Method and arrangement for combating a submerged target object

A method for combating a submerged target object through the intermediary of an active body which is deployable in an airborne mode, and which picks up a sonar contact with the target object from a helically descending searching trajectory below the water level. Also disclosed is an arrangement for combating a submerged target object, especially a double-hulled submarine, through the intermediary of an active body deployable in an airborne mode which is equipped with a sonar installation and with guidance media for the traversing of a helical gliding search trajectory. Upon contacting a target through the intermediary of a searching sonar which is more simply constructed in comparison with a homing sonar, the active body launches an effector which is equipped with an extremely rapid drive into linear attacking trajectory tangentially to the searching trajectory, and wherein the effector will detonate a warhead upon impact against a target.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a method for combating a submerged target 
object through the intermediary of an active body which is deployable in 
an airborne mode, and which picks up a sonar contact with the target 
object from a helically descending searching trajectory below the water 
level. Moreover, the invention is directed to the provision of an 
arrangement for combating a submerged target object, especially a 
double-hulled submarine, through the intermediary of an active body 
deployable in an airborne mode which is equipped with a sonar installation 
and with guidance media for the traversing of a helical gliding search 
trajectory. 
2. Discussion of the Prior Art 
The measures of the type which are under consideration herein are generally 
known from the disclosure of British Patent 1,347,462, in accordance with 
which a torpedo is deflected from a searching-sinking phase into a spiral 
trajectory upon making contact with a target with the switching of the 
sonar installation from searching operation to a target tracking operation 
so as to home onto the target at a renewed contact with the target by 
means of the currently employed tracking guidance system. 
The necessity for the provision of apparatus (from the standpoint of 
position-finding or bearing technology, propulsion technology and 
ammunition technology) for being able to implement a potentially 
successful torpedo attack against mines or submerged vessels, such as 
submarines, is in all instances extraordinarily high. Thus, for searching 
for a target and the tracking of a target it is necessary to provide for a 
mechanically or electrically pivotable sonar base possessing relatively 
large dimensions for obtaining the necessary solution or analysis, which 
requires a large torpedo diameter and resultingly considerably high 
propulsive power; whereas on the other hand; however, due to the large 
torpedo volume and the high propulsive power, this has as the result of 
causing high degree of probability of discovery or betrayal in addition to 
self-endangerment through the sonar-searching operation. In order that its 
own operation does not disturb the search-and-tracking sonar, it must be 
more frequently switched off for enabling a measuring-listening travel, 
which brings along a demand on control or guidance technology for the 
stabilization of the position of the torpedo in the water and an 
expenditure of time during the tracking of a target object. Moreover, the 
distance which must be traversed by an ordinary torpedo to the target 
object is limited, when it relates to a rapidly moving submersible, such 
as a submarine, whose speed must be substantially surpassed by that of the 
tracking or chasing torpedo, when the target object which has set itself 
in a timely manner into a fleeing movement could possibly still be 
reached. However, at a high traveling speed for the torpedo, on the other 
hand, there are again encountered restrictions with respect to its 
maneuverability, which is disadvantageous, in order to be able to swing 
from a drag curve which is unsatisfactory for the attack into an optimized 
advanced trajectory relative to the extrapolated target movement. Finally, 
by means of the ordinary torpedo, there must be transported 
extraordinarily large quantities of explosives into the closest possible 
proximity to the target object, inasmuch as the effectiveness from the 
standpoint of the ammunition technology is not predicated on a hit 
(comparable to a projectile), but on the initiation of water or hydraulic 
pressure waves for the transmission of such intense water or hydraulic 
pressure pulses, that the operational capability of the target object is 
disrupted thereby to at least to some lasting extent. On the other hand, 
the payload space for a warhead is restricted by the large volume which is 
required for the heavy electrical energy storage required for the 
electro-motorized torpedo propulsion system. 
SUMMARY OF THE INVENTION 
In recognition of these conditions, it is accordingly an object of the 
present invention to improve upon the measures as described hereinabove to 
such an extent as to be able to obtain an effective combating of a target 
located below water with a smaller, and to that extent also a less 
expensive and additionally, logically, a less complex projectile 
possessing a reduced inherent probability of discovery or betrayal and 
thereby a higher hitting effectiveness. 
The foregoing object is inventively achieved in that the inventive measures 
are attained whereby the active body glides along the searching trajectory 
without any own propulsion device to glide along the searching possessing 
its own propulsive drive, and upon contacting a target through the 
intermediary of a searching sonar which is more simply constructed in 
comparison with a homing sonar, launches an effector which is equipped 
with an extremely rapid drive into linear attacking trajectory 
tangentially to the searching trajectory, and wherein the effector will 
detonate a warhead upon impact against a target. 
Additionally, the foregoing object is also achieved through the provision 
of an arrangement of the type as described herein, in that the active body 
is an unpowered or propulsionless underwater glider, which is equipped 
with a target searching sonar which is much simpler in construction 
compared with a target-tracking sonar installation, and is designed as a 
carrier for an effector which is launchable therefrom, the latter of which 
is equipped with a high-speed underwater propulsion mechanism for 
traversing the distance between the launch from the glider in a direction 
tangentially to the gliding searching trajectory to the target object 
along an essentially linear attacking trajectory which is specified by the 
target-searching sonar. 
In accordance with the foregoing object, it is not necessary to provide for 
the large expenditure of explosives for the initiation of an adequate 
water-hammering effect in the target object inasmuch as the target object 
is attacked in a direct shot, such that a small quantity of explosives 
behind a suitable cladding will be adequate to not only rupture the 
external tanks but; for example, also rupture the pressure hull of a 
submarine. Implemented hereby is the firing of the herein so-called 
effector from a glider, which in the absence of a propulsion device and 
thusly at a low probability of discovery or betrayal, and a low sonar 
interference, as well as with savings of propulsion energy which 
commencing from a circular trajectory by means of an inclined forwardly 
fixedly oriented; effectively, from the standpoint of apparatus a simple 
searching sonar, responds to a coaxially forwardly detected target object, 
and starts the high-speed drive system, preferably a rocket-reaction drive 
of the effector. The latter then traverses extremely rapidly; In essence, 
not target-tracking but in a direct fire-line of sight, the distance to 
the target object, which in view of this surprisingly rapid approach has 
practically no chance of any defense or taking flight. Thus, it does not 
pertain to a torpedo-typical homing-defense method, but to a system 
attacking in direct fire or shot with a reusable propulsionless firing 
base in which there are arranged the essential components of the sonar 
intelligence system. 
Should the target object be missed by the direct firing trajectory, 
inasmuch as the target object, for example, was in the interim able to 
evade in a sideways direction, then after the passage of a 
reference-travel time determined by the searching sonar prior to the 
launch of the effector, the movement of the effector is changed over into 
a spirally descending approach or hitting trajectory from which, with a 
high degree of probability, there is again carried out in an 
effectiveness-optimized mode, a hit in the side of the target object. 
Accordingly, for this purpose, it is not necessary to provide any 
auxiliary sensor equipment on board the effector, inasmuch as the 
target-detecting sonar of the glider, from which the effector is launched, 
delivers a somewhat rough but sufficiently precise distance to the target, 
so as to supply to the effector at its firing, a reference-time 
information for the eventual commencement of the horizontal trajectory 
deviation. 
For the case, instance, in which the target object is not intended to be 
struck by the effector in either a direct short or from the deviated 
descending trajectory, the effector guidance can be so designed that in 
the normal instance there is effected an over-travel beyond the target 
object. Hereby, the effector is then additionally equipped with a simple 
proximity sensor which is oriented forward downwardly angled, which, in 
effect, does not coaxially forwardly emit any significant radiation 
tending to influence the probability of discovery, and due to its simple 
distance measuring-function will not be significantly disrupted by the 
inherent traveling noise produced by the effector itself. When this 
proximity sensor determines the over-travel above the target object, there 
is then carried out a conversion from the previous linear attacking 
trajectory into a steep falling or diving trajectory from above onto the 
target object. 
In order to still be able to swing immediately prior to striking the target 
into a expedient; namely, right-angled position for the effectiveness of 
its warhead, there can be provided on the effector a forwardly oriented 
mechanical guidance or steering device; for example, in the shape of 
spreader legs which are telescopable by means of stored spring force or 
contact initiated gas generators, which at an inclined approach to the 
target object, will impart a torque to the effector through suitable 
supporting moments into a perpendicular or normal orientation relative to 
the impact surface on the target. As a result thereof, the penetrating 
effectiveness of the effector or; in essence, of its warhead, is more 
expediently positioned and thusly optimized.

DETAILED DESCRIPTION 
In the scenario for the combating of a submerged target object in the shape 
of a submarine 11, as is illustrated in FIG. 1, whose approximate relative 
location has been determined by means of a sonar installation 12 on a 
search vehicle 13 (which can pertain to a submarine-hunting, i.e. 
subchasing helicopter or, as illustrated herein, to a surface vessel), the 
active body 14 for the combating of the target passes the largest part of 
the distance to the submarine 11 through the air above the water level 15 
in quasi-ballistic flight. For this purpose, the warhead 14, for example, 
as is known, is launched by means of a rocket propulsion mechanism 16 
located, for instance, on board the search vessel 13 (or on board a vessel 
acting in coordination therewith, which has the target coordinates 
transmitted thereto from the search vessel 13). After determining the 
initial launching speed the warhead 14 continues to fly in an inertial 
manner, after the rocket propulsion mechanism (booster) 16 has been 
expelled and dropped down. 
After entering the region 17 close to the target (which extend in a 
magnitude of a few hundred meter measured horizontally about the enemy 
submarine 11) then, in a known manner, there is initiated the steep 
descent from the ballistic trajectory 18 through activation of braking 
means 19; for instance, such as a parachute fastened to the tail end of 
the active body 14. This can be initiated; for example, either 
program-controlled from the search vessel 13 prior to the launch, or 
remote-controlled during flight, when the ballistic trajectory 18 has not 
already been calculated for a specified submersing region 20, in order to 
eliminate the need for special braking means 19 for leaving the traversing 
trajectory 18. Basically, the active body 14 can also be ejected directly 
in a close area above the target surroundings, such as from an aircraft or 
the like. 
In any event, the warhead 14 passes approximately vertically through the 
water level 15 into the region 17 close to the target. The entry into the 
water is detected on board the active body 14 through the changed 
conditions in the surroundings (another environmental medium and/or 
retardation encountered during entry into the water) so as to, on the one 
hand, separate therefrom the braking medium 19 which is generally 
disturbing during the movement through water (for example, such as a 
parachute) and, on the other hand, to set flow-dependently acting guidance 
means, such as control surfaces or adjustable gliding support surfaces, in 
a manner that in the region of immersion 20, there takes place already as 
closely as possible below the water level 15, a deflection of the 
approximately vertical entry into a propulsionless movement along a 
helically descending gliding search path 21. Moreover, as shown in FIG. 2, 
there is activated an eccentrically forwardly oriented target-searching 
sonar 22 on a glider 27 for the active body. With respect to the 
foregoing, this can pertain to an extremely simple installation from the 
standpoint of apparatus in comparison with the sonar installation of a 
homing torpedo; in particular, inasmuch as it is not necessary to 
implement any mechanical or electrical oscillation of the 
search-characteristics system and no connection from the standpoint of 
signal technology with a follow-up guidance device for the underwater 
course of travel. Thereby, notwithstanding the equipping with a relatively 
inexpensive target-searching sonar 22, it is also possible, inasmuch as 
the gliding searching trajectory 21 is traversed by the active body 14 
without the use of any propulsive device, by itself due to the reduction 
in the kinetic and potential energy, that no bearing or position-finding 
interferences are encountered which could be caused by the noise spectrum 
from its own propulsion aggregate. A further reduction in the cost of this 
target searching sonar 22 can be realized in that the submarine 11 which 
is positively to be attacked has already been acquired by means of the 
essentially more extensively equipped sonar installation 12 of the search 
vessel 13 so that characteristics which are specific to the target can be 
transmitted to the small target-searching sonar 22 and herein, as a 
result, the demands on signal processing technology for the target 
detection can be reduced to a further extent. 
Implemented expediently below the immersing area 20 is the conversion into 
the helical gliding search trajectory 21 in such a manner that the 
search-and-motion axis 23 initially subtends an acute angle during at 
least one revolution relative to the water level 15, so as to be able to 
acquire target objects standing relative closely below the water level 15, 
also only at snorkeling depth, at a still greater distance, in effect, not 
to search about therebelow. There is then carried out, either in a 
time-controlled mode or derived from the positional change in space of the 
active body 14, a reorientation of the guidance medium 24 (supporting 
surfaces and/or control rudder) for a shallow descending gliding search 
trajectory 21 for the scanning of the close region 17 in the surroundings 
about the immersing area 20 along generally spiral target-like successive 
sectors. For the most possibly gapless scanning of the surroundings it can 
be advantageous to orient the gliding search trajectory 21 as closely as 
possible to the horizontal and each time, after one revolution or spiral 
of travel, into a descent so as to be able to again pick-up kinetic energy 
for the next (therebelow located) horizontal search trajectory 21. The 
program control assignment for the radius of the trajectory and the path 
of the descent are oriented to the geometric target prescriptions in order 
not to miss this target. 
It is somewhat more expedient (as shown in FIG. 2) to deviate the 
transmitting characteristic 25 of the target-searching sonar 22 of the 
glider in the direction of the curvilinear travel (curvature of the 
gliding search trajectory 21) with respect to the receiving 
characteristics 26 which is coaxial with the axis of motion 23 by a fixed 
tilt or screw angle. As a result thereof, this will afford that any kind 
of target object can be already detected by the target-searching sonar 22 
prior to the swinging thereinto of the axis 23. 
As is illustrated in specific detail in FIG. 2, the active body 14 which is 
deployable above the water level 15 consists of an undriven or 
propulsionless glider 27 serving as a carrier and a launching device for 
an effector 28. The last-mentioned is launched coaxially forwardly from 
the glider 27 when there is detected forwardly in the receiving-and-motion 
movement axis 23 by the target-searching sonar 22 of the glider the 
submarine 11 which is to be attacked. Accelerated by means of a reaction 
propulsion mechanism 29, and two - point guided from a simple 
autopilot-inertial guidance 30 for the compensation of any kind of 
starting and drift disturbances pursuant to the extent of the bearing 
prescription during launch from the glider 27, the effector 28 "fires" 
along the launch orientation (and thereby tangentially to the gliding 
search trajectory 21) linearly forwardly towards the submarine 11. The 
tandem warhead 31 of the active body 14 is designed, for example, through 
the axial staggering of a hollow charge and a projectile-forming charge, 
to initially rupture the flooding chamber-outer hull of the submarine 11 
and then thereby with an immediately following explosives-formed 
projectile rupture the pressure hull of the submarine 11 so that the 
latter becomes incapable of operating. 
Although the effector 28 travels along its attacking trajectory 32 at an 
extremely high rate of speed along the axis 23, along which there has in 
front thereof been detected a submarine 11 which is to be attacked, it is 
not possible to preclude that the target object will not be struck 
directly along this axis. This is based on the fact that the submarine 11 
need not be stationarily positioned, it can move relatively rapidly, and 
above all pursuant to the localized conditions of sound propagation 
existing between the search sonar 22 of the glider and the detected 
submarine 11, there are encountered different bearing deviations during 
the propagation of the ultrasonic signal, as a result of which 
(corresponding to the diffraction of a beam of light at an angled 
radiation into a water surface), there actually exists a geometric 
deviation between direction towards the reflecting target object and the 
direction of incidence of the received echo signal. Consequently, there is 
expediently evaluated or plotted that the search sonar 22 of the glider 
also delivers an instantaneous information as to the distance to the 
target object; in essence, with respect to the transmitting-receiving 
characteristics 25, 26 of the detected submarine 11. Inasmuch as due to 
the combusting behavior of propulsion mechanism 28 of the effector there 
is previously known its cruising speed along the linear attacking 
trajectory 32, a target determination by means of the proximity sensor 33 
can no longer be expected from the original attacking trajectory 32' in 
accordance with a time interval corresponding with a distance which is to 
be measured commencing from the firing of the effector 28 from the glider 
27. The guidance means 36; for example, such as ailerons or flap wings 
and, possibly, stabilizer fins, must thereby be adjusted, in dependence 
upon time, namely, at the completion of an expected target-hitting time 
interval which is actually specified at this firing dependent upon 
distance, so as to provide a transition from the previous linear attacking 
trajectory 32 into a spirally descending target-hitting path 37, in order 
to be able to also attack the submarine 11 when it has moved from its 
original position in which it had been detected by the search sonar 22 of 
the glider. The radius and the widening in the spirals of the hitting 
trajectory are specified with respect to the type of target, such that the 
submarine 11 will be detected even during its fleeing movement after 
typically the latest two spiral circles with a high degree of probability. 
The deviation from the linear attacking trajectory 32' into the spiral 
target-hitting trajectory 37 can be effected in a directionally dependent 
manner as to which side the submarine 11 has offset itself relative to the 
original attacking trajectory 32'. For this purpose, a proximity sensor 33 
in the type of an echo depth finder need only be equipped with a 
transmitting-receiving characteristic as a sensor 34' which, with a 
sideways orientation, is oriented angled forwardly and downwardly. 
When on board the effector 28 it is permissible to provide for an increase 
in technological equipment in the interest of obtaining an enhanced 
hitting effectiveness, then the inertial guidance 30 of the effector 28 
which is launched from the glider 27 is expediently (as is considered 
symbolically simplified in FIG. 1) so set that the actual attacking 
trajectory 32" is anticipated to extend above the submerged submarine 11. 
In order to nevertheless be able to attain a hit; and, namely, a hit under 
an expedient striking angle against the submarine 11, the proximity sensor 
33 is designed for the incorporation of an additional characteristic in 
the form of at least one sensor or probe 34' which is oriented angled 
forwardly and downwardly. By means of this sensor or probe, as is 
illustrated in FIG. 1, there is detected the immediately anticipated 
travel over the submarine 11, inasmuch as the echo signals from the 
proximity sensor 33 now suddenly originate from a relatively good 
reflector at a short distance; in effect, can be simply distinguished from 
echoes received from the surrounding mass of water; in essence, from the 
further distanced ground of the water. As soon as the proximity sensor 33 
signals the anticipated passage over the submarine 11, the (inertial) 
guidance 30 switches from the linear travel of the attacking trajectory 
32" to a steep vertically tilting diving trajectory 35 so that the 
submarine will be struck with the greatest degree of probability under an 
expedient striking angle in the region of its deck structure. 
In the event of an inexpedient striking angle for the effector 28; for 
example, against a curved portion of the submarine 11, under circumstances 
it cannot be precluded that the projectile of the warhead 31 will only 
tangentially strike the wall of pressure hull of the target object; in 
effect, will not produce any effect in the pressure hull which could 
significantly adversely influence its condition of operational readiness. 
This effect can be basically reduced when the effector 28, immediately 
prior to striking against the submarine 11, is once again deflected into a 
normal or perpendicular direction relative to the latter. During the 
remaining, extremely short residual running time, the demands on providing 
sensor technology for the controlled guidance is in any event 
considerable, and with flow-dependently operating guidance means 36 
(control rudder in FIG. 2), this necessarily rapid guidance would hardly 
be able to be implemented. As a result thereof, pursuant to FIGS. 3 or 4, 
it is more expedient to employ a supporting lever guidance or steering of 
the type in that, immediately prior to striking against the submarine 11, 
spreader legs 38 are extended angled forwardly. In view of telescope-like 
extensions, or due to their linkage kinematics, they can thereafter 
project forwardly of the tip 39 of the effector. As is ascertainable from 
FIG. 3b; for instance, at least one of these extendable or spreader legs 
38 in front of the tip 39 of the effector contact against the outer 
surface of the submarine 11. In any case, the eccentric support for the 
approaching effector 28 causes its tilting into practically vertical 
striking orientation 40 (FIG. 3c). For the extension and latching of the 
spreader legs 38 in their effective operative position (as required, also 
for extension of telescopable parts) there can be utilized energy 
accumulators, for instance pursuant to FIG. 4, such as prestressed 
springs; however, still better are electrically-activatable pyrotechnic 
power elements, such as are generally known for the extension of swing 
wings or pivotable control surface employed in the technology relating to 
guided ammunition. As shown in FIG. 3a, during the rapid driven travel of 
the effector 28 along the outer hull (under circumstances, with a 
retracted telescopic component), retracted spreader legs 38 are 
expediently released for extension thereof in dependence upon the 
traveling time along the attacking trajectory 32, when for this activation 
there is not contemplated the provision of an additional coaxially 
forwardly oriented impact or proximity sensor. 
The kinematics of the transition into the hitting or striking direction 40 
can be influenced by means of the supporting moments; in effect, through 
the direction and magnitude of the offset of the articulation of the 
spreader legs 38 relative to the flow-dynamic center of gravity 41 of the 
effector 28. 
In the effector 28, as is illustrated in FIG. 4 in a partial longitudinal 
sectional representation, in contrast with the condition pursuant to FIG. 
3, the spreader legs 38 in the deploying position are articulated in 
forwardly folded contacting manner. As a result thereof, there are not 
extendable to such a length, but these variants evidence the advantage 
that the spreader legs 38 which are released from the deploying position 
through the effect of the oncoming or incident water flow are rapidly 
expanded until they are fixed in their spread-apart position through the 
latching engagement of a spring-loaded arresting element 43. The latching 
device 44 for the previously assumed deploying position can be released in 
an inertial-dependent manner through the impact against the target object 
or, more dependently, through a small proximity sensor 33, whereupon a 
transversely acting expanding spring 45 will extend each respective 
spreader leg 38 from its deploying position within the contour of the 
effector 28 to such an extent, that the extending force of the incident 
water flow can become effective. 
In order to prevent the tip 39 of the effector, after an acutely-angled 
impact against the outer surface of the target object which consists of a 
mild ductile steel or a polyethylene coating, during the pivoting about of 
the effector 28 into the optimized striking direction 40, from gliding off 
the submarine 11, in accordance with the possibility which is additionally 
considered in FIG. 4, provision can be made that approximately 
simultaneously with the release of the spreader legs 38 there is activated 
an anchoring arrangement 46. In the illustrated exemplary embodiment, this 
is symbolized by barbed hooks which, by means of a propellent charge 47, 
can be accelerated through a piston 48 located in a tubular guide 49, 
which can pertain to the cylindrical open standoff space in front of the 
warhead 31 for the formation of a hollow charge barb. In the narrowing 
front region of the tubular guide 49, the piston 48 is braked down and 
retained in place, whereas the anchoring arrangement 46, responsive to 
inertia, will lift away from the piston 48 and exits through the tip 39 of 
the effector in order to penetrate into the outer hull of the target 
object. This anchoring arrangement 46 is expediently constructed as a 
miniaturized projectile possessing a geometry which is full-cavitating in 
water and including an impact detonator. As a mechanical coupling between 
the forwardly-fired anchoring arrangement 46 and the effector 28, there 
can be provided; for instance, a cable-like connection 50. In consequence, 
there is assured that the tip 39 of the effector, during the pivoting 
movement (refer to FIG. 3b), will not displace itself significantly 
sideways and as a result, to be able to slide off from the target object. 
When after pivoting or swinging into the optimized striking direction 40, 
there is detonated the warhead 31, then the damming or cushioning 51 
present behind the space for the propellent charge 47, as well as the 
forwardly traveled piston 48 are pierced through by the hollow charge barb 
without any problem, so as to further rip open the anchoring location in 
the target object, prior to detonating of the projectile-forming main 
charge for damaging the pressure hull of the submarine 11.