Tilt-wing unmanned aerial vehicle for signals intelligence

Abstract

There is provided an unmanned aerial vehicle (UAV) comprising: a body; a first rotor positioned having blades that rotate in a first rotor plane that is parallel to a horizontal plane; a second rotor having blades that rotate in a second rotor plane that is parallel to the horizontal plane; a port wing and a starboard wing extending from the body; a port rotor unit rotatably coupled to a distal end of the port wing, wherein the port rotor unit comprises one or more port blades; and a starboard rotor unit rotatably coupled to a distal end of the starboard wing, wherein the starboard rotor unit comprises one or more starboard blades, wherein the UAV is configured such that the port rotor unit is rotatable between a vertical flight position, in which the port blades rotate in a first port rotor plane to provide lift, and a second port rotor plane that is substantially parallel to a frontal plane, and wherein the UAV is configured such that the starboard rotor unit is rotatable between a vertical flight position, in which the starboard blades rotate in a first starboard rotor plane to provide lift, and a second starboard rotor plane that is substantially parallel to a frontal plane.

Description

TILT-WING UNMANNED AERIAL VEHICLE FOR SIGNALS INTELLIGENCECROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority from GB patent application 2403401.9 filed 8 March 2024, the entire contents of which are hereby incorporated by reference.FIELD

[0002] The present invention is directed to an unmanned aerial vehicle (UAV) for application in various sectors, including military, law enforcement, and civilian. The UAV may be used for tasks such as surveillance, intelligence collection, and communication.BACKGROUND

[0003] Unmanned Aerial Vehicles (UAVs) are powered aerial vehicles that do not carry a human operator. UAVs may utilize aerodynamic forces to provide lift. UAVs may be autonomous or piloted remotely.

[0004] Commonly, UAVs may either be of a “fixed wing” type or a “rotor” type. Fixed wing UAVs may comprise a wing that is fixed to a central body of the UAV and extends away from the central body in a spanwise direction. In a fixed wing UAV, one or more propulsion systems may provide a forward thrust to accelerate the UAV in a forward direction. When moving in the forward direction, the wings may provide aerodynamic lift. Rotor-type UAVs may comprise one or more liftgenerating rotors.

[0005] UAVs have been increasingly deployed in roles related to surveillance and intelligencegathering due to their ability to navigate remote and hostile environments without the risk to human life. However, there are existing limitations in current UAV designs.

[0006] Current UAVs are commonly designed to have non-modifiable configuration. This limitation hampers their adaptability to a variety of missions and operational conditions, necessitating the deployment of different UAV models for varied tasks, thereby elevating operational costs and increasing logistical complexity.

[0007] Furthermore, UAVs may not be able to withstand adverse weather conditions. This may pose limitations on their operational abilities in adverse weather conditions, and increase a risk that a UAV is to able to perform an intended task.

[0008] Additionally, many UAVs equipped with SIGINT systems may exhibit a poor range or a poor sensitivity for detecting signals. Consequently, such UAVs may not be able to detect signals having a low strength or signals that are intentionally concealed. Furthermore, some UAVs may have a limited resistance to electromagnetic interference and / or a structure which impairs the functionality SIGINT systems onboard the UAV.

[0009] Some UAVs may be equipped with an electric propulsion mechanism. While electric UAVs provide environmentally-friendly operation and reduced operational noise, they may suffer from restricted range and endurance. Some UAVs may be equipped with a propulsion mechanism comprising a traditional combustion engine. UAVs utilizing traditional combustion engines provide extended operational durations but generate noise, potentially compromising stealth.

[0010] From a control and operational perspective, a large number of UAVs are reliant on line-of- sight or satellite communications. Uine-of-sight communication and satellite communication may be susceptible to disruption in specific terrains or through electronic warfare tactics.

[0011] Fixed wing UAVs may not be able to hover in a substantially stationary position for an extended period of time. A lack of extended hover ability further restricts the collection of stationary SIGINT data over areas of interest. Rotor-type UAVs may be inefficient and have a limited range.SUMMARY OF THE INVENTION

[0012] An object of the present invention is to provide an unmanned aerial vehicle (UAV) in which at least some of these limitations are mitigated.

[0013] Disclosed in the present application is a modular and weather-resistant UAV featuring an advanced Signals Intelligence (SIGINT) module and capacities for Vertical Takeoff and Landing (VTOL) and stable hover operations.

[0014] According to an aspect of the present invention, there is provided an unmanned aerial vehicle (UAV) comprising: a body; a first rotor positioned having blades that rotate in a first rotor plane that is parallel to a horizontal plane; a second rotor having blades that rotate in a second rotor plane that is parallel to the horizontal plane; a port wing and a starboard wing extending from the body; a port rotor unit rotatably coupled to a distal end of the port wing, wherein the port rotor unit comprises one or more port blades; and a starboard rotor unit rotatably coupled to a distal end of the starboard wing, wherein the starboard rotor unit comprises one or more starboard blades, wherein the UAV is configured such that the port rotor unit is rotatable between a vertical flight position, in which the port blades rotate in a first port rotor plane to provide lift, and a second port rotor plane that is substantially parallel to a frontal plane, and wherein the UAV is configured such that the starboard rotor unit is rotatable between a vertical flight position, in which the starboard blades rotate in a first starboard rotor plane to provide lift, and a second starboard rotor plane that is substantially parallel to a frontal plane.

[0015] By providing a UAV with the above-described structure, the UAV may be capable of Vertical Takeoff and Landing (VTOL) and stable hover, as well as fast and efficient flight over long distances. This may enable operation of the UAV in varied terrains and facilitate stationary SIGINT data collection.

[0016] According to another aspect of the present invention, there is provided an unmanned aerial vehicle (UAV) comprising a radial antenna arrangement, wherein the radial antenna arrangement comprises a plurality of antenna elements arranged in a radial configuration.BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings, in which corresponding reference symbols indicate corresponding parts.Figure 1 depicts a UAV in accordance with an embodiment of the present invention, with wing-tip rotors in a vertical configuration.Figure 2 depicts a UAV in accordance with an embodiment of the present invention, with the wing-tip rotors in a horizontal configuration.Figure 3 depicts a 3D representation of a UAV in accordance with an embodiment of the present invention.Figure 4 depicts a 3D representation of a UAV in accordance with an embodiment of the present invention.Figure 5 depicts a plan view of the wings.Figure 6A depicts a plot of glide ratio (a ratio of the horizontal distance travelled against the height lost in unpowered horizontal flight) velocity of the UAV.Figure 6B depicts a plot of range against velocity for the UAV.Figure 6C depicts a plot of endurance (maximum flight time) against velocity for the UAV.Figure 7A depicts an arrangement of directional antennae, in accordance with an embodiment of the present invention.Figure 7B depicts an arrangement of directional anetennae, in accordance with an embodiment of the present invention.Figure 8 depicts a functional diagram of a directional antenna subsystem.Figure 9 depicts a block diagram of a phased antenna array subsystem.Figure 10 depicts an overview of the general operating principle of the phased antenna array subsystem.Figure 11 depicts a block diagram of the directional antenna subsystem and the phased antenna array subsystemFigures 12A and 12B depicts a visual representation of the method for identifying a location of a source of a signal using lines of bearing.Figure 13 depicts an example user interface for the target location system.

[0018] The features shown in the Figures are not necessarily to scale, and the size and / or arrangement depicted is not limiting. It will be understood that the Figures include optional featureswhich may not be essential to the invention. Furthermore, not all of the features of the apparatus are depicted in each of the figures, and the Figures may only show some of the components relevant for describing a particular feature.DETAILED DESCRIPTION<Overview>

[0019] Figures 1 and 2 depict schematic representations of a UAV in accordance with an embodiment of the present invention. Figures 3 and 4 depicts a 3D renders of a UAV in accordance with an embodiment of the present invention.

[0020] Rotation of the UAV may be defined in relation to pitch, roll and yaw. Pitch rotation may be rotation around a pitch axis. Roll rotation may be rotation around a roll axis. Yaw rotation may be rotation around a yaw axis. These axes may be aligned with the UAV as is customary in the art of air vehicles. The pitch axis may be referred to as a lateral axis. The roll axis may be referred to as a longitudinal axis. The yaw axis may be referred to as a vertical axis. The lateral axis, the longitudinal axis and the yaw axis may be perpendicular to each other.

[0021] The UAV may be operable in vertical flight mode (depicted in Figure 1) and a horizontal flight mode (depicted in Figure 2). During a vertical flight mode, the direction of travel may be substantially parallel to the vertical axis. During a horizontal flight mode, the direction of travel may be substantially parallel to the longitudinal axis.

[0022] A horizontal plane may comprise the lateral axis and the longitudinal axis. A frontal plane may comprise the vertical axis and the lateral axis. A side plane may comprise the vertical axis and the longitudinal axis. A starboard-ward direction and a port-ward direction may be parallel to the pitch axis and opposite to one another. A forward direction and a rearward direction may be parallel to the longitudinal axis and opposite to one another. An upward direction and a downward direction may be parallel to the yaw axis and opposite to one another.

[0023] The UAV may comprise a body 2. The body 2 may be a fuselage. The body 2 may extend along the longitudinal axis. The body 2 may comprise a fore portion 201, a middle portion 202 and a aft portion 203. The fore portion 201 may be forward of the middle portion 202 and the aft portion 203. The aft portion 203 may be rearward of the middle portion 202 and the fore portion 201.

[0024] The UAV may further comprise one or more wings Ip, Is. For example, the UAV may comprise a port wing Ip and a starboard wing Is. The port wing Ip and the starboard wing Is may extend outwardly from the middle portion 202 of the body 2. A port wing root lOlp of the port wing Ip may be fixedly connected to the port side of the body 2. A starboard wing root 101s of the starboard wing Is may be fixedly connected to the starboard side of the body 2. The starboard wing Is may extend from the starboard wing root 101s to a starboard wing tip 102s in a starboard spanwise direction. The port wing Ip may extend from the port wing root 10 Ip to a port wing tip 102p in a portspanwise direction. Upper and lower surfaces of the wings Ip, Is may extend in planes that are substantially parallel to the horizontal plane.

[0025] The wings Ip, Is may be configured to generate lift when the UAV moves in the forward direction. That is, when the UAV moves in the forward direction, a force may be exerted on the wings Ip, Is in the upward direction. A cross-section of the wings Ip, Is may be an airfoil. The airfoil may be an airfoil suitable for generating lift when the UAV is in the horizontal flight mode. Upper and lower surfaces of the wings Ip, Is may be approximately parallel to the horizontal plane.

[0026] The starboard spanwise direction and the port spanwise direction may be parallel to the pitch axis. The starboard spanwise direction may be substantially parallel to the starboard-ward direction. The port spanwise direction may be substantially parallel to the port-ward direction.

[0027] In some embodiments, the starboard spanwise direction may not be substantially parallel to the starboard-ward direction, and the port spanwise direction may not be substantially parallel to the port-ward direction. For example, the wings Ip, Is may be swept. That is, there may be a non-zero angle between the port spanwise direction and the port-ward direction, which means that the port wing tip 102p may be rearward of the port wing root 10 Ip. Similarly, there may be a non-zero angle between the starboard spanwise direction and the starboard direction which means that the starboard wing tip 102s may be rearward of the starboard wing root 101s.

[0028] Figure 5 depicts a plan view of the wings Ip, Is from a position about the UAV. The port wing Ip and the starboard wing Is may be tapered. The cross-section of the starboard wing Is may decrease moving in the starboard spanwise direction. The cross-section of the port wing Ip may decrease moving in the port spanwise direction. The port wing Ip may have a leading edge 103p and a trailing edge 104p. The leading edges 103p, 103s may not be parallel to the trailing edges 104p, 104s. The starboard wing Ip may have a leading edge 103 s and a trailing edge 104s. The trailing edge 104s of the starboard wing Is and the trailing edge 104p of the port wing Ip may be approximately co-linear. The trailing edge 104s of the starboard wing Is may be approximately parallel to the starboard spanwise direction and the trailing edge 104p of the port wing Ip may be approximately parallel to the port spanwise direction. The leading edge 104s of the starboard wing Is may be angled backward. That is, the leading edges 104p of the port wing Ip may extend in the portward and the rearward directions and the leading edge 104s of the starboard wing Is may extend in the starboard-ward and the rearward directions. A port sweep angle may be an angle between the leading edge 103p of the port wing and the port spanwise direction, and a starboard sweep angle may be an angle between the leading edge 103 s of the starboard wing Is and the starboard spanwise direction. The port sweep angle and the starboard sweep angle may be less than 2.5°, preferably less than 2°, and further preferably les than 1.7°, and greater than 1° and preferably greater than 1.5°.

[0029] A chord line may be a line that is parallel to the roll axis and connects the leading edge 103p, 103s to the trailing edge 104p, 104s. A root chord CO (i.e. a distance between the leading edge 103p, 103s and the trailing edge 104p, 104s at the roots lOlp, 101s) may be greater than 350 mm,preferably greater than 400 mm and further preferably greater than 415 mm, and less than 500 mm, preferably less than 450 mm, and further preferably less than 425 mm. For example, the root chord CO may be approximately 420 mm. A mean aerodynamic chord MAC of the wings Ip, Is may be greater than 250 mm, preferably greater than 300 mm, and further preferably greater than 330 mm, and less than 400 mm, preferably less than 350 mm and further preferably less than 340 mm. For example, the root chord CO may be approximately 420 mm.

[0030] A span of the wings Ip, Is may be greater than 2 m, preferably greater than 2.5 m, and further preferably greater than 2.9 m, and less than 5 m, preferably less than 4 m, and further preferably less than 3.2 m. For example, the span of the wings Ip, Is may be 3 m.

[0031] The wings Ip, Is may be configured such that a stall speed thereof is less than 50 ms1, preferably less than 30 ms'1and preferably less than 20 ms1.

[0032] Rotation around the pitch axis may be positive in the pitch upward direction, i.e. in the clockwise direction when looking at the UAV from the port side. For example, the UAV may rotate around the pitch axis in the positive direction if the fore portion 201 of the body 2 moves upward relative to the middle portion 202 and the aft portion 203 of the body 2. Rotation around the yaw axis may be positive in the clockwise direction when looking at the UAV from above. For example, the UAV may rotate around the yaw axis in the positive direction if the fore portion 201 of the body 2 moves starboard-ward relative to the middle portion 202 and the aft portion 203 of the body 2. Rotation around the roll axis may be positive in the clockwise direction when looking at the UAV from the rear. For example, the UAV may rotate around the roll axis in the positive direction if the port wing Ip moves upward relative to the body 2 and the starboard wing Is.

[0033] The UAV may comprise a nose arrangement 9. The nose arrangement 9 may be connected to the fore portion 201 of the body 2. The nose arrangement 9 may comprise a sensor arrangement 901 and a sensor arrangement mount 902. The sensor arrangement mount 902 may be configured to be connected to the fore portion 201 of the body. The sensor arrangement 901 may be configured to be connected to the sensor arrangement mount 902. The sensor arrangement mount 902 may have a spherical or paraboloid portion 910 which forms the nose of the UAV. The UAV may comprise one or more sensors (not shown).

[0034] The sensor arrangement 901 may be rotatable. For example, one or more sensors (such as a camera) may be mounted on a 3 -axis gimbal. The sensor arrangement 901 may be mounted on a gimbal. The gimbal may be stabilized.

[0035] The sensor arrangement 901 is depicted in Figure 4. The one or more sensors may comprise an optical camera 910. The optical camera 910 may be capable of 40x zoom. The optical camera 910 may be a dual-sensor camera. The one or more sensors may comprise a thermal camera 904. The thermal camera 904 may be configured to detect infrared radiation with a wavelength greater than 8 pm and less than approximately 14 pm. The thermal camera 904 and the optical camera 910 may have a HD resolution of approximately 1920x1080. The one or more sensors may further comprise anoptical flow camera 905. The optical flow camera 905 may fix onto objects / pattems on the ground and if there is any change in position of that object / pattem, the optical flow camera 905 may report it as a movement in terms of velocity. The optical flow camera 905 and / or its associated control system may utilize odometry. The one or more sensors may comprise an EO / IR system.

[0036] The sensor arrangement 901 may further comprise a signal intelligence (SIGNT) system. The SIGNT system may comprise a phased array beamformer. The SIGNT system may be accommodated (and be surrounded by) a sensor arrangement body. The sensor arrangement body may be made out of a radio-transparent material. The radio-transparent material may be a polymer, e g. Teflon, PPL, PVC, and ABS.

[0037] The UAV may comprise one or more horizontal stabilizers 3p, 3s. For example, the UAV may comprise a port horizontal stabilizer 3p and a starboard horizontal stabilizer 3s. The horizontal stabilizers 3p, 3 s may extend outwardly from the aft portion 203 of the body 2. The horizontal stabilizers 3p, 3s may extend in a direction that is approximately parallel to the pitch axis. That is, the port horizontal stabilizer 3p may extend in a substantially port-ward direction from the body 2, and the starboard horizontal stabilizer 3 s may extend in a substantially starboard-ward direction from the body 2. The horizontal stabilizers 3p, 3s may have a cross-section that is an airfoil. The airfoil may be an airfoil suitable for generating a vertical force when the UAV is in the horizontal flight mode. Upper and lower surfaces of the horizontal stabilizers may extend in planes that are substantially parallel to the horizontal plane.

[0038] The horizontal stabilizers 3p, 3 s may be configured to stabilize the rotational motion of the UAV around the pitch axis when the UAV is in the horizontal flight mode. When the UAV is in the horizontal flight mode and flying at a constant pitch angle, the resultant pitch moment (from the forces acting on the wings Ip, Is and the horizontal stabilizers 3p, 3s) about the UAV’s center of mass can be zero. If the center of mass of the UAV is forward of a center of lift of the wings Ip, Is, the horizontal stabilizers may be configured such that a downward force is exerted thereon when the UAV is in the horizontal flight mode flying at a constant pitch angle.

[0039] The UAV may comprise a vertical stabilizer 4. The vertical stabilizer 4 may be connected to the aft portion 203 of the body 2. The vertical stabilizer 4 may extend from the body in a vertical direction. The vertical stabilizer 4 may extend upward from an upper surface of the body 2. Preferably, the vertical stabilizer 4 may extend downward from a lower surface of the body 2. This may ensure that fixed rotors can be accommodated on the upper surface of the body 2. The vertical stabilizer may be configured to stabilize the rotational motion of the UAV around the yaw axis when the UAV is in the horizontal flight mode. The vertical stabilizer 4 may extend in a plane that is parallel to the side plane.

[0040] The vertical stabilizer 4 may comprise a vertical stabilizer landing portion 401. The vertical stabilizer landing portion 401 may be disposed on a distal tip of the vertical stabilizer 4. The verticalstabilizer landing portion 401 may be, at least in part, below a lower surface of the body 2 and a lowermost point of the nose arrangement 9.

[0041] The UAV may comprise a plurality of control surfaces to control the rotation of the UAV around the pitch, roll and yaw axes.

[0042] For example, the UAV may comprise one or more flaps 6p, 6s. The one or more flaps 6p, 6s may be coupled to the wings 1. For example, a port flap 6p may be mounted to a trailing edge of the port wing Ip and a starboard flap may 6s be mounted to a trailing edge of the starboard wing 6s.

[0043] The flaps 6p, 6s may be rotatable relative to the wings Ip, Is. The flaps 6p, 6s may have a connected edge and an unconnected edge. The connected edge may be rotatably connected to the wing Ip, Is. The connected edges of the flaps 6p, 6s may be rotatably connected to the wings Ip, Is using any suitable connecting means, such as a hinged connection. The flaps 6p, 6s may be rotatable relative to the wings Ip, Is such that the unconnected edge can be above or below the wing Ip, Is, whilst the connected edge remains stationary relative to the wings Ip, Is. The effective area of the wings Ip, Is and the effective shape (e.g. camber) of the wings Ip, Is may be changed by rotation of the flaps 6p, 6s. Thus, aerodynamic properties of the wings Ip, Is (e.g. lift and drag) may be changed by rotation of the flaps 6p, 6s. Rotating the flaps 6p, 6s such that the unconnected edge is below the wings Ip, Is may result in increased lift.

[0044] The UAV may further comprise one or more slats (not shown). The slats may be similar to the flaps, but may be mounted on leading edges of the wings Ip, Is. The UAV may further comprise one or more spoilers (not shown). The spoilers may be mounted on a trailing edge of the wings Ip, Is in a similar manner to the flaps 6p, 6s. Rotating the spoilers such that an unconnected edge thereof is above the wings may reduce the lift generated by the wings Ip, Is. In some embodiments, the flaps 6p, 6s may perform the functionality of spoilers.

[0045] The UAV may comprise one or more elevators 7p, 7s. For example, the UAV may comprise a port elevator 7p and a starboard elevator 7s. The one or more elevators 7p, 7s may be coupled to the horizontal stabilizer 3p, 3s. The one or more elevators 7p, 7s may be mounted on a trailing edge of the horizontal stabilizers 3p, 3 s similarly to how the flaps 6p, 6s are mounted on the wings Ip, Is. The elevators 7p, 7s may be structurally and functionally similar to the flaps 6p, 6s. When the UAV is in the horizontal flight mode, the pitch of the UAV may be controlled be controlling the elevators 7p, 7s. Rotating the elevators 7p, 7s such that unconnected edges thereof are above the horizontal stabilizers 3p, 3 s may increase the downward force exerted on the horizontal stabilizers 3p, 3s, causing the UAV to rotate about the pitch axis in the negative direction, i.e. such that the fore portion 201 and the nose arrangement 9 move downward relative to the rest of the UAV. Rotating the elevators 7p, 7s such that the unconnected edges are below the horizontal stabilizers 3p, 3 s may decrease the downward force exerted on the horizontal stabilizers 3p, 3 s, causing the UAV to rotate about the pitch axis in the positive direction, i.e. such that the fore portion 201 and the nose arrangement 9 move upward.

[0046] The UAV may comprise a rudder 14. The rudder 14 may be connected to the vertical stabilizer 4. The rudder 14 may be rotatably connected to a trailing edge of the vertical stabilizer 4. Preferably, the rudder 14 may be accommodated within the vertical stabilizer 4. That is, the vertical stabilizer 4 may comprise a cut-out, and the vertical stabilizer 4 may be accommodated within the cutout. A forward edge of the rudder 14 may be rotatably connected to the vertical stabilizer 4. The forward edge of the rudder 14 may be rotatably connected to the vertical stabilizer 4 using any suitable connecting means, such as a hinged connection. A rearward edge of the rudder may not be connected to the vertical stabilizer 4. The rudder 14 may be rotatable around an axis that is parallel to the yaw axis, such that the rearward edge of the rudder 14 can protrude to the port or starboard side of the vertical stabilizer 4. Rotation of the UAV around the yaw axis may be controlled through control of the rotation of the rudder 14.

[0047] The UAV may comprise at least one fixed rotor 1101, 1102. For example, the UAV may comprise two fixed rotors 1101, 1102. The fixed rotors may be coupled an upper surface of the body 1. The UAV may comprise a fore fixed rotor 1101 and an aft fixed rotor 1102. The fore fixed rotor 1101 may be coupled to an upper surface of the fore portion 201 or the middle portion of the body 2. The aft fixed rotor 1102 may be coupled to an upper surface of the middle portion 202 or the aft portion 203 of the body 2. The fore fixed rotor 1101 may be coupled to the body 2 with a fore fixed rotor mount 1107. The aft fixed rotor 1101 may be coupled to the body 2 with an aft fixed rotor mount 1108.

[0048] The fore fixed rotor 1101 and the aft fixed rotor 1102 may each comprise one or more blades 1103-1106. For example, the fore fixed rotor 1101 may comprise two blades 1103, 1104 and the aft fixed rotor may comprise two blades 1105, 1106. The two blades 1103, 1104 on the fore fixed rotor 1101 may be connected to a fore fixed rotor axle (not shown). The two blades 1105, 1106 on the aft fixed rotor 1102 may be connected to an aft fixed rotor axle (not shown).

[0049] The blades 1103-1106 of the fore fixed rotor 1101 and the aft fixed rotor 1101 may be configured to rotate in a plane that is parallel to the horizontal plane. When rotating, the blades 1103- 1106 of the fore fixed rotor 1101 and the aft fixed rotor 1101 may generate lift. The fore fixed rotor 1101 and the aft fixed rotor 1101 may be fixed, i.e. the plane in which the blades 1103-1106 of the fore fixed rotor 1101 and the aft fixed rotor 1101 may not be changeable.

[0050] The UAV may further comprise a fore fixed rotor driving unit (not shown) and a fore fixed rotor axle (not shown). The two blades 1103, 1104 on the fore fixed rotor 1101 may be connected to the fore fixed rotor axle. The fore fixed rotor axle may be coupled to the fore fixed rotor driving unit. The UAV may further comprise an aft fixed rotor driving unit (not shown) and an aft fixed rotor axle (not shown). The two blades 1105, 1106 on the aft fixed rotor 1102 may be connected to the aft fixed rotor axle. The aft fixed rotor axle may be coupled to the aft fixed rotor driving unit. The fore and aft fixed rotor driving units may be disposed in the body 2 of the drone. Additionally or alternatively, the fore and aft fixed rotor driving units may be disposed in the fixed rotor mounts 1107, 1108. The fixedrotor mounts 1107, 1108 may be releasably coupled to the body 2. This may allow the fore and aft fixed rotor driving units to be easily changed or replaced.

[0051] The UAV may further comprise a tail propeller 13. The tail propeller may be coupled to the aft portion 203 of the body 2. The tail propeller may comprise one or more blades 1301, 1302. For example, the tail propeller 13 may comprise two blades 1301, 1302. The tail propeller may further comprise a tail propeller driving unit (not shown) and a tail propeller axle (not shown). The two blades 1301, 1302 on the tail propeller 13 may be connected to the tail propeller axle. The tail propeller axle may be coupled to the tail propeller driving unit. The tail propeller may comprise a tail propeller nacelle 1303.

[0052] The blades 1301, 1302 of the tail propeller 13 may be configured to rotate in a plane that is parallel to the frontal plane. When the blades 1301, 1302 of the tail propeller 13 rotate, they may exert a force on the UAV in the forward direction. The tail propeller 13 may be fixed, i.e. the plane in which the blades 1301, 1302 of the tail propeller 13 rotate may not be changeable.

[0053] The UAV may further comprise one or more wing rotor units 5s, 5p. For example, the UAV may further comprise a starboard wing rotor unit 5 s and a port wing rotor unit 5p. The starboard wing rotor unit 5s may be rotatably coupled to the starboard wing Is and the port wing rotor unit 5p may be rotatably coupled to the port wing Ip.

[0054] The starboard wing rotor unit 5s may comprise a starboard wing rotor 501s, a starboard rotor shaft (not shown), a starboard rotor driving unit (not shown), a starboard rotor housing 503s and a starboard wing -tip portion 504s. The starboard wing rotor shaft and the starboard rotor driving unit may be disposed in the starboard rotor housing 503s. The starboard wing rotor 501s may comprise one or more blades, . For example, the starboard wing rotor 501s may comprise two blades. The starboard wing rotor 501s may further comprise a starboard nacelle. The starboard nacelle may be an aerodynamic housing configured to cover a region in which the blades of the starboard nacelle are connected to the starboard wing rotor shaft. The shape of the starboard nacelle may be such that aerodynamic drag thereon is minimized when the blades of the starboard wing rotor rotate in a plane that is parallel to the frontal plane. The shape of the nacelle may be hemi -spherical, paraboloid or any equivalent thereof.

[0055] The starboard wing rotor unit 5s may further comprise a starboard landing portion 508s. The starboard landing portion 508s may be connected to the starboard rotor housing 503s. The starboard landing portion 508s may be disposed at an end of the starboard rotor housing 503s opposite to the end at which the starboard wing rotor 501s is disposed.

[0056] The starboard wing -tip portion 504s may be rotatably coupled to a distal end of the starboard wing Is. The starboard wing -tip portion 504s may have a cross-section that is an airfoil. The starboard rotor housing 503 s may be fixedly coupled to the starboard wing -tip portion 504s. The starboard rotor shaft and the starboard rotor housing 503 s may extend in a direction that is substantially parallel to a chord line of the starboard wing -tip portion 504s. A chord line of thestarboard wing -tip portion 504s is a line connecting a leading edge of the starboard wing -tip portion 504s and a trailing edge of the starboard wing -tip portion 504s.

[0057] The starboard rotor unit 5s may be rotatable relative to the starboard wing Is. The starboard rotor unit 5s may be rotatable through approximately 90° or more. For example, starboard rotor unit 5s may be rotatable through approximately 180° or more, or approximately 360°. The starboard rotor unit 5s may be rotatable around the starboard spanwise direction. The starboard rotor unit 5s may be rotatable around an axis which is approximately parallel to the pitch axis.

[0058] The starboard rotor unit 5s may be rotatably connected to the starboard wing Is using any appropriate technique. For example, the starboard rotor unit 5s may be rotatably connected to the starboard wing Is with a starboard connection system (not shown) which comprises a starboard connecting shaft extending through the starboard wing Is and the starboard wing -tip portion 504s.

[0059] The starboard rotor unit 5 s may be rotatable between a vertical flight position (see Figure 1) and a horizontal flight position (see Figure 2).

[0060] In the vertical flight position, the blades of starboard rotor 501s may rotate in a plane that is parallel to the horizontal plane, or a plane that is approximately parallel to the horizontal plane. In the vertical flight position, the blades of starboard wing rotor 501s may exert an upward force on the UAV, i.e. the blades of starboard wing rotor 501s may generate lift. In the vertical flight position, the chord line of the starboard wing -tip portion 504s may be approximately perpendicular to a chord line of the starboard wing Is. In the vertical flight mode, the starboard wing rotor 501s may be above the starboard wing Is in the vertical direction. In the vertical flight mode, the starboard landing portion 508s may be below the starboard wing Is in the vertical direction. In the vertical flight mode, the starboard landing portion 508s may extend below a lower surface of the body 2 and a lowermost point of the nose arrangement 9.

[0061] In the horizontal flight position, the blades of starboard wing rotor 501s may rotate in a plane that is parallel to the frontal plane, or a plane that is approximately parallel to the frontal plane. In the horizontal flight position, the blades of starboard wing rotor 501s may exert a forward force on the UAV, i.e. the blades of starboard wing rotor 501s may propel the UAV in the forward direction. In the horizontal flight position, the chord line of the starboard wing -tip portion 504s may be approximately parallel to the chord line of the starboard wing Is. In the horizontal flight position, the chord line of the starboard wing -tip portion 504s may be approximately parallel to the chord line of the starboard wing Is. In the horizontal flight position, the chord line of the starboard wing -tip portion 504s may be coincident with the chord line of the starboard wing Is at the point where the starboard wing -tip portion is connected to the starboard wing Is. In the horizontal flight position, starboard wing -tip portion 504s may act as a continuation of the starboard wing Is.

[0062] In the embodiment described above, the starboard wing rotor unit 5 has included the starboard wing -tip portion 504s which is rotatable relative to the starboard wing Is. However, this isnot essential. For example, the starboard rotor housing 503s may be rotatably connected to a starboard wing -tip (not shown).

[0063] The port wing rotor unit 5p may comprise a port wing rotor 501s, a port rotor shaft (not shown), a port rotor driving unit (not shown) a port rotor housing 503p and a port wing -tip portion 504p. The port wing rotor shaft and the port rotor driving unit may be disposed in the port rotor housing 503p. The port wing rotor 50 Ip may comprise one or more blades, . For example, the port wing rotor 50 Ip may comprise two blades. The port wing rotor 50 Ip may further comprise a port nacelle. The port nacelle may be an aerodynamic housing configured to cover a region in which the blades of the port nacelle are connected to the port wing rotor shaft. The shape of the port nacelle may be such that aerodynamic drag thereon is minimized when the blades of the port wing rotor rotate in the frontal plane. The shape of the nacelle may be hemi -spherical, paraboloid or any equivalent thereof.

[0064] The port wing rotor unit 5p may further comprise a port landing portion 508p. The port landing portion 508p may be connected to the port wing rotor shaft housing 503p. The port landing portion 508p may be disposed at an end of the port wing rotor shaft housing 503p opposite to the end at which the port wing rotor 50 Ip is disposed.

[0065] The port wing-tip portion 504p may be rotatably coupled to a distal end of the port wing Ip. The port wing-tip portion 504p may have a cross-section that is an airfoil. The port wing rotor shaft housing 503p may be fixedly coupled to the port wing-tip portion 504p. The port rotor shaft and the port rotor housing 503p may extend in a direction that is substantially parallel to a chord line of the port wing-tip portion 504p. A chord line of the port wing-tip portion 504p is a line connecting a leading edge of the port wing -tip portion 504p and a trailing edge of the port wing-tip portion 504p.

[0066] The port rotor unit 5p may be rotatable relative to the port wing Ip. The port rotor unit 5p may be rotatable through approximately 90° or more. For example, port rotor unit 5p may be rotatable through approximately 180° or more, or approximately 360°. The port rotor unit 5p may be rotatable around the spanwise direction of the port wing Ip. The port rotor unit 5p may be rotatable around an axis which is approximately parallel to the pitch axis.

[0067] The port rotor unit 5p may be rotatably connected to the port wing Ip using any appropriate technique. For example, the port rotor unit 5p may be rotatably connected to the port wing Ip with a port connection system (not shown) which comprises a port connecting shaft extending through the port wing Ip and the port wing-tip portion 504p.

[0068] The port rotor unit 5p may be rotatable between a vertical flight position (see Figure 1) and a horizontal flight position (see Figure 2).

[0069] In the vertical flight position, the blades of port wing rotor 50 Ip may rotate in a plane that is parallel to the horizontal plane, or a plane that is approximately parallel to the horizontal plane. In the vertical flight position, the blades of port wing rotor 501p may exert an upward force on the UAV, i.e. the blades of port wing rotor 50 Ip may generate lift. In the vertical flight position, the chord line ofthe port wing-tip portion 504p may be approximately perpendicular to a chord line of the port wing Ip. In the vertical flight mode, the port wing rotor 50 Ip may be above the port wing Ip in the vertical direction. In the vertical flight mode, the port landing portion 508p may be below the port wing Ip in the vertical direction. In the vertical flight mode, the port landing portion 508p may extend below a lower surface of the body 2, a lowermost point of the vertical stabilizer 4, and a lowermost point of the nose arrangement 9.

[0070] In the horizontal flight position, the blades of port wing rotor 50 Ip may rotate in a plane that is parallel to the frontal plane, or a plane that is approximately parallel to the frontal plane. In the horizontal flight position, the blades of port wing rotor 50 Ip may exert a forward force on the UAV, i.e. the blades of port wing rotor 501p may propel the UAV in the forward direction. In the horizontal flight position, the chord line of the port wing -tip portion 504p may be approximately parallel to the chord line of the port wing Ip. In the horizontal flight position, the chord line of the port wing-tip portion 504p may coincident with the chord line of the port wing Ip at the point where the port wingtip portion is connected to the port wing Ip. In the horizontal flight position, the port wing-tip portion 504p may act as a continuation of the port wing Ip.

[0071] In the embodiment described above, the port wing rotor unit 5 has included the port wing-tip portion 504p which is rotatable relative to the port wing Ip. However, this is not essential. For example, the port wing rotor shaft housing 503p may be rotatably connected to a port wing -tip (not shown).

[0072] The UAV may further comprise a fore landing portion 8. The fore landing portion 8 may be connected to a lower surface of the fore portion 201 or the middle portion 202 of the body 2. The fore landing portion 8 may extend downward from the lower surface of the body. The fore landing portion 8 may extend further downward than the starboard landing portion 508s, the port landing portion 508p and the vertical stabilizer landing portion 401.

[0073] The fore landing portion 8 may comprise a suspension system or shock absorbers. The suspension systes or shock absorbers in the fore landing portion may be configured to reduce the force exerted on the body 2 of the UAV during landing. The suspension system or shock absorbers may comprise damping components (not shown) configured to dissipate energy, thus reducing oscillation of the UAV after landing. The starboard landing portion 508s and the port landing portion 508p may also comprise suspension systems or shock absorbers. The vertical stabilizer landing portion 401 may also comprise a suspension system or shock absorbers.

[0074] In the embodiment depicted in Figures 3 and 4, the fore landing portion 8 comprises two legs 8p, 8s (a port leg 8p and a starboard leg 8s). The port leg 8p may extend downward and portward. The starboard leg 8s may extend downward and starboard-ward. The legs 8p, 8s of the fore landing portion 8 may form a V-shape. This may provide stability to the UAV when the UAV is on the ground.

[0075] The wing rotor driving units may comprise an electric motor or a hybrid comprising a conventional (i.e. fossil fuel) internal combustion engine and an electric motor. The wing rotor driving units may further comprise an electronic speed controller (ESC). The propeller driving unit may comprise an electric motor or a hybrid comprising a conventional (i.e. fossil fuel) internal combustion engine and an electric motor. The propeller driving unit may further comprise an ESC. The fixed rotor driving units may comprise an electric motor or a hybrid comprising a conventional (i.e. fossil fuel) internal combustion engine and an electric motor. The fixed rotor driving units may further comprise an ESC.

[0076] The driving units may be interchangeable. That is, the UAV may be configured such that the driving units can easily be removed and replaced. For example, the driving units may be releasably coupled to their respective housings.

[0077] The wing rotor driving units may be substantially the same as the propeller driving unit. The wing rotors 501p, 501s and the tail propeller 13 may have the substantially same ESC. The wing rotors 501p, 501s and the tail propeller 13 may have substantially the same propeller parameters, e.g., diameter and pitch.

[0078] If the UAV comprises an internal combustion engine, the UAV may comprise a fuel tank to hold fuel for the internal combustion engine. The UAV may comprise one or more batteries. Additionally or alternatively, the UAV may comprise a Hydrogen fuel cell. The fuel tank and / or the one or more batteries and / o the hydrogen fuel cell may be disposed in the body 2 of the UAV.

[0079] The UAV may be operable in a temperature range between - 40 °C and +50 °C. The UAV may be rain and snow resistant, with an ingress protection (IP) rating of UP66 in accordance with international standard EN 60529. The UAV may be resistant to high-pressure waterjets in any direction. The UAV may also be resistant to dust ingress.

[0080] The UAV may be foldable. For example, the wings Ip, Is and / or the horizontal stabilizers 3p, 3s may be foldable. For example, the wings Ip, Is and / or the horizontal stabilizers 3p, 3s may be foldable around an axes that are parallel to the roll axis. Thus, the wings Ip, Is and / or the horizontal stabilizers 3p, 3 s may be folded in the upward direction to reduce the length of the UAV in the lateral direction. This may facilitate easy storage and transportation.

[0081] The UAV may comprise a control system (not shown) to control the rotors, propellers, control surface, sensors etc. The control system may comprise an inertial measurement unit (IMU). The IMU may comprise one or more of gyroscopes, accelerometers and magnetometers. The IMU may provide data relating to at least one of: linear acceleration, angular acceleration, orientation, and specific gravity. From this data, other quantities such as velocity and position may be derived. The control system may further comprise altimeters and GPS receivers. The control system may use artificial intelligence (Al) to analyze the data generated by the gyroscopes, accelerometers and magnetometers (and other sensors) to accurately determine the position and orientation of the UAV. Continuous machine learning may be used to improve the algorithm for determining the position andorientation of the UAV from the data from the gyroscopes, accelerometers and magnetometers. The machine learning may use GPS data as reference data. Data processing algorithms in the control system (e.g. algorithms for processing the data from the gyroscopes, accelerometers and magnetometers) may utilize a customized Kalman fdter and a convolutional neural network. The control system may comprise one or more of an autopilot system, communication system, a navigation system, and driving unit control systems. The provision of an accurate IMU may mean that the UAV is not dependent on external data for navigation. Thus, the UAV may be resistant to signal-jamming.

[0082] Shielding from electromagnetic interference (EMI) may be provided to the UAV. EMI may interfere with the functioning of the control system. Thus, the provision of shielding makes the operation of the UAV may robust and reliable. The shielding may be integral to the walls of the body 2 of the UAV.

[0083] The UAV may be capable of flight in wind speeds of 30 ms1.<Vertical flight mode>

[0084] During takeoff, the UAV may operate in the vertical flight mode. During landing, the UAV may operate in the vertical flight mode. During hover, the UAV may operate in the vertical flight mode. During the vertical flight mode, the starboard rotor unit 5s and the port wing rotor unit 5p may each be in the vertical flight position. That is, the blades of the wing rotors 501p, 501s may be in a plane that is approximately parallel to the horizontal plane. Thus, the blades of the wing rotors 501p, 501s may exert an upward force on the UAV. During the vertical flight mode, the blades 1103-1106 of the fore fixed rotor 1101 and aft fixed rotor 1102 may rotate in a plane that is approximately parallel to the horizontal plane to exert an upward force on the UAV. That is, during vertical flight mode, all of the fore fixed rotor 1101, aft fixed rotor 1102, the starboard wing rotor unit 5 s and the port wing rotor unit 5p may rotate to exert an upward force on the UAV. Thus, in the vertical flight mode, the UAV may function in a similar way to a quadcopter. The fore fixed rotor 1101, aft fixed rotor 1102, the starboard wing rotor unit 5 s and the port wing rotor unit 5p may be configured such that, during the vertical flight mode, a maximum takeoff weight is greater than 15 kg, preferably greater than 20 kg and further preferably greater than 25 kg. The UAV may have a load capacity of greater than 2 kg, preferably greater than 3 kg and further preferably greater than 4 kg. For example, the UAV may have a load capacity of approximately 5 kg.

[0085] During the vertical flight mode, the direction of rotation of the blades 1103-1106 of the wing rotors 501p, 501s and the fixed rotors 1101, 1102 may not be particularly limited. In some embodiments, the rotors 501p, 501s, 1101, 1102 may rotate in opposing direction so a resultant moment of the moments exerted on the UAV by the wing rotors 501p, 501s and the fixed rotors 1101, 1102 may be 0. For example, two of the two wing rotors 501p, 501s and the two fixed rotors 1101, 1102 may rotate in the positive direction and two of the two wing rotors and two fixed rotors may rotate in the negative direction.

[0086] During the vertical flight mode, the orientation and direction of travel of the UAV may be controlled by tilting the wing rotor units 5p, 5s. The tilting of the wing rotor units 5p, 5 s to control the orientation and direction of travel of the UAV may be similar to the tilting of the wing rotor units 5p, 5 s described above in relation to transitioning the wing rotor units 5p, 5 s between the vertical flight position and the horizontal flight position. That is, to control the orientation and direction of travel of the UAV the port wing rotor unit 5p may be rotated around the port spanwise axis and the starboard wing rotor unit 5s may be rotated around the starboard spanwise axis.

[0087] The plane in which the blades, of the starboard rotor 501s rotate may be referred to as a starboard rotor plane. The plane in which the blades, of the port rotor 50 Ip rotate may be referred to as the port rotor plane. As described above, the starboard rotor plane and the port rotor plane may be approximately parallel to the horizontal plane. However, when the wing rotor units are tilted to control the orientation and direction of the UAV, an angle between the starboard rotor plane and the horizontal plane, and between the port rotor plane and the horizontal plane may be between -10° and 10°.

[0088] To control the UAV to move in the forward direction, the wing rotor units 5p, 5 s may be rotated around the spanwise axes in the negative direction. That is, the wing rotor units 5p, 5s may be rotated around the spanwise axes such that the wing rotors 501p, 501s move forward relative to the wings Ip, Is. This may mean that the force generated by the wing rotors 501p, 501s has a component in the upward direction and a component in the forward direction. Thus, the UAV may accelerate forward. Figure 3 depicts the wing rotor units 5p, 5s rotated so as to provide the UAV with a force in the forward direction. To control the UAV to move in the rearward direction, the wing rotor units 5p, 5s may be rotated around the spanwise directions in the positive direction. That is, the wing rotor units 5p, 5s may be rotated around the spanwise directions such that the wing rotors 501p, 501s move rearward relative to the wings. This may mean that the force generated by the wing rotors 501p, 501s has a component in the upward direction and a component in the rearward direction. Thus, the UAV may accelerate rearward.

[0089] To rotate the UAV around the yaw axis, the starboard wing rotor 501s and the port wing rotor 50 Ip may be rotated in different directions. For example, to rotate the UAV around the yaw axis in the positive direction, i.e. to rotate the UAV such that the fore portion 201 of the body 2 moves starboard-ward relative to the middle portion 202 and aft portion 203 of the body 2, the starboard rotor unit 5 s may be rotated around the starboard spanwise direction in the positive direction and the port rotor unit 5p may be rotated around the port spanwise direction in the negative direction. This may mean that the force exerted on the UAV by the starboard rotor unit 5 s has a component in the upward direction and a component in the rearward direction, and the force exerted by the port rotor unit 5p has a component in the upward direction and a component in the forward direction. Thus, the UAV may rotate around the yaw axis in the positive direction.

[0090] To rotate the UAV around the yaw axis in the negative direction i.e. to rotate the UAV such that the fore portion 201 of the body 2 moves port-ward relative to the middle portion 202 and aft portion 203 of the body 2, the starboard rotor unit 5 s may be rotated around the spanwise direction in the negative direction and the port rotor unit 5p may be rotated around the spanwise direction in the positive direction. This may mean that the force exerted on the UAV by the starboard rotor unit 5s has a component in the upward direction and a component in the forward direction, and the force exerted on the UAV by the port rotor unit 5p has a component in the upward direction and a component in the rearward direction. Thus, the UAV may rotate around the yaw axis in the negative direction.

[0091] Whilst the UAV is in the vertical flight mode (and, for example, during takeoff), the tail propeller 13 may compensate for forces exerted on the UAV by winds. For example, if a wind is blowing against the nose arrangement 9 of the body (i.e. if the wind is approaching from forward of the UAV and moving in a rearward direction), the propeller may rotate to exert a force on the UAV in the forward direction. This may be such that the UAV remains substantially stationary. If the wind is not approaching from forward of the UAV and moving in a rearward direction, the UAV may rotate around the yaw axis (as described above) so that the wind is approaching from forward of the UAV and moving in a rearward direction. Considering this, during vertical takeoff, it may be preferable for the initial position of the to be against the wind. That is, it may be preferable for the forward direction relative to the UAV to be opposite to the wind direction, such that the fore portion 201 of the body 2 is upwind of the aft portion 203 of the body 2.

[0092] The wing rotors 501p, 501s may be configured to control the rotation of the UAV around the roll axis. Specifically, the lift force generated by the wing rotors 501p, 501s may be controlled to control the rotation of the UAV around the roll axis. For example, to rotate the UAV around the roll axis in the positive direction, the wing rotors 501p, 501s may be controlled such that the port wing rotor 501p generates a greater force than the starboard wing rotor 501s. To rotate the UAV around the roll axis in the negative direction, the wing rotors 501p, 501s may be controlled such that the starboard wing rotor 501s generates a greater force than the port wing rotor 501p. In the same way, the wing rotors 501s, 501p may be able to stabilize the UAV in the roll direction. The thrust generated by the wing rotors 501s, 501p may be controlled by controlling the rotational velocity of the blades of the wing rotors.

[0093] The fore fixed rotor 1101 and the aft fixed rotor 1102 may be used to control the rotation of the UAV around the pitch axis. Specifically, the force exerted on the UAV by the fore fixed rotor 1101 and the aft fixed rotor 1102 may be controlled to control the rotation of the UAV around the pitch axis. For example, to rotate the UAV around the pitch axis in the positive direction, the fore fixed rotor 1101 and the aft fixed rotor may be controlled such that the fore fixed rotor 1101 exerts a larger force than the aft fixed rotor 1102. To rotate the UAV around the pitch axis in the negative direction, the fore fixed rotor 1101 and the aft fixed rotor 1102 may be controlled such that the aft1102 fixed rotor exerts a large force than the fore fixed rotor 1101. The thrust generated by the fixed rotors 1101, 1102 may be controlled by controlling the rotational velocity of the blades of the fixed rotors 1101, 1102.

[0094] Whilst the control surfaces are primarily configured to control the orientation of the UAV during the horizontal flight mode, they may also be used during the vertical flight mode. To control the orientation of the UAV, the control surfaces may require a rearward flow of air thereover. When the UAV is in the vertical flight mode, the requisite flow of air may be provided by the wind. Alternatively, in the vertical flight mode, tilting of the wing rotors 501s, 50 Ip may cause the UAV to accelerate the UAV in the forward direction to the extent that the air flow over the control surfaces is sufficient for the control surfaces to at least partially control the UAV.

[0095] For the landing, the speed of the UAV in the horizontal plane may be controlled to become substantially zero. After the UAV has decreased its horizontal speed to zero, it may start to decrease altitude. This may be done by decreasing the upward force generated by one or all of the wing rotors 501p, 501s and the fixed rotors 1101, 1102. This may be done by decreasing the rotational speed of the blades of the wing rotors 501p, 501s and the fixed rotors 1101, 1102.

[0096] During vertical landing, it may be preferable for the UAV to be oriented against the wind. This may be so that the tail propeller 13 can compensate for the wind. The tail propeller 13 may allow the UAV to takeoff and land in wind speeds of 20 ms'1.

[0097] During landing, lift may be provided by the fore fixed rotor 1101, the aft fixed rotor 1101 and the wing rotors 501p, 501s.

[0098] When reaching a landing surface, the UAV may land on the landing portions described above. The fore landing portion 8 may be extend further downward than other landing portions. Thus, when landing, the fore landing portion may come into contact with the ground first. The fore landing portion may comprise a suspension / damping system. When the fore landing portion 8 comes into contact with the ground, the suspension / damping system may gradually reduce the speed of the UAV before the other landing portions come into contact with the ground. The suspension systems and / or shock absorbers in the landing portions may ensure that the landing is “soft”, i.e. that the force exerted on the UAV when the UAV reaches the ground is not excessive, and that the UAV does not oscillate excessively.<Horizontal flight>

[0099] When looking to move a non-negligible distance (e.g. 10s, 100s, or 1000s of meters), the UAV may operate in the horizontal flight mode. During the horizontal flight mode, the wing rotor units 5p, 5s may be in the horizontal flight position. That is, the blades of the wing rotors 501p, 501s may rotate in a plane that is parallel to the frontal plane, and exert a force on the UAV in the forward direction. An upward force may be exerted on the wings Ip, Is as a result of aerodynamic lift.

[0100] During the horizontal flight mode, the blades of the fore fixed rotor 1101 and the aft fixed rotor 1102 may not rotate. During the horizontal flight mode, the blades of the fore fixed rotor 1101and the aft fixed rotor 1102 may remain stationary and be aligned with the longitudinal axis (and therefore aligned with the body 2 of the UAV). Consequently, the aerodynamic impact of the presence of the fore fixed rotor 1101 and the aft fixed rotor 1102 may be reduced.

[0101] During the horizontal flight mode, the control surfaces (e.g. the flaps 6, the elevators 7 and the rudder 14) may be used to control the orientation of the UAV, as described above. During the horizontal flight mode, the flaps 6, elevators 7 and rudder 14 may be used to stabilize the UAV.

[0102] During the horizontal flight mode, the flaps 6p, 6s may be used to control the orientation of the UAV about the roll axis. That is, the flaps 6p, 6s may act as ailerons. For example, the UAV may be controlled to rotate around the roll axis in the positive direction by rotating the starboard flap in the negative direction (i.e. deflecting the starboard flap up) and rotating the port flap in the positive direction (i.e. deflecting the port flap down). The UAV may be controlled to rotate around the roll axis in the negative direction by rotating the starboard flap 6s in the positive direction (i.e. deflecting the starboard flap 6s down) and rotating the port flap 6p in the negative direction (i.e. deflecting the port flap 6p up).

[0103] During horizontal flight, the flaps 6p, 6s may be used as flaperons. That is, the flaps 6 may be controlled to increase the lift (i.e. increase the upward force exerted on the wings Ip, Is). This may be done by rotating the flaps 69, 6s in the positive direction (i.e. deflecting the port flap 6p and the starboard flap 6s down). During horizontal flight, the flaps 6p, 6s may be used as spoilers. That is, the flaps 6p, 6s may be used to rapidly decrease the speed of the UAV. This may be done by rotating the flaps 6p, 6s in the negative direction (i.e. deflecting the flaps up).

[0104] During the horizontal flight mode, the fore fixed rotor 1101 and / or the aft rotor 1102 may be used to provide additional lift. This may be necessary when a high climb-rate is required. That is, this may be necessary when the UAV is required to increase its altitude rapidly. Additionally or alternatively, the fore fixed rotor 1101 and / or the middle rotor may be used to provide additional lift when the wings Ip, Is are not capable of providing sufficient lift. This may be the case when the UAV is moving with a velocity having a low component in the longitudinal direction.

[0105] During horizontal flight, the wing rotors 501p, 501s may be used to control the orientation of the UAV around the yaw axis. Specifically, the thrust generated by the port wing rotor 501p and the starboard wing rotor 501s may be controlled to rotate the UAV around the yaw axis. For example, to rotate the UAV around the yaw axis in the positive direction, the port wing rotor 50 Ip and the starboard wing rotor 501s may be controlled such that the port wing rotor 501p generates more thrust than the starboard wing rotor 501s, To rotate the UAV around the yaw axis in the negative direction, the port wing rotor 501p and the starboard wing rotor 501s may be controlled such that the starboard wing rotor 501s generates more thrust than the port wing rotor 501p.

[0106] The wing rotors 501p, 501s may be contra-rotating. For example, the port wing rotor 501p may rotate in a clockwise direction and the starboard wing rotor 501s may rotate in an anticlockwise direction.

[0107] During the horizontal flight mode, the UAV may have a cruise velocity of greater than 20 ms1, preferably greater than 25 ms'1and further preferably greater than 28 ms1, and less than 100 ms' ', preferably less than 50 ms'1and further preferably less than 32 ms'1. For example, the UAV may have a cruise velocity of approximately 30 ms'1The UAV may have a maximum velocity of 50 - 60 ms'1.

[0108] Figure 6A depicts a plot of glide ratio (a ratio of the horizontal distance travelled against the height lost in unpowered horizontal flight) velocity of the UAV. Figure 6B depicts a plot of range against velocity for the UAV. Figure 6C depicts a plot of endurance (maximum flight time) against velocity for the UAV. Glide ratio, range and endurance are all dependent on the velocity. The glide ratio, range and endurance all reach a maximum (i.e. an optimum) at approximately 30 ms'1. Increasing the speed beyond 30 ms'1may result in a decrease in the glide ratio, range and endurance. <Transition>

[0109] To transition from the vertical flight mode to the horizontal flight mode, the wing rotor units 50 Ip, 501s may be rotated from the vertical flight position to the horizontal flight position, as described above.

[0110] During at least a portion of the transition (at the start of the transition), the fore fixed rotor 1101 and the aft fixed rotor 1102 may continue to rotate in the horizontal plane. As the wing rotors 50 Ip, 501s approach the horizontal flight position, they will accelerate the UAV in the forward direction. Once the wing rotors 501p, 501s reach the horizontal flight position, the wing rotors 501p, 501s will continue to accelerate the UAV in the forward direction. During the transition from the vertical flight mode to the horizontal flight mode, the tail propeller 13 may also accelerate the UAV in the forward direction. As the velocity of the UAV in the forward direction increases, the upward force exerted on the wings Ip, Is will increase. As the wing rotors 501p, 501s accelerate the UAV in the forward direction and the airspeed increases, the rotational velocity of the blades of the fixed rotors may decrease so that the resultant vertical force acting on the UAV may remain substantially constant. Once the UAV reaches an airspeed threshold, the wings may provide sufficient upward force to equal the gravitational force exerted on the drone. At this point, the blades 1103-1106 of the fixed wing rotors 1101, 1102 may stop rotating, and be stationary and aligned with the body 2.

[0111] Transition from the horizontal flight mode to the vertical flight mode may comprise similar steps but in the reverse order. The UAV may start the transition by decelerating. This may result in the upward force exerted on the wings Ip, Is decreasing. When the threshold air speed is reached, the blades of the fore fixed rotor 1101 and the aft rotor 1102 may begin to rotate, and thus provide lift. Alternatively, the blades of the fore fixed rotor 1101 and the aft rotor 1102 may begin to rotate before the threshold horizontal air speed is reached. For example, the blades of the fore fixed rotor 1101 and the aft fixed rotor 1102 may begin to rotate when the airspeed is a predetermined amount more than the threshold horizontal air speed.

[0112] When another threshold air speed is reached, the wing rotor units 50 Ip, 501s may transition from the horizontal flight position to the vertical flight position. Alternatively, the wing rotor units 50 Ip, 501s may transition from the horizontal flight position to the vertical flight position before the threshold horizontal air speed is reached. For example, the wing rotor units 501p, 501s may transition from the horizontal flight position to the vertical flight position when the airspeed is a predetermined amount more than the threshold horizontal air speed.<Modular configuration>

[0113] The UAV may have a modular structure. The modular structure may provide the UAV with the ability to adapt to a variety of mission profiles and weather conditions.

[0114] The modular structure of the UAV may allow two or more propulsion mechanisms to be used therewith. Consequently, the UAV may be able to be adapted to satisfy stealth, endurance, and environmental impact requirements. Additionally or alternatively, the UAV may be able to be adapted to balance stealth, endurance and environmental considerations.

[0115] The nose portion arrangement 9 may be modular. That is, the nose arrangement 9 may be configured to be easily detachable and re-attachable from the body 2. The nose portion 9 may be detachable and re-attachable without the need for tools or a workshop. This may mean that the sensors carried by the UAV can be easily changed. This means that the capabilities of the UAV can be adapted for mission requirement.<SIGNT capability>

[0116] The UAV is designed with advanced SIGINT capabilities that ensure a broad range and sensitivity.

[0117] The UAV's structural composition may comprise a combination of radio-shielded and radio- transparent materials to optimize resistance to electromagnetic interference and the effectiveness of SIGINT operations. Antennas may be located in the tail of the UAV.

[0118] The UAV may be configured to detect communication signals and identify a source of the communication signals.

[0119] To detect the communication signals, the UAV may comprise an array of antenna elements. The array of antenna elements may be divided into a plurality of sub-arrays. Each sub-array may be sensitive to communication signals in a particular frequency range. For example, a first sub-array may be sensitive to communication signals within the frequency range 500 MHz - 3 GHz. A second sub-array may be sensitive to communication signals within the frequency range 2 - 5 GHz. A third sub-array may be sensitive to communication signals within the frequency range 5 - 12 GHz. A fourth sub-array may be sensitive to communication signals within the frequency range 8 - 12 GHz. Each of the sub-arrays may be a phased array.

[0120] By using an array of antenna elements which are divided into a plurality of sub-arrays, each sub-array corresponding to a different frequency range, a wide sensitivity range can be achieved.

[0121] An antenna control system may perform automatic switching of the antenna element by means of fast multiplexers and heterodyne elements.

[0122] There may be at least 4 antenna elements in the antenna array. Preferably, there may be 5 or more, 6 or more, 7, 8 or more, or 9 or more antenna elements in the antenna array. For example, there may be 10 antenna elements in the antennae array.

[0123] The antenna elements may be accommodated within a housing of the UAV. For example, the antenna elements may be accommodated within the body 2. The antenna elements may be accommodated within the aft portion 203 of the body 2. The antenna elements may be accommodated within the wings Ip, Is

[0124] The UAV may comprise a directional antenna subsystem. The directional antenna subsystem may comprise a radial antenna arrangement 920. In the radial antenna arrangement 920, the antenna elements may be arranged in a radial configuration. A radial antenna arrangement 920 is depicted in Figure 7A. The radial antenna arrangement 920 may comprise a shaft 922. The radial antenna arrangement 920 may comprise a plurality of antenna elements 921a-j . Each of the antenna elements 921a-j may comprise a flat conducting plate. Alternatively, the radial antenna may comprise a plurality of rods, each rod extending in a radial direction as the plurality of antenna elements 921a-j . In some examples, the radial antenna arrangement 920 may comprise 10 antenna elements 921a-j . Each of the antenna elements 921a-j may be mounted to the shaft. Each of the antenna elements 921a-j may extend radially outward from the shaft. The antenna elements 921a-j may be distributed circumferentially around the shaft. Each of the antenna elements may be separated from adjacent antenna elements by an angle of rotation around the shaft. The angle of rotation may be (360 / N)°, where N is the number of antenna elements 921a-j in the radial antenna arrangement 920. For example, in the case that there are 10 antenna elements 921a-j, each of the antenna elements may be separated from adjacent antenna elements by 36°.

[0125] Each of the antenna elements 921a-j may extend in a plane that is substantially parallel to a direction in which the shaft 922 extends. A shape of the antenna elements 921a-j may not be particularly limited. For example, each antenna element may comprise two arrow-shaped portions.

[0126] Another radial antenna arrangement 930 is depicted in Figure 7B. The radial antenna arrangement 930 may be similar to the radial antenna arrangement 920, except as described below. Each of the antenna elements 93 la-j may be rectangular. The radial antenna arrangement 930 may comprise one or more circumferential support members 933. The circumferential support members 933 may be connected to distal ends of each of the antenna elements 93 la-j to provide additional support. A shape of the antenna elements 93 la-j may be rectangular.

[0127] The antenna elements 92 la-j 93 la-j depicted in Figures 8A and 8B may be directional antennae. The antenna elements 92 la-j 93 la-j depicted in Figures 8 A and 8B may be configured to determine an angle of arrival (AO A) of a communication signal.

[0128] Each of the antennae elements may have a specific directional sensitivity. That is, for any of the antenna elements 921a-j 93 la-j, the strength of the signal detected may be dependent on the direction from which the signal arrives, relative to the antenna element. For each of the antenna elements, there may be a direction which corresponds to a maximum signal strength. Thus, the angle of arrival may be determined by considering the strengths of the signal detected by the plurality of antenna elements 92 la-j 93 la-j.

[0129] The directional antenna subsystem may further comprise a robust analog switch for multiplexing of the antenna sub-arrays. The directional antenna subsystem may further comprise a multi-channel SDR (software defined radio) DF (direction finding) converter and test generator. The directional antenna subsystem may further comprise a main processing unit for data computation and processing. The main processing unit may comprise a commercially available single board computer, such as a RaspberryPi (RTM). Figure 8 depicts a functional diagram of the directional antenna subsystem.

[0130] In addition to the radial antenna array subsystem (or, in some embodiments, as an alternative to the radial antenna array subsystem), the UAV may further comprise a phased antenna array subsystem employing digital beamforming controlled by one or more commercially available beamforming units such as the ADAR1000 manufactured by Analog Devices, Inc of Wilmington, MA. The phased antenna array subsystem may comprise a planar antenna array. The planar antenna array may comprise a plurality of antenna elements. For example, the planar antenna array may comprise approximately 32 antenna elements. A block diagram of the phased antenna array subsystem is depicted in Figure 9.

[0131] Figure 10 depicts an overview of the general operating principle of the phased antenna array subsystem.

[0132] Figure 11 depicts a block diagram of the directional antenna subsystem and the phased antenna array subsystem.

[0133] The directional antenna subsystem may be used to provide an initial estimate of the angle of arrival of a signal. The directional antenna subsystem may utilize an amplitude method to provide the initial estimate. The initial estimate for the angle of arrival may have an uncertainty of 0.26 radians (approx. 15 degrees).

[0134] The phased antenna array subsystem may be used to provide a refined estimate for the angle of arrival of the signal. The phased antenna array subsystem may utilize coherent interferometry to provide the refined estimate. The refined estimate for the angle of arrival may have an uncertainty of approximately 0.034 radians (approx. 2 degrees). The coherent interferometry may be used to compute direction of the signal and coherence level (reliability) simultaneously. This may result in improved performance. identification of emitter location>

[0135] The UAV may be provided with an autonomous or semi -autonomous routing algorithm for detecting and locating signal sources. The routing algorithm is responsive to detection of electromagnetic signals and modifies the flight trajectory of the UAV to enable accurate location of the signal source.

[0136] As described above, the UAV may be configured to determine an angle of arrival of a signal. During a flight path, the UAV may determine a plurality of angles of arrival from different locations. For each angle of arrival, a line of bearing (UOB) may be determined. The intersection of the lines of bearing for each angle of arrival may provide the location of the source of the signal. This method is depicted in Figures 12A and 12B. Sensor 1 and sensor 2 may be the same sensor but in different positions. This may be the case if the UAV has moved from a first position to a second position.

[0137] The UAV may comprise multiple signal detecting elements. If the UAV comprises multiple signal detecting elements, the UAV may further utilize time difference of arrival (TDOA) techniques to improve the accuracy of the determination of the source of the signal.

[0138] In general, a method of identifying a location of a target which emits a signal may comprise one or more of the following steps:(1) Detecting and registering a signal (i.e. an electromagnetic wave);(2) Obtaining an initial estimation of the AOA using the directional antenna subsystem;(3) Adjusting the orientation of the planar antenna array so that it is directed towards the location of the target, based on the initial estimate of the AOA. This step may only be performed if necessary.(4) Obtaining a refined estimation of the AOA azimuth parameter using coherent interferometry or the phased array.(5) Plotting a first line of bearing using the position of the UAV and the AOA;(6) Moving to a different location.(7) Repeating steps (2) to (5) at the different location to plot a second line of bearing.(8) Calculating the geoposition of the target by identifying the intersection of the first and second lines of bearing.

[0139] Optionally, lines of bearing from 3 or more, 4 or more, or 5 or more positions of the UAV may be considered when calculating the geoposition of the target.

[0140] Embedded software in the control system of the UAV may perform the following functions:(1) Processing of data from the antenna subsystems.(2) Performing mathematical calculations to determine the main characteristics of detected signals (e.g. time domain / frequency domain) and detection of AOA.(3) Reading data from sensors on the detector board and optionally associating sensor readings with contemporaneous GPS coordinates and digital compass readings.(4) Calculating the geolocation of the target and relative direction of the emitter.

[0141] The UAV may be in communication with a base station. At the base station, a device may run an operator program. The operating of the operator program may comprise the following steps:(1) Presenting a real-time visualization of the geolocations of detected targets on a map. Figure 13 depicts an example user interface for the target location system.(2) Notifying users of detected targets. A notification system may be configured to perform the notifying step. The notification system may comprise an API such that the notification system can communicate with other devices (e.g. tablet / mobile device / web application). This may allow notifications to be sent to the other devices. Notifications may include the geolocation of the target and the type of target (e.g. the type of signal intercepted).(3) Presenting a map with a visualization of the geolocation of one or more UAVs that are operational within a predetermined area.(4) Presenting a map with a visualization of the geolocation of newly detected targets.(5) Calculating a geolocation of detected targets using data from multiple UAVs and / or other detecting systems. This calculation may comprise the AOA method and additional refinement using TDOA reference method. This calculating may further comprise identifying an area of uncertainty, and the size of the area of uncertainty.<Autonomous routing>

[0142] A desired angular separation between lines of bearing may depend on a distance between the UAV and the source of the signal; the power of the source; and the accuracy of the AOA measurements. The desired angular separation may therefore be dependent on individual situation parameters. The desired angular separation may determine a drone trajectory (i.e. a drone flight plan, i.e. a route that the drone will take). Thus, the drone trajectory may be dependent on individual situation parameters.

[0143] The drone trajectory may be determined using a trajectory determination method. The trajectory determination method may be performed by the UAV, or the control system thereof. The trajectory determination method may comprise one of more of the following steps:(1) Define an area of interest.(2) Initiate a mission to the area of interest.(3) Monitor for targets. A target may be identified if a communication signal is detected.(4) Switch to reconnaissance mode. The switch to reconnaissance mode may be performed when a target has been identified.(5) Define a circular trajectory around the target.(6) Optimize the circular trajectory for energy efficiency and visibility for electronic reconnaissance. Optimization of the circular trajectory may comprise optimization of at least one of: the diameter of the circular trajectory, the altitude at which the UAV follows the circular trajectory; and the number of laps of the circular trajectory performed by the UAV.Communication systems>

[0144] EM interferences and the influence of Electronic warfare (EW) may cause issues for UAVs. Electronic Warfare may typically play a significant role in influencing UAVs. Electronic warfare may involve the use of electromagnetic radiation to hinder the operation of a communication system. Typically, UAVs may be reliant on communication links for remote control and data transmission. Electronic warfare techniques such as jamming or spoofing can disrupt or manipulate the communication signals between the UAV and its operator, rendering the drone uncontrollable or misdirecting its actions. Electronic warfare may also involve interference with navigation systems. UAVs may typically use Global Navigation Satellite Systems (GNSS) like GPS for accurate positioning and navigation. EW may involve jamming or interfering with GNSS signals, causing the UAV’s navigation system to lose accuracy or reliability, potentially leading to navigation errors or crashes.

[0145] The UAV may comprise a communication system which is capable of transmitting and receiving data in a stable manner without interference. To achieve this, the UAV may use a plurality of mechanisms for communication. The communication system may comprise a plurality of communication modules. Each communication module may operate independently. Each communication module may rely on a different technology. Thus, if the operation of one technology is interfered with or targeted by electronic warfare, the other technologies may be able to continue transmitting / receiving data. The communication modules may operate at different frequencies to each other. Further, the communication modules may rely on different communication protocols. Further, one or more of the communication modules may be capable of using a plurality of communication protocols. Thus, a wide variety of communication techniques (technologies / frequencies / protocols) are available. Even if some of the techniques (technologies / frequencies / protocols) are interfered with, it is likely that the UAV will still be able to communicate with an external receiver using other, unaffected techniques.

[0146] One or more of the communication modules may be operable in multiple frequency bands. Thus, if a specific frequency band is affected, the communication mode may still be able to operate successfully within another frequency band.

[0147] One or more of the communication modules may employ data encryption. This may ensure that data is not intercepted by parties other than the intended receiver.

[0148] The UAV may comprise customized antennae. The customized antennae may be configured to transmit maximum power. The customized antennae may be configured to have maximum sensitivity to received signals

[0149] One or more of the communication modules may employ a frequency hopping algorithm. Frequency hopping is a wireless communication technique used to enhance the security and reliability of communication systems by rapidly changing the frequency at which the signal is transmitted. This technique is particularly useful in Electronic Warfare (EW), military communications, and other scenarios where robust and secure communication is essential. Use of the frequency hoppingalgorithm may avoid interference, prevent eavesdropping, and enable code-division multiple access (CDMA) communications.

[0150] The switching of the transmission frequency may be controlled by a code known to the UAV (i.e. the telemetry module) and a receiving station. The frequency hopping algorithm involves systematically switching the transmission frequency among a predefined set of frequencies over time.

[0151] The frequency hopping algorithm may comprise a frequency set selection process. In the frequency set selection process, a set of frequencies (also known as channels) may be defined before communication begins. These frequencies may be selected to be varied. Diversity of channels may improve resistance to interference and jamming.

[0152] The frequency hopping algorithm may comprise a hop sequence generation. In the hop sequence generation, a predetermined sequence of channel numbers is generated. This sequence may define the order in which the transmitter will switch between the available frequencies.

[0153] During the operation of the frequency hopping algorithm, the transmitter (e.g. the UAV or a ground station) and receiver (e.g. a ground station or the UAV) may be synchronized to a common clock or timing reference. This synchronization may ensure that both devices switch frequencies simultaneously.

[0154] The frequency hopping algorithm may comprise a frequency hopping process. The communication module may operate at a given frequency for a given time (a transmission interval). At each transmission interval, the transmitter selects the next frequency in the hop sequence and starts transmitting on that frequency. The receiver is also aware of the hop sequence and switches its reception frequency in-sync with the transmitter.

[0155] The hop sequence may be changed dynamically to further enhance security and counteract jamming attempts. Frequency hopping patterns may be adjusted based on real-time conditions or predefined patterns to make interception or jamming more challenging.

[0156] By being capable of transmitting data at different frequencies, and changing these frequencies (e.g. through a frequency hopping algorithm) the UAV may be less susceptible to jamming. This may be because jamming targets specific frequencies.

[0157] Further, the frequency hopping algorithm may make the transmission of data more secure. This may be because interception of the whole data is difficult.

[0158] The communication system may comprise a telemetry module capable of telemetry. The telemetry module may be capable of collecting measurements or other data at remote locations and automatically transmitting the measurements or other data to receiving equipment for monitoring. Operation of the telemetry module may be autonomous. That is, the telemetry module may operate without external instructions and data. Transmission of data by the telemetry module may be performed within a frequency range of 800 MHz to 1,000 MHz. For example, transmission of data by the telemetry module may be performed within at a frequency of approximately 900 MHz.Additionally or alternatively, transmission of data by the telemetry module may be performed within afrequency range of 300 MHz to 500 MHz. For example, transmission of data by the telemetry module may be performed within at a frequency of approximately 400 MHz. In some embodiments, the telemetry module may transfer data at two different frequencies. For example, the telemetry module may transfer data at approximately 400 MHz and approximately 900 MHz. Transmission As such, the telemetry module may be able to transmit data over long distances. The telemetry module may be configured such that the telemetry module can transmit data at one of a number of frequencies. For example, the telemetry module may be configured such that the telemetry module can transmit data approximately 400 MHz and approximately 900 MHz.

[0159] The telemetry module may be capable of transmitting data at up to 345 kbps. The telemetry module may be capable of transmitting data with a power of greater than lOOmW. The telemetry module may be capable of transmitting data at a power of less than 2W.

[0160] The telemetry module may comprise a frequency hopping algorithm, which may be utilized when transmitting data.

[0161] The telemetry module may be configured to transmit data with a point-to-point connection. That is, the telemetry module may be configured to transmit data to a single, particular receiver. Additionally or alternatively, the telemetry module may be configure to transmit data with a point-to- multipoint connection. That is, telemetry module may be configured to broadcast data so it can be received by a plurality of receivers. In some embodiments, the UAV may be capable of operating in a point-to-point mode and a point-to-multi -point mode. The UAV may be further configured to switch between the point-to-point mode and the point-to-multi-point mode depending on situational requirements.

[0162] The telemetry module may be configured to operate in a master mode. The telemetry module may be configured to operate in a remote mode. The telemetry module may be configured to operate in a repeater mode. The telemetry module may be configured to operate in a master mode, a remote mode and a repeater mode. The UAV may be further configured to switch between the master mode, a remote mode and a repeater mode depending on situational requirements.

[0163] The telemetry module may be capable of operating at temperatures less than -50°C. For example, telemetry module may be capable of operating at -55°C. The telemetry module may be capable of operating at temperatures greater than 80°C. For example, the telemetry module may be capable of operating at 85°C.

[0164] The telemetry module may be configured to perform forward error correction (FEC). The forward error correction may be selectively performed (i.e. the forward error correction may be performed at some times but not performed at other times). Forward error correction may allow for packets of information that are lost during transmission to be recovered. This may be achieved by sending extra “parity” packets for every group (N) of packets. As long as the receiver receives a subset of packets in the group (at-least N-l) and the parity packet, up to a single lost packet in the group can be recovered.

[0165] The telemetry module may be configured to perform cyclic redundancy checks (CRC). For example, the telemetry module may be configured to perform 32-bit cyclic redundancy checks.

[0166] The telemetry module may be configured to transmit data using an advanced encryption standard (AES). For example, the telemetry module may be configured to transmit data using a 128- bit advanced encryption standard.

[0167] The communication system may comprise a video transmission module. The video transmission module may ne capable of transferring video data over a range of 50 km or more. The video transmission module may be capable of transferring video data at a rate if greater than 25 Mbps. The video transmission module may be capable of transferring video data with a total power output of 4 W. The video transmission module may be capable of transferring video data with a total output power of approximately 36 dBm (4 W). The video transmission module may be capable of multipleinput, multiple-output (MIMO). That is, the video transmission module may be configured to communicate with multiple devices simultaneously to drastically reduce wait times and speed up transmission. MU-MIMO may involve dividing up available network bandwidth into separate streams that share the connection equally. For example, the video transmission module may be capable of 2x2 MIMO, wherein the video transmission module is capable of dividing the network bandwidth into 2 separate streams.

[0168] The video transmission module may be capable of transferring video data with a frequency in a range of approximately 2.304 GHz to 2.390 GHz.

[0169] The video transmission module may be capable of Maximal Ratio Combining (MRC). The video transmission module may be capable of Maximal Likelihood (ML) decoding.

[0170] The video transmission module may be capable of performing a Low -Density Parity Check (LDPC).

[0171] Like the telemetry module, the video transmission module may be capable of transmitting data in a point-to-point mode of a point-to-multipoint mode. The video transmission module may be capable of operating within a mesh network topology. Low-Density Parity Check (LDPC).

[0172] The video transmission module may be capable of operating in Master, Remote, Relay, Mesh Modes.

[0173] The video transmission module may be capable of transmitting data with a low power consumption.

[0174] The video transmission module may comprise Serial & USB Ports. The video transmission module may comprise dual ethemet ports. For example, the video transmission module may comprise a local area network (LAN) port. Additionally or alternatively, the video transmission module may comprise a wide area network (WAN) port.

[0175] The video transmission module may be capable of Port Forwarding. The video transmission module may be capable of operating with an access control list (ACL). The video transmission module may be capable of operating with a firewall.

[0176] The video transmission module may be capable of operating in temperatures of less than - 30°C. For example, the video transmission module may be capable of operating in temperatures of - 35°C. The video transmission module may be capable of operating in temperatures of more than 80°C. For example, the video transmission module may be capable of operating in temperatures of 85°C.

[0177] The video transmission module may be configured to transmit data using an advanced encryption standard (AES). For example, the video transmission module may be configured to transmit data using a 128-bit advanced encryption standard. Additionally or alternatively, the video transmission module may be configured to transmit data using a 256-bit advanced encryption standard.

[0178] The video transmission module may be configurable via a local console. Additionally or alternatively, the video transmission module may be configurable via telnet. Additionally or alternatively, the video transmission module may be configurable via a web browser.

[0179] The video transmission module may be capable of local firmware upgrades. Additionally or alternatively, the video transmission module may be capable of remote firmware upgrades.

[0180] The UAV may comprise a satellite communication module. The satellite communication module may comprise an Iridium satcom module. The Iridium satellite constellation provides L band voice and data information coverage to the UAV, as well as two-way satellite messaging service to the UAV over the entirety of the Earth’s surface.

[0181] The satellite communication module may support Circuit-Switched Data. The satellite communication module may support Router-Based Unrestricted Digital Internetworking Connectivity Solutions (RUDICS). The satellite communication module may support Iridium Short Burst Data® (SBD®). The satellite communication module may be capable of Iridium Push-To-Talk (PTT).

[0182] The UAV may further comprise a GSM transmission module. GSM means Global System for Mobile Communications. The GSM module may be configured to transmit data at approximately 900 MHz and / or approximately 1800 MHz. The GSM module may be a 3G GSM transmission module. The GSM module may be an LTE GSM transmission module. LTE means long term evolution.

[0183] The UAV may comprise a midrange a midrange transmission module. The midrange transmission module may transmit data at a frequency of approximately 400 MHz to approximately 433 MHz. The midrange transmission module may utilse a Low Power Wide Area Networking (LoRaWAN) transmission protocol.

[0184] The UAV may comprise one or more of the different modules described above. The different modules may be all in one system, i.e. may not be physically separate devices. However, operation of the modules may be independent.

[0185] The provision and use of multiple communication modules can help avoid interference from other communication systems or jamming sources operating on specific frequencies.<Examples of use>

[0186] The advanced detection capabilities and robust design of the current invention, an unmanned aerial vehicle (UAV) equipped with an advanced SIGINT module, enable its deployment for the detection of a wide array of anti-UAV systems and numerous Electronic Warfare (EW) units, while maintaining operational safety.

[0187] A first example is in anti-UAV systems. This UAV's SIGINT module is capable of detecting a diverse range of anti-UAV systems, extending to radar-guided surface-to-air missile systems, infrared-guided systems, and anti-UAV artillery systems. By intercepting the electronic signals emitted from the radar or communication systems of these threats, the UAV can accurately locate such hazards from a safe distance.

[0188] A second example is in electronic warfare (EW) units. The UAV is also engineered to detect a variety of Electronic Warfare units within its operational range. These encompass electronic attack systems, electronic support systems, and electronic protection systems. By identifying the signals emitted by these systems, the UAV can locate and identify such units, even at substantial distances. The SIGINT module's operational range from 10 MHz to 13 GHz covers a significant portion of the spectrum utilized by these systems, thus enabling the UAV to detect a comprehensive range of threats.

[0189] Given the UAV's all-weather operation capability and its robust construction, it is ideally suited for missions in hostile environments. It is capable of hovering or patrolling for extended periods, collecting crucial SIGINT data while remaining outside the effective range of enemy air defenses or electronic warfare systems.

[0190] Additionally, owing to the UAV's modular design, it can be fitted with different propulsion systems tailored to the mission requirements. For example, for missions where stealth is crucial, an electric propulsion system, which operates silently, can be employed. Conversely, for missions demanding endurance or extended range, the UAV can utilize a hydrogen fuel cell or hybrid propulsion system. This flexibility allows the UAV to be customized to meet the demands of any given mission, enhancing its likelihood of success.

[0191] While specific embodiments of the invention have been described above, it will be appreciated that the invention may be practiced otherwise than as described. The descriptions above are intended to be illustrative, not limiting. Thus, it will be apparent to one skilled in the art that modifications may be made to the invention as described without departing from the scope of the claims set out below.

[0192] Aspects of the invention are described in the following numbered clauses.1. An unmanned aerial vehicle (UAV) comprising: a body; a first rotor positioned having blades that rotate in a first rotor plane that is parallel to a horizontal plane;a second rotor having blades that rotate in a second rotor plane that is parallel to the horizontal plane; a port wing and a starboard wing extending from the body; a port rotor unit rotatably coupled to a distal end of the port wing, wherein the port rotor unit comprises one or more port blades; and a starboard rotor unit rotatably coupled to a distal end of the starboard wing, wherein the starboard rotor unit comprises one or more starboard blades, wherein the UAV is configured such that the port rotor unit is rotatable between a vertical flight position, in which the port blades rotate in a first port rotor plane to provide lift, and a second port rotor plane that is substantially parallel to a frontal plane, and wherein the UAV is configured such that the starboard rotor unit is rotatable between a vertical flight position, in which the starboard blades rotate in a first starboard rotor plane to provide lift, and a second starboard rotor plane that is substantially parallel to a frontal plane.2. The UAV according to clause 1, wherein the horizontal plane is defined by a roll axis and a pitch axis, the frontal plane is defined by the pitch axis and a yaw axis and a side plane is defined by the roll axis and the yaw axis, wherein the roll axis, pitch axis and yaw axis are perpendicular to each other.3. The UAV according to clause 2, wherein the body extends along the roll axis.4. The UAV according to any of the preceding clauses, wherein: the UAV is configured to travel in a direction that is substantially parallel to the roll axis during a horizontal flight mode; the UAV is configured to travel in a direction that is substantially parallel to the yaw axis during a vertical flight mode; the UAV is configured to control the port rotor unit and the starboard rotor unit to be in the horizontal flight position during the horizontal flight mode; and the UAV is configured to control the port rotor unit and the starboard rotor unit to be in the vertical flight position during the vertical flight mode.5. The UAV according to any of the preceding clauses, wherein: the port wing extends in a port spanwise direction; the port rotor unit is rotatable around the port spanwise direction; the starboard wing extends in a starboard spanwise direction; and the starboard wing is rotatable around the starboard spanwise direction.6. The UAV according to any of the preceding clauses, wherein the first rotor plane and the second rotor plane are fixed.7. The UAV according to any of the preceding clauses, further comprising a propeller coupled to a tail end of the body, the propeller comprising propeller blades that rotate in a propeller plane that is parallel to the frontal plane.8. The UAV according to clause 7, wherein the propeller plane is fixed.9. The UAV according to any of the preceding clauses, wherein, in the vertical flight mode: an angle between the first starboard rotor plane and the horizontal plane may be between -10° and 10°; and an angle between the first port rotor plane and the horizontal plane may be between -10° and 10°.10. The UAV according to any of the preceding clauses, wherein: the starboard rotor unit comprises: a starboard wing rotor having the starboard blades, a starboard rotor driving unit, a starboard rotor housing for accommodating the starboard rotor driving unit and a starboard wing-tip portion; and the port rotor unit comprises: a port wing rotor having the port blades, a port rotor driving unit a port rotor housing for accommodating the port rotor driving unit and a port wing-tip portion.11. The UAV according to clause 10, wherein the starboard wing -tip portion is rotatably coupled to the starboard wing and the port wing-tip portion is rotatably coupled to the port wing.12. The UAV according to clause 10 or 11, wherein; when the port rotor unit is in the vertical flight position, a chord line of the port wing-tip portion is substantially perpendicular to a chord line of the port wing; when the port rotor unit is in the horizontal flight position, the chord line of the port wing-tip portion is substantially parallel to the chord line of the port wing; when the starboard rotor unit is in the vertical flight position, a chord line of the starboard wing-tip portion is substantially perpendicular to the chord line of the starboard wing; when the starboard rotor unit is in the horizontal flight position, the chord line of the starboard wingtip portion is substantially parallel to the chord line of the starboard wing.13. The UAV according to any of the preceding clauses, wherein; the first rotor comprises two first rotor blades and the second rotor comprises two second rotor blades; and when the UAV is in the horizontal flight mode, the first rotor blades and the second rotor blades do not rotate, and remain aligned with the roll axis.14. The UAV according to any of the preceding clauses, wherein the UAV is configured to transition from the vertical flight mode to the horizontal flight mode by performing the following steps: rotating the port rotor unit and the starboard rotor unit from the vertical flight position to the horizontal flight position; accelerating the UAV to increase an airspeed; once a first threshold airspeed has been reached; stopping the rotation of the first rotor blades and the second rotor blades.15. The UAV according to any of the preceding clauses, wherein the UAV is configured to transition from the horizontal flight mode to the vertical flight mode by performing the following steps:decelerating the UAV to decrease an airspeed; once a second threshold airspeed has been reached, starting the rotation of the first rotor blades and the second rotor blades; and once a third threshold airspeed has been reached; rotating the port rotor unit and the starboard rotor unit from the horizontal flight position to the vertical flight position.16. The UAV according to any of the preceding clauses, wherein: the port rotor unit comprises a landing portion disposed at an end of the port wing rotor unit that is opposite to the port rotor; and the starboard rotor unit comprises a landing portion disposed at an end of the starboard wing rotor unit that is opposite to the starboard rotor.17. The UAV according to any of the preceding clauses, further comprising a fore landing portion configured to form a lowermost point of the UAV.18. The UAV according to clause 18, wherein the fore landing portion comprises a suspension system and or shock absorber.19. The UAV according to any of the preceding clauses, wherein the one or more of the first rotor, second rotor, port rotor unit and starboard rotor unit are powered by an internal combustion engine and / or an electric motor.20. The UAV according to any of the preceding clauses, further comprising a battery and / or a hydrogen fuel cell.21. The UAV according to any of the preceding clauses, further comprising a navigation system configured to determine a route for the UAV to follow.22. The UAV according to any of the preceding clauses, further comprising an autopilot system configured to control the UAV to follow a route.23. The UAV according to clause 23, wherein the autopilot system is configured to control the UAV to follow the route based on data provided by an inertial measurement unit.24. The UAV according to clause 24, wherein the autopilot system is configured to perform continuous machine learning to improve the ability of the autopilot system to control the UAV to follow the route based on data provided by the inertial measurement unit, wherein the continuous machine learning uses GPS data as reference data.25. The UAV according to any of the preceding clauses, further comprising a nose arrangement coupled to a fore portion of the body, wherein the nose arrangement comprises a sensor arrangement.26. The UAV according to clause 26, wherein the nose arrangement is removably coupled to the fore portion of the body.27. The UAV according to any of clause 26 or 27, wherein the sensor arrangement comprises one or more of: an optical camera, a thermal camera, an optical flow camera, a directional antenna array, and a phased antenna array.28. An unmanned aerial vehicle (UAV) comprising a radial antenna arrangement, wherein the radial antenna arrangement comprises a plurality of antenna elements arranged in a radial configuration.29. The UAV according to clause 28, wherein proximal portions of each of the plurality of antenna elements are mounted to a shaft, and each of the antenna elements extend radially outward from the shaft.30. The UAV according to clause 29, wherein the plurality of antenna elements are distributed circumferentially around the shaft.31. The UAV according to clause 28 to 30, wherein an angle between an antenna element and an adjacent antenna element is approximately equal to (360 / N)°, wherein N is the number of antenna elements.32. The UAV according to any of clauses 28 to 31, wherein there are 10 or more antenna elements, optionally wherein there are exactly 10 antenna elements.33. The UAV according to clauses 28 or 32, wherein the plurality of antenna elements are flat, conductive plates.34. The UAV according to any of clauses 28 to 33, further comprising a controller configured to determine an angle of arrival (AOA) of a communication signal using the radial antenna arrangement.35. The UAV according to clause 34, wherein the controller is configured to determine the AOA of the communication signal by considering the signal strength detected by each of the plurality of antenna elements.

Claims

CLAIMS1. An unmanned aerial vehicle (UAV) comprising: a body; a first rotor positioned having blades that rotate in a first rotor plane that is parallel to a horizontal plane; a second rotor having blades that rotate in a second rotor plane that is parallel to the horizontal plane; a port wing and a starboard wing extending from the body; a port rotor unit rotatably coupled to a distal end of the port wing, wherein the port rotor unit comprises one or more port blades; and a starboard rotor unit rotatably coupled to a distal end of the starboard wing, wherein the starboard rotor unit comprises one or more starboard blades, wherein the UAV is configured such that the port rotor unit is rotatable between a vertical flight position, in which the port blades rotate in a first port rotor plane to provide lift, and a second port rotor plane that is substantially parallel to a frontal plane, and wherein the UAV is configured such that the starboard rotor unit is rotatable between a vertical flight position, in which the starboard blades rotate in a first starboard rotor plane to provide lift, and a second starboard rotor plane that is substantially parallel to a frontal plane.

2. The UAV according to claim 1, wherein the horizontal plane is defined by a roll axis and a pitch axis, the frontal plane is defined by the pitch axis and a yaw axis and a side plane is defined by the roll axis and the yaw axis, wherein the roll axis, pitch axis and yaw axis are perpendicular to each other, optionally wherein the body extends along the roll axis.

3. The UAV according to any of the preceding claims, wherein: the UAV is configured to travel in a direction that is substantially parallel to the roll axis during a horizontal flight mode; the UAV is configured to travel in a direction that is substantially parallel to the yaw axis during a vertical flight mode; the UAV is configured to control the port rotor unit and the starboard rotor unit to be in the horizontal flight position during the horizontal flight mode; and the UAV is configured to control the port rotor unit and the starboard rotor unit to be in the vertical flight position during the vertical flight mode.

4. The UAV according to any of the preceding claims, wherein: the port wing extends in a port spanwise direction; the port rotor unit is rotatable around the port spanwise direction; the starboard wing extends in a starboard spanwise direction; and the starboard wing is rotatable around the starboard spanwise direction.

5. The UAV according to any of the preceding claims, wherein the first rotor plane and the second rotor plane are fixed.

6. The UAV according to any of the preceding claims, further comprising a propeller coupled to a tail end of the body, the propeller comprising propeller blades that rotate in a propeller plane that is parallel to the frontal plane, optionally wherein the propeller plane is fixed.

7. The UAV according to any of the preceding claims, wherein, in the vertical flight mode: an angle between the first starboard rotor plane and the horizontal plane may be between -10° and 10°; and an angle between the first port rotor plane and the horizontal plane may be between -10° and 10°.

8. The UAV according to any of the preceding claims, wherein: the starboard rotor unit comprises: a starboard wing rotor having the starboard blades, a starboard rotor driving unit, a starboard rotor housing for accommodating the starboard rotor driving unit and a starboard wing-tip portion; and the port rotor unit comprises: a port wing rotor having the port blades, a port rotor driving unit a port rotor housing for accommodating the port rotor driving unit and a port wing-tip portion, optionally wherein the starboard wing-tip portion is rotatably coupled to the starboard wing and the port wing-tip portion is rotatably coupled to the port wing.

9. The UAV according to claim 8, wherein; when the port rotor unit is in the vertical flight position, a chord line of the port wing-tip portion is substantially perpendicular to a chord line of the port wing; when the port rotor unit is in the horizontal flight position, the chord line of the port wing-tip portion is substantially parallel to the chord line of the port wing; when the starboard rotor unit is in the vertical flight position, a chord line of the starboard wing -tip portion is substantially perpendicular to the chord line of the starboard wing;when the starboard rotor unit is in the horizontal flight position, the chord line of the starboard wing-tip portion is substantially parallel to the chord line of the starboard wing.

10. The UAV according to any of the preceding claims, wherein; the first rotor comprises two first rotor blades and the second rotor comprises two second rotor blades; and when the UAV is in the horizontal flight mode, the first rotor blades and the second rotor blades do not rotate, and remain aligned with the roll axis.

11. The UAV according to any of the preceding claims, wherein the UAV is configured to transition from the vertical flight mode to the horizontal flight mode by performing the following steps: rotating the port rotor unit and the starboard rotor unit from the vertical flight position to the horizontal flight position; accelerating the UAV to increase an airspeed; once a first threshold airspeed has been reached; stopping the rotation of the first rotor blades and the second rotor blades.

12. The UAV according to any of the preceding claims, wherein the UAV is configured to transition from the horizontal flight mode to the vertical flight mode by performing the following steps: decelerating the UAV to decrease an airspeed; once a second threshold airspeed has been reached, starting the rotation of the first rotor blades and the second rotor blades; and once a third threshold airspeed has been reached; rotating the port rotor unit and the starboard rotor unit from the horizontal flight position to the vertical flight position.

13. The UAV according to any of the preceding claims, wherein: the port rotor unit comprises a landing portion disposed at an end of the port wing rotor unit that is opposite to the port rotor; and the starboard rotor unit comprises a landing portion disposed at an end of the starboard wing rotor unit that is opposite to the starboard rotor.

14. The UAV according to any of the preceding claims, further comprising a fore landing portion configured to form a lowermost point of the UAV, optionally wherein the fore landing portion comprises a suspension system and or shock absorber.

15. The UAV according to any of the preceding claims, wherein the one or more of the first rotor, second rotor, port rotor unit and starboard rotor unit are powered by an internal combustion engine and / or an electric motor, optionally wherein the UAV further comprises a battery and / or a hydrogen fuel cell in the case that one or more of the first rotor, second rotor, port rotor unit and starboard rotor unit are powered by the electric motor.

16. The UAV according to any of the preceding claims, further comprising a navigation system configured to determine a route for the UAV to follow, optionally wherein the UAV further comprising an autopilot system configured to control the UAV to follow a route.

17. The UAV according to claim 16, wherein the autopilot system is configured to control the UAV to follow the route based on data provided by an inertial measurement unit.

18. The UAV according to claim 17, wherein the autopilot system is configured to perform continuous machine learning to improve the ability of the autopilot system to control the UAV to follow the route based on data provided by the inertial measurement unit, wherein the continuous machine learning uses GPS data as reference data.

19. The UAV according to any of the preceding claims, further comprising a nose arrangement coupled to a fore portion of the body, wherein the nose arrangement comprises a sensor arrangement, optionally wherein the nose arrangement is removably coupled to the fore portion of the body, further optionally wherein the sensor arrangement comprises one or more of: an optical camera, a thermal camera, an optical flow camera, a directional antenna array, and a phased antenna array.

20. An unmanned aerial vehicle (UAV) comprising a radial antenna arrangement, wherein the radial antenna arrangement comprises a plurality of antenna elements arranged in a radial configuration.

21. The UAV according to claim 20, wherein proximal portions of each of the plurality of antenna elements are mounted to a shaft, and each of the antenna elements extend radially outward from the shaft, optionally wherein the plurality of antenna elements are distributed circumferentially around the shaft.

22. The UAV according to claim 20 or 21, wherein an angle between an antenna element and an adjacent antenna element is approximately equal to (360 / N)°, wherein N is the number of antenna elements.

23. The UAV according to any of claims 20 to 22, wherein there are 10 or more antenna elements, optionally wherein there are exactly 10 antenna elements.

24. The UAV according to claims 20 to 23, wherein the plurality of antenna elements are flat, conductive plates.

25. The UAV according to any of claims 20 to 24, further comprising a controller configured to determine an angle of arrival (AOA) of a communication signal using the radial antenna arrangement, optionally wherein the controller is configured to determine the AOA of the communication signal by considering the signal strength detected by each of the plurality of antenna elements.

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