WO2022013547A1

WO2022013547A1 - Apparatus and methods for disabling aerial vehicles

Info

Publication number: WO2022013547A1
Application number: PCT/GB2021/051798
Authority: WO
Inventors: James William BIRD; Nikita Jasmine GREENIDGE
Original assignee: Synbiosys Ltd
Priority date: 2020-07-14
Filing date: 2021-07-13
Publication date: 2022-01-20
Also published as: GB202010860D0

Abstract

A projectile launching system (300) and projectile (100) are described. The projectile launching system (300) is configured to be mounted upon an aerial vehicle (1000) and comprises a projectile launcher (200) and a counterweight launcher (301). The projectile launcher (200) comprises a firing mechanism (302) for firing the projectile (100) in a first direction and a firing mechanism (303) for firing a counterweight (500) in a second, substantially opposite direction. The projectile (100) comprises a weighted tip (103) and an expandable net (113) connected between a plurality of movably mounted arms (107). The arms (107) are moveable to a deployed position in which the net (113) is spread between the arms (107). Methods of disabling aerial vehicles are also described.

Description

APPARATUS AND METHODS FOR DISABLING AERIAL VEHICLES

BACKGROUND OF THE INVENTION

[0001] The present disclosure relates to apparatus and methods for disabling aerial vehicles. More particularly, but not exclusively, this invention relates to a projectile for arresting aerial vehicles. The invention also concerns projectile launching systems and methods of disabling a target aerial vehicle.

[0002] Malicious unmanned aerial vehicles (UAV), or drones, can penetrate into sensitive and/or restricted areas and can thereby both a civilian and military threat. Some conventional systems for disabling such UAVs, such as radar-guided missiles, are expensive, and can be ineffective if the drone is too small to be detected by sensors, or if the UAV performs erratic and unpredictable evasion manoeuvres.

[0003] One way of arresting a malicious target UAV is to use another UAV that has some means of targeting and disabling the target UAV. For example, the “DroneCatcher” made by Delft Dynamics B.V. is a UAV that has a gun that is able to fire an expanding net to entangle and thereby arrest a target drone. US20180162529A1 also discloses a UAV-mounted net gun arrangement.

[0004] A problem with UAV-mounted net launching arrangements is that the net is fired with a relatively slow speed, and the expanded net experiences high drag when moving through the air. As such, these arrangements can have a limited range and target accuracy. Furthermore, such systems can be too heavy to be mounted onto small, manoeuvrable host UAVs which would be agile enough to be effective in a fast playing dog fight with a another small and manoeuvrable target UAV.

[0005] Recoil is also a problem where a projectile is fired from a host UAV, as the recoil force imparted upon the host UAV when the projectile is fired can adversely affect control of the host UAV and the accuracy with which the projectile is fired.

[0006] The present invention seeks to mitigate the above-mentioned problems. Alternatively or additionally, the present invention seeks to provide an improved projectile for disabling aerial vehicles, improved projectile launching systems, and improved methods of disabling a target aerial vehicle. SUMMARY OF THE INVENTION

[0007] The present invention provides, according to a first aspect, projectile comprising a body, a weighted tip connected to the body at or towards a first end of the body, a plurality of arms movably mounted in relation to the body, and an expandable net connected between the arms, wherein the arms are moveable between a stowed position in which the net is stowed and a deployed position in which the arms net is spread between the arms.

[0008] The projectile is configured to arrest and entangle aerial vehicles. In particular, the projectile is configured to arrest unmanned aerial vehicles, also known as drones. However, in principle, the projectile could be used to arrest a variety of flying objects. The projectile is intended to be fired with its weighted tip forwards and with the deployed net behind the weighted tip. The mass of the weighted tip is such that the centre of mass of the projectile is positioned forwards of the aerodynamic centre of the projectile when the projectile is moving with its weighted tip forwards and with its arms in the deployed position. This ensures that the projectile does not tumble when moving in its deployed configuration.

[0009] The body may be elongate. Preferably the arms are of equal length. However, it is within the scope of the invention for the arms to be of differing length. The body may define a body axis. In the stowed position the arms may be oriented at a first angle with respect to the body axis. In the deployed position the arms may be oriented at a second angle with respect to the body axis. The second angle may be greater than the first angle. The second angle may be between 45 degrees and 135 degrees to the body axis. The second angle may be between 80 and 100 degrees. The second angle may be substantially 90 degrees such that the arms are oriented substantially perpendicularly to the body axis when in the deployed position. The first angle may be between -10 (or 350) degrees and +10 degrees. As such, the arms may be angled towards or away from the body when stowed. Alternatively, the arms may be substantially parallel to the body when in the stowed position. [0010] The arms may be pivotally mounted in relation to the body and pivotable between the stowed position and the deployed position. The arms may be mounted to the body at pivot points. An arm may be pivotally mounted to the body at or near a first distal end of the arm. When the arms are in the deployed configuration, the centre of mass and centre of aerodynamic drag may lie on the body axis. The projectile may be configured symmetrically about the body axis.

[0011] The arms may be resiliently biased towards the deployed position. Configured as such, the arms may be movable against their resilient bias towards the stowed position. The resilient bias may be achieved through the use of, for example, a spring. Alternatively, the resilient bias could be achieved by designing the arms to bend from the deployed position to the stowed position, such that the bending stiffness of the arms causes the arms to move towards their deployed positions. The projectile may further comprise stoppers that are configured to prevent the arms moving beyond the deployed position. A stopper may comprise a tether connected between an arm and the body, wherein the tether is held under tension when the arm is in the deployed position. Each arm may be tethered to the main body to prevent the arms moving beyond the deployed position. The tether may be connected to the arm at, or near a distal end of the arm. The tether may be connected to the body at or near a position adjacent to the weighted tip. Alternatively, the stopper may comprise a stopping block that is mounted to the body such that the arms are configured to move into abutment with the stopping block to prevent them moving beyond the deployed position. The stopping block may be positioned on the opposite side of the arms to the weighted tip. In other embodiments, the stopper may comprises a hinged and/or bistable mechanism.

[0012] The projectile may additionally comprise a latch mechanism configured to hold the arms of the projectile in the stowed position. The latch may be configured to release the arms at a set time after the projectile has been fired, thereby delaying the deployment of the arms so that the net does not expand when the device first leaves the barrel. Such an arrangement can increase the range of the projectile.

[0013] There may be three or more arms movably mounted in relation to the body at substantially equispaced positions around a body axis. There may be four arms. A net is connected between each of the arms. A net may be connected to each arm along substantially all of the length of each arm. The net may be held under tension when the arms are in the deployed position. There may be a separate net, or net portion, connected between each of the arms, or there may be a single net which is connected to all of the arms. When in the deployed position, the net may define a region of at least 0.5 m². Generally, it is envisaged that the net is between 0.1 m² and 0.75 m² in size. However, the size of the net will depend on the size of the intended target drone, so it is within the scope of the invention for the net to be a range of sizes. For example, the net may be 1 m², or greater. In some instances, the net may be as small as 0.05 m². The arms may be mounted to the main body at, or towards, a second, opposite end of the main body. The body may have a length along the body axis at least equal to the length of the longest arm.

[0014] When in the stowed position, the arms may be positioned wholly within a region defined at one end by the weighted tip and at another end by a second, opposite end of the body. When in the stowed position, the free distal ends of the arms may be located adjacent or towards the weighted tip. When moving towards the deployed position, the free distal ends of the arms may move away from the weighted tip. The arms and net in the stowed position may define a cross-sectional dimension about the body axis, and the arms and net may be moveable to a position in which the cross-sectional dimension is approximately equal to a cross-sectional dimension of the weighted tip. The size of the cross sectional dimension of the arms and net in the stowed position may vary along the body axis. For example, the cross-sectional dimension of the arms and net when in the stowed position may be smaller in the region where the arms are mounted in relation to the main body and larger towards the distal ends of the arms, or vice versa. The arms and net in the stowed position may define a diameter.

[0015] It is envisaged that the weighted tip generally makes up between 40 and 95% of the total mass of the projectile. The weighted tip may comprise at least 50% of the mass of the projectile. For example, the weighted tip may make up between 70 to 80% of the total mass of the projectile. For higher speed requirements, the weighted tip may account for more of the mass of the projectile, for example up to 90 to 95 %. The centre of mass of the projectile may be in the region of the weighted tip when the projectile is in the deployed position. For example, the centre of mass may be in the body, slightly behind the weighted tip. Alternatively, the centre of mass may be within the weighted tip. The centre of mass may be closer to the weighted tip than to the opposite end of the body. [0016] The projectile may comprise a base at or towards a second end of the body. The base may be shaped to fit within a barrel of a projectile launcher. For example, the base may be substantially cylindrical. The base may be configured such that a firing mechanism can impart a force on the base to launch the projectile from the projectile launcher.

[0017] According to a second aspect of the invention, there is provided a projectile launching system configured to be mounted upon an aerial vehicle. The projectile launching system comprises a projectile launcher and a counterweight launcher. The projectile launcher is configured to hold an elongate projectile and comprises a firing mechanism for firing the projectile in a first direction. The counterweight launcher is configured to hold a counterweight and comprises a firing mechanism for firing a counterweight in a second, substantially opposite direction.

[0018] The projectile launching system of the second aspect of the invention is provided with a counterweight launcher such that, when the system is used to launch a projectile from a host UAV, a counterweight can be launched to mitigate the effect of recoil.

[0019] The projectile launcher may be configured to fire a projectile according to the first aspect of the invention. The projectile launcher may comprise a barrel or tube in which the projectile can be stored and fired from. The counterweight launcher may comprise a barrel or tube in which the projectile can be stored and fired from. The projectile launcher and counterweight launcher may be formed by a single body, for example, a single tube. In this case, a single firing mechanism, for example, a volume of pressurised gas positioned between the counterweight and projectile, could be used to simultaneously launch the counterweight and projectile. The counterweight may be any suitable material. For example, it may be metal or plastic, it may be a single mass or it may comprise multiple masses. It may for example be in pellet form. The counterweight may comprise a liquid such as, for example, water. Where a liquid is used, the counterweight may comprise a sabot, or similar, to aid with expelling the liquid from the counterweight launching tube.

[0020] The projectile launching system may be configured to be releasably mounted to the vehicle. This may be useful where the vehicle needs to jettison the projectile launching system or, where the vehicle is carrying a disabled target UAV in a tethered projectile, the vehicle can leave the target UAV in a desired location by releasing the projectile launching system. The vehicle may be an aerial vehicle. The vehicle may be an unmanned aerial vehicle. The projectile launcher may define a first axis and the counterweight launcher may define a second axis. The axes of the projectile launcher and counterweight launcher may be parallel. The projectile launcher and counterweight launcher may be coaxially aligned.

[0021] The projectile launching system may be configured to launch the projectile and the counterweight substantially simultaneously. The projectile launching system may be configured to launch the projectile at a first velocity and the counterweight at a second velocity, the first velocity and second velocity being selected such that the projectile and counterweight are launched with substantially equal and opposite momentum. This gives the advantage that the effects of recoil on the aerial vehicle are mitigated. As such, firing of the projectile may not adversely affect the control of the aerial vehicle.

[0022] According to a third aspect of the invention, there is provided a projectile launching assembly including the projectile launching system according to the second aspect of the invention and a counterweight, wherein the counterweight is releasably tethered to the projectile launching system. The counterweight may comprise a parachute. The parachute may be packed into a deployment bag. The counterweight may be connected to a projectile. The parachute may be configured to deploy via a static line connected between the parachute and the projectile launching system. A projectile may be tethered to the parachute. The projectile may be realisably tethered to the parachute. [0023] According to a fourth aspect of the invention, there is provided a projectile launching assembly including the projectile launching system according to the second aspect of the invention and a projectile according to the first aspect of the invention. The projectile is releasably tethered to the projectile launching system. Such an arrangement enables a target UAV to be disabled by the projectile. The target UAV, which is entangled by the net of the projectile, can then be carried by the host UAV to a specific location. For example, the host UAV could carry the target UAV back to a base and release the releasable tether to leave the target UAV at the base.

[0024] According to a fifth aspect of the invention, there is provided a projectile launching assembly including an unmanned aerial vehicle and a projectile launching system according to the second aspect of the invention, wherein the projectile launching system is mounted to the unmanned aerial vehicle. The projectile launching system may be releasably tethered to the unmanned aerial vehicle.

[0025] According to a sixth aspect of the invention, there is provided a method of disabling a target aerial vehicle comprising the steps of: from a host aerial vehicle, launching a projectile in a first direction, towards the target aerial vehicle, at a first velocity, causing movement of an ensnarement net of the projectile from a stowed position to a deployed position such that the target aerial vehicle becomes entangled in the ensnarement net, substantially simultaneously to the step of launching the projectile, from the host aerial vehicle, launching a counterweight in a second direction at a second velocity, the first and second velocities being selected such that the counterweight and projectile are launched with momentums which result in the net change of momentum of the host aerial vehicle being substantially zero.

[0026] The counterweight may be launched in a substantially opposite direction to the projectile. The method may comprise the further step of deploying a parachute from the counterweight, the parachute being connected to the projectile. The target aerial vehicle may therefore fall out of the sky under the control of the parachute. The parachute may be deployed via a static line arrangement connected between the counterweight and the host aerial vehicle.

[0027] It will of course be appreciated that features described in relation to one aspect of the present invention may be incorporated into other aspects of the present invention. For example, the method of the sixth aspect of the invention may incorporate any of the features described with reference to the apparatus of the first to fifth aspects of the invention and vice versa.

DESCRIPTION OF THE DRAWINGS

[0028] Embodiments of the present invention will now be described by way of example only with reference to the accompanying schematic drawings of which:

FIG. 1 shows a UAV-arresting projectile according to an embodiment of the invention, the projectile is shown in a stowed configuration within a barrel of a projectile launching system;

FIG. 2 shows the projectile of FIG. 1 outside of the barrel of the projectile launching system, the projectile is shown in a deployed configuration;

FIG. 3 is a view of the projectile in the deployed configuration in the direction of the arrow “A” in FIG. 2;

FIG. 4 A shows an embodiment of a projectile comprising stopping members configured to prevent the arms of the projectile from moving beyond their deployed positions;

FIG. 4B shows an embodiment of a projectile comprising hinged bistable mechanisms configured to prevent the arms of the projectile from moving beyond their deployed positions;

FIG. 5 A shows the weighted tip of an embodiment of the projectile wherein the tip is barbed;

FIG. 5B shows the weighted tip of an embodiment of the projectile wherein the tip is explosive;

FIG. 5C shows the weighted tip of an embodiment of the projectile wherein the tip is adhesive;

FIG. 5D shows the weighted tip of an embodiment of the projectile wherein the tip is magnetic;

FIGS. 6A to 6C are a sequence of images showing the projectile being fired from a rotary wing host UAV carrying a projectile launching device according to an embodiment of the invention, the projectile is fired to arrest a target UAV; FIGS. 7A and 7B are a sequence of images showing the projectile being fired from a host UAV carrying a projectile launching device according to a different embodiment of the invention;

FIGS. 8 A and 8B are a sequence of images showing the projectile being fired from a host UAV carrying a projectile launching device according to a further embodiment of the invention;

FIG. 9 shows a projectile that has been fired from a host UAV carrying a projectile launching device according to a further different embodiment of the invention;

FIG. 10 shows a host UAV carrying a projectile launching device according to a further different embodiment of the invention;

FIG. 11 shows a host UAV carrying a projectile launching device according to a further different embodiment of the invention;

FIG. 12 shows a fixed-wing UAV carrying a projectile launching device according to an embodiment of the invention; and

FIG. 13 shows a projectile launching device configured as part of a ground-based launching system.

DETAILED DESCRIPTION

[0029] An unmanned aerial vehicle-arresting projectile 100 according to an embodiment of the invention is shown in a stowed configuration in FIG. 1 and in a deployed configuration in FIG. 2. The projectile 100 comprises a body 101 in the form of an elongate shaft, with a substantially conical weighted tip 103 connected to the body 101 at a first end 1011 of the body 101 and a cylindrical base 105 connected at a second, opposite end 1012 of the body 101. In this case, the mass of the projectile is approximately 1 kg and the weighted tip makes up approximately 70% of this mass. The projectile comprises four arms 107 which are pivotally mounted to the body 101 at pivot points 108 adjacent to the cylindrical base 105. As can be best seen in FIG. 3, which corresponds to a view of the projectile 100 when in the deployed configuration in the direction of the arrow labelled “A” in FIG. 2, the arms 107 are equispaced around an axis X defined by the body 101. The arms 107 are biased towards their deployed configurations shown in FIG. 2 by springs 109 connected between the arms 107 and the main body 101. Tethers 111 are connected between the distal ends 1071 of the arms 107 and the first end 1011 of the body 101. As can also be best seen in FIG. 3, the projectile 100 comprises a net 113 formed by net portions 113 A - D connected between the arms 107.

[0030] The projectile is shown in FIG. 1 in its stowed configuration within the barrel 200 of a launcher. The arms 107 are substantially the same length as the body 101, such that they can be stowed in a position in which the arms 107 are almost parallel with the axis X defined by the body 101 and in which the arms 107 are positioned between the weighted tip 103 and the base 105, with the distal ends 1071 of the arms 1071 being positioned adjacent the weighted tip 103.

[0031] When the projectile 101 is inside the barrel 200, the arms 107 abut the wall 201 of the barrel 200 and the resilient bias of the springs 109 cannot move the arms 107 into their deployed configuration. As can be seen in FIG. 1, the arms 107 are not quite parallel with the body 101 when in the stowed configuration within the barrel 200. This is because the outer diameter D1 of the projectile in the region of the pivot points 108 is smaller than the inner diameter DB of the barrel 200. The resilient bias of the springs 109 pushes the arms 107 outwards until their distal ends 1071 abut the wall 201 of the barrel 200, therefore the outer diameter D2 of the projectile in the region of the distal ends 1071 of the arms 107 is equal to inner diameter DB of the barrel 200. In this case, the weighted tip has an outer diameter DT approximately equal to the inner diameter of the barrel 200 such that, when in the stowed configuration, the projectile 100 has a bullet-like profile and such that when the projectile is fired out of the barrel, the wetted area is effectively defined by the weighted tip 103.

[0032] When the projectile is fired out of the barrel 200 in the direction indicated, the resilient bias of the springs 109 pushes the arms 107 such that the arms pivot about their respective pivot points 108 away from the body 101 towards their deployed configurations. As the arms 107 and net 113 open, aerodynamic drag acts in conjunction with the springs 109 to move the arms 107 to their fully deployed configurations shown in Figure 2, where the uppermost arm 107 has been pivoted in a clockwise direction to its deployed configuration and the lowermost arm 107 has been pivoted in an anticlockwise direction to its respective deployed configuration. The tethers 111 act as stoppers to prevent the arms 107 from moving beyond their deployed configurations shown in Figure 2, the tethers 111 thereby being held in tension when the arms are deployed. In other embodiments of the invention, the projectile 100’ may comprise stopping members 111’ in place of the tethers 111 , as shown in FIG. 4A, which are configured such that the arms 107’ rotate into abutment with and are prevented from moving beyond their deployed positions by the stopping the stopping members 111’. In some embodiments of the invention, the projectile 100” may comprise hinged bistable mechanisms 111” which are configured to act as stoppers to prevent the arms 107” from moving beyond their deployed positions by, as shown in FIG. 4B.

[0033] In this case, the tethers 111 hold the arms at an angle A of 85 degrees with respect to the axis X defined by the body 101. Figure 3 depicts the wetted area of the projectile when in the deployed configuration, as can be seen, the net portions are spread between the four arms 107 to form a square net for arresting a UAV. The deployed area of the net 113 is approximately 0.5 m² in this instance.

[0034] The relative positions of the weighted tip 103 and deployed net 113 mean that when the projectile 100 is fired at its intended firing speed, which in this case is approximately 40 metres per second, the aerodynamic centre CD is quickly put behind the centre of mass CM, which in this case is in the body 101, slightly behind the weighted tip 103. The aerodynamic centre and the centre of mass CM being aligned on the axis X. This arrangement prevents the projectile 100 from tumbling in flight, makes the projectile 100 more robust to the effects of crosswinds and ensures that the largest area of the net 113 is presented to the target UAV.

[0035] While the presently described embodiment of the projectile 100 comprises a substantially conical weighted tip 103, the weighted tip may take on a variety of forms in other embodiments of the invention. For example, the tip may be barbed 1031, as shown in FIG. 5A, or explosive 1032, as shown in FIG. 5B, in order to cause damage to the target drone 2000. Or the tip may be adhesive 1033, as shown in FIG. 5C, or magnetic 1034, as shown in FIG. 5D in order to help ensure that that project sticks to the target UAV 2000 upon impact.

[0036] The process of firing the projectile 100 from a host UAV 1000 to arrest a target UAV 2000 will now be described with reference to FIG. 6A to FIG. 6C. The projectile barrel 200 forms part of a projectile launching system 300 that is mounted upon the host drone, as shown in FIG. 6 A. The projectile launching system 300 also comprises a counterweight barrel 301. The projectile 100 is contained in the projectile barrel 200 and a counterweight 500 is contained within the counterweight barrel 301. The projectile barrel 200 comprises a firing mechanism 302 configured to fire the projectile 100 out of the projectile barrel, and counterweight barrel 301 comprises a firing mechanism 303 configured to fire the counterweight 500 out of the counterweight barrel 301 in the opposite direction to the projectile 100. The projectile barrel 200 and counterweight barrel 300 are aligned along an axis Z such that the reaction forces exerted when the projectile 100 and counterweight 500 are fired act on the host UAV 1000 with the same moment arm.

[0037] To mitigate the effect of recoil on the drone when the projectile 100 is fired at a target UAV 2000, the projectile 100 and counterweight 500 are fired simultaneously, with the counterweight being fired at a velocity such that the momentum of the counterweight 500 with respect to time is of equal magnitude to the momentum of the projectile 100. The reaction forces exerted on the host UAV 1000 by the firing projectile 100 and counterweight are therefore equal and opposite in direction with respect to time, and result in zero net moment being exerted on the drone.

[0038] When the projectile 100 leaves the projectile barrel, the arms 107 move to their deployed configuration, with the net 113 being spread between the arms 107. The projectile 100 then impacts the target UAV 2000 and the target UAV becomes entangled in the 113. The target UAV 2000 is then brought to the ground by the projectile 100, with the counterweight also falling to the ground, as shown in FIG. 6C.

[0039] A projectile launching system 310 according to a different embodiment of the invention is shown as mounted upon the host drone 1000 in FIG 7A. The projectile launching system 310 is substantially identical to the projectile launching system 300 described with respect to FIG. 6A to 6C. However, the projectile launching system comprises tethers 314 connected to the projectile 100 and the counterweight 500 such that the entangled target UAV 2000 and the counterweight 500 can be taken to a specified location and brought to the ground under the control of the host drone 1000, as shown in FIG. 7B.

[0040] A projectile launching system 320 according to a further embodiment of the invention is shown as mounted upon the host drone 1000 in FIG 8 A. The projectile launching system 320 is substantially identical to the projectile launching system 300 described with respect to FIG. 6A to 6C. However, in this case, the counterweight 510 the is connected to the projectile 100 via a tether 315 and the counterweight 510 comprises a deployable parachute 511. The projectile launching system 320 is configured to deploy the parachute 511 via a static line arrangement 323. Within the counterweight barrel 321, the parachute 511 is stored in a parachute deployment bag 325 that is tethered to the projectile launching system 320 via the static line 323. The deployment bag is configured such that when the counterweight 510 is fired from the counterweight barrel 321, the momentum of the counterweight 510 pulls the parachute 511 out of the parachute deployment bag 325 to deploy the parachute 511, leaving the static line 323 and parachute deployment bag 325 connected to the projectile launching system 320 as shown in FIG. 8A. The parachute therefore deploys upon launch of the counterweight 510. The tether 315 is long enough in this instance to ensure that the projectile can reach the target UAV 2000 without being held back by the parachute 511. The projectile 100 impacts and entangles the target UAV 2000, and the target UAV 2000 is be brought to the ground under the control of the parachute 511, as shown in FIG. 8B. In other embodiments of the invention the parachute is configured to deploy only after the target UAV 2000 has been impacted by the projectile.

[0041] A projectile launching system 330 according to a further different embodiment of the invention is shown as mounted upon the host drone 1000 in FIG 9. In this case, the projectile launching system 330 is releasably mounted to the host drone via releasable mounts 331 such that the launching system can be jettisoned from the host UAV 1000. In this case, the counterweight 530 is again connected to the projectile 100 via a tether 335 and the counterweight 530 comprises a deployable parachute 531. In addition, the projectile 100 and counterweight 530 are connected to the launching system 330 via a further tether 336. The tethers 335, 336 comprise release points 337, 338, and 339 arranged such that the tethered projectile 100 and counterweight 530 can be released via release point 337, the counterweight 530 can be released from the projectile launching system 330 and/or projectile via release point 338, and the projectile 100 can be released from the parachute 531 and/or projectile launching system 330 via release point 339. Such an arrangement enables a variety of UAV capture scenarios. For example, the projectile 100 and counterweight 530 can be fired without releasing the parachute 531 and a captured target UAV 2000 can be taken to a specified location by the host UAV 100, which is still tethered to the projectile 100. The tether 336 can then be released and the parachute 531 can be deployed to let the target UAV 2000 fall to the ground under the control of the parachute 531. If, for example, the host UAV 1000 comes under fire while the host UAV 1000 is in the process of transporting the captured target UAV, the host UAV can release the entire launching system from releasable mounts 331 in order to make a quick escape.

[0042] A projectile launching system 340 according to another embodiment of the invention is shown as mounted upon the host UAV 1000 in FIG 10. The projectile launching system comprises a three projectile launching barrels 200A, 200B, 200C, and three corresponding counterweight launching barrels 301 A, 301 B, 301 C.

[0043] A projectile launching system 350 according to another embodiment of the invention is shown as mounted upon the host drone 1000 in FIG 11. The projectile launching system comprises a projectile launching barrel 200 positioned side-by-side with a counterweight launching barrel 301. Such an arrangement can reduce the length of projectile launching system. In this case the counterweight 500 is positioned further away from the centroid of the host UAV 1000 than the projectile 100, so the counterweight must be fired at a velocity such that its momentum is less than that of the projectile and such that the net moment on the host UAV is substantially zero.

[0044] While the projectile launching system has been described above as being mounted to and launched from a rotary -winged host UAV 1000, the projectile launching system can by fitted on any aircraft. For example, in some embodiments of the invention, the projectile launching system 300 may be mounted upon a fixed-wing UAV 4000, as shown in FIG. 12. The projectile launching system 300 may be even be hand-held, or configured as part of a ground-based launching system 5000, as shown in FIG. 13; in these instances, the projectile launching system may not need to fire a counterweight to counteract the recoil of a projectile being fired.

[0045] In an embodiment of the projectile not shown in the drawings, the projectile additionally comprises a latch mechanism configured to hold the arms of the projectile in the stowed position. The latch can be operated at a set time after the projectile has been fired to release the arms, thereby delaying the deployment of the arms so that the net does not expand when the device first leaves the barrel. Such an arrangement can increase the range of the projectile.

[0046] Where in the foregoing description, integers or elements are mentioned which have known, obvious or foreseeable equivalents, then such equivalents are herein incorporated as if individually set forth. Reference should be made to the claims for determining the true scope of the present invention, which should be construed so as to encompass any such equivalents. It will also be appreciated by the reader that integers or features of the invention that are described as preferable, advantageous, convenient or the like are optional and do not limit the scope of the independent claims. Moreover, it is to be understood that such optional integers or features, whilst of possible benefit in some embodiments of the invention, may not be desirable, and may therefore be absent, in other embodiments.

Claims

1. A projectile launching system configured to be mounted upon an aerial vehicle, the projectile launching system comprising a projectile launcher and a counterweight launcher, wherein the projectile launcher is configured to hold an elongate projectile and comprises a firing mechanism for firing the projectile in a first direction, and wherein the counterweight launcher is configured to hold a counterweight and comprises a firing mechanism for firing a counterweight in a second, substantially opposite direction.

2. A projectile launching system according to claim 1, wherein the projectile launching system is configured to launch the projectile and the counterweight substantially simultaneously.

3. A projectile launching system according to claim 1 or claim 2, wherein the projectile launching system is configured to launch the projectile at a first velocity and the counterweight at a second velocity, the first velocity and second velocity being selected such that the projectile and counterweight are launched with substantially equal and opposite momentum.

4. A projectile launching system according to any preceding claim, wherein the projectile launching system comprises a projectile launching tube and a counterweight launching tube, and wherein the projectile launching tube and the counterweight launching tube are substantially coaxially aligned.

5. A projectile launching assembly including the projectile launching system according to any preceding claim and a counterweight, wherein the counterweight is releasably tethered to the projectile launching system.

6. A projectile launching assembly including the projectile launching system according to any of claims 1 to 4 and a counterweight, wherein the counterweight comprises a parachute, the counterweight being configured to be connected to a projectile.

7. A projectile launching assembly according to claim 6, wherein the parachute is configured to deploy via a static line connected between the parachute and the projectile launching system.

8. A projectile launching assembly according to any of claims 5 to 7 further including an unmanned aerial vehicle, wherein the projectile launching system is mounted to the unmanned aerial vehicle.

9. A projectile comprising a body, a weighted tip connected to the body at or towards a first end of the body, a plurality of arms movably mounted in relation to the body, and an expandable net connected between the arms, wherein the arms are moveable between a stowed position in which the net is stowed and a deployed position in which the net is spread between the arms, wherein the mass of the weighted tip is such that, when the projectile is fired with its weighted tip forwards, the centre of mass of the projectile is positioned forwards of the aerodynamic centre of the projectile when the arms are in the deployed position.

10. A projectile according to claim 9, wherein the weighted tip comprises at least

40% of the mass of the projectile.

11. A projectile according to claim 9 or claim 10, wherein the centre of mass of the projectile is within or in the region of the weighted tip when the arms are in the deployed configuration.

12. A projectile according to any of claims 9 to 11, wherein the body defines a body axis and wherein, in the stowed position the arms are oriented at a first angle with respect to the body axis and in the deployed position the arms are oriented at a second angle with respect to the body axis, the second angle being greater than the first angle.

13. A projectile according to claim 12, wherein the second angle is between 45 degrees and 135 degrees to the body axis.

14. A projectile according to claim 12 or claim 13, wherein the first angle is between

-10 degrees and 10 degrees.

15. A projectile according to any of claims 12 to 14, wherein the arms are pivotally mounted in relation to the body and are pivotable between the stowed position and the deployed position.

16. A projectile according to any of claims 9 to 15, wherein the arms are resiliently biased towards the deployed position.

17. A projectile according to any of claims 9 to 16, wherein the projectile further comprises stoppers that are configured to prevent the arms moving beyond the deployed position.

18. A projectile according to claim 17, wherein a stopper comprises a tether connected between an arm and the body, wherein the tether is held under tension when the arm is in the deployed position.

19. A projectile according to any of claims 9 to 18, wherein there are three or more arms movably mounted in relation to the body at substantially equispaced positions around a body axis.

20. A projectile according to any of claims 9 to 19, wherein a net is connected between each of the arms.

21. A projectile according to any of claims 9 to 20, wherein the arms are mounted to the main body at, or towards, a second, opposite end of the main body.

22. A projectile according to any of claims 9 to 21, wherein the body has a length along the body axis at least equal to the length of the longest arm.

23. A projectile according to claim 22 configured such that, when in the stowed position, the arms are positioned wholly within a region defined at one end by the weighted tip and at another end by a second, opposite end of the body.

24. A projectile according to any of claims 9 to 23, wherein the arms and net in the stowed position define a cross-sectional dimension about the body axis, and wherein the arms and net are moveable to a position in which the cross- sectional dimension is approximately equal to a cross-sectional dimension of the weighted tip.

25. A projectile launching assembly including the projectile launching system according to any of claims 1 to 4 and a projectile according to any of claims 9 to 24, wherein the projectile is releasably tethered to the projectile launching system.

26. A method of disabling a target aerial vehicle comprising the steps of: from a host aerial vehicle, launching a projectile in a first direction, towards the target aerial vehicle, at a first velocity, causing movement of an ensnarement net of the projectile from a stowed position to a deployed position such that the target aerial vehicle becomes entangled in the ensnarement net, substantially simultaneously to the step of launching the projectile, from the host aerial vehicle, launching a counterweight in a second direction at a second velocity, the first and second velocities being selected such that the counterweight and projectile are launched with momentums which result in the net change of momentum of the host aerial vehicle being substantially zero.

27. A method according to claim 26 comprising the further step of: deploying a parachute from the counterweight, the parachute being connected to the projectile.

28. A method according to claim 27, wherein the parachute is deployed via a static line arrangement connected between the counterweight and the host aerial vehicle.