IL226015A - Extended range trajectory-correctable mortar projectile - Google Patents

Description

Technical Field The present invention relates to the field of weapon systems, and more particularly to the enhancement of the performance of projectiles launched from available artillery barrels, such as from mortar barrels.

Technical Problem The problem relates to the desire of upgrading the capabilities of existing artillery pieces by enhancing the rounds without incurring the need to replace the existing barrels launchers. For example, by striving to enhance the projectiles to achieve extended range and increased precision of striking a desired target while avoiding the need to change available mortar artillery pieces. Proposed solutions endeavor to apply advanced technology used for guided missiles to rather inexpensive mortar bombs, thereby dethroning such bombs from their status of low cost rounds of ammunition. Such advanced technology requires the addition of aerodynamic surfaces and of deflectable fins to the projectiles. The deployment of wings and fins, their control and guidance mechanisms all require parts turning the former sturdy mortar bombs into delicate guided weapons.

Solution to Problem Instead of deploying wings to enable the projectile to glide after passing beyond the peak of the trajectory to extend the operational range, enhanced aerodynamic allows to obtain the desired result. For example, a short 120 mm mortar barrel may easily accept a slender subcaliber projectile, thus of lesser than caliber diameter, supported by a sabot until exit out of the muzzle, for achieving extended range. Furthermore, simple monolithic electro-optic guidance devices may enhance target strike precision.

As an alternative to fins for course correction, behind- trajectory-peak and/or close-to-target guidance may be provided for example by micro-rocket thrusters controlled by an electro-optic guidance unit.

In broad lines, the solution to the problem is thus provided by integrating a monolithic guidance unit and micro-rocket motors in a slender aerodynamic body, built as a subcaliber projectile.

Description of Embodiments Figs. 1 to 7 are schematic illustrations of various exemplary embodiments of the present invention.

Fig. 1 shows a first exemplary embodiment illustrating possible main portions of a slender aerodynamic body configured as a subcaliber projectile 10. The following portions may be disposed in sequence end to end, starting from the front F to the rear R of the projectile 10: I. seeker and guidance portion; II. course correction portion; III. warhead portion; and IV. stabilization portion.

As shown in Fig. 2, at least one sabot 12 may be configured to include at least two sabot portions 14 to support the projectile 10 in the interior of the barrel B.

The seeker and guidance portion I may include a dome 16, a GPS antenna 18 and a control unit 20.

The dome 12 may be transparent to radiation and may hold a semi-active laser 22 operative as a target detection device, but other devices capable of deriving target data may also be used. Typical devices may be for example, a four quadrant seeker, an IR seeker, or an HR seeker. The seeker and guidance portion I may include one or more target detection devices. The GPS antenna 18 may be configured to derive position information for use of an at least one seeker device. The semi-active laser 22 and the GPS antenna 18 may preferably be coupled to the control unit 20. The control unit 20 or signal processing unit 20 may have a processor, not shown, configured to run image analysis and signal processing programs and provide commands to the course correction portion II.

The course correction portion II may carry a distribution of a plurality of micro thrusters 24, which may be selected as one-shot miniature rocket motors. A belt of such micro-thrusters 24 may be disposed in angular distribution and envelope the periphery of the course correction portion II. Belts of such miniature rocket motors 24 may be stacked in layers which may be disposed longitudinally along the length L of the projectile 10.

The operation of one or more of the micro-thrusters 24 applies a momentary force perpendicular to the length of the projectile 10 and is therefore able to deflect the trajectory thereof when in flight. One such micro-thruster 24 or pulser 24, having a diameter of say 1 cm and a length of 2 cm, and holding some 1.5 gr of propellant may burn for about 0.005 seconds, and may provide an impulse of 3Nsec. A micro thruster 24 may be commanded to operate by the seeker and guidance portion I during the post-apex portion of the ballistic trajectory of the projectile 10. This means that course correction commands may be given past the apex and until just before impact with a target T, which is not shown in the Figs.

The micro-thrusters 24 may thus for example operate for the correction of the ballistic trajectory according to optical signals derived by the seeker and guidance portion I from a laser illuminated target T. In turn, the optical signals may be forwarded to and processed by the control unit 20 to output commands that may be provided as command signals to the micro-thrusters 24.

The warhead portion III may include the actual warhead 26, a casing 28, an explosive charge 30, and a fuze 32 or safe and arm device 32 configured for the initiation of the explosive charge 30. The warhead portion III is thus a payload 34 configured for the attack and/or destruction of a selected target T toward which the projectile 10 is fired and guided. The configuration of the warhead portion III may be adapted to the type of target T against which a projectile 10 is fired.

A soft target T may require a proximity fuze 32P to initiate for example, a controlled fragmentation warhead 36, shown as a partial cross-section in Fig. 4, where the casing 28 may define a volume for holding fragments, such as shrapnel or bearing balls for example. The fuze 32 is shown to be preferably disposed at the front of the controlled fragmentation warhead 36. However, the semi-active laser 22 operating in association with the control unit 20 may derive a preset selected distance above ground and allow functioning or function to forward an initiation command to the box 32P, or fuze 32P of the controlled fragmentation warhead 36. If desired, an impact fuze 321 disposed preferably at the front of the controlled fragmentation warhead 36 to activate the explosive charge 30.

To defeat an armored target T, a shaped charge or a hollow charge 38 shown as a cross-section in Fig. 5, may be selected and may be initiated by an impact fuze 321 disposed preferably at the rear 30R of the explosive charge 30, even though other fuze dispositions may be chosen. Evidently, although not shown in the Figs., two hollow charges 38 in tandem may also be implemented.

For a fortified position, such as a bunker for example, it might be best to operate a penetration warhead 40, illustrated as a cross-section in Fig. 6. The casing 28 may have thick walls and may be appropriately shaped and built out of high strength material, such as superior quality resistant steel. A delayed operation fuze 32D is preferably chosen to initiate the penetration warhead 40. Such a fuze 32D may be preset to initiate the explosive charge 30 under selected conditions. Such an initiation condition may be for example: initiation following a predetermined delay of time after impact, or initiation when the projectile comes to a standstill after impact, or initiation following a predetermined distance after having passed through and out of an obstacle, such as a wall for example.

In Fig. 1, the stabilization portion IV which forms the tail at the rear R of the projectile 10, is shown to supports the stabilization fins 42, and may be configured to carry charges of propellant 44 which are not shown in the Figs. The stabilization portion IV may either slope down into a truncated cone TC from the diameter D of the projectile 10 towards a frustum at the rear R thereof, or terminate in a substantially cylindrical portion C of diameter d as shown in Fig. 2.

The fins 42 may be aligned axially with the length L of the projectile 10, or may be slanted relative thereto by say 5° for example, to provide some degree of spin during flight in trajectory.

For a stabilization portion IV shaped as a truncated cone TC, axial propellant charges, not shown in the Figs., may be inserted into a hollow interior portion of the cone, whereas ring propellant charges, not shown in the Figs., may be affixed to the cylindrical portion C.

The number of fins 42 may be selected as desired above a minimum of at least three fins. The diameter of the fins 42 may be selected as at most the caliber BD, or barrel bore diameter BD of the barrel B, but preferably not less than the diameter D of the projectile 10. For fins 42 of diameter BD as depicted in Figs. 1 and 2, one sabot 12 may suffice to support the projectile 10 in the barrel. However, for fins 42 having a diameter lesser than the barrel bore diameter BD of the slender body SB, as depicted in Fig, 7, more than one sabot 12 may be used.

For launch by a 120 mm mortar for example, the subcaliber projectile 10 may have a slender body SB with a diameter ranging between 60 to 20 mm, or between 55 and 45 mm, but preferably of 50 mm. The projectile 10 may reach a length L of between 160 to 40 cm, but may preferably have a length L of 50 cm. When launched with the maximal allowable charge of propellant 44, the projectile 10 reaches an extended range in excess of 10 km.

According to the description hereinabove, there is provided a method for enhancing the performance of a projectile 10 for an available mortar barrel, as well as a projectile therefor. The projectile may be configured as a subcaliber round for achieving extended range, and may have a plurality of micro-thrusters for achieving trajectory correction. The mortar barrel may have a smooth bore or a riffled bore and the mortar may be muzzle-loaded or breech-loaded. The trajectory correction(s) may include at least one trajectory-end correction and/or at least one post trajectory apex correction.

The subcaliber projectile 10 may be supported by at least one sabot and each sabot may be made out of at least two sabot portions.

The warhead of the subcaliber may be selected as a penetration warhead, a controlled fragmentation warhead, a hollow charge warhead, or a general purpose warhead. Collateral damage is mitigated by trajectory-corrected enhanced precision strike.

The projectile may have stabilization fins that are selected as fins aligned with the length of the projectile or slanted thereto, and the diameter of the fins may extend to at most the bore of the mortar barrel.

Optics of the subcaliber projectile 10 may be implemented as monolithic optics or solid state optics. Since the projectile 10 may be free of moving parts or elements, i.e. free of parts or portions requiring deflection and/or deployment, the subcaliber may be considered as a solid state round, just like a conventional mortar bomb.

For persons skilled in the art, the description hereinabove is sufficient to allow the implementation and use of the projectile 10, and therefore, a detailed description is superfluous.

Reference Signs List

Claims (14)

1. A method for enhancing performance of a projectile for an available mortar, the method comprising the steps of: configuring the projectile as a subcaliber round for achieving extended range, and providing a plurality of micro-thrusters for achieving trajectory correction.

2. The method of claim 1, wherein the mortar barrel has one of a smooth bore and a riffled bore.

3. The method of claim 1, wherein the mortar is loaded as one of a muzzle-loaded mortar and a breech-loaded mortar.

4. The method of claim 1, wherein the trajectory correction includes at least one trajectory-end correction.

5. The method of claim 1, wherein the trajectory correction includes at least one post trajectory- apex correction.

6. The method of claim 1, wherein the subcaliber is supported by at least one sabot.

7. The method of claim 1, wherein the subcaliber is supported by at least one sabot, and each at least one sabot is made out of at least two sabot portions.

8. The method of claim 1, wherein the subcaliber has a warhead selected as one of a penetration warhead, a controlled fragmentation warhead, a hollow charge warhead, and a general purpose warhead.

9. The method of claim 1, wherein collateral damage is mitigated by enhanced trajectory corrected precision strike.

10. The method of claim 1, wherein: the projectile has stabilization fins selected as one of fins aligned with the length of the projectile and fins slanted thereto, and a diameter of the fins extends to at most a bore diameter of the mortar barrel.

11. A projectile for an available mortar, the projectile comprising: a subcaliber round configured to achieve extended range, and a plurality of micro-thrusters configured to achieve trajectory correction(s) selected as one of or as both mid-course trajectory correction(s) and end of trajectory correction(s).

12. The projectile of claim 11, wherein the mortar barrel has one of a smooth bore and a riffled bore.

13. The projectile of claim 11, wherein the mortar is loaded as one of a muzzle-loaded mortar and a breech-loaded mortar.

14. The projectile of claim 11, wherein the trajectory correction is a trajectory-end correction.