WO2025237779A1

WO2025237779A1 - Shotgun cartridge for anti-aerial vehicle combat and an aerial vehicle adapted for using such munition

Info

Publication number: WO2025237779A1
Application number: PCT/EP2025/062513
Authority: WO
Inventors: Kenneth SKORPEN
Original assignee: Blinktroll Robotics Aps
Current assignee: Blinktroll Robotics Aps
Priority date: 2024-05-14
Filing date: 2025-05-07
Publication date: 2025-11-20
Anticipated expiration: 2026-11-14
Also published as: DK182198B1; DK202400413A1

Abstract

The present invention relates to a shotgun cartridge for anti-aerial vehicle combat.

Description

Shotgun cartridge for anti-aerial vehicle combat and an aerial vehicle adapted for using such munition

Technical field of the invention

The present invention relates to anti-aerial vehicle combat.

Background of the invention

The integration of drones into modern military operations has fundamentally transformed the nature of warfare, offering both tactical advantages and new strategic complexities. These unmanned aerial vehicles (UAVs) are employed in diverse roles ranging from reconnaissance missions to the delivery of lethal payloads, each application bringing its own set of challenges and implications.

Reconnaissance and surveillance are among the most common uses of drones on the battlefield. Equipped with high-resolution cameras, thermal imaging, lidar, and radar, drones can provide real-time data about enemy movements and positions without risking human lives. This capability allows for more informed decisionmaking and precise targeting, which is crucial in modern warfare’s fast-paced environment. The information gathered through these surveillance missions can significantly enhance situational awareness, allowing military forces to monitor hostile territories continuously and detect threats from a safe distance. However, the use of surveillance drones also raises privacy concerns and issues of sovereignty, as these drones can operate discreetly across borders and gather sensitive information without the host nation’s consent.

Drones are also widely used for offensive operations, particularly for the delivery of payloads. These payloads can range from conventional explosives to more sophisticated weaponry, such as guided missiles and cluster bombs. The ability of drones to strike targets with high precision reduces the need for ground operations, minimizing military casualties. Moreover, drones’ payload delivery capabilities are not limited to conventional military uses. They can be adapted for various roles, such as deploying countermeasures, and electronic warfare tools. This versatility makes drones an invaluable asset in asymmetric warfare, where they can be used not just for direct combat but for a broader strategic purpose to support and sustain military operations under challenging conditions.

The proliferation of drone technology means that it’s not just state actors that have access to these capabilities, but also non-state actors including terrorist groups and insurgent forces, who can use these tools for disruptive purposes. The accessibility of drone technology raises the risk of these tools being used in terrorist attacks, espionage, and other illegal activities.

As the defensive and offensive capabilities of drones evolve, so too must the strategies to protect against them. Anti-drone technologies and electronic warfare have become a critical component of national defence strategies. Techniques such as signal jamming, hacking, and physical interception systems are being developed to mitigate the threat posed by hostile drones.

Among the various methods developed to address this challenge, projectile systems stand out due to their effectiveness and adaptability.

Projectile systems designed to intercept drones typically function by launching a missile or another type of projectile that can disable a drone either through direct impact or by deploying a capture mechanism, such as a net in close proximity to the target. This method is particularly effective because it combines the immediacy of a kinetic response with the precision required to minimize collateral damage in populated or sensitive environments.

These systems can be mounted on ground vehicles, stationary platforms, or even on other aircraft, providing versatility in deployment based on the specific scenario. The projectiles themselves are engineered to track and home in on drones using advanced guidance systems that can include infrared homing, radar guidance, or visual targeting. Upon reaching the drone, the projectile can either strike it directly, disrupting its operational capabilities through physical force, or deploy a net to entangle the drone’s propellers, bringing it down without triggering any onboard explosives that might be present.

The development of these projectile systems is driven by the need to provide quick and decisive responses to UAV threats, especially in scenarios where other interception methods might fail due to environmental factors or the agility of the target drone.

However, current methods have limitations, as most solutions requires specialized equipment to launch, and little focus has been on solutions that can be used by foot soldiers. The increasing use of drones on the battlefield poses significant challenges for foot soldiers who often find themselves inadequately equipped to deal with these aerial threats. Current drone interception systems, such as projectile systems, net launchers, and electronic warfare solutions, are typically designed for vehicle or base deployment. These systems are often too bulky, complex, and resourceintensive to be operated by individual soldiers in the field. This gap in capabilities leaves infantry units particularly vulnerable to drone attacks or surveillance, compelling them to resort to more primitive methods, such as using their firearms.

When confronted with an immediate drone threat, soldiers may attempt to shoot them down with their standard-issue handguns or rifles. This approach, however, is largely ineffective for several reasons. Firstly, the small size and high manoeuvrability of drones make them difficult targets to hit with bullets, especially when they are operating at higher altitudes or moving at high speeds. The typical engagement range of small arms is much less than what is required to effectively counter most drones, which can hover and manoeuvre beyond the effective range of a rifle or handgun.

The ineffectiveness of handguns and rifles against drones highlights a critical vulnerability in current military tactics and underlines the need for more portable and effective anti-drone technologies that can be integrated into individual soldier kits. Some advancements are being made in this area, such as compact directed-energy weapons (DEWs) that can disable drones by disrupting their electronic systems with focused energy beams. However, these technologies are still in the developmental stages and are not yet widely deployed.

Developing lightweight, easy-to-use, and effective drone countermeasures for foot soldiers is essential. As drone technology continues to evolve and proliferate, the adaptation of infantry defence strategies and the development of new countermeasures will be crucial in maintaining the safety and effectiveness of ground troops against these airborne threats. The ongoing research and innovation in this field are vital to ensure that soldiers are not only equipped to handle current threats but are also prepared for future advancements in drone warfare.

US5189250 (A) discloses a projectile adapted to be fired from a smooth bore weapon, such as a shotgun, by means of a cartridge containing a propellant charge. The projectile comprises a generally cylindrical casing and a warhead assembly, the warhead being hollow to accommodate an explosive charge and an initiator, the casing being formed with a firing pin spring biased to a safety position and locked in the safety position by a spring biased safety pin. The spring biased safety pin is adapted to release the firing pin in a predetermined period of time after the projectile exits from the weapon. The casing includes a plurality of fins foldable within the cartridge, but which deploy radially on leaving the weapon.

Description of the invention

It is an object of the present invention to provide a specialized munition for standard firearms that are more effective against drones.

It is another objective to provide a specialized munition for standard guns mounted on UAVs for use in inter UAV combat.

The inventors of the present invention have developed a specialized cartridge for shotguns such that they can be used in anti-aerial vehicle combat.

A first aspect relates to a shotgun cartridge for anti-aerial vehicle combat, the cartridge comprising:

- a case forming the outer shell and base of the shotgun cartridge;

- a primer arranged at the centre of the base;

- a projectile; - a first propellant adapted for driving the projectile; and

- a wad arranged between the first propellant and the projectile; wherein the projectile is a single projectile positioned at least partly within the case, and comprising: i) a payload; ii) a second propellant adapted for driving the payload; iii) a propellant activation mechanism adapted for igniting the second propellant; and iii) a target sensor unit adapted for sensing a target, and for activating the propellant activation mechanism upon identification of said target.

Another aspect relates to an aerial vehicle comprising;

- a shotgun, or shotgun mechanism; and

- a cartridge according to the present invention.

Embedding a shotgun-like firing mechanism into a drone means to integrate a mechanism into a drone that replicates the function of a shotgun. This would involve designing a firing apparatus that can handle one or multiple rounds of shotgun cartridges according to the present invention and discharging them automatically. Alternatively, pre-loaded multi-barrel constructs are possible.

The firing mechanism could e.g., utilize a revolving chamber with multiple barrels or a specially designed magazine that allows for quick and sequential firing of rounds. The firing mechanism is preferably configured to be integrated with the drone’s control systems. The recoil produced by the firing mechanism must be accounted for in the drone’s design to prevent destabilization during firing. This might involve the implementation of advanced gyroscopic systems or automatic adjustment features that can counteract the destabilizing forces generated by the recoil.

The shotgun cartridge consists of several key components, each crafted from specific materials to ensure functionality and safety. The outer case is usually made of plastic, designed to contain all internal components, and provide a weatherresistant exterior. The base of the case, often made of brass, houses the primer, a small, sensitive compound, preferably encased in a metal cup. When struck by a shotgun’s firing pin, the primer ignites, initiating the firing process. Following the primer is the first propellant, which may consist of nitrocellulose and optionally stabilizers and modifiers to control the burn rate. The ignited propellant generates a high-pressure gas, which is crucial for propelling the projectile. A wad separates the propellant from the projectile. The wad may be made from felt, cardboard, or plastic, which serves multiple functions. It acts as a gas seal, ensuring that the expanding gases efficiently push the projectile forward rather than escaping around it. Additionally, the wad cushions the projectile during the firing process, protecting it from damage and melting due to the intense heat. When the shotgun cartridge is fired, a sequence of precisely controlled events leads to the separation of the wad from the rest of the components, allowing the projectile to reach its target effectively. Upon triggering the firing mechanism, the shotgun’s firing pin strikes the primer, which ignites and subsequently sets off the propellant contained within the cartridge. As the propellant burns, it generates a rapid expansion of high-pressure gases within the cartridge casing.

These gases exert a forceful push against the wad, propelling it forward. The wad serves as a crucial barrier that seals the gases behind it, ensuring that all the generated pressure is directed towards driving the wad and the encased projectile out of the barrel. The design of the wad allows it to maintain a tight seal against the shell casing, preventing gas escape and maximizing propulsion efficiency.

As the wad and projectile exit the barrel, they encounter dramatically reduced air pressure compared to the high-pressure environment within the barrel. This sudden change in pressure, combined with increased air resistance, significantly slows down the wad. However, the projectile, being denser, continues its trajectory with minimal resistance. The slowed wad therefore falls away from the projectile, allowing it to continue towards the target unimpeded.

The material properties of the wad, typically a lightweight plastic, are engineered to withstand the explosive forces of the propellant and to quickly decelerate once outside the confines of the barrel. This ensures that the wad does not affect the projectile pattern adversely, fulfilling its role in shotgun ballistics. The wad may in some embodiments be of a cup and petal structure. This design is carefully engineered to optimize the delivery of the projectile after firing. The primary components of this structure are the cup that holds the projectile and the petals that manage its release.

The base of the wad may be configured to form a deep cup in which the projectile is contained. This cup may be important for several reasons. Firstly, it serves as the direct containment for the projectile. Upon ignition of the propellant, the gases generated exert pressure on the base of this cup. The integrity and shape of the cup are vital as they must withstand the initial explosive forces while ensuring that the projectile is pushed forward uniformly. The material choice, typically a form of resilient polyethylene, is crucial as it must not deform under pressure, which would alter the dynamics of the projectile’s discharge.

In some embodiments, extending from the rim of the cup are one or more petals. These petals may be designed to peel back or bloom as the wad exits the shotgun barrel. The opening of these petals serves multiple functions. As the wad is propelled through the barrel by the expanding gases, the petals help maintain a tight seal against the barrel walls, preventing gas from escaping around the sides, thereby maximizing the forward thrust received by the projectile. Once the wad leaves the barrel, the petals’ design allows them to catch the air, which helps them to open further and slow down rapidly. This rapid deceleration is crucial for allowing the projectile to continue its trajectory toward the target without interference from the wad.

The propellant is typically a form of smokeless powder, which is chosen over traditional black powder for its ability to burn more cleanly and efficiently, producing far less smoke and more energy. The primary component of smokeless powder is preferably nitrocellulose, a nitrate ester of cellulose, which burns rapidly and provides the necessary propulsion for the projectile. In some cases, nitro glycerine is also added, creating a double-base powder that further enhances the energy output.

To ensure the stability and longevity of the propellant, stabilizers, such as diphenylamine may be incorporated. These stabilizers are used to neutralize acidic by-products from the decomposition of nitrocellulose, thereby preventing the propellant from becoming unstable and potentially hazardous over time.

Additionally, various modifiers may be added to the propellant to tailor its burning characteristics to specific needs. For instance, substances like camphor can be used to adjust the burn rate, slowing it down to ensure a more consistent performance as the projectile travels through the barrel of the shotgun. Modifiers may also include flash suppressants, like potassium sulphate, to reduce the visible muzzle flash when the shotgun is fired.

Compared to a traditional shotgun cartridge, where the projectile being launched away from the shotgun barrel is a plurality of spherical pellets, the projectile of the present invention is a single complex projectile. This projectile is obviously positioned at least partly within the case, although other constructs, where parts of the projectile may overlap with the case, would also be contemplated to be within the scope of the invention.

The projectile comprises four core features: a payload, a second propellant adapted for driving the payload, a propellant activation mechanism adapted for igniting the second propellant, and a target sensor unit adapted for sensing a target, and for activating the propellant activation mechanism upon identification of a target.

The projectile generally operates on the principle of using a (chemical) propellant that, when ignited, creates high-pressure gases. These gases generate the necessary force to expel the payload at high velocities. The payload may be pellets, or a construct that fragments when the propellant is ignited, such as wires. The payload is preferably made from metals, such as lead, steel, tungsten (wolfram), bismuth, and various alloys and composites, each selected for its unique attributes. Lead has been traditionally favoured for pellets due to its high density and malleability, which enable it to retain kinetic energy over distance and make it effective for close-range combat. However, due to environmental and health concerns associated with lead toxicity, alternative materials may be considered. Steel is known for its hardness and durability and is another preferred material. It withstands high pressures and maintains its shape upon firing, characteristics valued in military applications where penetration and resilience against deformity are crucial. Steel pellets are effective in piercing armour.

Tungsten (wolfram) stands out for its exceptional density and hardness, coupled with a high melting point, making it suitable for armour-piercing applications.

Although more expensive than lead or steel, tungsten’s performance in penetrating hard targets justifies its cost in specific military contexts.

Bismuth serves as an environmentally friendly alternative to lead, sharing a similar density but without the toxicity.

Furthermore, the development of composite materials, integrating metals with ceramics, for example, allows for the optimization of ballistic properties such as aerodynamic stability and reduced radar visibility. These composites can be engineered to meet specific operational demands, enhancing the effectiveness of munitions against varied aerial vehicle targets (e.g., UAV targets).

In one or more embodiments, the payload comprises a plurality (e.g., tens to hundreds) of pellets, preferably spheres, and preferably arranged into a hemispherical shape at the tip of the projectile. This configuration provides for a directional delivery of the payload. The target sensor unit may be embedded in the centre of this hemispherical shape, preferably arranged to have a clear sight, i.e., to unobstructed being able to transmit and receive, e.g., radio waves, infrared light, or laser light.

In one or more embodiments, the payload comprises a plurality (e.g., tens to hundreds) of pellets, preferably spheres, arranged into a cylindrical shape with a cavity. This embodiment allows for a more scattered delivery of the pellets.

In one or more embodiments, at least a part of the second propellant is positioned within the above-mentioned cavity.

The second propellant is preferably of the same type as the first propellant, as discussed above. The propellant activation mechanism adapted for igniting the second propellant is preferably an electrical ignition mechanism. Electrical ignition mechanisms represent a significant technological advancement in munitions, enhancing precision, reliability, and safety. These systems typically incorporate an igniter equipped with a bridge wire, a power source, and a sophisticated control circuit, creating a highly efficient ignition process.

The igniter, central to the system, usually contains a small amount of a sensitive explosive or pyrotechnic compound that is electrically ignitable. Embedded within this igniter is the bridge wire, a resistive element that heats up when an electric current passes through it. The source of this current may be a battery or capacitor, designed to deliver the necessary power instantly upon command.

Control over the ignition process may be managed by a control circuit that includes switches, sensors, and potentially a microcontroller. This circuit may be programmed to initiate the current flow based on a variety of operational parameters such as timing, altitude, or proximity to a target. These parameters can be adjusted to meet specific tactical needs, making the system highly adaptable to different antiaerial vehicle (e.g., UAV) combat scenarios.

When the ignition process is initiated, e.g., automatically by a timer, or in response to environmental cues, such as velocity or G-force, the control circuit activates, sending a current through the bridge wire. This current causes the wire to heat rapidly, igniting the explosive or pyrotechnic compound within the igniter. The resultant combustion generates high-pressure gases, which in turn ignite the main propellant charge, propelling the munition’s payload.

The advantages of electrical ignition over traditional mechanical systems are manifold. The precision in timing that electrical systems offer is e.g., critical for the precise targeting. Additionally, the reduction in mechanical components minimizes the potential for failure, enhancing the reliability of the projectile. Safety is another key benefit, as electrical systems can be equipped with multiple safety interlocks that prevent accidental ignition, ensuring activation only under specific, predefined conditions. Another important feature in the projectile is the target sensor unit, which is adapted for sensing a target, and for activating the propellant activation mechanism upon identification of the target.

The projectile has embedded a target recognition mechanism to improve accuracy and efficacy on the battlefield. The target recognition mechanism may be simple, just configured to recognize an object, or more sophisticated and designed to identify specific targets. Both methods may utilize a variety of detection modalities including radar, lidar, infrared, and sometimes a combination of these technologies.

In one or more embodiments, the target sensor unit comprises a proximity sensor unit, preferably a radar unit. This embodiment allows the target sensor unit to timely deliver the payload by activating the propellant activation mechanism upon identification of the target and the distance thereto.

The radar unit may be configured to emit radio waves that reflect off objects/targets, allowing the projectile to detect and preferably track objects/targets based on the return signal. This capability may enable the projectile to home in on specific radar signatures, often those emitted by enemy aerial vehicles, which are typically indicative of military assets.

Lidar, which uses laser light to map physical objects, provides another layer of target recognition. Although less common than radar due to its sensitivity to atmospheric conditions like fog or smoke, lidar can offer highly accurate, high-resolution images of targets. This precision is particularly valuable in cluttered environments where distinguishing between targets and non-targets based on shape and size is crucial.

In some embodiments, multiple sensing technologies are combined to enhance their target detection and engagement capabilities under a wider range of operational conditions. For example, integrating radar and lidar with infrared sensors allows the projectile to perform well both day and night and in various weather conditions.

Infrared sensors detect heat signatures from aerial vehicles, adding another method for ensuring that the projectile can find and hit its intended target even when visual conditions are poor, or the target is attempting to hide its electronic emissions. With advancements in Al and machine learning, the target sensor unit may become more autonomous and capable of complex decision-making processes during the projectile’s flight. This progression points toward a future where munitions could independently conduct nuanced battlefield analysis and make real-time adjustments to maximize mission success and minimize unintended consequences.

One or more safety mechanisms may be integrated into the projectile to avoid unintended explosions. As an example, the target sensor unit may comprise a motion sensor configured to block/prevent the target sensor unit from activating the propellant activation mechanism if a measured motion is below a pre-defined threshold value. The motion sensor may e.g., be an accelerometer, or preferably, a G-force switch. A G-force switch, when integrated into the projectile (and preferably being part of the target sensor unit), may serve a critical role in controlling the activation of various functions based on the experienced acceleration forces. The G- force switch is typically designed to withstand the intense acceleration that occurs as the projectile is propelled from a shotgun. Upon firing, the sudden and extreme acceleration generates G-forces high enough to activate the switch. This activation might be used to arm the projectile, preferably initiating a sequence that readies the projectile’s explosive and/or electronic component, for operation at a predetermined time or impact condition.

The fundamental operation of the G-force switch in this setting relies on its ability to detect the specific threshold of acceleration. This is usually achieved through a mechanical setup where a mass within the switch shifts upon experiencing the G- forces at firing, thus completing an electrical circuit, or otherwise moving the switch to an "on" state. This change in state is crucial for the timing and control of the projectile’s operational features, ensuring that activation occurs only under the correct firing conditions and not while it is being handled or transported.

In one or more embodiments, the projectile comprises a tail. Incorporating a tail into the projectile construct significantly enhances its functionality by improving aerodynamic stability and accuracy. The tail, often designed with fins or stabilizers, plays a crucial role in the flight behaviour of the projectile. When the projectile is fired, it is subjected to various forces, including gravitational pull, drag, and lift, which can alter its trajectory and impact accuracy. The tail’s design counters these effects by stabilizing the projectile’s flight.

This stabilization is primarily achieved through the tail fins or stabilizers, which help to maintain the projectile’s orientation and direction. As the projectile moves through the air, air flows over the fins or stabilizers, creating lift perpendicular to the direction of airflow. This lift force is crucial for countering any unwanted rotation or wobble in the projectile, allowing it to maintain a straighter and more predictable flight path.

In one or more embodiments, the projectile is designed/configured such that its tail is adapted for being in a retracted configuration before launch and then adapted for being in an extended configuration during or after launch. This design serves multiple strategic and functional purposes.

The retracted tail allows for a more compact shotgun cartridge, which is crucial for efficient storage and transport. In military contexts, where space is at a premium on ships, aircraft, or land vehicles, the ability to minimize the space occupied by ammunition is essential. It enables the packing of more units into the same space, thus optimizing logistics and deployment capabilities.

Once the projectile is launched, the tail extends, significantly improving the aerodynamic profile of the projectile. This transformation is crucial for stabilizing the projectile’s flight path almost immediately after launch, maximizing its aerodynamic efficiency. The extended tail helps to maintain the projectile’s orientation and direction, thereby enhancing its accuracy and reducing deviations due to external forces like wind or gravitational pull.

Lastly, the retractable design contributes to the overall safety and reliability of the shotgun cartridge as safety mechanisms may be integrated into this functionality. E.g., the retracted configuration may include a fail-safe mechanism where a circuit is broken, while the extended configuration closes the circuit, thereby allowing the projectile to detonate when the timing is right. In one or more embodiments, the projectile further comprises a case forming the outer shell and base of the projectile. The case may be made of plastic or metal, designed to contain all internal components of the projectile, and provide a weatherresistant exterior.

In one or more embodiments, the case comprises a lens or radome arranged at the tip of the projectile. This part may be seen as part of the target sensor unit.

When the target sensor unit comprises a radar or lidar system, the inclusion of a lens or protective covering, such as a radome in radar applications, plays a critical role in both shielding the delicate internal components and optimizing the function of these sensing technologies. A radome, the protective enclosure for a radar, is designed to withstand environmental adversities like wind and rain, safeguarding the radar’s antenna while allowing it to transmit and receive signals unimpeded due to the electromagnetic transparency of the materials used. This transparency is crucial as it ensures that the protective barrier does not interfere with the radar operation, allowing for accurate signal processing.

For lidar systems, which rely on light rather than radio waves, lenses perform essential functions in directing and focusing the emitted laser beams. These optical components adjust the shape and trajectory of the laser pulses, which is pivotal for achieving precise distance measurements. The lens ensures that the light emitted and received is finely tuned for maximum resolution and accuracy, while also protecting the internal laser elements from external contaminants and environmental conditions.

Moreover, these lenses often incorporate optical filters to eliminate unwanted light from sources other than the lidar’s laser, such as sunlight, thereby enhancing the fidelity of the data captured. This filtering is integral to maintaining the clarity and reliability of the lidar’s sensory input.

It should be noted that embodiments and features described in the context of one of the aspects of the present invention also apply to the other aspects of the invention. Brief description of the figures

Figure 1 shows a perspective view or a shotgun cartridge according to various embodiments of the present invention.

Figure 2 shows a projectile according to various embodiments of the present invention.

Figure 3 shows a bottom view of shotgun cartridge according to various embodiments of the present invention.

Detailed embodiments of the invention

In the present context, the term “in general” when used when mentioning a feature relating to the present invention, it must be understood that the feature may be used with all embodiments of the invention, even if the mentioning is made in the detailed part of the document.

Figure 1 shows a perspective view or a shotgun cartridge according to various preferred embodiments of the present invention.

The shotgun cartridge 100 is adapted for anti-aerial vehicle combat and comprises a case 110 and a projectile 120. The case 110 is here shown transparent to better show other components and forms the outer shell and base of the shotgun cartridge 100. The projectile can be interpreted as a complex payload. In the shown example, the case 110 completely covers the projectile 120, but embodiments where the tip of the projectile 120 is visible are also within the scope of the invention. A primer 112 is arranged at the centre of the case’s base, followed by a first propellant 114. As discussed above, the ignited first propellant 114 generates a high-pressure gas, which is crucial for propelling the projectile 120. A wad 116 separates the first propellant 114 from the projectile 120. The structure and purpose of the wad is discussed above.

The projectile 120 (see Figure 2) comprises a case 123 (here shown partly transparent) forming the outer shell and base of the projectile 120, a payload 122, a second propellant 124 adapted for driving the payload 122, a propellant activation mechanism (not shown) adapted for igniting the second propellant 124, a target sensor unit 129 adapted for sensing a target, and for activating the propellant activation mechanism upon identification of said target, and a tail 121.

Generally, the target sensor unit 129 may be a part of the propellant activation mechanism. The propellant activation mechanism comprises an electrical ignition mechanism comprising a control circuit that can be switched off an on. The tail 121 is adapted for being in a retracted configuration within the case 110 (see Figure 1) and in an extended configuration after being launched from the case 110 (see Figure 2). In the shown embodiments, when the tail 121 is in its retracted configuration within the case 110, the control circuit is switched off, and when the tail 121 is in its extended configuration, the control circuit is switched on. The switch for the control circuit is formed partly in the tail 121 and partly in the case 123 forming the outer shell and base of the projectile 120. As an example for such a switch configuration, the case is provided with a recess 123A operably and slidably connected to a protrusion 121 A formed in the tail 121. A spring 121 B forces the tail into its extended configuration and also actively pushes the wad 116 away from the projectile 120 during launch.

A bottom view of the shotgun cartridge’s tail 121 may be seen in Figure 3, here embodied as a plurality of tail fins encased in a circular strut to enhance the projectile’s aerodynamic properties and its control during flight. This configuration is commonly referred to as a “ring tail” design and may generally be used in combination with other embodiments than the ones shown in the figures.

The circular strut, essentially a ring that encircles the tail fins, serves multiple purposes. Firstly, it provides structural support to the tail fins, which are crucial for stabilizing the projectile’s flight. By securing the fins within a solid framework, the strut ensures that they maintain their optimal orientation and alignment relative to the body of the projectile 120. This alignment is critical for maintaining a stable trajectory, as any misalignment could cause the projectile to deviate from its intended path. Secondly, the circular strut aids in the aerodynamic performance of the projectile 120. The ring helps to streamline airflow around the tail section, reducing aerodynamic drag and improving the lift-to-drag ratio. This smoother airflow contributes to greater flight efficiency and stability, particularly at high speeds. The reduced drag also means that the projectile 120 can maintain higher velocities over longer distances, enhancing its range.

Returning to the target sensor unit 129, it is here shown comprising a proximity sensor unit 127 with a lens cover 128 embedded in the case 123, a control unit 126, and a battery unit 125 adapted for power supply.

In general, other types of sources of electrical energy may be used as power source, such as piezoelectric elements that convert mechanical energy into electrical energy and vice versa. In the field of ammunition electronics, they play a crucial role in harnessing the energy generated during the firing process to power electronic components or systems integrated into the ammunition.

When a shotgun is fired, there is a rapid and powerful release of mechanical energy. This energy can be harnessed through the use of piezoelectric materials, typically placed strategically within the structure of the ammunition. These materials have a unique property: when subjected to mechanical stress or vibration, they generate a voltage across their surfaces. This phenomenon is known as the piezoelectric effect. As the shotgun fires, the sudden pressure and vibrations cause the piezoelectric elements to deform, generating electrical energy in the form of voltage spikes.

These voltage spikes can then be captured and stored using appropriate circuitry. The energy harvested from the piezoelectric elements can be utilized to power various electronic components embedded within the shotgun cartridge, such as sensors or electronic fuses.

The mass of the shown shotgun cartridge 100 is preferably of a weight within the range of 20-60 gram and is configured to travel with a speed of within the range of 100-400 meters per second. The projectile’s payload is only partly shown and would preferably fill the entire space between the second propellant 124, target sensor unit 129, and the case 123. As an example, the payload 122 may be less dense in the rear and mid-section of the case 123, e.g., consisting of 1-3 layers of pellets. The tip of the projectile may be relatively denser with payload (e.g., 5-10 layers of pellets), forming a hemispherical shape at the tip of the projectile, although still with place for the target sensor unit 129 at the centre of the shape.

The second propellant 124 is preferably triggered near the tail 121 , enabling the detonation to travel upwards, thus creating a directed or semi-shaped charge. The payload 122 can, as discussed above, e.g., be steel, lead, tungsten, or wires. The payload 122 can be separated from the second propellant 124 by a thin metal mesh, or otherwise held in place with adhesive.

References

100 Shotgun cartridge

110 Case

112 Primer

114 First propellant

116 Wad

120 Projectile

121 Tail

121A Protrusion

121B Spring

122 Payload

123 Case

124 Second propellant

125 Battery unit

126 Control unit

127 Proximity sensor unit

128 Lens or radome

129 Target sensor unit

Claims

1 . A shotgun cartridge (100) for anti-aerial vehicle combat, the cartridge comprising:

- a case (110) forming the outer shell and base of the shotgun cartridge;

- a primer (112) arranged at the centre of the base;

- a projectile (120);

- a first propellant (114) adapted for driving the projectile (120); and

- a wad (116) arranged between the first propellant (114) and the projectile (120); wherein the projectile (120) is a single projectile positioned at least partly within the case (110), and comprising: i) a payload (122); ii) a second propellant (124) adapted for driving the payload (122); and iii) a propellant activation mechanism adapted for igniting the second propellant (124); characterized in that the projectile further comprises: iv) a target sensor unit (129) adapted for sensing a target, and for activating the propellant activation mechanism upon identification of said target.

2. The shotgun cartridge (100) according to claim 1 , wherein the payload (122) comprises a plurality of pellets, preferably spheres, arranged into a hemispherical shape at the tip of the projectile (120).

3. The shotgun cartridge (100) according to claim 2, wherein the payload (122) further comprises a plurality of pellets, preferably spheres, arranged into a cylindrical shape with a cavity.

4. The shotgun cartridge (100) according to claim 3, wherein at least a part of the second propellant (124) is positioned within said cavity.

5. The shotgun cartridge (100) according to any one of the claims 1-4, wherein the target sensor unit (129) comprises a proximity sensor unit (127), preferably a radar unit.

6. The shotgun cartridge (100) according to any one of the claims 1-5, wherein the target sensor unit (129) is powered by a battery unit (125).

7. The shotgun cartridge (100) according to any one of the claims 1-6, having a total weight within the range of 10-100 grams.

8. The shotgun cartridge (100) according to any one of the claims 1-7, wherein the projectile (120) further comprises a motion sensor unit operably connected with the target sensor unit (129) and configured for activating the target sensor unit (129) upon the reach of a pre-defined motion threshold value.

9. The shotgun cartridge (100) according to claim 8, wherein the motion sensor unit comprises a G-force switch.

10. The shotgun cartridge (100) according to any one of the claims 1-9, wherein the projectile (120) further comprises a case (123) forming the outer shell and base of the projectile (120).

11. The shotgun cartridge (100) according to claim 10, wherein the case (123) comprises a lens or radome (128) arranged at the tip of the projectile (120).

12. The shotgun cartridge (100) according to any one of the claims 1-11 , wherein the projectile (120) further comprises a tail (121) comprising fins or stabilizers adapted for stabilizing the projectile’s flight.

13. The shotgun cartridge (100) according to claim 12, wherein the tail (121) is adapted for being in a retracted configuration within the case (110) and in an extended configuration after being launched from the case (110).

14. The shotgun cartridge (100) according to claim 13, wherein the propellant activation mechanism adapted for igniting the second propellant comprises an electrical ignition mechanism comprising a control circuit, wherein when the tail (121) is in its retracted configuration within the case (110), the control circuit is switched off, and wherein when the tail (121) is in its extended configuration, the control circuit is switched on.

15. The shotgun cartridge (100) according to claim 14, wherein the projectile (120) further comprises a case (123) forming the outer shell and base of the projectile (120), wherein the switch for the control circuit is formed partly in the tail (121) and partly in the case (123).

16. An aerial vehicle comprising;

- a shotgun, or shotgun mechanism; and

- a shotgun cartridge (100) according to any one of the claims 1-15.