Note: Descriptions are shown in the official language in which they were submitted.
CA 02356591 2001-08-13
Specifications:
This invention relates to the method and apparatus for protecting the warhead
of a
ballistic missile from the projectiles of an Antimissile Defence System (later
AMDS).
The idea is to protect the warhead of the ballistic missile from the
projectile by
creating a layer of fragments in front of the warhead that will damage and/or
change the
orientation of the projectile of the AMDS and by performing an avoiding
manoeuvre to
avoid hitting that projectile. The layer of protecting fragments is created by
an apparatus
(fragment dispenser) that detaches from the warhead after the latter reaches
an open
space and moves into the required position using propulsion jets under control
of its own
navigation system.
To implement this method, the warhead 1 (see Fig.l) is equipped with one or
more pairs of side shooting devices 2 and compact radar attachment 3. The one
or more
pairs of the side jet engines 8 can be used instead of shooting devices as
shown on Fig.2.
The shooting device 2 is a small canon that shoots the weight 4 in the
direction
perpendicular to the trajectory of the warhead and gives an impulse of speed
to the
warhead. Side jet engines or shooting devices are located in position so their
longitudinal
axis passes through the centre of gravity (C.G.) of the warhead with attached
radar so that
their use will not lead to the rotation of the warhead. The use of the
shooting device may
be preferable to the use of jet engines because it gives the impulse to the
warhead in a
much shorter period of time. The size of the weights 4 depends on the mass of
the
warhead with the radar attachment and the speed at which the weight leaves the
shooting
device, but it should provide the warhead with a speed impulse that is enough
to avoid
hitting the projectile of AMDS (discussed later). The radar attachment 3 in
the front of
the warhead is used to determine the speed and/or distance to the projectile
of the AMDS
and give the control signal to deploy the side jet engine or shooting device.
It uses the
Doppler effect to separate the signal reflected from the projectile and the
signals reflected
from the objects with a speed close to the speed of the warhead.
As an option, the warhead could be equipped with foil shells (rockets) 5 as
shown
on Fig. l to impede the determination of the precise location of the warhead
by land- or
sea-based early warning radars. The foil shells (rockets) use small jet
engines to leave
their holding containers 6 and, after moving a certain distance from the
warhead (for
example, thirty to sixty meters), switch on breaking jets so that the speed of
the shells
(rockets) is close to that of the warhead. The shells then spread the cloud of
metal foil at
speeds about 10 cm/sec (0.3 foot per sec) so that the estimated size of the
cloud will vary
from approximately 20 meters (60 feet) after the first 100 seconds after
deployment to 70
- 1 SO meters (200 - 500 feet) after 350 - 750 seconds after deployment when
the attempt
of interception by the AMDS will probably take place (we assume that the
flight time of
the warhead of intercontinental ballistic missile lies in the range of
approximately 700-
1500 seconds depending on the distance).
In addition to the systems mentioned above, the fragment dispenser 7 is
attached
to the warhead (Fig.l). The fragment dispenser (see Fig.3) is an autonomous
apparatus
used to create the layer of mechanical fragments in front of the warhead. It
consists of a
CA 02356591 2001-08-13
platform l, control and navigational module (control module) 2, a set of jet
engines 3 to
perform the necessary manoeuvres and equipment to create the layer of
fragments in
space. This equipment consists of the hard inner shell 4 with holes) 5
containing the gas
reservoir 6 filled with compressed gas, connected to the gas valve with
calibrated orifice
7. The gas valve can be opened or closed by commands from control module 2.
The hard
inner shell is covered with a balloon 8 made of rubber or other gas-tight
expandable
material.
The layers of fragments 9 surround the balloon 8 and are held together by the
walls of platform 1, made of two halves that are held together with locks 10
and could be
detached from each other and fly away under the force of springs 11 on the
command,
given by control module 2, to open the locks 10. The springs 11 could be
mechanical,
pneumatic or another type.
The weight of fragments 9 is determined by the task the system is designed to
perform. Thus if the task is to damage optical systems of the projectile of
AMDS, the
weight of fragments could be between 1.4 - 11 milligrams each and size
(assuming the
material is quartz Si02) 1 - 2 mm (approx 1/64" - 1/32"). If the task is to
damage and/or
disorient the projectile of AMDS the weight of fragments could be
approximately 4
grams each and size (assuming the material is steel) around 10 mm (approx
3/8"). It is
possible to use bigger or smaller fragments as well as a mixture of fragments
of different
sizes. Taking in account that the speed of a warhead and therefore of the
fragments is
around 5000 - 7000 meters per second and the speed of the projectile of AMDS
should
be similar (probably not less than 2500 - 3000 meters per second to be able to
intercept
the warhead), these sizes of fragments should be sufficient to cause
substantial damage to
the optical systems or to the projectile itself depending on the size of the
fragments used.
Since the kinetic energy of the object is equal mv2/2 where m is mass and v is
velocity of
the object, hitting the projectile with steel fragment weighing around 4 grams
at the
speeds mentioned above is the approximate equivalent of shooting directly at
the
projectile from an artillery canon with shells weighing 0.3 - 0.5 kilogram).
The bigger fragments are arranged in such a way that after being given an
impulse
of speed by the expanding balloon they would form the layer with an even
distribution of
fragments so the positions of fragments in the front semisphere of the layer
do not
coincide with the positions of fragments in the rear semisphere to increase
the probability
of the collision between the projectile of AMDS and fragments and therefore
decrease the
amount and total weight of fragments in the fragment dispenser.
After the warhead reaches an open space, the fragment dispenser detaches from
the warhead and using one or more of its jet engines accelerates away from the
warhead,
then brakes (after rotating 180 degrees or using another jet engine(s)) and,
using its jets,
positions itself so that its speed equals the speed of the warhead, it has the
same trajectory
as the warhead and removed from the warhead on distance L (see Fig.4) between
200 -
10000 meters. This distance depends on the time that the warhead needs to
perform the
avoidance manoeuvre.
CA 02356591 2001-08-13
The control module 2 (Fig.3) then sends the command to open the locks 10,
causing both halves of platform 1 to separate and move away, and after that
opens the gas
valve 7. The compressed gas from the gas reservoir 6 passes through the
calibrated
orifice to the inner shell 4 and through the holes) S expands the balloon 8.
The size of the orifice is chosen so that the balloon gives the impulse of
speed
approximately 1 - 5 cm per second (1/2 - 2 inches per second) to the layer of
fragments
depending on the flight time of the warhead. This creates a slowly expanding
layer of
fragments (see Fig.4, the distance L is equal 200 - 10000 meters as mentioned
above). In
this way, the diameter D of the layer of fragments will be equal 8 - 10 meters
in the
middle section of the warhead's trajectory where interception could take place
and will
reach up to 20 meters in 200 - 1000 seconds after deployment depending on
initial speed
of the fragments.
Assuming that the cross size of the projectile of the AMDS is close to 25 - 30
cm
(10 -12 inches) the total number of fragments used for damaging and/or
disorientation of
the projectile should be close to 5000 (i.e. approximately 16 fragments per
square meter
of the cross section of the layer with an average distance between them around
25 cm (10
inches) when the diameter of the layer reaches 20 m) and the total weight of
fragments
will reach approximately 20 kilograms (assuming the 10 mm (3/8 ") steel
fragments
weighting around 4 grams each are used).
If the system is used for damaging the optical devices of the projectile of
AMDS,
then the average distance between fragments should be close to 1 cm (i.e.
smaller than
the diameter of the lenses of the optical devices on projectile of AMDS) and
the total
number of fragments is equal to approximately 3,000,000. If the size of each
fragment is
1 - 2 mm and fragments are made of quartz weighting 1.4 - 11 milligrams each,
then the
total weight of fragments will be between 4.5 - 34.5 kilograms.
A mixture of smaller and bigger fragments can be used to damage the optical
devices and the projectile itself.
After the balloon gives the required impulse to the fragments, the control
module
closes the gas valve to prevent an explosion of the balloon that could cause
the
deformation of the approximately spherical shape of the layer of fragments.
When the projectile 4 of AMDS (see Fig.4) approaches the layer of fragments 2,
the radar, attached to the warhead, gives the signal to deploy the side jet
engine or the
shooting device of the warhead. The radar uses the Doppler effect to
distinguish the
signal reflected by the projectile of AMDS from the signals reflected by the
fragment
dispenser, fragments and other objects with speeds close to speed of the
warhead. The
speed impulse given to the warhead should be big enough to move the latter a
distance
close at least to 1 meter (approx. 3 feet) perpendicular to the original
trajectory in
approximately 0.1 - 1 second (since distance L (see Fig.6) is equal 200 -
10000 meters
and the sum of the speeds of the warhead and projectile of AMDS could be close
to 5 -
km per second) to avoid hitting the projectile of AMDS. Based on these
assumptions,
the weight of the projectile of the warhead's shooting device can be
determined
CA 02356591 2001-08-13
depending on its speed and the weight of the warhead. Thus, if the required
side speed of
the warhead is equal to 1 meter per second and the weight of the warhead is
around 80
kilograms, then the weight of projectile should be close to 0.8 kilograms if
its speed is
100 meters per second.
In addition, the detached halves 3 of the particle dispenser (Fig.4) can serve
as
false targets for the projectile 4 of AMDS.
After the projectile 4 of AMDS passes by (let us say approximately 2-3 seconds
after the initial signal from the radar), the second jet or shooting device is
deployed to
give the impulse to the warhead in the opposite direction to keep it on
trajectory close to
the original one.
As mentioned above, two or more pairs of the side jets or shooting devices can
be
used on the warhead to deal with the situation when more than one projectile
of AMDS is
deployed against the same warhead. In this case they are used sequentially,
pair after pair.
When the projectile of antimissile defence system reaches the layer of
fragments
it will hit one or more of them causing damage to its optical system, to
itself (or to both,
depending on the sizes of the fragments used) and will lose orientation since
in most
cases the fragment will hit the projectile off its centre of gravity and cause
the projectile
to rotate.
Taking in account that to avoid hitting the layer of fragments, the projectile
of
AMDS should be at least 5 -10 meters off trajectory of the warhead in no more
than 1
second before the planned collision, it makes it difficult for the projectile
of AMDS to
correct its trajectory to hit the warhead.
The use of the system to protect the warhead from the projectile of AMDS could
add approximately SO kg or more to the weight of the warhead (including 20 -
30
kilograms of fragments, fragment dispenser with fuel for its jets, radar
attachment and
side shooting devices or jets). That will lead to the decreased range of the
ballistic
missile. The possible solution is to use multiple warheads missiles with a
decreased
number of warheads, but equipped with the protective system described in this
document.
Another possible use of the system similar to the one described in this
document
is to increase the effectiveness of the projectile of AMDS by attaching the
expanding
balloon with a layer of fragments similar to that one on fragment dispenser to
the
projectile of AMDS itself. In this case fragments could be arranged so they
create only
one semisphere and the size of fragments could be significantly bigger than of
those in
fragment dispenser used to protect the warhead. The balloon can be deployed
when the
projectile of AMDS is close to the warhead (let us say 0.5 - 1 second before
collision)
and spread fragments with speed around 1 - 2 meters per second (3 - 7 feet per
second)
so they create a semisphere with diameter around 2 meters at the moment of
reaching the
warhead (or more, or less depending on circumstances) thus increasing the
effective cross
section of the projectile of AMDS. In this case the total number of required
fragments
could be around SO (i.e. 16 per square meter with an average distance 25 cm
(10")
CA 02356591 2001-08-13
between them) and their weight could be approximately 200 grams each
(approximately
kilograms in total, depending on circumstances and the allowable weight of the
projectile). Such a fragment hitting the warhead at speed of a few thousands
meters per
second should create significant damage to the warhead or destroy it.
