Method for performing exo-atmospheric missile's interception trial

A Method for Performing Exo-Atmospheric Missile’s Interception Trial

FIELD OF THE INVENTION

This invention is in the field of performing exo-atmospheric missile's interception trials.

BACKGROUND OF THE INVENTION

Ground to ground (GTG) missiles have become an efficient weapon which can cause a significant damage to military and civilian infra-structures, and thereby they serve as a strategic tool in favor of states which attack their enemies (either offensively or defensively as a result of an attack originated by the enemy). In light of this ever increasing threat an anti missile technology has been developed, such as the plan designated star war, the arrow anti-missile technology (deployed and used by the Israel Defense Forces) and others. The anti missile technology, such as the arrow system is capable of tracking the oncoming ground to ground missiles and launch e.g. from a protected territory an anti-missile missile (AMM) (referred to also as kill vehicle - KV) which flies along a flight trajectory which substantially collides with that of the oncoming threat. The anti-missile missile approaches the oncoming threat (in safe distance from the protected territory) and destroys it by using hit to kill method or by activating appropriate kill warhead which destroys at least the active war head of the threat and thereby prevents the arrival of the threat (or damaging debris) to the protected territory.

In the last few years a wide range of new treats have been introduced such as the Shihab 3, Sihab 2000, Zelzal, Scud C and others, each of which having its unique flight characteristics, such missile geometry, flight dynamics, IR and or RF signature, etc. The different flight characteristics of each threat impose a new challenge for Kill vehicle which should be upgraded to handle also the new threat.

In order to assure proper operation in real life scenario the upgraded kill vehicle should be tested against a simulated treat having flight characteristics that resemble that of the real threat. Thus, for example, with the introduction of the Shihab 3 and after obtaining sufficient intelligent information as to the missile's flight characteristics, the kill vehicle should be retrofitted in order of duly handle also this newly introduced threat. In order to validate the efficiency of the kill vehicle against the threat in a real-life scenario, it must undergo field experiments in which it is launched and attempts to intercept the threat. However, typically the country which develops Arsenal of KVs such as Israel does not have access to a real GTG missile (in the latter example, Israel is not likely to have at its disposal a sample Iranian Shihab 3) and accordingly the technological challenge is not only to duly retrofit the KV, but also to develop a dummy threat which simulate the flight characteristics of the GTG missile. The latter is normally a costly and long procedure which not only poses financial constraint on the defense project, but also extends the turn key date, since it normally takes few years to develop a dummy missile that has exactly the same flight characteristics as that of the GTG missile. By the time that the KV has been successfully retrofitted and tested against the newly introduced threats, new threats may emerge that have not as yet been adequately addressed. The defending state is thus exposed to absorb significant damages due to the fact that the KV is not adapted (and duly tested) to destroy newly introduced threats.

It is also known that the destruction of GTG missile before it hits the friendly territory is a difficult task considering the very high relative velocities between the KV and the GTG missile. The kill duration is thus very short and should be viewed accurately in order to determine whether the warhead portion of the GTG missile has been destroyed. The very short duration during which the hit occurs as well as the far distance from a ground station (considering that the interception is performed Exo-Atmospheric) poses a significant challenge on tracking means for providing high quality kill assessment.

There is thus a need in the art to provide for a technique for performing ExoAtmospheric missile's interception trial which can be applicable shortly after introducing of new threats and which significantly simplifies (in terms of cost and time) the procedure of developing a dummy threat that emulates the flight characteristics of the GTG missile.

There is a further need in the art to provide for a method which will facilitate a high quality kill assessment of the interception.

SUMMARY OF THE INVENTION

In accordance with an embodiment of the invention there is provided an inflatable dummy target fittable into a carrier missile capable of being released from the carrier missile during exo-atmospheric flight; upon release, the dummy target or portion thereof is capable of being inflated and manifest characteristics that resemble a GTG missile characteristics, wherein said GTG missile characteristics include IR signature, RF signature and GTG missile geometry.

Tn accordance with an embodiment of the invention there is further provided an inflatable dummy target fittable into a carrier missile capable of being released from the carrier missile during exo-atmospheric flight; upon release, the dummy target or portion thereof is capable of being inflated and manifest exo-atmospheric flight dynamics that resemble a GTG missile exo-atmospheric flight dynamics.

In accordance with an embodiment of the invention there is still further provided a carrier missile accommodating at least one inflatable dummy target, each dummy target capable of being released from the carrier missile during exo-atmospheric flight; upon release, the dummy target or portion thereof is capable of being inflated and manifest characteristics that resemble a GTG missile characteristics, wherein said GTG missile characteristics include IR signature, RF signature and GTG missile geometry.

In accordance with an embodiment of the invention there is still further provided a carrier missile accommodating at least one inflatable dummy target, each dummy target capable of being released from the carrier missile during exo-atmospheric flight; upon release, the dummy target or portion thereof is capable of being inflated and manifest characteristics that resemble a GTG missile characteristics, wherein said GTG missile characteristics include exo-atmospheric flight dynamics.

In accordance with an embodiment of the invention there is still further provided a method for generating dummy target characteristics that resemble (GTG) missile characteristics, comprising.

(a) releasing an inflatable dummy target from a carrier missile;

(b) inflating said dummy target or portion thereof using gas, thereby manifesting dummy target geometry characteristics that resemble the GTG missile characteristics, and whereby the dummy target's characteristics manifest RF signature that resemble missile RF signature and whereby dummy target's characteristics manifests IR signature that resembles IR signature of the GTG missile.

In accordance with an embodiment of the invention there is still further provided a method for generating dummy target characteristics that resemble (GTG) missile characteristics, comprising:

releasing an inflatable dummy target from a carrier missile; inflating said dummy target or portion thereof using gas; and releasing gas through at least one nozzle that is fitted in said dummy target manifests exo-atmospheric flight dynamics that resemble exoatmospheric flight dynamics of a GTG missile.

In accordance with an embodiment of the invention there is still further provided an inflatable dummy target fittable into a carrier missile capable of being released in a wrapped form from the carrier missile during exo-atmospheric flight; upon release, the dummy target or portion thereof is capable of being inflated and manifest exo atmospheric flight dynamics that resemble a GTG missile exo-atmospheric flight dynamics, whereby said dummy target exo-atmospheric flight dynamics are achieved in said inflated form notwithstanding of initial un controlled perturbations of the dummy target in a wrapped form.

In accordance with an embodiment of the invention there is still further provided a method for performing exo-atmospheric Ground-to-Ground missile's interception trial, comprising:

(a) launching a carrier accommodating at least one dummy target;

(b) launching an interceptor for exo-atmospheric interception of the dummy target;

(c) releasing an inflatable dummy target from a carrier missile;

(d) inflating said dummy target or portion thereof, the dummy target has characteristics that resemble a GTG missile characteristics;

(e) re-routing a flight trajectoiy of the dummy target during releasing from the carrier for at least (i) facilitate sensing of interception during the END GAME, (ii) assuring that the carrier being substantially out of the field of view of the interceptor during the END-GAME if it is required by interception scenario, and (iii) assuring that the carrier being substantially in the field of view of the interceptor during the END-GAME at the pre-defined location relative to dummy target if it is required by interception scenario (f) sensing the interception process (g) Communicating the sensed data.

In accordance with an embodiment of the invention there is still further provided a method for simplifying exo-atmospheric Ground-to-Ground (GTG) missile's interception trial, comprising:

(a) providing at least one dummy target that is manufacturable in considerable simpler manufacturing process than a GTG missile, and capable of manifesting characteristics that resemble characteristics of the GTG missile;

(b) providing a common carrier missile capable of accommodating at least one dummy target irrespective of the characteristics thereof;

whereby said common carrier missile is capable of being launched and being configured to release at least one dummy target at selected exoatmospheric location, for testing the ability of an interceptor missile to intercept said dummy target at exo-atmospheric interception ροίηζ thereby testing the interceptor's operational feasibility to destroy the GTG missile.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand die invention and to see how it may be carried out in practice, a preferred embodiment will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

Fig. 1 illustrates a sample dummy target interception scenario, in accordance with embodiments of the invention;

Fig. 2A illustrates a flow diagram of a sequence of operation for providing dummy target interception, in accordance with certain embodiments of the invention;

Fig. 2B, illustrates schematically a re-routing technique in accordance with certain embodiments of the invention;

Fig. 3A illustrates schematically a dummy target releasing mechanism, in accordance with an embodiment of the invention;

-רFig. 3B illustrates schematically a flowchart of the operational stages for releasing and activating a dummy targetdummy target, in accordance with certain embodiments of the invention;

Figs. 4A-C illustrate schematically a more detailed dummy targetdummy target releasing mechanism, in accordance with an embodiment of the invention;

Figs. 5A-B illustrate schematically a dummy targetdummy target in wrapped and inflated forms respectively, in accordance with an embodiment of the invention.

Figs. 6A-B illustrate schematically a front and side views of a dummy targetdummy target in accordance with an embodiment of the invention;

Figs. 6C illustrates schematically an enlarged view of a nozzle fitted in a dummy targetdummy target, in accordance with an embodiment of the invention;

Figs. 7A-B illustrate schematically nozzle shapes fitted in a dummy target dummy target, in accordance with an embodiment of the invention;

Figs. 8A-B illustrate schematically a respective front and side views of a dummy target, serving for explaining dynamic equations, in accordance with an embodiment of the invention; and

Fig. 9A-B illustrate set of equations serving for explaining the dynamics exoatmospheric flight characteristics of a dummy target dummy targef in accordance with certain embodiment of the invention.

Fig.lOA-D illustrate schematically a dummy target in accordance with another embodiment of the invention;

Fig. 11A-B illustrate schematically means for generating appropriate flight dynamics in a dummy target, in accordance with certain embodiments of the invention.

Fig.12 illustrates schematically a IR signature activation curve, in accordance with certain embodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Unless specifically stated otherwise, as apparent from the following discussions, it is appreciated that throughout the specification discussions, utilizing terms such as , processing, computing, calculating, determining, or the like, refer to the action and/or processes of a computer or computing system, or processor or similar electronic computing device, that manipulate and/or transform data represented as physical, such as electronic, quantities within the computing system's registers and/or memories into other data, similarly represented as physical quantities within the computing system's memories, registers or other such information storage, transmission or display devices.

Before moving on, it should be noted that in the context of the invention whenever the term ground to ground (GTG) missile is referred to, it likewise applies to reentry vehicle (RV) e.g. in the case of multi stages missiles.

Note also that in the case of axi-symmetric dummy target, any reference to the pitch axis likewise applies to the yaw axis. For example, pitch angular velocity likewise applies to yaw angular velocity.

Bearing this in mind, attention is first drawn to Fig. 1 illustrating schematically a sample dummy target interception scenario, in accordance with an embodiment of the invention. As shown, a carrier missile 11 is launched and flies along exo-atmospheric flight trajectory 12. At a certain post boost stage, the motor is separated and discarded (not shown) and the remaining portion of the carrier continues to fly leaving the atmosphere and proceeds along exo-atmospheric flight trajectory. Also shown is an antimissile missile (KV) (referred to also as interceptor) 13 having associated radar system (not shown) being configured to track an oncoming GTG missile (in this case the dummy target) and invoke a launch command to the interceptor. The latter flies along an exoatmospheric flight trajectory 14 that is designated to a collision course whereupon the interceptor (substantially collides with the oncoming GTG missile (in this case the dummy target).

Note that there are two main killing mechanisms used by target interceptions by interceptors well known from prior art may:

• Hit to kill (using of interceptor body for GTG war head destroying) used typically although not necessarily in exo-atmospheric kill scene.

• Activation killing war head at a close proximity to the dummy target, a kill war head that is fitted in the interceptor is invoked, for destroying at least die war head of the GTG missile, thereby rendering it inoperable. In this case the kill war head is designated to kill the dummy target. This technique is used typically although not necessarily in endo atmospheric kill scene.

Choosing of killing method depends on many technical and other uncertainties like typical miss distance at interception, sensitivity of lethality on incidence angle, target characteristics uncertainties including the exactly place of GTG war head/ war head activator etc. The technique according to the invention is suitable for both types of interceptors killing mechanisms. The only additional limitation for success kill assessment performance at the case of killing war head mechanism is that the carrier should be away from the interceptor’s war head fragments beam.

As specified above, in order to assure proper operation in a real life scenario, the KV should be tested against a missile having flight characteristics that resemble that of the real GTG missile threat. Providing an accurate simulated threat of the kind specified normally involves long and costly design and manufacturing procedures which pose inherent limitations that were discussed in detail above.

Thus, in accordance with the invention, there is provided a method for performing exo-atmospheric Ground-to-Ground missile's interception trial. To this end, in accordance with certain embodiments, a carrier 11 that accommodated at least one dummy target (not shown in Fig. 1) is launched. At a certain location 15, an inflatable dummy target is released from a carrier missile, and upon release, the dummy target is inflated and manifests characteristics that resemble those of a GTG missile, all as will be explained in greater detail below. An interceptor 13 is launched for exo-atmospheric interception of the dummy target. The dummy target 16 continues to fly along the specified flight trajectory (or in accordance with certain embodiments along re-routed flight trajectory 17 as shown in Fig. 1). Note that the reason of re-routing the flight trajectory of the dummy target will be discussed in greater detail below. As will be further discussed below, the dummy target has a simple structure and can be easily manufactured to have characteristics such as IR signature, RF signature, geometry and/or dynamics that resemble those of the GTG missile, in considerable simpler design and manufacturing process than those of simulation missile as used in accordance with the prior art.

Reverting now to Fig. 1, upon release of the dummy target, the flight trajectory of the carrier missile may be re-routed 18 so as to facilitate sensing of interception process during the END GAME wherein the interceptor 13 attempts to intercept the dummy target at interception point 19. Note also that in accordance with certain embodiments the trajectory of the carrier may be re-routed to as to assure that the carrier being substantially out of the field of view of the interceptor during the END GAME if it is required by interception scenario. Otherwise the carrier may be used as an additional object in interceptor field of view if that is required by testing interception scenario (for example for validation of discrimination algorithm etc.)

After having sensed the kill scene, e g. by acquiring images of the interception process, the sensed data can be communicated, for example, to a remote ground station, for, say assessing the quality of the kill - determining of the key kill parameters like miss distance, incidence angle etc.

The interception scenario that was described in Fig. 1 is by no means binding. For example, the invention is not bound by a carrier of the kind specified, the interception rout of the interceptor or the dummy target and others, there manner of sensing the interception process, etc.

Having described a typical interception scenario, there follows a description (with reference to Fig. 2A) of a sequence of operation for providing dummy target interception, in accordance with certain embodiments of the invention. Thus, at stage 21a, a carrier that accommodated at least one dummy target is launched. There follows a staging phase 21b and sustainer ignition stage 21c for entering the carrier to a desired exo-atmospheric trajectory 21d. Note that in 21d there is also a re-routing of the carrier's trajectory whenever necessary. Next, at a certain location in the exo-atmosphere, an inflatable dummy target is released 22 from a carrier missile (see also 15 at Fig. 1).

Next (23), the dummy target is inflated such that it has RF signature geometry and other flight characteristics that resemble those of a GTG missile of interest. At this stage 24, the flight trajectory of the dummy target is rerouted (see, for example, 18 in Fig. 1) whilst the carrier keeps tracking the dummy target 25. . The re-routing achieves at least the following: (i) the new route deviates from the flight trajectory of the dummy target (see, for example, 17 in Fig. 1) so as to facilitates sensing of kill scene when the interceptor attempts to intercept the dummy target during the END GAME (for example, exo-atmospheric site 19 depicted in Fig. 1).

Note that in accordance with certain embodiments, the re-routing of the flight trajectory of the carrier is designed accordingly to the interception test objectives:

• to assure that the carrier being substantially out of the field of view of the interceptor during the END GAME 19. This killing scenario is more suitable to non separate target interception scenario were the carrier does not form part of the intercepted target. In other words, the interceptor is aimed towards the inflatable dummy target only. In this case it may be desired to retain the carrier outside the FOV of the interceptor during the END GAME, since otherwise the interceptor may home onto the carrier instead of the designated dummy target of interest. The dummy target as may be recalled imitates the real target.

• to assure that the carrier being in the field of view of the interceptor at the proper distance for example in case of multistage target scenario. This scenario is suitable to a situation that the interceptor views the various stages of the target and should discern which the target of interest is. Thus, for example, the interceptor should view (during END GAME) the dummy target (imitating the real target) and the carrier and decide that the real threat is the dummy target therefore homing onto the latter and ignoring the carrier which does not pose a real threat. Note that the re-routing of the flight trajectory of the carrier may be performed for meeting also other requirements, all as required and appropriate depending upon the particular application.

Reverting to Fig. 2A, while the dummy target is re-routed and the carrier tracks the dummy target (24 and 25, respectively), the ground station (which is in charge on the launching of the interceptor) acquires the dummy target 26 and applies defense program planning 27 for launching the interceptor missile 28. The latter is launched 29a, undergoes staging 29b, as well as sustainer ignition 29c and commences dummy target acquisition sequence 29d (only after the dummy target has obtained the desired target characteristics, e.g. it acquired the desired IR signature and to this end, the dummy target skin is heated 201 (as wש be explained in greater detail below with reference to Fig. 12).

Simultaneously, the ground control controls the interception sequence 202.

Next, the carrier senses at the interception point. The sensing can be achieved by, e.g. image acquisition means attached to the carrier or by way of another non limiting example by image acquisition means that are released from the carrier for acquiring sky view of the interception scene at the interception ροϊηζ all as will be described in greater detail below. The interceptor now homes onto the dummy target 203 and intercepts the dummy target 204 at the interception point ״The dummy target is destroyed 205, and the carrier which senses the interception point performs kill assessment 206 and the sensed data is communicated e.g. to a remote ground station 207 which is capable of assessing the success extent of the interception 208. In accordance with certain embodiments, the ability to acquire sky view of the interception point from a proximate location (say from the carrier or from acquisition means released therefrom) constitutes a significant advantage compared to a situation where the view of the interception scene is obtained from a remote location such as ground station. Obtaining sky view from a shorter distance allow clear view of the kill scene which may facilitate accurate assessment of the interception and in the case of partial or full failure applying the desired modifications in order to achieve successful result in subsequent trials.

Reverting now to Fig 2A, after intercepting the dummy target, its debris enter the atmosphere and are burned 209. Hie carrier (having accomplished its mission) is guided 210 to a prior planned falling area (e.g. in order not to fall onto a friendly territory), as will be explained in greater detail below and likewise, the interceptor is guided to a preplanned falling area (as will be explained in greater detail below 211).

Bearing this in mind, attention is drawn to Fig. 2B, illustrating schematically a rerouting technique in accordance with certain embodiments of the invention. Thus, at the release location (201), the dummy target flies in velocity V! at a direction depicted schematically by vector V! (202). There is a need to confer a small lateral velocity component Δν (203) (Δν « V!) which necessary entails deviation of the carrier missile from direction (202) to a re-routed direction designated by vector V₂ (204). The lateral velocity component can be realized, e.g. by activating a small rocket or say activating another techniques like pyro technique charge, pneumatic or mechanical energy sources etc. (not shown), all as known per se. The velocity component Δν is determined to give rise to a re-routed flight trajectory of the carrier 205 which as specified above achieves least the following: (i) the new route deviates from the flight trajectory of the dummy target (206) so as to facilitates sensing of interception scene when the interceptor 207 attempts to intercept the dummy target at the interception point (208). As also specified above, in accordance with certain embodiments, the re-routing of the flight trajectory of the carrier is designed accordingly to the interception test objectives.

As may be recalled, the dummy target has substantially the same characteristics as those of the simulated GTG missile, and accordingly, if the interceptor succeeds in destroying the dummy target, then the likelihood of successful interception of real GTG threat by the same type of interceptor significantly increases.

In accordance with certain embodiments, the -Exo-Atmospheric missile's interception trial allows to destroy in a controlled fashion both the interceptor and the carrier missiles after the interception event. This is shown schematically in 101 of Fig. 1, illustrating the falling trail of the interceptor and 102 illustrating the falling trail of the carrier. Assuming that the interception point is selected to be in an unpopulated area (or the sea) the both missiles (interceptor and carrier) should sink into the deep sea after the interception test. It should be noted that at in accordance with the prior art where the target is a ballistic missile having characteristics that resemble the target GTG missile the safety range problem is very complicate in case of exo- atmospheric interception:

• The target missile is coming towards Israel and destroyed by interceptor during interception test. As a result some of high energy uncontrollable target missile debris flies towards the populated area inside the country and there is a risk that the debris will fall in a populated territory or even in a territory of neighboring country. This safety problem called “Near Safety Problem”.

• On the other hand the interceptor missile is also destroyed during interception and its high energy uncontrollable debris may fly towards the populated territory far away from Israel. Such kind of safety problem called “Far Safety Problem”.

• Some of said debris after interception process could have vector of velocity that significantly different from velocity of original missile. This statistical behavior of debris increases the required safety range from interception point to populated territories and in additional defines the maximum altitude of interception tests.

• The complex of noted safety problems generally eliminates performance of exo-atmospheric interception tests at Israel.

Proposed method of interception test provides solution for both types of noted safety problems (near and far):

• After the interception remain two controllable missiles (carrier and interceptor) and parts of dummy target (in case of successful test) or unharmed dummy target (in case of unsuccessful test).

• At both cases the dummy target or its parts will be burned during re-entry into earth atmosphere and wouldn’t reach the earth surface.

• Unharmed and fully controllable carrier missile could be led exactly into the appropriate area in the sea.

• Interceptor after colliding with dummy target may be lightly damaged and destroyed by fully controlled self destruction mechanism.

• None of noted bodies produces dangerous high energy uncontrolled debris during interception

In accordance with certain other embodiments, there is a need to simulate a GTG missile that is likely to be launched from a far distance (e.g. from a far enemy state). To this end, the carrier should have been launched from a trial territory being of substantially similar distance to what would have been the distance had the real GTG been launched and in this case the carrier would fly along the longer flight trajectory. Similar to the GTG missile, the dummy target (which emulates the GTG missile) is likely to fly in a similar flight trajectory as that of the real threat simulating thus a real threat scenario. However, for certain countries (for instance, Israel) which would desire to perform the interception trial in accordance with the teachings of the invention, there is no access to such far territory for launching the carrier therefrom . There is thus a need to launch the carrier missile from a shorter distance (giving rise to shorter flight trajectory) however achieving a flight trajectory that resembles the long one which a GTG missile would have been flied had it been launched from the farther enemy territory. Thus, in accordance with certain embodiments, and as illustrated by way of non-limiting example in Fig. 1, the carrier 11 is launched from location D2 (giving rise to a distance of D2-D1 from the interceptor 13 launching location DI). However, it would have been desired to launch the carrier from location D3 since the distance D3-D1 (>D2-D1) is the actual distance from which a real threat would have been launched had the enemy commenced an act of war. There is thus a need, in accordance with certain embodiments, to cope with the specified limitation where there is no accessible territory at location D3 and nevertheless achieving a flight trajectory that simulates that of a real threat. Thus, in accordance with certain embodiments the carrier is launched from D2, however, when the dummy target is released, it is re-routed to a trajectory having characteristics similar to the longer flight trajectory (i.e. had the carrier been launched from D3). This is illustrated by back tracking the re-routed flight trajectory of dummy target 16 (see trajectory 103 marked in dashed line) to a virtual launching point D3. Of course, D1,D2 and d3 are provided by way of example only and the dummy target can be directed to a different desired trajectory depending on the desired virtual launching location. The re-routed flight trajectory of the dummy target simulates thus a launch of the dummy target from a further distance than the actual launching point of the carrier.

Having described a typical dummy target interception scenario and a sequence of operational stages in accordance with certain embodiments of the invention, there follows a description that pertains to the dummy target structure and operation in accordance with certain embodiments of the invention. Fig. 3A illustrates schematically a dummy target releasing mechanism, in accordance with an embodiment of the invention. As shown the carrier 31 accommodates dummy targets 32 and 23 that are located in a designated compartment inside the missile. As will be explained in greater detail below, the dummy targets are stored in the compartment in a wrapped form and are inflated upon release.

Turning now to Fig. 3B, there is shown a flowchart of the operational stages for releasing and activating a dummy target, in accordance with certain embodiments of the invention. Thus, when the missile arrives a given location at space (e.g. 15, as described with reference to Fig. 1, above), 301 a known perse activation means are invoked (e g. activating pyro technique charge, pneumatic or mechanical energy sources etc.), and the .dummy targets are released to the space 302. Upon release, the dummy targets are inflated, using, say, air that is pressurized by a pressure vessel or a gas generator 303 (as described in greater detail below). The air inflates the dummy target. The dummy target is now ready 205 and flies in a designated file trajectory (e.g. 17), as described with reference to Fig. 1 above.

Turning now to Figs. 4A-C, they illustrate schematically a more detailed dummy target releasing mechanism, in accordance with certain embodiment of the invention.

Thus, the dummy targets are accommodated in designated compartment(s) (in this example compartments 42 and 43 of carrier missile 41, such that each compartment accommodates one dummy target in a wrapped form. Upon release, say by invocation of an air bag 44, the dummy target is ejected to space and is filled with air generated by a pressure vessel or a gas generator and transformed (in its inflated state) to an object having geometry that resembles that of the missile 45, as shown in Fig. 4B. As specified above with reference to Fig. 1, the release occurs at a desired stage.

Turning now to Figs. 5A-B, they illustrate schematically a dummy target in wrapped and inflated forms, respectively, in accordance with certain embodiments of the invention. Thus, the dummy target in its wrapped position is inflated (upon release see Fig. 5B) by gas originated from known per se pressure vessel or gas generator 51. The gas inflates the dummy target such that its geometry 52 resembles that of the missile. A non limiting manner for achieving desired RF signature is by coating the skin of the dummy target with a proper material, thereby achieving RF signature that resembles that of the flying missile and the temperature such that it manifests an IR signature that resembles that of the flying missile. The dummy target skin may be heated by using of the known from prior art methods like:

• Chemical surface heating by known per se electrically activated composition, which upon activation can generate a desired temperature which extends for a pre-defined duration • Dummy target surface heating by the gas injected by gas generator In this case accordance with certain other embodiments, there is employed another gas generator (not shown) which is configured to serve as a backup for maintaining a required temperature (for achieving the designated IR signature) and for generating sufficient internal pressure so as to keep the geometry of the dummy target substantially intact. The invention is not bound by the number of gas generators that a re used.

In accordance with the embodiments described above, the dummy target manifests IR signature and/or RF signature and/or geometry characteristics that resemble those of the missile.

There follows a description in accordance with certain embodiments of the invention which concerns achieving exo-atmospheric flight dynamics of the dummy target that substantially match that of the missile. Thus, attention is now drawn to Figs. 6A-B, illustrating schematically a front and side views of a dummy target, serving for explaining dynamic equations, in accordance with an embodiment of the invention. As shown, in the side view of Fig. 6A, two nozzles fitted in the dummy target (at locations 62 and 63). In response to ejection of gas from the specified nozzles, two opposite forces Fl and F2 are applied to dummy target 60 forcing a pitch movement of the dummy target about lateral axis 61 (constituting the center of gravity of dummy target 60). In addition, and as shown in a front view of the dummy target 60 (Fig. 6B), two additional nozzles 65 and 66 force roll motion of the dummy target a in response to ejection of gas therethrough. By this example, the pitch motion illustrated in Fig. 6A and the roll motion illustrated in Fig. 6B give rise to dummy target exo-atmospheric flight dynamics that should resemble those of the Ground to Ground missile. As will be explained in detail below, in accordance with certain embodiments, the gas pressure inside the dummy target and nozzle dimensions are exemplary parameters which are a priori designed to achieve the desired pitch and roll motions.

Fig. 6C illustrates a lateral cross section of a nozzle, in accordance with certain embodiments of the invention. The nozzles depicted in the embodiments of Figs. 6B and 5C (e.g. 62 of Fig. 5A) may have the shape as illustrated by way of example in Fig. 6C. Note that the invention is not bound by the use of 2 nozzles per channel (i.e. pitch or roll) as depicted by way of example with reference to figs. 6B and 6C. In accordance with certain embodiments, the number of nozzles in the roll channel are at least two and the number of nozzles in the pitch channel is at least one.

Note also that the invention is not bound by the specific locations of the nozzles in the periphery of the dummy target. The invention is likewise not limited to the specific nozzle shape as depicted in Fig. 6C. Another non limiting examples of nozzles are illustrated in Figs. 7A and Fig .7B.

Turning now to Figs 8 and 9, they illustrate schematically a front 81 and side 82 views of a dummy target, serving for explaining dynamic equations, in accordance with an embodiment of the invention. Figs. 9A-B illustrate set of equations serving for explaining the dynamics exo-atmospheric flight characteristics of a dummy targef in accordance with certain embodiments of the invention.

Turning at first to the side view, it shows one nozzle fitted in the dummy target (at locations 83). Note that unlike Fig. 6 where two nozzles are depicted in the example of Fig. 8 A only one is depicted. As was explained above, the invention is not bound to the use of one or two nozzles. As shown, in response to ejection of gas from the specified nozzle 83 a force Fl is applied to dummy target 80 forcing a pitch movement of the dummy target about lateral axis 84 (constituting the center of gravity of dummy target 80). The pitch motion is around the Z axis. Due to the symmetric shape of the dummy target, it moves in a similar fashion about the Y axis. As will be explained in greater detail with reference to the equations of Fig. 9,1 (85 in Fig. 8 A) designates the distance between the center of gravity and the nozzle. P_c stands for the gas pressure inside the dummy target. Tuning now to Fig. 8B, it shows a front view of the dummy target. By this example (unlike Fig. 6B), only one nozzle 86 is utilized, wherein in response to release of gas through the nozzle, a force F2 is generated and applied to the dummy target giving rise to roll motion about axis X. 7? (87) stands for the radius of lateral circular cross section of the dummy target that crosses the nozzle.

As will be explained below with reference to Fig. 9, the motion of the dummy target in the roll and pitch channels, give rise to dummy target exo-atmospheric flight dynamics that resembles those of the Ground to Ground missile.

It should be noted that in order to achieve exo-atmospheric flight dynamics of the dummy target that resembles that of the missile, the dummy target should develop an angular accelerations in the pitch channel and the roll channel that will give rise corresponding angular velocity which substantially match that of the missile. Moreover, the angular accelerations (in the respective channels) should be dropped to substantially zero once the target velocities are achieved. Having arrived to the desired velocities (and eliminating the acceleration), the dummy target will maintain these angular pitch and toll velocities as it flies in the space achieving thus exo-atmospheric flight dynamics that resemble those of the GTG missile. The set of equations described below with reference to Figs. 9A and 9B will explain how to arrive to desired angular accelerations in the specified channels.

Bearing this in mind, attention is drawn to Fig. 9A, illustrating set of equations serving for explaining the dynamics exo-atmospheric flight characteristics of a dummy target, in accordance with certain embodiment of the invention. Thus, and as shown in equation 91, F stands for the nozzle thrust (see e.g. Fl in fig. 8A) and is calculated as the product of Pc (signifying the pressure in the closed volume of the dummy target, see e.g. fig. 8A) 93 , signifying Nozzle area (94) and a coefficient Q 95 having a value of ~1.2. Note that A is easily measurable and Cfis constant. The calculation of Pc is discussed in more detail with reference to Fig. 8B below, and, accordingly, F can be calculated.

The angular accelerations in the roll channel and the pitch channel (96 and 97, respectively) are calculated as Inertial Moment M divided by Inertial I. As shown, for example in equation 97, M is calculated as a summed product of F and I where the former is given in equation 91 (and discussed above) and the latter is a priori known (see 85 in Fig. 8A). The Σ over i sums i products of F and /, where i stands for the number of nozzles, (by the embodiment of Fig. 7 A only 1 nozzle is utilized). In the example of calculating angular acceleration in the pitch channel (equation 97), the relevant Inertia is along either the Y axis (or symmetrically the Z axis) and therefore is designated in 97 as Ιγγ. Note that Ιγγ is measurable in a well known manner to a person versed in the art.

Similarly, in equation 96 (defining the angular acceleration in the roll channel), M is calculated as a summed product of F and R where the former is given in equation 91 (and discussed above) and the latter is a priori known ( see 87 in Fig. 8B). ^,The Σ over j sums j products of F and R, where j stands for the number of nozzles (by the embodiment of Fig. 8B only 1 nozzle is utilized). In the example of calculating angular acceleration in the roll channel (equation 96), the relevant Inertia is along the X axis (and therefore is designated in 97 as Ιχχ״ Note that is measurable in a well known manner to a person versed in the art.

Moving on to Fig. 9B, there follows a description for calculating P_c, which as may be recalled is required in order to determine F (see equation 91).

Thus, P_c (t) is dependent upon a constant R (which is determined by pressure vessel or gas generator property), Gas temperature T 903 inside the dummy target, VOL signifies the volume of the dummy target. m_in 904 signifies the rate of flow per unit time generated by the pressure vessel or gas generator. This value is determined according to the generator specification. m_out905, in its turn, stands for the rate of flow of the gas flowing out of the dummy target (through the nozzles) and complies with equation 906. Note that the parameters that affect m_out are Pc(t) which is determined iteratively (see 901), which is the nozzle's area, T standing for the gas temperature (see 901) and const that is determined by the geometry of the nozzle and the gas property.

It is thus appreciated that the number of nozzles (z and i), the area of the nozzle (A_exit), the Inertia Ιγγ _י Ιχχ, gas temperature T, dummy target's volume VOL , nozzle location (relative to the center of gravity) R and /, (calculated based on the above parameters) and, m_in can all be determined in order to arrive to the specified desired angular velocity in the pitch and roll channels.

Note also that there is an inherent behavior of the dummy target which supports the desired achievement of pitch and roll angular velocities. Thus, when the dummy target is ejected to space in a wrapped form, it has a small moment of inertia around the three axes and due to a random parasitic load resulting from the ejection process, the wrapped dummy target manifests a random angular velocities in the respective axes. After the inflation the moment of inertia dramatically increases (e.g. in about 3 order of magnitude) and consequently the angular velocities in the respective axes is significantly reduced thereby allowing to control the specified angular roll and pitch velocities so as to achieve dummy target exo-atmospheric flight dynamics that resemble that of the RV. It is therefore appreciated that the specified process facilitates obtaining desired dummy target exo-atmospheric flight dynamics (in the pitch and roll channels) notwithstanding of the initial uncontrolled perturbations.

The requirement dynamic characteristics may be achieved also by usmg of well known from prior art flywheel mechanisms but it’s using seems problematic for present application because of relatively high weight consumption (flywheels and their power sources).

Note that whereas the specified description with reference to certain embodiments referred to a situation that the dynamics of the dummy target resembles that of a real target during a significant portion of the exo-atmospheric flight duration, this is not necessarily always the case. In certain embodiments, the specified dynamic characteristics are activated during a shorter term, say during the END GAME section only. Note also (and as will be explained in greater detail below), that the invention is not bound by the specified technique for generating appropriate dummy target dynamics.

The exo-atmospheric Ground-to-Ground missile's interception trial has been described with reference to non limiting embodiments of dummy targets as described with reference to Figs. 5, 6, 7, 8 and 9. There follows a description with reference to Fig. 10 illustrating schematically a dummy target in accordance with another embodiment of the invention. Unlike the dummy target depicted in Fig. 5B, in accordance with this embodiment, the dummy target is not an inflatable whole object (see rear and side views in Figs. 10B and 10D, respectively) but rather composed of a chassis of inflatable ducts e.g. 1000,1001 which are inflated using e.g. a pressure vessel or a gas generator of the kind described above. The pitch and roll dynamics may be achieved using nozzles, e.g. 1002-1003(in Fig. 10C) for the pitch and the 1004-1005 (in Fig. 10A) for the roll to achieve dynamics that comply with the algorithmic expressions discussed in detail with reference to Figs. 8-9, mutatis mutandis. The ducts are wrapped with appropriate sheets (not shown) giving rise to a dummy target having a shape similar to that described with reference to the embodiments depicted above. The shape of the body achieves the desired geometry characteristics of the dummy target, as discussed in detad above. The RF signature is achieved by using a material that have RF signature similar to that of the GTG missile (as discussed in detail with reference to the previous embodiments, above). As may be recalled in the previous embodiments, the IR signature was achieved by using a surface chemical heating by known per se electrically activated composition, which upon activation can generate a desired temperature which extends for a pre-defined duration or heating the dummy target surface by the gas injected inside the dummy target from gas generator.

The invention is not bound to the means for generating flight dynamics in the manner specified above. Thus, in accordance with certain other embodiments and as illustrated with reference to Fig. 11A-B , a flywheel 1100 is fitted in the inflatable dummy target and is activated by a motor (not shown) at desired timing for rotating about its lateral axis 1101 (in a direction indicated by arrow 1102). As a result, the dummy target will rotate in an opposite direction (specified by arrow 1103) as stipulated by the respective mertial moments ratio, ah as know per se, so as to achieve die desired roll dynamics. Turning to Fig. 1 IB, the pitch dynamics is achieved by fitting a flywheel 1105 a normal orientation relative to flywheel 1100. Flywheel 1105 rotates about its lateral axis 110« in a direction indicated by arrow 1107 to thereby achieve rotation of dummy target in an opposite direction (specified by arrow 1108) as stipulated by the respective inertial moments ratio, all as know per se , so as to achieve ihe desired pitch dynamics. In order to achieve angular acceleration (or deceleration) so as to achieve the appropriate pitch and roll dynamics, the flywheels are accelerated/decelerated using the respective motors, all as known per se. The placement of flywheels in Ihe manner specified including the related motors and gimbals is generally known per se and therefore not further expounded upon herein.

As may be recalled the trial is in fact fully controlled smce the launch timing of the carrier and the interceptor are fully controlled, and likewise also the release timing of the dummy target as well as ihe timing of the interception and Ihe location of the interception point are all planned in advance. It is also noted that the operational specification of the interceptor are well known insofar as the minimal distance from target that is required to sense IR signature are concerned. In other words, when the interceptor is too far away from the target (by this embodiment the dummy target) it is insensitive to the IR signature of the target. Accordingly, in accordance with certain embodiments, die dummy target's IR signature is activated only during the END GAME such that the interceptor can sense the IR signature. With reference to the embodiment of Fig. 12, this means *at *e electrically operated heating composition is activated at a predefined tinting when *e interceptor is sufficiently close to sense *e IR signature of *e target This enables to activate *e IR signature generation means for only a limited period. This is illustrated in Fig. 12, which illustrates schematically an IR signature activation curve, in accordance wi* certain embodiments of *e invention. As shown, *e IR signature is activated only at the end game 1200 (i.e. when *e temperature rises). Whilst *e description wi* reference to Fig. 12 exemplified activation of *e IR signature not throughout *־ entire exo-atmosphenc flight session (i.e. through only a partial session, such as *e END GAME), *e invention is not bound to activate only IR signature through a partial exo-atmospheric flight session. Thus, o*er charactenstics, such as RF signature and generating desired dummy target dynamics may be activated through partial session such as the END GAME.

As specified above *e carrier is capable of acquiring *e sky view of *e kill scene. In accordance wi* certain embodiments this is achieved by utilizing *e technique disclosed in WO 2006/025049 a system and me*od for destroying a flying object

Those versed in *e art will readily appreciate that in accordance wi* various embodiments of *e invention *ere is provided a me*od for simplifying exoatmospheric Ground-to-Ground (GTG) missile's interception trial, *at *eludes:

(a) providing at least one dummy target *at is manufacturable in considerable simpler manufacturing process *an a GTG missile, and capable of manifesting characteristics *at resemble characteristics of *e GTG missile;

(b) providing a common carrier missile capable of accommodating at least one dummy target irrespective of the characteristics thereof;

whereby said common carrier missile is capable of being launched and being configured to release at least one dummy target at selected exoatmospheric location, for testing the ability of an interceptor missile to intercept said dummy target at exo-atmospheric interception point, thereby testing the interceptors operational feasibility to destroy the GTG missile.

(c) Providing a kill assessment information from the kill scene including achieved miss distance, angle of incidence etc.

As used herein, the phrase for example, such as and variants thereof describing exemplary implementations of the present invention are exemplary in nature and not limiting. Reference in the specification to one embodiment, an embodiment, some embodiments, another embodiment, other embodiments or variations thereof means that a particular feature, structure or characteristic described in connection with the embodiments) is included in at least one embodiment of the invention. Thus the appearance of the phrase one embodiment, an embodiment, some embodiments, another embodiment, other embodiments or variations thereof do not necessarily refer to the same embodiments). It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination. While the invention has been shown and described with respect to particular embodiments, it is not thus limited. Numerous modifications, changes and improvements within the scope of the invention will now occur to the reader. In embodiments of the invention, fewer, more and/or different stages than those shown in the drawings may be executed.

The present invention has been described with a certain degree of particularity, but those versed in the art will readily appreciate that various alterations and modifications may be carried out without departing from the scope of the following Claims.