Note: Descriptions are shown in the official language in which they were submitted.
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ANTI TORPEDO SYSTEM
The present invention relates generally to anti torpedo defeat system, and
more particularly
to a ship based anti torpedo defeat system as a final close range
neutralisation system and
method.
BACKGROUND
Munitions are provided in a number of different forms, for a number of
different applications.
Typically, a particular munition will be used for a particular application or
intention. Incoming
torpedoes are typically prevented by barriers, or by anti-torpedo torpedoes.
The use of anti-
torpedo torpedoes, for example deck-launched torpedoes launched from the deck
of a vessel, or
those launched from a nearby submarine, helicopter or airplane. The use of
torpedoes might
overcome some of the problems discussed above with regard to range, mainly
because torpedoes
are self-propelled. However, torpedoes may be slow to deploy. Additionally, it
may be difficult to
engage with the torpedo at close range, ie time to deploy or from
simultaneously launched
torpedoes.
SUMMARY OF INVENTION
According to a first aspect of the invention, there is provided an anti-
torpedo system,
suitable for use on a ship, comprising operably linked;
i) a combat management system comprising a high frequency hull mounted
sonar, to
determine the current position and track ( depth and underwater trajectory) of
a torpedo,
ii) a plurality of direct fire munitions, each comprising an ogive
portion terminating with a
water drag reduction element, an energetic payload and a programmable fuze for
initiating said payload,
iii) an auto-fuze setting system, for setting the time of initiation of the
programmable fuze,
and
iv) a gun management system for:
receiving the current position and track of said torpedo from the combat
management
system, and
aiming and firing of said munitions, based on the received position and track
of the
torpedo, such as to cause each fired munition to arrive at or proximate to
said torpedo
and to cause initiation of the payload.
The gun management system may comprises at least one gun barrel, a fire
control
system to fire the munition from said gun, an aiming system to control the
direction of the gun
barrel. The gun management system determines the aim of said gun barrel, based
on the current
position, ie depth and track of the torpedo. The gun management system causes
the activation
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of the fire control system to fire said each direct fire munition to cause
each fired munition to arrive
at or proximate to said torpedo and to cause initiation (ie detonation) of the
payload.
The combat management system comprises the high frequency hull mounted sonar
as
the primary means of target acquisition and tracking, however further target
acquisition systems
may be used, especially when trying to determine the nature of the torpedo.
Preferably the combat
management is operably linked to a target deconfliction system, to ensure the
identified target is
said torpedo.
Further secondary sonar systems may be provided.
The use of direct fire munitions allows for the ability of rapid rates of
fire, the direct fire
munition may have any calibre of munition that comprises a fuse and HE charge,
preferably the
calibre in the range of 12.7mm to 40mm. Larger calibre systems would work but
offer low rates
of fire, and systems like 4 or 5inch naval shells, are designed for deployment
at multiple km
ranges, rather than sub-km. Further, 4 or 5inch naval shells may have
explosive outputs that
when fired nearby could cause extensive blast damage to the ship or platform.
The medium
calibre munitions provide gun systems which can return rapid rates of fire
from at least a few
hundred rounds per minute, up to thousands at the 12.7mm range.
There may be one or more gun management systems, such that there are one or
more gun
barrel calibres, the selection of the calibre being dependant on the proximity
of the target torpedo
to the ship's hull. The munition launch criteria may comprise at least one of
launch timings and
fuze settings. There may be first and second gun barrels they may be: the same
gun barrel, and
the first and second munitions are launched at different times; or the first
and second gun barrels
are different gun barrels, at different locations on the ship. There may be a
first gun barrel on a
first ship or platform and second gun barrel on second ship or platform. The
second ship or
platform may be part of a fleet, it may be an autonomous vessel.
The ammunition comprises the water drag reduction element, which may be
selected
from any means such as an active element or passive element. The passive
element may be
surface, ie a shape which causes the water to change to a more gaseous state.
Preferably the
water drag reduction element may be a supercavitating surface feature,
arranged to vaporise the
water.
In a further arrangement the water drag reduction element may comprise an
active
element, such as for example a gas generator, shaped charge, arranged to
provide the energetic
displacement of the water, for reducing water drag for the projectile into a
body of water.
The anti-torpedo system may be operated at the highest rate of fire for the
given munition
type. Alternatively, the system may be operated to allow an additive blast
effect at the target
torpedo. In use there may be a first munition and a second munition, co-
ordinating the timing of
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the triggering of the first explosive charge in the first munition and the
second explosive charge
in the second munition to establish a co-ordinated explosive event at the
target torpedo.
The programmable fuze, may preferably be operated using a delay timer to
provide
initiation of said fuze at a timing to coincide with the munitions expected
arrival at the target
torpedo. It may also be advantageous for the fuze to be further adapted to
trigger the payload in
accordance with one or more of:
after a predetermined time period after entering the water;
upon detection of a target sonar signature;
upon detection of a target magnetic signature;
upon detection of a target electric field signature;
at a predetermined pressure under the water surface;
at a predetermined depth under the water surface;
at a predetermined speed-of-sound in water; or
upon impact with said torpedo under the water surface.
The use of selected munitions being selectively programmed to respond to
different
stimuli, may increase the ability of the munition to effectively neutralise
the target torpedo. The
selection of the trigger stimuli being selected by determination of the target
type, depth, position
and track.
The neutralisation of the target torpedo is any event which prevents the
torpedo from
.. reaching its intended target and detonating its payload to cause damage to
said intended target.
The neutralisation may be, but not limited to a variety of events, such as,
for example, the
detonation of the torpedo's payload, the rupture of fuel tanks, neutralising
the torpedo's homing
sensors to disorientate, masking or obscuring the presence of the ship from
the torpedo's sensors,
incapacitating the drive, steering or propulsion system to inhibit its
manoeuvrability or damaging
the buoyancy of the torpedo to cause it to sink.
Co-ordinating the timing of the triggering of the first explosive charge and
the second
explosive charge to establish a co-ordinated explosive event at the torpedo,
may comprise co-
ordinating munition launch criteria.
It will be appreciated that one or more features as described in relation to
munition-like
aspects or arrangements of the present invention may be used in combination
with or in place of
one or more features of projectile-like aspects or arrangements, and the other
way around. More
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generally, any one or more features described in relation to any one aspect
may be used in
combination with, or in place of, any one or more features of any one or more
other aspects of
the invention, unless such replacement or combination would be understood by
the skilled person
to be mutually exclusive, after reading of the present disclosure.
LIST OF FIGURES
For a better understanding of the invention, and to show how arrangements of
the same
may be carried into effect, reference will now be made, by way of example, to
the accompanying
diagrammatic Figures in which:
Figure 1 schematically depicts a vessel launching a munition (or, generally, a
projectile)
from a gun barrel;
Figure 2 schematically depicts the munition launched by the vessel of Figure
1;
Figure 3 schematically depicts the munition of Figures 1 and 2 being directed
towards a
body of water, in accordance with an example arrangement;
Figure 4 schematically depicts how a fuze of the munition of Figures 1 to 3
may be adapted
to initiate a main, explosive, charge of a munition, under the water, in
accordance with particular
criteria, according to example arrangements;
Figure 5 schematically depicts a component for reducing water drag as forming
part of the
munition or projectile, in accordance with a different arrangement;
Figure 6 schematically depicts a component for reducing water drag as forming
part of the
munition or projectile, in accordance with a different example arrangement;
and
Figure 7 schematically depicts general methodology associated with reducing
water drag
for a projectile entering water, in accordance with example arrangements.
DESCRIPTION
There are numerous disadvantages associated with existing apparatus and
methods for
engaging or generally interacting with incoming underwater targets. These
range from a limited
range of some existing munitions used for such purposes, to the limited
accuracy of existing
munitions, or the significant expense associated with existing munitions. In
general, there exists
no relatively inexpensive, rapidly deployable, and yet accurate munition, or
related assembly or
methodology, for engaging or generally interacting with underwater objects
(e.g. targets) in a
desirable manner.
According to the present invention, it has been realised that the problems
associated with
existing approaches can be largely overcome in a subtle but effective and
powerful manner. In
particular, it has been realised that an anti-torpedo system can be provided.
The munition
comprises an explosive charge and a programmable fuze. The munition is adapted
to be fired
directly into the water at the incoming threat. Significantly, the munition is
adapted to be launched
from a gun barrel. This means that the munition typically (and practically
likely) includes, or is at
least used in conjunction with, a propelling explosive, and is capable of
being explosively
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propelled and withstanding such explosive propulsion. This is in contrast
with, for example, an
anti-torpedo torpedo.
The munition is adapted to be launched and then enter a body of water,
typically within
which body of water a torpedo target to be engaged with is located. The fuze
of the munition is
adapted to trigger the explosive charge of the munition underwater, for
example in accordance
with pre-set criteria. The use of a gun barrel also ensures high degree of
accuracy of ranging and
general targeting.
The invention is subtle but powerful. The invention is subtle because it
perhaps takes
advantage of some existing technologies, in the form of firing a munition from
a gun barrel. At the
same time, the munition will typically be a projectile, therefore including no
form of self-propulsion.
This means that the munition is relatively simple and inexpensive. Altogether
then, this means
that the munition according to example arrangements can be used to accurately,
cheaply,
effectively, and generally efficiently engage with the torpedo. Also, the use
of a munition that is
capable of being launched from a gun barrel means that multiple munitions can
be launched very
quickly in succession from the same gun barrel, or in succession and/or in
parallel from multiple
gun barrels, optionally from different ships or platforms, or optionally being
targeted onto or into
the same location or vicinity at or proximate to the target torpedo.
There may be one target torpedo engagement or a synchronous multiple target
torpedo
engagements, either performed form one or more platforms.
While munitions or in general projectiles launched from a gun barrel will, of
course, be
adapted for launch from such a gun barrel (e.g. and therefore able to survive
that launch with little
or no damage), there may nevertheless be a need to facilitate safe or
effective entry of the
munition into a body of water. This is because the munition may impact that
body of water with
considerable speed and impact. For a medium calibre direct fire munition it is
not desirable to
consider soft entry, ie to slow the munition prior to entry into the water.
Clearly hard entry causes
impact with the water which may cause damage to, or destruction of, the
munition, or initiation of
the payload, which is undesirable. This risk needs to be balanced with the
need to maintain a
ballistic, or as close to ballistic, or as close to a predictable, trajectory
as possible, so that any
targeting of the target torpedo, or co-ordination of targeting of a target
torpedo with one or multiple
munitions, can be implemented in a practical, reliable and consistent manner.
One way of overcoming one or more of these problems, if not all of these
problems, is to
reduce water drag for the munition or projectile, for example, by interacting
with an area or region
of water into which the munition is to be targeted. This means that slowing or
arresting of the
munition is reduced, while at the same time minimising or avoiding the risk of
damage of the
munition as it enters the water. And also preventing or limiting significant
changes in trajectory of
the munition as it enters the water.
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Figure 1 schematically depicts a system 1 in accordance with an example
arrangement. In
this example, the assembly comprises a vessel 2 located on a body of water 4.
The vessel
comprises a gun 6 having a gun barrel 8. the vessel comprises a high frequency
hull mounted
sonar 7, optionally other detectors may be used, to detect the presence of the
target torpedo.
A munition 10 is shown as being explosively launched from the barrel 8
directly into the
water 4 towards the target torpedo 5 Figure 2 shows the munition 10 of Figure
1 in more detail.
The munition 10 comprises a fuze system 20, in this example located in a nose
or head of the
munition 10. The munition 10 also comprises an explosive charge 22. The fuze
system 20 is
arranged to trigger the explosives charge 22, when the munition 10 is in the
water, and at a
suitable target location (e.g. at a target object, or target region of water),
or for example meeting
certain triggering criteria.
Prior to being fired, the munition 10 (or more particularly its fuze system
20) is programmed.
The programming might take place within the gun, within the barrel, or even
within a particular
range after launch of the munition 10, for example by wireless transmission or
similar. The
programming might be undertaken to implement or change particular fuze
criteria, for example to
trigger the explosives charge 22 within the munition 10 in accordance with
particular criteria.
Typically, in order to achieve this programming, the munition 10 will comprise
a fuze system 20
that is programmable in nature. In other words, the fuze system 20 is able to
be programmed or
configured as desired.
The criteria for triggering the charge 22 can take one or more of a number of
different forms,
for example: after a predetermined time period after the munition has entered
the water; upon
detection of a target sonar signature; upon detection of a target magnetic
signature; upon
detection of a target electric field signature; at a predetermined pressure
under the water surface;
at a predetermined depth under the water surface; at a predetermined salinity
of water; at a
predetermined temperature of water; at a predetermined speed-of-sound in the
water; or upon
impact with a target under the water surface. All of these are environmental
conditions.
As will be discussed in more detail below, the triggering, or timing of that
triggering, might
also relate to the reception of a co-ordinating data signal, for example
received from another
munition, or an object different to (i.e. not including) another munition, for
example to co-ordinate
the triggering of the explosive charges of multiple munitions and establish a
co-ordinated
explosive event.
As is typical for munitions fired from a gun barrel, the munition may be
arranged to be
launched from a rifled gun barrel. Alternatively the munition may be fin-
stabilised. The exact
configuration would be dependent on the required application.
The munition may be fired from the barrel by a mechanical firing pin, electric
or thermal
ignition.
Of course, care will need to be undertaken to ensure that the combination of
munition
properties (e.g. size, weight, shape, component parts, and so on) and firing
specifications (e.g.
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explosive propulsion, launch angle) is such that the munition 10 does not
explode on launch.
Further as the torpedo may be heading towards the vessel, there may need to be
care as to
ensure that at very acute angles that the gun does not fire munitions at the
deck of the vessel.
There may be an electronic virtual mask or actual barrier to prevent such
occurrence.
Turning to Figure 3, shows an overview of the system, which is split into 3
interconnected
levels; the ship level systems 200, the gun level systems 210 and the
projectile level systems
220.
The centre of the ship level systems is the combat management system 230. This
takes
information from the high frequency desk mounted sonar and any other target
acquisition
systems to identify and locate the incoming torpedo. Information is then
exchanged with the
target deconfliction system 240 to minimise the chance of friendly fire from
occurring.
Once the target has been identified, is in range and no friendly units are in
the line of
fire then the information is passed to the gun level systems 210. The key
information will be the
torpedo location, depth and velocity. The gun management system will then aim
the weapon in
the correct direction (taking into account any deflection of the projectile's
path due to striking to
water's surface) and will calculate an appropriate fuze timer delay. The
combat management
system may be linked to one or more gun level systems, either on the ship or
one on or more
further platforms.
The fuze may be configured to detonate at the same depth as the torpedo using
the
following information:
The depth of the torpedo from the combat management system.
The angle of incidence of the projectile onto the water from the aiming
subsystem/gun
management system.
Either the firing from the gun or the impact on the water as a zero time to
start the delay
timer.
A model (either theoretical or empirical) of how the projectile will
decelerate in the
water.
The time delay required will be constantly changing as the torpedo progresses
and the
angle of the gun fire changes. Therefore so the system will be configured to
individually set the
fuze of every projectile just prior to/at the point of firing/at the point of
exit from the barrel. Once
the fuze is set and gun is pointing in the correct direction the fire control
system will fire the
round.
Figure 4 shows the munition 10 after it has impacted upon and entered into the
body of
water 4, and is descending down through the water 4. Figure 4 shows that the
fuze system of the
munition 10 may be adapted to trigger 40 an explosive charge within the
munition 10 to
successfully and effectively engage with the torpedo target 42.
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As discussed above, the triggering 40 might be achieved by triggering the
explosives
charge after a particular time 44, for example from one or more of a
combination of launch from
the gun barrel as described above, and/or a predetermined time period after
entering the water 4
(e.g. an environmental condition). This latter time period will typically
equate to a particular depth
46 within the water 4 (e.g. based on expected or calculated rate of descent).
Alternatively, the
triggering 40 may occur at the particular depth 46 in combination with or
irrespective of the timing
44. For example, an alternative or additional approach might involve the
direct detection of depth
(via one or more sensors or similar). Depth may detected based on time, as
above, or perhaps
based on water pressure under the surface, the salinity of the water, the
temperature of the water
or even the predetermined speed-of-sound in the water. All of these may be
indicative of depth
within the water, for example which had been known in advance from mapping of
the area, from
physics principles, and/or sensed by the munition 10 via one or more sensors
when descending
through the water 4.
Of course, the fuze may also be adapted to trigger the explosives charge upon
impact with
the torpedo target 42. However, it may be safer to employ some form of depth-
activation, so that
the munition 10 explodes at/near the depth of the torpedo target 42, avoiding
possible
unintentional explosions at or near objects that are not torpedo targets 42.
As above, the fuze may be programme with such criteria, or related criteria
necessary for
the fuze to trigger 40 the explosive as and when intended. Also discussed
above, the triggering
of the fuze 10 will almost certainly be based on an environmental condition of
some kind, for
example one or more of the conditions described above, including a period of
time for which the
munition 10 has been in the water. Again, and simply to be clear, all the
conditions above will
equate to environmental conditions, including such as, for example, detection
of a target sonar
signature, detection of a target magnetic signature, detection of a target
electric field signature,
and so on. In other words, the triggering of the explosives charge might
advantageously require
an environmental trigger of some kind. This means that while a degree of
programming or hard
wiring of triggering criteria might be provided, for example in the fuze
system of the ignition, or
programmed into the munition, an element of environmental sensing or
triggering is required..
Additionally, this might assist in the co-ordination of the triggering of
explosives charges of
multiple munitions when located underwater, to establish a co-ordinated
explosive event at a
target location, for example a particular pattern of explosions relative to
that target location, and/or
where the munitions explode at the same time, or in a particular sequence, and
so on.
. For instance, the use of munitions allows for multiple munitions to be
launched in rapid
succession, in combination, in parallel, from a single gun barrel, from
different gun barrels, or from
gun barrels of the same platform (e.g. vessel), or from different gun barrels
of different platforms
(e.g. different vessels). This flexibility brings about a subtle yet powerful
further advantage. This
is the co-ordination of the triggering of explosive of multiple munitions,
launched from one or more
guns.
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Figure 5 schematically depicts a projectile 140 according to an example
arrangement. The
projectile might comprise a fuze system and related explosive charge as
discussed above. In this
example, the component for reducing water drag is located in a nose or head of
the projectile
140. The component comprises a gas generator 144 arranged to eject gas from an
outlet 146,
typically at a location of the projectile 140 that is to come into first
contact with the water at a
location 148 of water entry.
The gas generator 144 might take any one of a number of different forms, and
could
advantageously comprise a rocket motor which is a relatively simply,
straightforward and effective
element for generating bubbles in water. The gas generator 144 might be
initiated during flight of
the projectile 140, for example just before impact with the region 148 of
water 4. Bubbles
generated by the generator 144 will adhere to or generally move along an outer
surface of the
projectile 140, meaning that the projectile 140 enters the water 4 at the
target location 148 more
readily, and more smoothly, thus ensuring that an expected or predicted
trajectory is maintained,
or better maintained than if the gas generator 144 was not used. Bubbles might
also simply be
provided ahead of the projectile 140, for much the same benefit.
Figure 6 shows an alternative example of projectile 150 in which a nose or
head 152 of the
projectile comprises a component for interacting with the water 4 in the form
of a charge, and
typically a shaped charge 154. The charge 154 may be triggered to detonate or
explode just
before impact with target location 148 of the body of water 4, to at least
partially vaporise the
water or more generally introduce bubbles in the location 148, to soften water
entry for the
projectile.
Figure 7 shows a yet further example of a projectile 160. In this example, a
head or nose
162 of the projectile 160 is provided with a supercavitating surface feature
164, arranged to
vaporise the water at the target location when the projectile and its surface
feature 164 comes
into contact with that target location 148. Typically, the supercavitating
surface feature 164 might
comprise one or more supercavitating grooves, which are simplistic surface
features useful for
introducing the required vaporisation of the water, and associated reduction
in water drag for the
projectile 160 as a whole.
Although a few preferred arrangements have been shown and described, it will
be
appreciated by those skilled in the art that various changes and modifications
might be made
without departing from the scope of the invention, as defined in the appended
claims.
