U.S. patent application number 12/074943 was filed with the patent office on 2010-05-06 for remote explosion of improvised explosive devices.
This patent application is currently assigned to Stellar Photonics, L.L.C.. Invention is credited to Michael Challenger, David L. Cunningham, Ingrid Fuhriman, Robert Fuhriman, JR., Donald Limuti, Weihao Long, Stephen E. Moody, David M. Shemwell.
Application Number | 20100107859 12/074943 |
Document ID | / |
Family ID | 42129867 |
Filed Date | 2010-05-06 |
United States Patent
Application |
20100107859 |
Kind Code |
A1 |
Cunningham; David L. ; et
al. |
May 6, 2010 |
Remote explosion of improvised explosive devices
Abstract
A method and apparatus triggers motion triggered improvised
explosive devices (IEDs) from a distance outside the device's zone
of destruction. IEDs having infrared motion detection trigger
mechanisms are detonated by passing remotely generated laser beams
over the area within which the IED is located. The moving reflected
background scattering of light from the passing laser beams as well
as possible direct passing laser illumination of the IED infrared
motion detector activate the IED trigger mechanism, causing the IED
to detonate. Operation of the invention is remote from the
destruction zone of the IED, thereby preserving personnel and
materiel.
Inventors: |
Cunningham; David L.;
(Kirkland, WA) ; Moody; Stephen E.; (Woodinville,
WA) ; Fuhriman; Ingrid; (Bellevue, WA) ;
Fuhriman, JR.; Robert; (Bothell, WA) ; Limuti;
Donald; (Kirkland, WA) ; Long; Weihao;
(Kirkland, WA) ; Challenger; Michael; (Bothell,
WA) ; Shemwell; David M.; (Newcastle, WA) |
Correspondence
Address: |
Anthony Claiborne
849 136th Ave. N.E.
Bellevue
WA
98005
US
|
Assignee: |
Stellar Photonics, L.L.C.
Bellevue
WA
|
Family ID: |
42129867 |
Appl. No.: |
12/074943 |
Filed: |
March 8, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60905957 |
Mar 9, 2007 |
|
|
|
Current U.S.
Class: |
86/50 |
Current CPC
Class: |
F41H 13/0062 20130101;
F42D 5/04 20130101; F41H 11/16 20130101 |
Class at
Publication: |
86/50 |
International
Class: |
F42B 33/06 20060101
F42B033/06 |
Claims
1. An apparatus for remote detonation of a motion detection
triggered improvised explosive device, comprising: a laser
assembly, comprising a laser emitting infrared radiation; and
optics receiving radiation from the laser and emitting the
radiation as a beam projected on an area in the vicinity of the
improvised explosive device; and a means for moving the projection
area of the beam in the vicinity of the improvised explosive
device.
2. A device according to claim 1, wherein the means for moving the
projection area of the beam comprises a vehicle on which the laser
assembly is mounted.
3. A device according to claim 1, wherein the optics comprises
lenses shaping the projected beam.
4. A device according to claim 3, wherein the optics shapes the
projected beam to form an elongated projection having a major axis
and a minor axis, the major axis having a length more than twice
the length of the minor axis in the projection area.
5. A device according to claim 1, wherein the optics comprise a
scanner.
6. A device according to claim 1, wherein the laser emits infrared
radiation in the range of 8 to 14 micrometers in wavelength.
7. A mobile apparatus for detonation of a remotely located motion
detection triggered improvised explosive device, comprising: a
vehicle; and at least one laser assembly affixed to the vehicle,
the laser assembly comprising a laser emitting infrared radiation;
and optics receiving radiation from the laser and emitting the
radiation as a beam projected on an area in the vicinity of the
improvised explosive device, whereby, responsive to the motion of
the vehicle, the area in which the beam is projected in the
vicinity of the improvised explosive device is moved, thereby
triggering the detonation of the device.
8. A method for detonating a motion detection triggered improvised
explosive device, comprising: projecting an infrared laser beam on
a first area in the vicinity of the improvised explosive device,
and moving the projection of the beam to a second area in the
vicinity of the improvised explosive device.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority from provisional U.S.
patent application No. 60/905,957 filed Mar. 9, 2007, entitled
"System to defeat improvised explosive devices based on passive IR
sensors."
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to improvised explosive devices that
are triggered by infrared motion detectors. More specifically, this
invention relates to methods for remotely triggering the explosion
of such devices and to apparatus for practicing such methods.
[0004] 2. Description of the Related Art
[0005] In the modern battlefield, enemy combatants such as
terrorists or guerillas often use improvised explosive devices
(IEDs) as instruments of warfare. Such devices are fabricated in an
improvised manner and comprise conventional chemical explosives
with a trigger mechanism. In use, IEDs are typically hidden in a
fixed location and are designed to be triggered, causing an
explosion when a moving target (such as personnel or vehicles)
moves into the explosive destruction zone in the proximity of the
IED.
[0006] Trigger mechanisms for IEDs have included proximally
operated manual electrical switches (in the case of suicide
bombers) and remotely operated improvised electronic apparatuses
based upon cellular telephone or radio signaling. Due to the
limited and unpredictable availability of personnel for suicide
bombing, and due to the effectiveness of radio frequency jamming in
preventing the operation of cellular telephone and radio signal
operated triggers, enemy combatants in recent years have shifted to
the use of motion detectors as a preferred trigger mechanism for
IEDs.
[0007] A motion detector trigger mechanism for an IED typically
comprises a commercial off-the-shelf infrared motion detection
transducer coupled with trigger electronics designed to ignite the
IED explosive when the transducer detects motion in proximity to
the device, typically on the order of 10 meters in the case of
personnel and somewhat farther in the case of vehicles. In its
normal operation, such a device detects target motion and explodes
when the target is within the destruction zone of the IED. While
the improvised nature of IEDs is such that their zone of
destruction varies, a typical motion-activated IED is fashioned so
that its zone of destruction roughly matches the range of its
motion detector, again on the order of 10 meters or so. Because
such devices detonate automatically without the need for a human
operator, and because they are not susceptible to radio frequency
jamming, they have been particularly lethal and effective
battlefield weapons.
[0008] If, however, such devices can be triggered remotely, when
personnel and equipment are outside the destructive zone, the
effectiveness of these IEDs as weapons is nullified, saving lives
and materiel.
BRIEF SUMMARY OF THE INVENTION
[0009] The present invention is a method and apparatus for
triggering certain improvised explosive devices (IEDs) from a
distance outside the device's zone of destruction. IEDs having
infrared motion detection trigger mechanisms are detonated by
passing remotely generated laser beams over the area within which
the IED is located. The moving reflected background scattering of
light from the passing laser beams as well as possible direct
passing laser illumination of the IED infrared motion detector
activate the IED trigger mechanism, causing the IED to detonate.
Operation of the invention is remote from the destruction zone of
the IED, thereby preserving personnel and materiel.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0010] The foregoing objects, as well as further objects,
advantages, features and characteristics of the present invention,
in addition to methods of operation, function of related elements
of structure, and the combination of parts and economies of
manufacture, will become apparent upon consideration of the
following description and claims with reference to the accompanying
drawings, all of which form a part of this specification, wherein
like reference numerals designate corresponding parts in the
various figures, and wherein:
[0011] FIG. 1a is a graphical representation of prior art infrared
motion detection;
[0012] FIG. 1b illustrates voltage output over time from an
infrared motion detection sensor;
[0013] FIG. 2 is a depiction of the invention as deployed on a
vehicle;
[0014] FIG. 3 is a schematic representation of one embodiment of
optics for the present invention;
[0015] FIG. 4 is; a schematic representation of a scanner serving
as optics for the present invention; and
[0016] FIG. 5 is a depiction of the invention deployed on a vehicle
wherein a plurality of lasers is employed.
DETAILED DESCRIPTION OF THE INVENTION
[0017] The typical infrared motion detector is comprised of a
package with a sensor having two pyroelectric elements. Each
pyroelectric element is composed of a crystalline material that
generates a surface electric charge when exposed to infrared
radiation. Within the operating range of incident energy, the
surface charge generated by an element is proportional to the
amount of radiation striking the crystalline material. While sensor
elements are sensitive to radiation over a wide range of
wavelengths, the detector package typically is fitted with an
optical filter window to limit detectable radiation to a range of
approximately 8 to 14 .mu.m, corresponding to the principal range
of wavelengths of infrared radiation emitted by an object at the
temperature of the human body. Sensor packages available at present
are responsive to radiation energy on the order of 1 microjoule
incident upon the package.
[0018] In practice, the two elements in a detector sensor are
typically arranged to provide output of opposing polarity.
Accordingly, when both elements are simultaneously exposed to equal
levels of radiation, the output voltages from the sensor elements
cancel each other and there is no net output voltage from the
sensor. It is only when the elements are simultaneously exposed to
different levels of radiation that the sensor provides output
voltage. Changes in the output voltage, then, correspond to changes
in the relative radiation levels to which the two elements are
exposed.
[0019] To eliminate noise and erroneous readings, the motion
detector circuitry is typically provided with an electronic filter
to attenuate signals of frequencies too high to correspond to
movement of humans. Generally, such filters are low-pass filters
calibrated to attenuate signals on the order of 10 Hz or higher in
frequency.
[0020] The detector further comprises a means for focusing
radiation incident upon the sensor. Without such focusing means,
the range of resolution of the sensor is limited. Generally
speaking, among common sensors currently available, absent such
focusing means, an infrared source that is farther than about 1.5
meters from the sensor cannot be resolved by the elements to
provide a significant resulting output voltage, regardless of
position of the source.
[0021] Various focusing means are used to extend the range of
resolution of infrared motion detectors. Most common is a form of
Fresnel lens or a parabolic mirror placed between the sensor and
the target area. Such an arrangement may extend the detection range
of the motion detector to greater than 30 meters.
[0022] In addition to focusing means for extending the range of
resolution, motion detector installations may employ various means
for narrowing the field of view of the detector. Such means are
employed when it is desired to narrow the target area within which
motion is to be detected and are common in improvised explosive
devices, where detonation is desired only when the target is within
a fairly confined zone of destruction. Commonly employed means for
narrowing the field of view include a pinhole lens, in which a
sheet of IR opaque material is perforated with a small hole and
placed in front of the sensor in the manner of a pinhole camera.
Such a pinhole lens may serve both to focus infrared radiation
incident on the sensor (and may in fact substitute for standard
focusing means such as the Fresnel lens discussed above) as well as
to narrow the detector's field of view. Alternatively, field of
view is also commonly narrowed in IEDs by simply placing a tube on
the order of 50 mm in length over the front of the sensor, thereby
narrowing the field of view to objects appearing in the field of
the tube aperture.
[0023] In typical installations, the detector is positioned so that
the sensor's two elements lie in a roughly horizontal plane. An
infrared radiation source passing across the field of view of the
sensor in a horizontal direction will activate first one and then
the second sensor element. The detection of change in sensor
voltage corresponding to such sequential activation is processed by
detector electronic circuitry to indicate that motion has been
detected within the field of view of the motion detector.
[0024] FIG. 1a illustrates the operation of a typical motion
detector diagrammatically. Sensor 102 is comprised of two elements,
each of which receives incident radiation along lines 104, 106
respectively. Focusing means 108 extends the detection range of
sensor 102, resulting in a field of view of width 110 along the
range of the sensor. As discussed above, focusing means 108 may be
a Fresnel lens serving simply to extend the range of sensor 102.
Alternatively or in addition, again as discussed above, focusing
means 108 may provide a means to narrow the field of view of sensor
108 to no more than width 110. In any case, a source of infrared
radiation moving horizontally along line 112 within field of view
110 provides radiation incident first along line 104 to one element
of sensor 102 and then along line 106 to the other element of
sensor 102, thereby generating changing voltage from the sensor
over time as illustrated in FIG. 1b. Such a characteristic voltage
pattern from the sensor indicates that motion has been detected.
Responsive to receipt of such a voltage pattern from the sensor,
motion detector electronic circuitry provides signaling indicating
motion has been detected.
[0025] The present invention activates the motion detector and
thereby triggers the IED by transmitting radiation over the area in
which the IED trigger is located in such a manner that the motion
detector of the IED responds as if a moving target object were
within the range and field of view of the motion detector sensor.
By transmitting such radiation from a point outside the destructive
zone of the IED, the present invention causes the detonation of the
IED remotely, avoiding harm to personnel and equipment.
[0026] In order to activate the motion detector trigger, the sensor
must receive radiation from the invention in the detection
wavelength range of the trigger's sensor that also is incident to
the sensor at an energy level sufficient to create surface charge
in the sensor's elements. A carbon dioxide laser, which transmits
at principal wavelength bands centered between about 9.4 to 10.6
.mu.m, provides radiation in the detection range of infrared motion
detectors commercially available today, which are outfitted with
optical filters for sensitivity to infrared radiation in the range
of approximately 8 to 14 .mu.m, as discussed earlier. For effective
activation of a single sensor element, such radiation must be
incident upon the element to provide at least the minimum energy
exposure (the product of exposure time and power of radiation
incident upon the element) to activate the sensor element. Required
exposure to activate a sensor element in commonly available
detectors today is on the order of 1 microjoule. Accordingly, there
is an inverse relationship between the power of a radiation source
and the exposure time required to activate a sensor element, as
illustrated in table 1 below.
TABLE-US-00001 TABLE 1 Radiation power versus required exposure
time to activate a single detector element Radiation power Required
Exposure time (microwatts) (sec) 0.10 10.00 1.00 1.00 10.00 0.10
100.00 0.01
[0027] Finally, for effective activation of the motion detector
sensor, the incident radiation must activate one and then the other
element of the sensor in sequence within the period of time for
which the motion detector is calibrated for motion detection.
Transition of activation from one element to the other in too brief
a time will result in a signal from the sensor that will be
attenuated by typical motion detector circuitry and therefore would
not be treated as indicative of positive motion detection.
[0028] Positive motion detection is indicated by changes in
radiation incident on the detector within the constraints outlined
above. The present invention exposes the detector to such changes
in radiation by moving a projected laser beam over an area in the
vicinity of the detector. As the beam moves over the area, changes
in incident radiation cause the motion detector to create a signal
indicating motion in the area, in turn triggering the detonation of
the IED.
[0029] Embodiments of the present invention employ various means to
move the beam of the present invention over the area in the
vicinity of the detector. In some embodiments, a laser projecting
apparatus is affixed to a vehicle or other automotive device. In
such embodiments, the beam projected by the apparatus moves over a
projection area with the motion of the vehicle. Other embodiments
may employ movable mirrors, prisms or other reflective or
refractive devices to sweep the projected beam over an area in the
vicinity of the detector. In yet other embodiments, the laser
projecting apparatus itself may be moved in such a fashion that its
projected beam moves over an area in the vicinity of the detector.
Examples of such latter embodiments include hand-held or
swivel-mounted laser projecting apparatus. It is intended that all
such means of moving the projected beam over an area in the
vicinity of the IED motion detector are within the scope of the
present invention.
[0030] The radiation may be directly incident from a projecting
laser device upon the detector. Alternatively, a detector may be
triggered by radiation from a projecting laser device that is
reflected by the environment to the detector. Because of the
relatively low reflectivity of the typical battlefield environment,
lasers effective to cause triggering by reflection must be
considerably more powerful than lasers effective to cause
triggering by direct illumination of the detector.
[0031] In application, embodiments of the invention intended for
battlefield deployment are transportable to areas where
motion-triggered improvised explosive devices may be located.
Preferred embodiments may be mobile and may be used to sweep an
area for such explosives, causing the detonation of IEDs while
personnel and materiel remain outside zones of destruction.
[0032] FIG. 2 illustrates one mobile embodiment of the invention.
Laser 202 mounted on vehicle 204 employs optics 206 to project beam
208 which is swept over an area where motion-activated IEDs are
believed to be deployed.
[0033] In some embodiments, optics 206 may be fixed so that beam
208 is projected at a fixed angle from vehicle 204. For such
embodiments, sweeping of beam 208 over a target zone takes place
when vehicle 204 is in motion. In such embodiments, it is
advantageous for optics 206 to cause beam 208 to be narrow and
tall, thereby providing a wide stripe of radiation in the target
zone and increasing the probability that a sweep of the beam will
result in activating an IED motion detector. One such embodiment of
optics 206 is described in greater detail below in reference to
FIG. 3.
[0034] FIG. 3 is a diagrammatic representation of one embodiment
employing a beam 208 that is fixed in orientation. A beam of
radiation 305 from laser 202 is expanded by first beam expanding
lens 304 to form expanding cone 307. Second beam expanding lens 308
recollimates the beam to emit a beam 208 of larger diameter than
beam 305. Cylindrical lens 306 placed between lenses 304 and 308
causes beam 309 to diverge along its vertical dimension, so that
when recollimated beam 208 reaches the target area, it will be
narrow and tall in the image plane. As will be understood by those
of skill in the art, components of optics 206 may be selected and
adjusted to produce a beam configuration of a desired height and
width as projected in the target area.
[0035] In one embodiment of the invention projecting a beam 208 of
fixed angle from vehicle 204, laser 202 operates at 200 watts and
optics 206 cause beam 208 to form a projection measuring
183.times.2.5 centimeters at a target zone roughly 23 meters
distant from laser 202. The sweep of the beam across the target
zone when vehicle 204 is traveling at speeds ranging from 32 to 80
kilometers per hour causes activation of motion detectors in the
target zone at a distance more than twice the diameter of the
nominal 10 meter destruction zone of the IED.
[0036] Other embodiments of the invention may employ optics 206 to
vary the angle at which beam 208 is projected from vehicle 204 over
time, resulting in scanning by beam 208 over an area in the target
zone. As will be appreciated by those of skill in the art, such
variation of the angle of beam 208 may be achieved by employment of
scanner technology in optics 206, whereby suitably adapted
galvanoelectric scanning mirrors are employed to deflect the path
of beam 208 so that it scans an appropriate area over time in the
target zone. One such embodiment of optics 206 is described in
greater detail below in reference to FIG. 4.
[0037] FIG. 4 is a diagrammatic representation of an embodiment of
optics 206 employing a beam 208 that has been deflected by scanning
technology to traverse a given area. A beam 404 emitted by laser
202 is deflected two-dimensionally by a galvanometer scanner 408,
the deflection resulting in scanning beam 208 covering area 420.
The galvanometer scanner 408 consists of a pair of beam deflecting
galvano-mirrors 413 and 417 for x-axis (horizontal scanning
direction) and y-axis (vertical scanning direction) respectively,
the two axes of the mirrors perpendicular to each other at the
center of oscillation, and of a pair of servo-motors 410 and 414
for angle control of mirrors 413 and 417. Controller 406, acting
through drivers 412, 416, controls oscillation of mirrors 413, 417
by motors 410, 414, thereby deflecting beam 206 to cover scanned
area 420 within the target zone.
[0038] In one embodiment of the invention employing scanning
technology to vary the angle at which beam 208 is projected from
vehicle 204 over time, laser 202 operates at 60 watts and optics
206 is configured to produce a beam that scans an area roughly
1.25.times.2.5 centimeters within the target zone over a 2 hertz
frequency. This embodiment has been effective in triggering motion
detectors at a distance of 18 meters, again outside the destruction
zone of a typical motion-activated IED. As will be clear to those
of skill in the art, with higher powered lasers, scan deflection
and frequency of optics 206 may be adjusted to result in larger
scanned areas within the target zone, thereby increasing the
effectiveness of such embodiments.
[0039] Embodiments need not be limited to employment of a single
source of laser radiation. Multiple sources of laser radiation may
be used simultaneously to cover a wider target area. Turning to
FIG. 5, vehicle 502 is outfitted with two larger roof-mounted laser
units, 504, 506, emitting beams of radiation 508, 510 respectively,
as described above. Vehicle 502 is further outfitted with two
smaller bumper-mounted laser units, 512, 514, emitting beams of
radiation 516, 518 respectively. Beams 508, 510, 512 and 514 may
each be directed to a different portion of the target area,
ensuring more thorough target area coverage than is provided by a
solitary beam. Such embodiments may employ more powerful lasers
focused to cause triggering principally by radiation reflected by
the environment to the IED motion detector, along with less
powerful lasers focused to cause triggering principally by direct
illumination of the detector.
[0040] Such an embodiment with multiple sources of laser radiation
has effectively employed a roof-mounted 200 watt laser and a
bumper-mounted 25 watt laser. The beam from the roof-mounted laser
was expanded by optics along the lines of those discussed in
reference to FIG. 3 above to provide a horizontally oriented
138.times.2.5 centimeter beam approximately 25 meters in front of
the vehicle. The beam from the smaller, bumper-mounted laser was
similarly expanded to form an elongated beam shape oriented at
approximately 45 degrees and optimized for a target approximately
one meter to the side and 8 meters in front of the laser
source.
[0041] Embodiments need not be limited to vehicle-mounted devices.
Portable lasers along with portable power supplies may be adapted
for hand-held triggering of distant IEDs by foot soldiers.
Similarly, embodiments need not be limited to land-based
deployment. Airborne vehicles such as helicopters and low-flying
drone aircraft may also be effectively outfitted with the present
invention for the remote detonation of motion detection triggered
improvised explosive devices.
[0042] Although the detailed descriptions above contain many
specifics, these should not be construed as limiting the scope of
the invention but as merely providing illustrations of some of the
presently preferred embodiments of this invention. Various other
embodiments and ramifications are possible within its scope.
[0043] While the invention has been described with a certain degree
of particularity, it should be recognized that elements thereof may
be altered by persons skilled in the art without departing from the
spirit and scope of the invention. Further, while specific numbers
and parameters have been set forth in keeping with the present
state of the art, it will be understood that, if specifics of
motion detector technology or improvised explosive device change
over time, such numbers and parameters may be adjusted
appropriately by persons of skill in the art and remain within the
scope of the present invention. Accordingly, the present invention
is not intended to be limited to the specific forms set forth
herein, but on the contrary, it is intended to cover such
alternatives, modifications and equivalents as can be reasonably
included within the scope of the invention. The invention is
limited only by the following claims and their equivalents.
* * * * *