A COUNTERMEASURE SYSTEM
5
FIELD OF THE INVENTION
The invention relates to countermeasure systems for protecting a target from an
incoming threat, in particular, a countermeasure system configured for neutralizing such a
10 threat by illuminating it with an electromagnetic radiation in a suitable range of
wavelengths.
BACKGROUND OF THE INVENTION
It is well known in the field of defense to use countermeasure systems for
protecting a target from an incoming projectile. In particular, when the incoming
projectile is a guided missile, it is known to use countermeasure systems which are
configured for disrupting the navigational, guiding or telemetry facility of either the
missile or the sight guiding the same.
2 0 There are also known countermeasure systems comprising a variety of sensing
elements configured for discovering an approaching missile, and an illumination system
(NIR, UV, etc.) configured for neutralizing the missile by illuminating it with an
electromagnetic radiation in a suitable range of wavelengths.
There are further known countermeasure systems in which the illumination
25 system is mounted onto a platform which is capable of rotation and/or linear
displacement and is configured for directing the system's illumination beam towards the
threat, based on information from the sensing elements.
There are many hundreds of thousands of antitank guided missiles (ATGMs)
worldwide. A significant part of ATGMs are in the hands of terrorists, presenting danger
30 to civilians and law enforcement. ATGMs are relatively simple to use, they have high
hitting probability and high destruction power. ATGMs were used and can be used
against tanks, armored personnel carriers (APC), busses, trains, other vehicles. low flying
aircrafts, troops, posts, buildings, bridges, fuel stations, oil installations, airports, and
many other strategic objects and platforms. Protection against ATGMs requires very
complicated and expensive equipment, because there are several types (generations) of
5 different ATGMs operating according different guiding concepts.
There are attempts to protect objects using various hard kill layers including, a
reactive armor (a layer that explodes under impact of a missile and destroys it), using
exploding projectiles that intercept and destroy incoming missiles, and using
omnidirectional exploding cartridges, that destroy everything around the protected object,
10 including the incoming missile.
As a result of limited budgets and to avoid collateral damage, many objects
remain unprotected, and there are casualties each year from terrorists attacks by ATGMs.
A low cost solution for protection against ATGMs without any collateral damage is
required.
15 There are several generations of ATGMs. Most of the ATGMs are equipped with
a control unit. The control unit includes an optical sight and means to transfer control
signals to the missile. The optical sight includes at least one of the following channels: a
visual channel (operating in the visible part of spectrum), an infrared channel (operating
in the near infrared part of spectrum) and a thermal channel (operating in the far infrared
20 part of spectrum).
First generation of ATGMs is based on guidance by manual commands from an
operator. The operator sees the target and the missile, and guides the missile to the target
by issuing direction corrective commands (using a joystick). The commands are
transferred to the missile by a wire that connects the missile and the control unit. The
25 missile will deviate from the correct path, and it will be deflected, if operator will not
issue corrective commands during period of 1 second.
Second generation of ATGMs is based on automatic guidance of the missile. The
missile indicates its location via emission of IR radiation backward towards the sight /
control unit. The control unit detects the IR radiation and calculates deviation of the
30 missile from the optical axis of the sight. The control unit issues a corrective signal,
which is delivered to the missile. The optical sight shall be pointed on the target.
Interruption of this process will result in missile deflection.
Second plus generation of ATGMs is also based on automatic guidance of the
missile. The guidance method is so called laser beam riding. The sight / control unit emits
5 a laser beam parallel to optical axis of the sight. The laser beam is directed to the target,
when sight is pointed on the target. Laser beam sensor of the missile receive laser
radiation from the sight/control unit, that is the sensor is directed backward the missile.
The missile detects deviation of its position from the laser beam, and then it makes
corrections to stay in the center of laser beam. It shall be noted that this generation of
10 ATGMs can be fired from relatively long distances of more than 5 km, and that it takes a
long time for the missile to fly to the target. The missile will deviate from the path to
target, and it will be deflected, if operator will not keep sight on the target, or if the
missile will not be able to detect the laser beam for some time for any reason including
obscuration of the missile sensor, or if the missile sensor will be illuminated by a
15 countermeasure laser jamming radiation.
Third generation of ATGMs is equipped with optical sensors on a basis of "fire
and forget". The sensors can operate in visible, IR, NIR or FIR part of the spectrum. The
sensors "see" the target. Operator shall bring the field of view of sensor on the target and
lock the target to the missile. The missile will fly to the target automatically using signals
20 from the optical sensors. Interruption of normal operation of the optical sensor will result
in missile deflection.
SUMMARY OF THE INVENTION
According to one aspect of the subject matter of the present application, there is
25 provided a countermeasure system for protecting a target against a threat of a certain
type, said system comprising:
- a sensing system including at least a first sensor configured for detecting a threat
within a wide-angle sector and configured for producing a first directional signal
indicative of a first angular zone of location of said threat, and a second sensor
30 configured for detecting said threat within a narrow-angle sector narrower than said wide
angle sector, and configured for producing a second directional signal indicative of a
second angular zone of location of said threat, said second zone being narrower than said
first zone;
- an illumination source configured for emitting an illumination beam capable of
neutralizing a detected threat of said type;
5 - a control arrangement operative for receiving said first and said second
directional signal from said first and said second sensors, respectively, and for outputting
corresponding first and second tracking signals;
- a drive arrangement controllable by said control arrangement, and operative for
moving said second sensor in response to said first tracking signal so as orient said
10 second sensor to face towards said first zone; and
- beam directing means for directing said illumination beam from the illumination
source towards said second zone based on said second tracking signal.
The drive arrangement can be in the form of a gimbal carrying said second sensor
and, possibly, said beam directing means (with or without the illumination source) and
15 constituting at least a part of said drive arrangement for the second sensor and, possibly,
at least a part of said beam directing means. The arrangement can be such that a central
axis of the second sensor and an optical axis of said illumination beam along which it is
emitted from the system (i.e. an operative direction of the illumination beam), are
oriented towards one area remote from said countermeasure system, the gimbal being
20 rotatable about at least one rotary axis thereof so as to ensure that said area coincides with
said second zone.
The gimbal can be a two axis gimbal configured for directing of optical head. It is
a mechanical device that provides angles of rotation of 360 degrees in azimuth and 10
degrees to 90 degrees in elevation. It can be powerful enough to rotate the optical head
25 from initial orientation to the desired orientation within less than 5 seconds. In particular,
the gimbal can include two motors and two gears, two position sensors (for example
encoders), and two mechanical interfaces for attachment of the gimbal to the platform
and for attachment of the optical head to the gimbal.
Under the above arrangement, once the second sensor is directed towards the first
30 zone based on said first tracking signal, the operative direction of the illumination beam
is already facing in the proper direction for affecting the threat. Thus, only minor
corrections, based on said second tracking signal, are required in order to bring the
operative direction of the illumination source into exact positioning for affecting the
threat.
Alternatively, the illumination source and/or the beam directing means can be
5 movable relative to the gimbal to bring the illumination beam to the second zone, when
required. Under one example, the illumination source and/or the beam directing means
can be movably mounted onto the gimbal and be configured to be displaced/rotated with
respect to the gimbal by the drive arrangement.
The beam directing means of the countermeasure system can comprise a beam
10 orientation device configured for directional deflection of the beam produced by the
illumination source towards said threat. Specifically, the arrangement can be such that,
regardless of where the illumination source is located, its illumination beam always
impinges on the beam orientation device. The device can then be
displaced/rotated/manipulated based on said second tracking signal so that the direction
15 beam impinging thereon is deflected towards the second zone and the incoming threat.
The beam orientation device can include a mirror arrangement configured for
receiving the directional beam and deflecting it, or it can be a prism arrangement under
which the directional beam passes through at least one prism thereby being deflected in
the proper direction.
2 0 In particular, the deflector can be a beam steering device which comprises a
mirror or a pair of mirrors, tilted in two orthogonal directions. Various engines /actuators
can be used to tilt the mirrors, for example piezo-electical motors or galvanometric
motors, or voice coil motors. Refractive deflectors can include a pair of optical wedges
(Risley prisms). The wedges shall be rotated around optical axis to change deflection
25 direction. In general, reflective deflectors are faster, and refractive deflectors are more
accurate.
All the components of the countermeasure system or at least its gimbal can be
mountable on a base platform (for example, a platform configured for carrying and
displacing the system such as a vehicle). The first sensor can be either mountable on the
30 platform separately from the gimbal or mounted on the gimbal, or mountable at a location
external to the remainder of the countermeasure system and the platform.
The first sensor can be configured and/or movable so that the wide-angle sector
has angular extension X1 in the range 0 < X1 I 360°, and the first angular zone
established by it can have an angular extension XZ1 up to 0.5X1, more particularly, up to
0.25X1, and still more particularly, up to 0.1X1. To achieve a desired angular extension
5 X of the first sensor's wide-angle sector, the first sensor can be rotatable about an axis
that can be parallel to or coincide with the rotary axis of the gimbal, thereby allowing the
first sensor's rotary scanning of the surrounding space.
The first sensor can provide a field of view of 360 degrees in azimuth and about
I0 degrees to 90 degrees in elevation.
10 The second sensor can be selected so that its narrow angle sector has an angular
extension X2 that is at least not smaller than that of the first zone, i.e. X2 2 XZ1. The
relation between X2 and XZI can be, for example, X2 2 I.lXZ1, more particularly X2 2
1.4XZ I, even more particularly X2 2 1.8XZ1 and still more particularly X2 2 2XZ 1.
The first zone and the narrow sector can have a respective first and second central
15 axis, which divides them into two equal halves, so that when the first sensor determines
within its field of view the first zone, in which the threat has been detected, moving the
second sensor based on the first tracking signal such as to align the central axis of the
narrow sector thereof with that of the first zone determined by the first sensor, will
inevitably result in the second sensor's narrow sector including the threat therein. In
20 other words, the above arrangement inevitably results in that, under any circumstance, the
threat falls within the field of view of said second sensor.
The system can further include shock absorbers or dampeners configured for
protecting the system, when mounted on the base platform, from mechanical and other
damage during displacement of the platform. In particular, the arrangement can be such
25 that the shock absorbers/dampeners have an angular degree of freedom about the axis of
rotation of the gimbal chosen not to be greater than at least one of the following:
the angular extension of said first angular zone; and
the FOV of the second sensor.
The first sensor can be a wide warning receiver of any known type, e.g. a missile
30 warning system (MWSW), and it can include a laser detector (i.e. be a wide laser
warning receiver - WLWRW), a radar or an electro-optic system EOS. Under various
design embodiments of the MWSW, the EOS can include at least one of a bolometric
sensor, a UV sensor, a VIS sensor, a NIR sensor, a TV camera, an IR senor, a SWIR
sensor, a position sensitive device, or a matrix of photodiodes.
The detection range of the radarIEO can be up to 7 km. It is preferably up to 2 km
5 to reduce cost. Detection range of the bolometric sensor can be up to 7 km. It is
preferably up to 2 km to reduce cost.
The above described infra-red ranges should be understood as follows:
Near infrared light source can operate in the spectral range of 700 nm to 1100 nm.
Preferred color of near infrared light source is in the range of 800 nm to 1000 nm, where
10 sensitivity of near infrared sensors is high. Light sources in the range of 1500nm-1700
nm have advantages of eye safety and of covert operation;
Far infrared light source can operate in the spectral range of 2 um to 20 um.
Preferred color of far infrared light source is in the transparency windows of the
atmosphere, at wavelengths about 2000 nm - 5000 nm and 8000 nm - 12000 nm. For
15 example, far infrared source can be a carbon dioxide laser or a quantum cascade laser
operating in the range of 10000 nm - 1 I000 nm.
Light sources can be various gas lasers, electrically pumped semiconductor lasers,
quantum cascade lasers, solid state lasers, optically pumped semiconductor lasers with
frequency doubling, fiber lasers, optical parametric oscillators, light emitting diodes,
20 lamps.
The second sensor can be a narrow warning receiver of any known type, and it
can also include a laser detector (i.e. be a narrow laser warning receiver - NLWRN), a
radar or an electro-optic system EOS. Under various design embodiments of the second
sensor, the EOS can include at least one of a bolometric sensor, a UV sensor, a VIS
25 sensor, a NIR sensor, a TV camera, an IR senor, a SWIR sensor, a position sensitive
device, or a matrix of photodiodes.
In accordance with a specific example. the narrow field of view sensor for
detection of laser beam illumination can be located within a combined device using the
same or common optics, detector and electronics.
3 0
In the above latter alternative, the illumination source of the countermeasure
system can include a jammer device configured for producing a jammer signal which is
effective for neutralizing specific types of threats.
It is appreciated that the countermeasure system is not limited to a single first
5 sensor or to a single second sensor and can comprise a plurality of each of the sensors.
For example, the system can comprise four first sensors, each sensor providing field of
view of more than 90 degrees in azimuth. The system can also comprise several second
sensors as well.
The illumination source can be configured to include a plurality of illumination
10 emitting devices, each of which can be, for example, any one or more of the following:
an NIR illuminator;
an VIS illuminator;
an FIR illuminator;
a matrix of photodiodes;
a gas laser;
a solid state laser;
a semiconductor laser;
a fiber laser;
a fiber coupled laser;
a quantum cascade laser;
an optically pumped semiconductor laser;
an optical parametric oscillator;
a second harmonic generator;
a frequency doubler;
a dye laser;
a Raman laser;
a light emitting diode; and
a lamp
Furthermore, the illumination source can be configured to include devices for
30 emitting illumination at different parts of optical spectrum, e.g. visible, near infrared and
far infrared part of the optical spectrum. The illumination source can be further
configured so that all these devices can be operated simultaneously for emitting radiation
in several parts of the spectrum at the same time.
Regardless of which arrangement is used for appropriately positioning the
directional beam of the illumination source (via deflection or displacement together or
5 separately from the gimbal), the directional beam can be configured for being directed to
at least one of the following:
- the threat itself; and
- a sight of the threat.
In particular, when the threat is a laser beam rider and the sight provides the laser
10 beam by which the threat is guided, the directional beam can be effective for disrupting
the sight's operation, thereby preventing proper guiding of the threat and effectively
neutralizing it.
In connection to the above, the following should also be considered:
Each light source can be configured to provide a sufficient radiant intensity to
15 create a sufficient irradiance to saturate a corresponding channel of the sight. The
required output power of light source can be proportional to the second order of output
divergence of light source. Required output power increases very fast with increase of
divergence and cost of light source increases as well. Small divergence allows keeping
the output power and the cost of light low. However, since it is difficult to illuminate the
20 sight with narrow light beam, and it is easy to miss the sight, the present countermeasure
system allows knowing the direction to the sight with high accuracy and deflecting the
light beam with high accuracy. Accurate direction to the sight is measured with narrow
field of view laser beam receiver and with narrow field of view sensor for detection of
retro reflections. Accurate direction to the missile is measured with narrow field of view
25 thermal camera or FIR or UV sensors. Accurate laser beam deflection is provided with
the 2 axis deflector or with precise circuits and mechanics of the gimbal.
Among light sources, the NIR source is least expensive. Divergence of this source
is set large enough to illuminate the sight using low accuracy directions measured by
panoramic sensors and using low accuracy aiming of the two axis gimbal. That brings the
30 sight into field of view of narrow field of view sensors. They measure direction to the
sight more accurately, allowing better pointing of light sources on the sight.
Correspondingly, divergence of visible and far infrared light sources is reduced, and cost
of the sources is relatively low. This provides relatively low cost of the countermeasure
system.
The NIR source can include a narrow laser beam. The narrow laser beam can be
5 used for illumination in direction of the missile.
According to another aspect of the subject matter of the present application, there
is provided a method for protecting a target against a threat by affecting the threat by an
illumination beam, the method including the steps of:
detecting, using a first sensor, a wide zone indicative of an approximate location
10 of said threat;
outputting to a control arrangement a first directional signal indicative of said
wide zone;
providing, by the control arrangement, a first tracking signal to a drive
arrangement corresponding to said first directional signal;
15 directing a second sensor towards said wide zone based on said first tracking
signal;
detecting, using said second sensor, a narrow zone indicative of more accurate
location of said threat, said narrow zone being narrower than said wide zone;
outputting to the control arrangement a second directional signal corresponding to
20 said second zone;
providing, by the control arrangement, a second tracking signal to the drive
arrangement corresponding to said second directional signal; and
directing, based on said second tracking signal, said illumination beam towards
said second zone to affect the threat.
25 It is noted that in the case of step (d), if central axis of the second sensor is aligned
with optical axis of the illumination beam, performing step (d) results in bringing said
illumination source in close proximity with direction towards said threat.
Regarding the arrangement of the illumination source and/or beam directing
means previously described with respect to the countermeasure system, step (h) of the
30 method can be performed by one of the following:
(hl) if the illumination source is fixedly mounted onto said gimbal - revolving the
gimbal about at least one of its axes;
(h2) if the illumination source is movable with respect to the gimbal -
movinglrevolving the illumination source with respect to the gimbal; and
5 (h3) if the countermeasure comprises a beam orientation device -
movingldisplacing the device.
The countermeasure system can also include a feature under which, if the
countermeasure detects that it is unsuccessful in jamminglstoppingldisrupting the threat,
it can be configured for alerting the target to change its position with respect to its
10 original position, thereby causing the threat to miss it. Alternatively, for moving targets,
the system can alert the target to stoplnot continue in its original route (direction of
speed).
It is appreciated that the above countermeasure system can be employed not only
in stationary structures (houses, buildings, bases etc) but also in mobile units such as land
15 vehicles, marine vessels, aircrafts etc.
It is also appreciated that the countermeasure system provides protection against
the above projectiles at a predetermined range. Hence, for large structureslunits, it may be
required to provide several such countermeasure systems which are spread across the area
of the structurelunit. Alternatively, an arrangement can be provided for displacing at least
20 one countermeasure system along the structurelunit in order to provide proper coverage.
As a particular example, while the countermeasure system can singly be used to
successfully protect a vehicle (e.g. ATV), for marine vessels such as a ship, several such
countermeasure systems can be used.
25 BRIEF DESCRIPTION OF THE DRAWINGS
In order to understand the subject matter of the present application and to see how it
can be carried out in practice, at least one embodiment will now be described, by way of
non-limiting example only, with reference to the accompanying drawings, in which:
Fig. 1 is a schematic top view of an interposition of the countermeasure system
30 according to prior art, including a sight, a threat commanded by the sight and an object to
be protected from the threat by the system, shown during a first stage of operation of the
system;
Fig. 2A is a schematic top view of the interposition shown in Fig. 1A during a second
stage of operation of the countermeasure system;
5 Fig. 2B is a schematic block diagram representation of a sensor arrangement used in
the system shown in Fig. 2A;
Fig. 2C is a schematic top view of the interposition shown in Fig. IA, when dealing
with a threat of a different type, shown during a first stage of operation thereof;
Fig. 2D is a schematic top view of the interposition shown in Fig. 1C during a second
10 stage of operation of the countermeasure system;
Figs. 3A and 3B are schematic interpositions of the object to be protected and of the
sight when the latter is exposed to the directed illumination source of the countermeasure
system during two respective stages of operation thereof;
Fig. 4A is a schematic block diagram of the countermeasure system of Fig. 1A;
15 Fig. 4B is a schematic illustration of a driving arrangement of the gimbal shown in
Fig. 4A;
Fig. 5A is a schematic isometric view of the countermeasure system shown in Fig.
3A;
Fig. 5B is a schematic isometric view of an optical head used in the countermeasure
20 system shown in Fig. 3B; and
Fig. 6 is a schematic block diagram of the operation of the countermeasure system
shown in Figs. 1 A to 3C.
DETAILED DESCRIPTION OF THE DRAWINGS
Attention is first drawn to Fig. 1A which represents a countermeasure system
according to the prior art. It comprises a gimbal and a wide Laser Warning Receiver
(LWRw). The LWRw has a field of view of 360" and is configured for detecting an
incoming missile and to disable the missile using appropriate allumination.
5 Attention is then drawn to Figs. 2A and 2B in which a countermeasure system
according to the subject matter of the present application is shown, generally being
designated as 1, and comprising:
- an operational station including:
o a two-axes gimbal 10;
o a illumination source system 20
o a control arrangement 30 (shown in Fig. 4B); and
o a drive arrangement 40 (shown in Fig. 4B);
- a first, wide field of view sensor arrangement 50 having a wide field of view; and
- a second, narrow field of view sensor arrangement 60 having a narrow field of
15 view.
In particular, the first sensor 50 is configured for detecting a threat within a wideangle
sector and configured for producing a first directional signal indicative of a first
angular zone of location of the threat, and the second sensor is configured for detecting
the threat within a narrow-angle sector narrower than the wide angle sector, and
20 configured for producing a second directional signal indicative of a second angular zone
of location of the threat, the second zone being narrower than the first zone;
The illumination source 20 is configured for emitting an illumination beam in
various ranges of the electromagnetic spectrum capable of neutralizing an incoming
threat of a given type;
2 5 The control arrangement 30 is operative for receiving the first and the second
directional signal from the first and the second sensors 50, 60, respectively, and for
outputting corresponding first and second tracking signals to the drive arrangement 40.
The drive arrangement 40, being controllable by the control arrangement, is operative
for moving the second sensor 60 in response to the first tracking signal so as orient the
30 second sensor 60 to face towards the first zone.
The system I can also comprise beam directing means for directing the illumination
beam from the illumination source towards the second zone based on the second tracking
signal.
The gimbal 10 is configured for carrying the second sensor 60 and, possibly, the
5 beam directing means (with or without the illumination source) and constituting at least a
part of the drive arrangement for the second sensor and, possibly, at least a part of the
beam directing means. The arrangement can be such that a central axis of the second
sensor and an optical axis of the illumination beam along which it is emitted from the
system (i.e. an operative direction of the illumination beam), are oriented towards one
10 area remote from the countermeasure system, the gimbal being rotatable about at least
one rotary axis thereof so as to ensure that the area coincides with the second zone.
It is appreciated that the first sensor 50 can cover a wide sector of 360" angle and at a
range of R while the second sensor 60 can cover a second, narrower sector of about 3-5"
at a range of r. The ranges R and r are measured with respect to a circle at the center of
15 which the operational station 10 of the system is positioned. It is appreciated that the cost
of a sensor is affected, inter alia, by the range thereof and by the accuracy thereof (i.e. its
indicated detection zone). Therefore, the above arrangement allows utilizing a
combination of sensors where one is of lower accuracy but higher range and vise versa.
Under the above arrangement, once the second sensor is directed towards the first
20 zone based on the first tracking signal, the operative direction of the illumination beam is
already facing in the proper direction for affecting the threat. Thus, only minor
corrections, based on the second tracking signal, are required in order to bring the
operative direction of the illu~nination source into exact positioning for affecting the
threat.
2 5 Alternatively, the illumination source and/or the beam directing means can be
movable relative to the gimbal to bring the illumination beam to the second zone, when
required. Under one example, the illumination source and/or the beam directing means
can be movably mounted onto the gimbal and be configured to be displaced/rotated with
respect to the gimbal by the drive arrangement.
With further reference to Figs. 2A and 2B, a threat Th is shown being launched from
a sight S and incoming towards a target Ta (not shown) located in the vicinity of the
countermeasure system 1.
In construction, the first sensor 50, due to its wide field of view, can be located at
5 various positions at the vicinity of the target Ta. To the contrary, the second sensor 60 is
mounted onto the gimbal 10 and is configured for revolving therewith.
The first sensor can be configured and/or movable so that the wide-angle sector
has angular extension XI in the range 0 < XI I 360°, and the first angular zone established
by it can have an angular extension Xzl up to 0.5XI, more particularly, up to 0.25XI, and
10 still more particularly, up to O.lXI. To achieve a desired angular extension X of the first
sensor's wide-angle sector, the first sensor 50 can be rotatable about an axis that can be
parallel to or coincide with the rotary axis of the gimbal 10, thereby allowing the first
sensor's rotary scanning of the surrounding space.
The second sensor 60 can be selected so that its narrow angle sector has an
15 angular extension X2 that is at least not smaller than that of the first zone, i.e. X2 2 XZI.
The relation between X2 and XZI can be, for example, X2 2 l.lXzl, more particularly X2
2 1 .4XZ1e, ven more particularly X2 2 1 .8XzI and still more particularly X2 2 2XZ1.
The first zone and the narrow sector can have a respective first and second central
axis, which divides them into two equal halves, so that when the first sensor determines
20 within its field of view the first zone, in which the threat has been detected, moving the
second sensor based on the first tracking signal such as to align the central axis of the
narrow sector thereof with that of the first zone determined by the first sensor, will
inevitably result in the second sensor's narrow sector including the threat therein. In
other words, the above arrangement inevitably results in that, under any circumstance, the
25 threat falls within the field of view of the second sensor.
With reference to the above, as the countermeasure system does not initially know
which threat it will be faced with, each of the sensor arrangements 50, 60 is equipped
with multiple sensors for covering the majority of threats which are expected against the
protected object.
30 In particular, the first sensor unit comprises a wide laser warning receiver (LWRw) 52
and a wide missile warning receiver (MWSw) 54, the former being suitable for detecting
Gen 2+ missiles while the latter is suitable for detection of Gen 1, Gen 2 and Gen 3
missiles. With particular reference to Fig. 2B, the second sensor unit 60 is also equipped
with various sensors, specifically, a narrow laser warning receiver (LWRN) 62 and an RD
sensor 64, a narrow Radar 65, a thermal camera 66 and/or other narrow EOS 67.
5 The illumination source system 20 is also equipped with a plurality of illumination
sources in a plurality of illurnination spectrum ranges, configured for illumination and
neutralization of various types of threats.
The operation of the countermeasure system 1 will now be described with specific
reference to Fig. 2B:
10 When the LWRw 52 detects an incoming threat (in the present case laser beam rider
rnissile controlled by a sight S), it outputs a first directional signal to the control
arrangement 30 which, in turn, generates a first tracking signal configured for instructing
the drive arrangement to rotate the gimbal 10 in the general direction of the threat Th.
As a result of rotation of the gimbal 10, the second sensor 60 is now generally aligned
15 with the threat Th, and can detect its position in a more accurate manner. It is noted that
one of the advantages of such an arrangement lies in the fact that it eliminates the need to
use the second sensor 60 as the single sensor (instead of the first, wide field of view
sensor 50). while providing essentially the same accuracy in detecting an incoming threat.
According to a specific example of the countermeasure system S, the illumination
20 source 20 is also mounted onto the gimbal 10, and the direction of its beam is aligned
with the direction of the second sensor 60. In this manner, when the second sensor 60 is
aligned with the threat Th based on the first tracking signal, the beam of the illumination
source 20 is also aligned with the threat, requiring only very minor adjustments for
reaching maximal accuracy.
25 Furthermore, the arrangement can be such that the first, wide field of view sensor 50
has an error margin of about 3-4", i.e. an error margin which is smaller than the view
angle of the second sensor 60 (about 3-5"). As a result, when the first sensor 50 detects
the threat Th and the gimbal 10 is revolved towards it, the second sensor 60 will
inevitably be directed such that its detection angle encompasses the threat Th.
30 Thereafter, upon detection by the LWRN 62 of the second sensor unit 60, the latter
outputs a second directional signal to the control arrangement 40 which, in turn, generates
a second tracking signal configured for instructing the drive arrangement to rotatebly
adjust the a directional beam of the illumination source 20 towards the updated direction
of the threat Th.
Once the gimbal 10 and the illumination source are properly oriented with respect to
5 the incoming threat based on the second tracking signal, the illumination source begins
illuminating the threat by VIS and FIR radiation. As far as the sight of the threat is
located behind the missile along the direction from the target to the missile, the sight is
also illuminated by VIS and FIR radiation. As a result of the above, the sight operation is
disturbed; the missile is neutralized and misses the target Ta.
10 Turning now to Figs. 2C and 2D, the operation of the system will now be explained in
the event that a Gen 1, 2 or 3 missiles is directed at the object to be protected.
When the MWSw 54 detects an incoming threat it outputs a first directional signal to
the control arrangement 30 which, in turn, generates a first tracking signal configured for
instructing the drive arrangement to rotate the gimbal 10 in the general direction of the
15 threat Th.
Thereafter, the threat Th and its launch station (sight) are illuminated by a jammer
signal based on Near lnfra Red (NIR) radiation.
It is appreciated that in both cases, once the illumination source is turned on, it emits
intense light towards the sight, saturating vision of the operator. The effect is similar to
20 saturation of vision by bright sun light. The operator cannot see the target using visible
channel of the sight. The NIR light source saturate TV channel, if it exists in the sight. No
image of the target is available on the TV channel screen. The FIR source saturates
thermal channel. No thermal image of the target is available on the thermal channel
screen. The operator cannot see the target using all available to him equipment, and he
25 misses the target. It is possible that the missile will be deflected at a long distance, even
before entering into detection range of MWRw. The laser jammer emits NIR radiation in
the same direction. As a result, the missile is deflected.
A similar operation is performed when no LWRw detection occurs, but MWRw
detects a missile. The optical head is pointed towards the missile, and a signal from
30 LWRn is verified. If no detection by LWRn occurs, that indicates that the missile is not a
laser beam rider. All light sources are then switched on. The missile is illuminated by
powerful light, and the area behind the missile is illuminated as well. The sight is situated
behind the missile, so it is also illuminated by the light sources. The visible channel, the
TV channel and the thermal channel of the sight becomes saturated, and the operator
cannot keep aiming the sight on the target, thus missing it.
5 When both the missile and the sight are detected, the illumination source 10 is
accurately aligned and directed towards the threat Th and towards the sight in a sequence,
illuminating one after another. When multiple threats are detected, the illumination
source 10 is accurately aligned and directed towards each threat Th and towards each
sight in a sequence.
10 The term 'in sequence' refers to applying the method of detection and countermeasure
in alternating order to one threat and then to the other. In case a sight and a threat are
concerned, countermeasure will affect the position of the threat, thereby indicating which
is the threat and which is the sight.
The time frame of operation is approx. 0.5 sec. for operating the countermeasure
15 means while it can take approx. 5-15 sec. for the threat to reach the target from the
moment of detection - depending on the detection system.
Turning now to Figs. 3A and 3B, the system 1 is shown during operation when
illuminating a sight of a threat. In Fig. 3B, as opposed to Fig. 3A, directed laser beams of
visible light (VIS) and far infra-red (FIR) are used for the retro detection reflected off the
20 sight. In particular, in Fig. 3B the beams are deflected or scanned over and extended
angle to ensure illumination ofthe sight.
Attention is now drawn to Figw. 4A and 4B, in which a schematic representation of
the system 1 is shown. In particular, it is observed that the base of the system 1 is
constituted by a gimbal 10 positioned on a leg 12.
25 At the base of the gimbal 10 there is located the wide sensor 50, whereas the optical
head 20 of the system 1 comprises both the second narrow sensors 60 (including narrow
LWRn 62 and narrow Radar 65, a narrow thermal camera 66 or other narrow electro
optical sensors 67) as well as the illumination sources NIR 22, VIS 24 and FIR 26.
It is appreciated that in the configuration shown in Figs. 4A and 4B, the entire
30 illumination system 20 as well as the narrow sensor 60 is configured for being revolved
by the gimbal 10, while the wide sensor 50 can remain stationary. Specifically, the optical
head 20 is configured for being fitted to a gimbal platform 19 via frame 29 (shown in Fig.
5B), thereby allowing rotation of the optical head 20 in the direction mentioned above.
A more specific illustration is provided in Figs. 5A and 5B, in which the construction
of the system 1 is shown. In particular, it is observed that the system I is configured for
5 attachment to a station or target via a base platform attachment 14, located at the base of
the leg 12.
It is noted that since the system 1 is mounted on a base platform, it can further
include shock absorbers or dampeners configured for protecting the system, when
mounted on the base platform, from mechanical and other damage during displacement of
10 the platform. In particular, the arrangement can be such that the shock
absorbers/dampeners have an angular degree of freedom about the axis of rotation of the
gimbal chosen not to be greater than at least one of the following:
- the angular extension of the first angular zone; and
- the FOV of the second sensor.
15 Turning now to Fig. 5B, it is observed that the optical head 20 is constructed such that
the second sensor 60 including retro detector 64 are positioned on one side of the optical
head 20 together with the NIR and VIS illumination sources, while the FIR illumination
source is located on an opposite side of the optical head 20, but still facing the same
direction (towards an intended threat).
20 It is noted that separation of illumination sources 22, 24, 26 prevents overlap of
output light beams at short distances. It improves laser safety via reduction of possibility
of simultaneous exposure of humans with multiple illumination sources. Taking into
account that the Geneva Convention prohibits permanent damage to an enemy eyesight,
separation of the light source also allows convenient conforming to the Geneva
25 convention.
Another reason for placement of illumination sources 22, 24, 26 and second sensor 60
at two opposite sides of optical head 20 is to provide a place for attachment of gimbal 10
at the center of optical head. This way the optical head can be balanced with respect to
center of gimbal, thus providing for fast and accurate positioning of the optical head.
30 Finally, attention is drawn to Fig. 4, in which a block diagram of the operation of the
system I is shown. Specifically, the system I is, at least at first, has no way of
determining which sort of threat is launched towards it. Therefore, all sources of
illumination are used, until the system detects a certain effect on the incoming threat.
It is also appreciated that if not change in the progression of the threat is detected, the
system 1 is configured for indicating to an operator that the incoming threat is one which
the system is, at least partially, unable to handle (for various reasons), thereby alerting the
operator for performing one of the following:
- if the target is at rest - to change its position with respect to the threat; and
- if the target is in motion - to perform at least one of the following:
o change its course of motion; and
o stop moving.
CLAIMS:
1. A countermeasure system for protecting a target against a threat of a certain type,
said system comprising:
5 - a sensing system including at least a first sensor configured for detecting a threat
within a wide-angle sector and configured for producing a first directional signal
indicative of a first angular zone of location of said threat, and a second sensor
configured for detecting said threat within a narrow-angle sector narrower than said wide
angle sector, and configured for producing a second directional signal indicative of a
10 second angular zone of location of said threat, said second zone being narrower than said
first zone;
- an illumination source configured for emitting an illumination beam capable of
neutralizing a threat of said type;
- a control arrangement operative for receiving said first and said second
15 directional signal from said first and said second sensors, respectively, and for outputting
corresponding first and second tracking signals;
- a drive arrangement controllable by said control arrangement, and operative for
moving said second sensor in response to said first tracking signal so as orient said
second sensor to face towards said first zone, and
20 - beam directing means for directing said illumination beam from the illumination
source towards said second zone based on said second tracking signal.
2. A countermeasure system according to Claim 1, wherein the system further
comprises a gimbal carrying said second sensor.
3. A countermeasure system according to Claim 1 or 2, wherein said system further
25 cornprises said beam directing means and constituting at least a part of said drive
arrangement for at least one of the following:
- the second sensor; and
- at least a part of said beam directing means.
4. A countermeasure system according to Claim 1, 2 or 3, wherein the arrangement
is such that a central axis of the second sensor and an optical axis of said illumination
5 beam along which it is emitted from the system are oriented towards one area remote
from said countermeasure system, the gimbal being rotatable about at least one rotary
axis thereof so as to ensure that said area coincides with said second zone.
5. A countermeasure system according to Claim 4, wherein the arrangement is such
that once the second sensor is directed towards the first zone based on said first tracking
10 signal, the operative direction of the illumination beam is already facing in the proper
direction for affecting the threat.
6. A countermeasure system according to Claim 2 or 3, wherein at least one of the
illumination source and the beam directing means is movable relative to the gimbal to
bring the illumination beam to the second zone, when required.
15 7. A countermeasure system according to Claim 6, wherein the illumination source
and/or the beam directing means are movably mounted onto the gimbal and are
configured for being displaced/rotated with respect to the gimbal by the drive
arrangement.
8. A countermeasure system according to any one of the preceding Claims, wherein
20 the beam directing means of the countermeasure system comprise at least a beam
orientation device configured for directional deflection of the beam produced by the
illumination source towards said threat.
9. A countermeasure system according to Claim 8, wherein the arrangement is such
that, regardless of where the illumination source is located, its illumination beam always
25 impinges on the beam orientation device.
10. A countermeasure system according to Claim 8 or 9, wherein the device is
configured for being placed/rotated/manipulated based on said second tracking signal so
that the direction beam impinging thereon is deflected towards the second zone and the
incoming threat.
11. A countermeasure system according to Claim 8, wherein the beam orientation
device includes at least one of the following:
5 - a mirror arrangement configured for receiving the directional beam and deflecting
it; and
- a prism arrangement under which the directional beam passes through at least one
prism thereby being deflected in the proper direction.
12. A countermeasure system according to any one of the preceding claims, wherein
10 all the components of the countermeasure system are mountable on a base platform.
13. A countermeasure system according to Claim 12, when dependent on Claim 2,
wherein the first sensor is mounted on either of the following:
- a platform separately from the gimbal;
- on the gimbal; and
15 - a location external to the remainder of the countermeasure system and the
platform.
14. A countermeasure system according to any one of the preceding claims, the first
sensor is configured and/or movable so that the wide-angle sector thereof has angular
extension XI in the range 0 < XI 2360".
20 15. A countermeasure system according to Claim 14, wherein the first angular zone
established by the first sensor has an angular extension Xzl up to 0.5XI, more
particularly, up to 0.25X1, more particularly, up to O.lXI, and still more particularly, up
to 0.02XI.
16. A countermeasure system according to Claim 14 or 15, wherein said first sensor is
configured for being rotatable about an axis parallel to or coinciding with the rotary axis
of a gimbal, thereby allowing the first sensor's rotary scanning of the surrounding space.
17. A countermeasure system according to Claim 14, 15 or 16, wherein the second
5 sensor is selected so that its narrow angle sector has an angular extension X2 that is at
least not smaller than that ofthe first zone, i.e. X22 XZ1.
18. A countermeasure system according to Claim 17, wherein the relation between X2
and Xzl is X2 2 1 . IXzl, more particularly X2 2 1.4Xzl, even more particularly X2 2
1 .8Xz1 and still more particularly X2 2 2XZ1.
10 19. A countermeasure system according to any one of the preceding claims, wherein
the first zone and the narrow sector have a respective first and second central axis, which
divides them into two equal halves.
20. A countermeasure system according to Claim 19, wherein when the first sensor
determines within its field of view the first zone, in which the threat has been detected,
15 moving the second sensor based on the first tracking signal such as to align the central
axis of the narrow sector thereof with that of the first zone determined by the first sensor,
inevitably results in the second sensor's narrow sector including the threat therein.
21. A countermeasure system according to any one of the preceding claims, wherein
the system further includes shock absorbers or dampeners configured for protecting the
20 system, when mounted on the base platform, from mechanical and other damage during
displacement of the platform.
22. A countermeasure system according to Claim 2 1, wherein the arrangement is such
that the shock absorbers or dampeners have an angular degree of freedom about the axis
of rotation of a gimbal chosen not to be greater than at least one of the following:
25 - the angular extension of said first angular zone; and
- the angular extension of the narrow angle sector of said second sensor.
23. A countermeasure system according to any one of the preceding claims, wherein
said first sensor is a wide warning receiver of at least one of the following:
- a wide laser warning receiver (LWRw);
- a wide missile warning system (MWSw).
5 24. A countermeasure system according to Claim 23, wherein said MWSw is a radar
or an electrooptic system EOS.
25. A countermeasure system according to Claim 24, wherein the EOS includes at
least one of the following: a bolometric sensor, a UV sensor, a VIS sensor, a NIR sensor,
a TV camera, an IR senor, a SWIR sensor, a position sensitive device, or a matrix of
10 photodiodes.
26. A countermeasure system according to any one of the preceding claims, wherein
said second sensor is at least one of the following:
- a narrow laser warning receiver - NLWRN; and
- a narrow radar,
- a narrow EOS including at least one of the following: a bolometric sensor, a UV
sensor, a VIS sensor, a NIR sensor, a TV camera, an TR senor, a SWIR sensor, a position
sensitive device, or a matrix of photodiodes, .
27. A countermeasure system according to any one of the preceding claims, wherein
the illumination source of the countermeasure system includes a jammer device
20 configured for producing a jammer signal which is effective for neutralizing specific
types of threats.
28. A countermeasure system according to any one of the preceding claims, wherein
said system comprises a plurality of at least one of said first sensor and said second
sensor.
29. A countermeasure system according to any one of the preceding claims, wherein
the illumination source is configured to include a plurality of illumination emitting
devices, each of which can be any one or more of the following: an NIR illuminator, an
VIS illuminator, an FIR illuminator, a gas laser, a solid state laser, a semiconductor laser,
5 a fiber laser, a fiber coupled laser, a quantum cascade laser, an optically pumped
semiconductor laser, an optical parametric oscillator, a second harmonic generator, a
frequency doubler, a dye laser, a Raman laser, a illumination emitting diode and a lamp.
30. A countermeasure system according to any one of the preceding claims, wherein
said illumination source is configured to include devices for emitting illumination at
10 visible, near infrared and far infrared parts of optical spectrum.
31. A countermeasure system according to Claim 3 I, wherein all these devices can be
operated simultaneously for emitting radiation in several parts of the spectrum at the
same time.
32. A countermeasure system according to any one of the preceding claims, wherein
15 said directional beam is configured for being directed to at least one of the following:
- the threat itself: and
- a sight of the threat.
33. A method for protecting a target against a threat by the countermeasure system of
Claims 1 to 33, the method including the steps of:
(a) detecting, using a first sensor, a wide zone indicative of an approximate
location of said threat:
(b) outputting to a control arrangement a first directional signal indicative of said
wide zone;
(c) providing, by the control arrangement, a first tracking signal to a drive
arrangement corresponding to said first directional signal;
(d) directing a second sensor towards said wide zone based on said first tracking
signal:
(e) detecting, using said second sensor, a narrow zone indicative of more accurate
location of said threat, said narrow zone being narrower than said wide zone;
(f) outputting to the control arrangement a second directional signal
corresponding to said second zone;
(g) providing, by the control arrangement, a second tracking signal to the drive
arrangement corresponding to said second directional signal; and
(h) directing, based on said second tracking signal, said illumination beam
10 towards said second zone to affect the threat.
34. A method according to Claim 34, wherein in step (d), if a central axis of the
second sensor is aligned with optical axis of the illumination beam, performing step (d)
results in bringing said illumination source in close proximity with direction towards said
threat.
15 35. A method according to Claim 34 or 35, wherein step (h) of the method is
performed by one of the following:
(hl) if the illumination source is fixedly mounted onto said gimbal - revolving the
gimbal about at least one of its axes;
(h2) if the illumination source is movable with respect to the gimbal -
20 moving/revolving the illumination source with respect to the gimbal; and
(h3) if the countermeasure comprises a beam orientation device -
moving/displacing the device.