in various environmental conditions; and CLU PRVT.
The All-up-Round Test Sets includes: Extreme temperature testing;
Missile tracker testing (Track rate error, Tracking sensitivity);
Seeker/focal plane array testing (Cool-down time, Dead/defective
pixels, Seeker identification); Pneumatic leakage; Continuity
measurements; Ready time; and Guidance sections (Guidance commands,
Fin movement).
Components
Missile
Warhead
The Javelin missile’s tandem warhead is a high-explosive antitank
round. This round utilizes an explosive shaped charge to create a
jet of
superplasticity deformed
metal formed from trumpet-shaped metallic liners. The result is a
high velocity jet that can penetrate armor.
The Javelin counters the advent of
explosive reactive armor (ERA). ERA
panels lie over a vehicle’s main armor and explode when struck by a
warhead. This explosion does not harm the vehicle’s main armor, but
causes steel panels to fly into the path of the antitank round’s
jet, so that the jet expends its most potent energy cutting through
the panels, rather than through the main armor. The Javelin uses
two shaped-charge warheads in tandem. The precursor charge sets off
the ERA and clears it from the path of the main charge, which then
penetrates the target’s primary armor.
A two-layered
molybdenum liner is used
for the precursor and a copper liner for the main charge.
To protect the main charge from the explosive blast, shock, and
debris caused by the impact of the missile's nose and the
detonation of the precursor charge, a blast shield is used between
the main and precursor charge. This was the first
composite material blast shield and the
first that had a hole through the middle to provide a jet that is
less spread out.
A newer main charge liner produces a higher velocity jet. This
change makes the warhead more effective as a penetrator and
smaller, with more room for propellant to increase the missile's
range.
Electronic arming and fusing, called Electronic Safe Arming and
Fire (ESAF), is used. The ESAF system enables the firing and arming
process to proceed, while imposing a series of safety checks on the
missile. ESAF cues the launch motor after the trigger is pulled.
When the missile reaches a key acceleration point (indicating that
it has cleared the launch tube), the ESAF initiates a second arming
signal to fire the flight motor. After another check on missile
conditions (target lock check), ESAF initiates final arming to
enable the warheads for detonation upon target impact. When the
missile strikes the target, ESAF enables the tandem warhead
function (provide appropriate time between the detonation of the
precursor charge and the
detonation of
the main charge).
Propulsion
Most rocket launchers require a large clear area behind the gunner
to prevent injury from backblast, and thus cannot be fired from
within a building. To address this shortcoming without increasing
recoil to an unacceptable level, the Javelin system uses a
soft launch mechanism. A launch motor using
conventional rocket
propellant ejects the
missile from the launcher, but stops burning before the missile
clears the tube. The flight motor is ignited only after a delay to
allow for sufficient clearance from the operator. To save weight,
the two motors are integrated with a
burst
disc between them; it is designed to tolerate the pressure of
the launch motor from one side, but to easily rupture from the
other when the flight motor ignites. Both motors use a common
nozzle, with the flight motor's exhaust flowing through the
expended launch motor. Because the launch motor casing remains in
place, an unusual annular (ring-shaped) igniter is used to start
it; a normal igniter would be blown out the back of the missile
when the flight motor ignited and could injure the operator.
In the event that the launch motor malfunctions and the launch tube
is overpressurized -- for example, if the rocket gets stuck -- the
Javelin missile includes a pressure release system to prevent the
launcher from exploding. The launch motor is held in place by a set
of shear pins, which fracture if the pressure rises too high and
allow the motor to be pushed out the back of the tube.
Seeker
As a fire-and-forget missile, after launch the missile has to be
able to track and destroy its target without the gunner. This is
done by coupling an onboard imaging IR system (different from CLU
imaging system) with an onboard tracking system.
The gunner uses the CLU’s IR system to find and identify the target
then switches to the missile’s independent IR system to set a track
box around the target and establish a lock. The gunner places
brackets around the image for locking.
The seeker stays focused on the target’s image continuing to
recognize as the target moves or the missile’s flight path alters
or as attack angles change. The seeker has three main components:
1)
focal plane array (FPA); 2)
cooling and calibration; and 3) stabilization.
1) Focal plane array (FPA) - The seeker assembly is encased in a
dome which is transparent to the FPA long-wave
infrared radiation. The IR radiation passes through
the dome and then through lenses that focus the energy. The IR
energy is reflected by mirrors on to the FPA. The seeker is a
two-dimensional staring FPA of 64x64
MerCad
(HgCdTe) detector elements
[40150]. The FPA processes the signals from the
detectors and relays a signal to the missile’s tracker.
The staring array is a photo-capacitive device where the incident
photons stimulate electrons and are stored in the detector as an
accumulated charge. The electrons are discharged, pixel by pixel,
as currents to a
readout
integrated circuits attached at the rear of the detector. A
better
photovoltaic mechanism in which
a voltage signal is developed directly from the impact of the
photons and charge storage is done in the readout rather than in
the detector material.
2) Cooling/Calibration - The FPA must be cooled and calibrated. The
CLU’s IR detectors are cooled using a Dewar flask and a
closed-cycle
Stirling engine. But in
the missile there is not sufficient room. So prior to launch, a
cooler mounted on the outside of the launch tube activates the
electrical systems in the missile and supplies cold gas from a
Joule-Thompson expander to the missile detector assembly while the
missile is still in the launch tube. When the missile is fired this
external connection is broken and coolant gas is supplied
internally by an onboard argon gas bottle. The gas is held in a
small bottle at high pressure and contains enough coolant for the
duration of the flight of approximately 19 seconds.
The seeker is calibrated using a chopper wheel. This device is a
fan of 6 blades: 5 black blades with very low IR emissivity and one
semi-reflective blade. These blades spin in front of the seeker
optics in a synchronized fashion such that the FPA is continually
provided with points of reference in addition to viewing the scene.
These reference points allow the FPA to reduce noise introduced by
response variations in the detector elements.
3) Stabilization - The platform on which the seeker is mounted must
be stabilized with respect to the motion of the missile body and
the seeker must be moved to stay aligned with the target. The
stabilization system must cope with rapid acceleration, up/down and
lateral movements. This is done by a
gimbal
system,
accelerometers, spinning mass
gyros (or
MEMS), and motors to drive changes in
position of the platform. The system is basically an
autopilot. Information from the gyros is fed to
the guidance electronics which drive a torque motor attached to the
seeker platform to keep the seeker aligned with the target. The
wires that connect the seeker with the rest of the missile have no
friction to keep the seeker platform balanced.
Tracker
The tracker is key to guidance/control for an eventual hit. The
signals from each of the 4,096 detector elements in the seeker are
passed to the FPA
readout
integrated circuits which reads then creates a
video frame that is sent to the tracker system
for processing. By comparing the individual frames the tracker
determines the need to correct so as to keep the missile on target.
The tracker must be able to determine which portion of the image
represents the target. The target is initially defined by the
gunner who places a configurable frame around it. The tracker then
uses
algorithms to compare that region of
the frame based on image, geometric, and movement data to the new
image frames being sent from the seeker, similar to
pattern recognition algorithms. At the
end of each frame the reference is updated. The tracker is able to
keep track of the target even though the seeker’s point of view can
change radically in the course of flight.
To guide the missile the tracker locates the target in the current
frame and compares this position with the aim point. If this
position is off center the tracker computes a correction and passes
it to the
guidance system which
makes the appropriate adjustments to the four moveable tail fins,
as well as six fixed wings at mid-body. This is an
autopilot. To guide the missile the system has
sensors that check that the fins are positioned as requested. If
not, the deviation is sent back to the controller for further
adjustment. This is a
closed-loop
controller.
There are three stages in the flight managed by the tracker: 1) an
initial phase just after launch; 2) a mid-flight phase that lasts
for most of the flight; and 3) a terminal phase in which the
tracker selects the sweet spot for the point of impact. With
guidance algorithms, the autopilot uses data from the seeker and
tracker to determine when to transition the missile from one phase
of flight to another. Depending on whether the missile is in top
attack or direct attack mode, the profile of the flight can change
significantly. The top attack mode requires the missile to climb
sharply after launch and cruise at high altitude then dive on the
top of the target (curveball). In direct attack mode (fastball),
the missile cruises at a lower altitude directly at target. The
exact flight path which takes into account the range to the target
is calculated by the guidance unit.
Launch Tube Assembly
Both men carry a disposable tube called the Launch Tube Assembly
which houses the missile and protects the missile from harsh
environments. The tube also has built in electronics and a locking
hinge system that makes attachment and detachment of the missile to
and from the Command Launch Unit a very quick and simple
process.
Command Launch Unit
The gunner carries a reusable Command Launch Unit (in addition to
the Launch Tube Assembly) more commonly referred to as a CLU
(pronounced "clue"). The CLU is the targeting component of the two
part system. The CLU has three views which are used to find,
target, and fire the missile. The CLU may also be used separately
from the missile as a portable thermal sight. Infantry are no
longer required to stay in constant contact with
armored personnel carriers and
tanks with thermal sights. This makes the
troops more flexible and able to perceive threats they would not
otherwise be able to detect. In 2006 a contract was awarded to
Toyon Research Corporation to begin development of an upgrade to
the CLU enabling the transmission of target image and
GPS location data to other units.
Day view
The first view is a 4× magnification day view. It is mainly used to
scan areas for light during night operation because light is not
visible in the thermal views. It is also used to scan during times
following the sunrise and sunset when the thermal image is hard to
focus due to the natural rapid heating and/or cooling of the
earth.
NFOV (Narrow Field of View)
The second view is the 4x magnification night view, and shows the
gunner a thermal representation of the area viewed. This is also
the primary view used due to its ability to detect
infrared radiation and
find both troops and vehicles otherwise too well hidden to detect.
The screen shows a "green scale" view which can be adjusted in both
contrast and brightness. The inside of the CLU is cooled by a small
refrigeration unit attached to the
sight. This greatly increases the sensitivity of the thermal
imaging capability since the temperature inside the sight is much
lower than that of the objects it detects. Due to the sensitivity
this causes, the gunner is able to "focus" the CLU to show a very
detailed image of the area being viewed by showing temperature
differences of only a few degrees. The gunner operates this view
with the use of two hand stations similar to the
control stick found in modern
cockpits. It is from this view that the
gunner focuses the image and determines the area that gives the
best heat signature on which to lock the missile.
Thermal view 2
Once the best target area is chosen the gunner presses one of the
two triggers and automatically is sent to the third view. The third
view is a 9x magnification thermal view. This process is similar to
the automatic zoom feature on most modern cameras. This view is
also available along with the previously mentioned views, all of
which may be accessed with press of a button. It is not as popular
however, because a high magnification view takes longer to scan a
wide area. This view allows the gunner to further aim the missile
and set the guidance system housed inside the actual missile.
During this view is when information is passed from the CLU,
through the connection electronics of the Launch Tube Assembly, and
into the missile's guidance system. If the gunner feels
uncomfortable with firing the missile, he can still cycle back to
the other views without having to fire the missile. When the gunner
is comfortable with the target picture he pulls the second trigger
and establishes a "lock”. The missile launches after a short
hesitation.
Training
A great familiarity of each control and swift operation needs to be
achieved before the unit can be deployed efficiently.
American troops are trained on the system at the Infantry School in
Fort
Benning, Georgia, for two weeks. The soldiers are taught
basic care and maintenance, operation and abilities, assembly and
disassembly, and the positions it can be fired from. Soldiers are
also taught to distinguish between a variety of vehicle types even
when only a rough outline is visible. The soldiers must accomplish
several timed drills with set standards before being qualified to
operate the system in both training and wartime situations. There
are also smaller training programs set up on most Army bases that
instruct soldiers on the proper use of the system. At these courses
the training program might be changed in small ways. This is most
commonly only minor requirements left out due to budget, the amount
of soldiers vs. simulation equipment, and available time and
resources. Both types of training courses have required proficiency
levels that must be met before the soldier can operate the system
in training exercises or wartime missions.
Advantages and disadvantages
Advantages
The portable system is easy to separate into main components and
easy to set up when needed. Compared to more cumbersome anti-tank
weapon systems, the difference is noticeable. For example, a
TOW requires a heavy tripod stand, a
bulky protective case for the thermal sight, a larger, longer
launch tube, and requires much more time to assemble and prepare.
The Javelin (although still very heavy) is lighter than the other
missiles and their necessary parts.
Although the CLU's thermal imaging may hinder aiming, its thermal
targeting allows the Javelin to be a
fire-and-forget system. This gives the firer
an opportunity to be out of sight and possibly moving to a new
angle of fire, or out of the area by the time the enemy realizes
they are under attack. This is much safer than using a
wire-guided system where the firer must stay
stationary to guide the missile into the target.
Another advantage is the Javelin's power at impact. The missile's
tandem shaped
charge warhead is made to penetrate
reactive armor. The Javelin was created with
the intent to be able to penetrate any tank armor and was tested on
the
M1 Abrams. With the
top attack mode it has an even greater ability to
destroy the tank because it can attack where most tanks are
weakest.
The
soft launch capability of the
Javelin allows it to have only a minimal
backblast area. In addition to reducing the
visible launch signature from the enemy, this enables the Javelin
to be fired from inside a wide variety of structures, which gives
the Javelin advantages in urban fighting over the widely used
AT4 (which has a very large backblast area,
although this is lessened in the AT4 CS). A large backblast area
would seriously injure personnel if fired from inside a small
structure, and may betray the location of the launch to enemy
observers.
The missile also has a greater range than the system it replaces,
the
M47 Dragon.
Disadvantages
The main drawback of the complete system (missile, tube, and CLU)
is its total weight. The system is designed to be portable by
infantry on foot and weighs more than the original specified weight
the Army called for.
Another drawback of the system is the reliance on a thermal view to
acquire targets. The thermal views are not able to operate until
the refrigeration component has cooled the system. The manufacturer
estimates 30 seconds until this is complete, but depending on the
ambient temperature, this
process may take much longer. Also, Javelins, and Javelin missiles
are rather expensive. A single Javelin unit costs about $125,000,
and a missile costs about $80,000.
Operators
- has decided to buy Javelin launchers for its military, 200 launchers and 840 missiles
being acquired.
- has bought three launchers and 12 missiles for its special
forces (intended for Afghanistan mission) .
- is
evaluating the Javelin system for the Indian
Army after the Israeli Spike anti-tank missile failed evaluations
in hot, desert
conditions.http://www.dnaindia.com/india/report_india-s-next-big-buy-is-a-missile-from-us_1295087
- : 24 launchers and 120 missiles
- : 100 launchers and 526 missiles. Delivery from 2006, in use
from 2009.
- In July 2008 Raytheon received a $115 million contract to
supply the Javelin to the United Arab Emirates and Oman.
- : 40 launchers and 360 missiles
- In 2002, Taiwan bought 360 Javelin missiles and 40 launcher
units for $39 million. The contract also included training devices,
logistics support, associated equipment and training.
- In 2008, the United States issued a congressional notification
for the sale of a further 20 launchers and 182 more missiles.
-
- In January 2003, the UK Ministry of Defence
announced that it had decided to procure Javelin for the Light
Forces Anti-Tank Guided Weapon System (LFATGWS) requirement. It
entered UK service in 2005 replacing the MILAN
and Swingfire systems.
-
- In 2003 the United States General Accounting Office (GAO)
reported that the Army had lost 36 Javelin command launch units in
Iraq totaling approximately $2.8M.[40151] The NY Times later reported supply
chain problems at military armories and warehouses in 2004 and
expressed concerns of weapons falling into enemy hands.[40152]
See also
References
- http://www.army-technology.com/projects/javelin/
- Army Technology - Javelin.
- [1]
-
http://www.globalsecurity.org/military/systems/munitions/javelin.htm
-
http://www.rttc.army.mil/whatwedo/primary_ser/insdev/jets.htm
- http://www.designation-systems.net/dusrm/m-148.html
- Bahrain Requests 160 Javelins & 60
CLUs
- Army Techonology - Javelin.
- A-report(in czech)
- Raytheon Press Release July 29, 2008
- Lockheed Martin press release
- MOD press release
- Javelin - Army Technology
External links