System and method for controlling an intervention unmanned aerial vehicle

Abstract

A system (1) and a method for controlling an intervention unmanned aerial vehicle, UAV, (10) to intervene with an intruding UAV (2) is described. The system (1) comprises at least two detection devices (3, 3'), each comprising a digital camera (4, 4') for imaging of the intruding UAV (2) or an intervention UAV (10), a rangefinder (7, 7'), a transmitter (9, 9') for remote control of the intervention UAV (10). The detection devices (3, 3') are configured to track the intruding UAV (2) or the intervention UAV (10) by adjustment of the direction. The system (1) is configured to assign a first detection device (3) to track the intruding UAV (2) and a second detection device (10) to track the intervention UAV (10). The second detection device (3') is configured to control the transmitter (9') to remote control the intervention UAV (10) to intervene with the intruding UAV (2), using the direction of the digital camera (4) of the first detection device (3), the distance measured by the rangefinder (7) of the first detection device (3), the direction of the digital camera (4') of the second detection device (3') and the distance measured by the rangefinder (7') of the second detection device (3').

Description

[0001] SYSTEM AND METHOD FOR CONTROLLING AN INTERVENTION UNMANNED

[0002] AERIAL VEHICLE

[0003] TECHNICAL FIELD

[0004] The application relates to a system and a method for controlling an intervention unmanned aerial vehicle, UAV, to intervene with an intruding UAV.

[0005] BACKGROUND ART

[0006] Flying drones also known as Unmanned Aerial Vehicles, UAV, have been used for military and civilian applications for many years. The use of UAVs for illegal surveillance, sabotage, or attacks has become increasingly common with the falling prices UAVs commercially available to the public. In recent military conflicts, drones have been used for attacks on infrastructure, for attacks on personnel and vehicles and for surveillance.

[0007] The increasing use of UAVs for the above-described applications have made it increasingly important with defence against drones. Presently, civilian defence against drones consists of detection and jamming devices, wherein the detection commonly has been visual detection by human guards. At facilities equipped with radars, such as airports, radars have been used for the detection of drones.

[0008] For military applications radars are the most common means for detection and are combined with air defence guns or anti air missile systems. A drawback with using radars for detection is that the enemy may detect the radar signal. The enemy may then localize and destroy the radar.

[0009] US 2020 / 0108924 A1 describes a system for detecting UAVs using microphones wherein the system comprises an intervention unit in the form of an autonomous UAV.

[0010] US 9862489 B1 describes a system for detecting UAVs using acoustic detection wherein the system comprises an intervention unit in the form of projectiles or an autonomous UAV. US 11 ,594,141 B1 describes system and methods to neutralize an attacking UAV based on acoustic features.

[0011] SUMMARY OF THE INVENTION

[0012] An objective of the present invention is to provide a system for intervention of an UAV, which system enables the use of less complex intervention UAVs than the systems of the prior art.

[0013] The above object is provided by a system according to the independent claims.

[0014] Additional advantages are provided by the features of the dependent claims.

[0015] According to a first aspect a system for controlling an intervention unmanned aerial vehicle, UAV, to intervene with an intruding UAV, is provided. The system comprises at least two detection devices, each comprising a digital camera for imaging of the intruding UAV or and intervention UAV, the digital camera having a lens with an optical axis defining a direction, a rangefinder configured to measure a distance from the rangefinder to the intruding UAV or the intervention UAV, and a transmitter for remote control of the intervention UAV.

[0016] The detection devices are configured to track the intruding UAV or the intervention UAV by adjustment of the direction, and wherein the detection devices are configured to be in communication with each other. The system is configured to assign a first detection device to track the intruding UAV and a second detection device to track the intervention UAV. The second detection device is configured to control the transmitter to remote control the intervention UAV to intervene with the intruding UAV, using the direction of the digital camera of the first detection device, the distance measured by the rangefinder of the first detection device, the direction of the digital camera of the second detection device and the distance measured by the rangefinder of the second detection device.

[0017] The system according to the first aspect provides a favourable system for intervention of intruding UAVs. The intervention UAVs used in the system do may be produced at a low cost as the intervention UAVs do not have to have navigation equipment. The remote control of the intervention UAVs is performed using the second detection device which tracks the movement of the intervention UAV.

[0018] The remote control of the intervention UAV may utilize IR communication. IR communication makes it very difficult for a counterpart to find and destroy the intervention UAV. It is possible to use other communication methods such as radio, WiFi or similar.

[0019] The range finder may be a laser range finder. Laser range finders are accurate and relatively cheap.

[0020] The assignment of the first detection device and the second detection device may be performed autonomously by the detection devices. Each one of the detection devices may be configured to determine autonomously whether they are the most suitable detection device. The determination may be based on information sent between the detection devices.

[0021] It might be difficult to detect an intruding UAV using only the detection devices. To facilitate detection of an intruding UAV, the system may comprise a microphone array and a central unit with a processor configured to be in communication with the microphone array, the first detection device and the second detection device. The microphone array may comprise a plurality of directional microphones, wherein each microphone is configured for detection of sound from a specific solid angle in a specific direction from the microphone array. The central unit may be configured to analyse with the processor the detected sound, to identify an intruding UAV, and when the intruding UAV has been identified, determine with the processor an intrusion direction corresponding to a direction from the microphone array to the intruding UAV. The central unit may be configured to transmit a first initiation signal to at least the first detection device, such that first detection device may direct the optical axis of the digital camera towards the intruding UAV based on the determined intrusion direction, and to transmit a second initiation signal to at least the second detection device, such that the second detection device may deploy an intervention UAV and control the optical axis of the digital camera to be directed towards the intervention UAV.

[0022] If the central unit is to transmit a first initiation signal to only the first detection device, the central unit must determine which detection device is to be the first detection device. The initiation signal may comprise the determined intrusion direction.

[0023] Alternatively, the determined intrusion direction may be sent separately.

[0024] An advantage of using a microphone array is that it is passive and thus difficult to detect. As an alternative it is possible to use a radar for detection of intruding UAVs.

[0025] As an alternative, the central unit broadcasts the initiation signal and the determined intrusion direction to all detection devices. The detection devices may then autonomously determine if they are the most suitable detection device to assign itself as the first detection device and start tracking the intruding UAV.

[0026] Similarly, the detection devices may autonomously determine if they are the most suitable detection device to assign itself as the second detection device and start to remote control an intervention UAV.

[0027] If two detection devices determine that it is the most suitable detection device to assign itself as the first detection device, they both receive information on this as well as information on the identity of the other detection device. Each detection device may have a priority list over the detection device. The detection device with lower priority might stop tracking the intruding UAV. There are other alternatives for handling the situation with two or more detection devices determining that they are the most suitable detection devices to assign themselves as the first detection device.

[0028] The processor may be configured to identify an intruding UAV based on an analysation of the frequency spectrum of the detected sound.

[0029] The central units, and detection devices, may be in wireless communication with each other in a mesh net. Thus, not all pairs of the central units and detection devices must have a direct communication link. However, information is forwarded within the mesh net so that all central units and detection devices, receives the information transmitted from one of the central units and detection devices. Information is sent within the mesh net so that at least all detection devices, have all information relevant to them. The communication in the mesh net is preferably made using IR radiation or by wire to avoid detection. If the detection devices are movable the communication is preferably wireless and by IR. Alternatively, the communication may be based on 5G WiFi communication using a base station as mentioned above in relation to the description of Figure 1 . In some embodiments the central units only have to transmit information and does not receive all information.

[0030] The central unit may be integrated with the microphone array. As the microphone array is passive it is hard to detect. Thus, there is no strong reason to separate the microphone array and the central unit. The benefit of having the central unit integrated with the microphone array is that the wires between the central unit and the microphone array are short.

[0031] The central unit, the first detection device, and the second detection device, may be separate units, wherein the transmitter is configured to remote control the intervention UAV to intervene with the intruding UAV, using also the position of the first detection device and the position of the second detection device. Also in a system without a central unit and with the first detection device, and the second detection device as separate units, the transmitter may be configured to remote control the intervention UAV to intervene with the intruding UAV, using also the position of the first detection device and the position of the second detection device. It is favourable to have the central unit, the first detection device, and the second detection device as separate units as this minimizes the risk of all being destroyed by a counterpart at the same time. The positions may either be determined by an operator or autonomously by the detection devices using geolocation devices.

[0032] The central unit may be in communication by wire with the first detection device and the second detection device. This is a robust way of communication and is not possible for a counterpart to disturb.

[0033] The central unit may in wireless communication with the first detection device and the second detection device. With a wireless communication it is possible to have the first detection device and the second detection device movable for example by having them integrated with UAVs. In this way the detection devices may regroup periodically to minimize the risk for them to be destroyed by a counterpart. Thus, the first detection device and the second detection device may be movable.

[0034] The wireless communication between the central unit, the first detection device and the second detection device may be based on IR communication. IR communication is not sensitive to disturbance from the outside. The system may comprise a base station for 5G WiFi communication, wherein the central unit communicates with the first detection device and or the second detection device using the base station. This is an alternative to IR communication.

[0035] The base station may be movable. This gives the advantage that the base station may regroup periodically to minimize the risk for the base station to be destroyed by a counterpart. The base station may be autonomously movable.

[0036] The transmitter may communicate with the intervention drone using the base station. This is an alternative to using IR based communication. 5G WiFi communication is also relatively difficult to detect for a counterpart as it is short ranged.

[0037] The central unit, the first detection device and the second detection device may comprise geolocation devices for determination of the position of the first detection device and the position of the second detection device. This is an important feature if the first detection device and the second detection device are movable as their positions after regrouping should be transmitted to the other of the central unit, the first detection device and the second detection device. The first detection device and the second detection device may be autonomously movable.

[0038] The first detection device, and the second detection device, may be configured to be in one of at least an active mode and an inactive mode, and configured to switch from the inactive mode to an active mode at receipt of an activation signal, wherein the central unit is configured to transmit an activation signal when an intruding UAV has been identified, to put the first detection device and the second detection device in the active mode. By having an inactive mode, the electricity consumption may be minimized and facilitate operation from a battery.

[0039] The first detection device may configured to provide information on a first angular deviation of the direction to the intruding UAV in relation to the direction of the digital camera of the first detection device based on the position of the intruding UAV in an image from the digital camera of the first detection device, and the second detection device may be configured to provide information on a second angular deviation of the direction to the intervention UAV in relation to the direction of the digital camera of the second detection device based on the position of the intervention UAV in an image from the digital camera of the second detection device, and wherein the transmitter is configured to remote control the intervention UAV to intervene with the intruding UAV also based on the first angular deviation and the second angular deviation. With such information on angular deviation the precision of the intervention may be increased.

[0040] The lenses of the detection devices may be zoom lenses and each detection device may be configured to control adjustment of the zoom of the lens of the detection device. Zoom lenses facilitates the tracking of the intruding UAV and enables an improvement of the precision of the intervention.

[0041] The digital cameras may be night vision cameras. Night vision cameras improve the tracking in low light conditions.

[0042] The transmitter may be configured to transmit light, preferably infrared, IR, light. Communication using IR is robust and not sensitive to disturbance from a counterpart.

[0043] An intervention system comprises a system according to the first aspect and at least one intervention UAV, wherein the intervention UAV comprises a receiver for reception of a remote-control signal from the transmitter. The intervention UAV may comprise an intervention means configured to be triggered at the receipt of a trigger signal by the receiver.

[0044] The intervention means may be chosen from, an explosive charge, lines, nets, and chemical substances.

[0045] According to a second aspect a method is provided for controlling a remote-control intervention unmanned aerial vehicle, UAV, to intervene with an intruding, UAV. The method comprises the steps of receiving a first direction from a first detection device comprising a first digital camera which has a first lens with a first optical axis defining the first direction, wherein the first detection device images and tracks an intruding UAV by adjustment of the first direction, and receiving a first distance from a first rangefinder which measures the first distance from the first rangefinder to the intruding UAV. The method also comprises the steps of receiving a second direction from a second detection device comprising a second digital camera which has a second lens with a second optical axis defining the second direction, wherein the second detection device images and tracks the intervention UAV by adjustment of the second direction, and receiving a second distance from a second rangefinder which measures the second distance from the second rangefinder to the intervention UAV. The method also comprises determining, using the first direction, the first distance, the second direction and the second distance, the necessary instructions to be provided to the intervention drone to make the intervention drone to intervene with the intruding UAV, and controlling a transmitter to transmit the necessary instructions to the intervention UAV, such that the intervention UAV intervenes with the intruding UAV.

[0046] The method according to the second aspect has corresponding advantages as those described for the first aspect.

[0047] Microphones are passive devices and for that reason the position of the microphone array is very difficult to detect. Microphones work also for detection when it is dark, when it is raining or snowing and when it is foggy.

[0048] The analysing of the sound signal may be based on analysation of the frequency of the sound. UAVs are often propelled by rotors which emit sound with specific frequency spectra. The frequency spectra are recognisable.

[0049] By connecting the control unit by wire to the microphone array and to the at least one intervention unit, the system is not sensitive to jamming.

[0050] In the following embodiments will be described with reference to the appended drawings on which:

[0051] BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 shows schematically a system according to an embodiment.

[0053] Figure 2 shows an image registered by the first digital camera.

[0054] Figure 3 shows schematically a system comprising a plurality of central units and microphone arrays. DETAILED DESCRIPTION

[0055] In the following detailed description different embodiments will be described with reference to the appended drawings. The drawings are not drawn to scale. The same reference numeral is used for similar features in the different drawings.

[0056] Figure 1 shows schematically a system 1 for intervention of an intruding unmanned aerial vehicle, UAV, 2. The system 1 comprises a first detection device 3 comprising a first digital camera 4 for imaging of the intruding UAV 2, the first digital camera 4 having a first lens 5 with a first optical axis 6 defining a first direction. The direction of the first optical axis 6 is adjustable around two axes such that the movement of the intruding UAV 2 may be followed. The first detection device 3 also comprises a first rangefinder 7, such as a laser rangefinder, configured to measure a first distance D1 from the first rangefinder to the intruding UAV 2. The first detection device 3 is configured to track the intruding UAV 2 or an intervention UAV 10 by adjustment of the first direction, i.e. , the direction of the first optical axis 6. The first detection 3 device comprises a first transmitter 9 for remote control of an intervention UAV 10. As will be described below with reference to Figure 2 the first detection device 3 is assigned to track the intruding UAV 2. The first lens 5 and the second lens 5’ may be zoom lenses.

[0057] The system 1 comprises a second detection device 3’ configured to communicate with the first detection device 3, wherein the second detection 3’ device comprises a second transmitter 9’ for remote control of an intervention UAV 10. In Figure 1 a group of inactivated intervention UAVs 10’ is also shown. The second detection device 3’ also comprises a second digital camera 4’ configured for imaging of the intervention UAV, the second digital camera 4, having a second lens 5’ with a second optical axis 6’ defining a second direction. The second detection device 3’ also comprises a second rangefinder 7’ configured to measure a second distance D2 from the second rangefinder 7’ to the intervention UAV 10. The second detection device 3’ is configured to track the intervention UAV 10 or the intruding UAV by adjustment of the second direction, i.e., the direction of the second optical axis. As will be described below with reference to Figure 2 the second detection device 3’ is assigned to track the intervention UAV 10. The first digital camera 4 and the second digital camera 4’ are night vision cameras. The system 1 according to the embodiment of Figure 1 , comprises a microphone array 15, and a central unit 22 with a processor 23 configured to be in communication with the microphone array 15, the first detection device 3 and the second detection device 8. The microphone array 15 comprises a plurality of directional microphones16-21 , wherein each microphone 16-21 is configured for detection of sound from a specific solid angle in a specific direction from the microphone array. In Figure 1 the solid angle, within which a first microphone 16 detects sound, is illustrated with the dashed lines 24. The central unit 22 is configured to analyse with the processor 23 the detected sound, to identify an intruding UAV 2. 3. The processor may be configured to identify an intruding UAV based on an analysation of the frequency spectrum of the detected sound.

[0058] When the intruding UAV 2 has been identified, the central unit 22 determines with the processor 23 an intrusion direction corresponding to a direction from the microphone array 15 to the intruding UAV 2. The determination of the intrusion angle is in principle done by determining which one of the microphones 16-21 in the microphone array that picks up a signal. In the embodiment of Figure 1 it is illustrated that the intruding UAV 2 is within the solid angle 24 of the first microphone 16. This limits the volume in which the intruding UAV may be positioned. By increasing the number of microphones 16-21 the volume in which the intruding UAV 2 may be is decreased. It is also possible to get an approximate measure of the distance D3 from the first microphone to the intruding UAV 2 from the signal strength, i.e. , the sound volume of the drone. The signal strength decreases as the inverse of the distance squared. Thus, even if the volume may vary between different types of UAVs 2, the strong dependence of the signal strength on the distance still gives an indication of the distance D3.

[0059] When it has been determined that an intruding UAV 2 is present and an intrusion angle has been determined, the central unit 22 transmits initiation signals to the first detection device 3 and the second detection device 3’, and information on the intrusion angle and possibly also information on the distance D3 from the first microphone to the intruding UAV 2. Each detection device 3, 3’, has information on the position of the other detection device 3, 3’, as well as information on the position of the microphone array 15. Based on the intrusion angle, the distance D3 from the first microphone to the intruding UAV 2, the position of the other detection device 3, 3’, as well as information on the position of the microphone array 15, each detection device 3, 3’, determines whether it is the most suitable to track the intruding UAV 2. The determination may be made by a respective processing unit 11 , 1 T, of the detection devices 3, 3’. When the first detection device 3 has determined that it is most suitable to track the intruding UAV 2 is starts tracking the intruding UAV by controlling the first optical axis 6 of the first digital camera 4 to be directed towards the intruding drone 2 based on the determined intrusion direction. The first detection device 3 also transmits a signal with information that it has determined to track the intruding UAV 2. The determination that the first detection device is most suitable to track the intruding UAV 2 may be done using a predefined algorithm. In case more than one detection device 3, 3’, determines itself to be most suitable to track the intruding UAV 2 they become aware of this by the signals from the other detection device(s) 3, 3’. The detection devices may for example have an arbitrary priority order, such that the detection device with a lower priority order stops tracking the intruding UAV 2. The second detection device 3’ determines, using the second processing unit 1 T, that it is most suitable to remote control an intervention UAV to intervene with the intruding UAV 2. The second detection device 3’ controls the deployment of an intervention UAV 10 and controls the second optical axis 13 of the second digital camera 4’ to be directed towards the intervention UAV 10. Consequently, the detection devices autonomously assign themselves to be the first detection device 3 and to start tracking the intruding UAV, or to be the second detection device 3’ and to start remote control of an intervention UAV 10. This makes the system robust and redundant. This will be described in further detail below with reference to Figure 2. As an alternative, the assignment of the detection devices 3, 3’, could be performed by the central unit 22.

[0060] When the first detection device 3 assigns itself to tracking the intruding UAV the first detection device directs the first optical axis 6 of the first camera 4, towards the volume in which the intruding UAV 2 has been detected to identify the intruding UAV 2. When the first identification device 3 has found the intruding UAV 2, first identification device starts tracking the intruding UAV 2 and monitors the distance to the intruding UAV 2. The first detection device may start with the first zoom lens 5 zoomed out to maximize the field of view of the first camera. After having found the intruding UAV the first zoom lens may be zoomed in on the intruding UAV.

[0061] The first detection device 3, the second detection device 3’, are configured to be in one of at least an active mode and an inactive mode. In the inactive mode only a transceiver 12, 12’, and the processing unit 11 , 11’, of the detection devices are active. When an initiation signal has been received and the respective processing units 11 , 1 T, have assigned the first detection device 3 and the second detection device 3’, the processing units are configured to switch the detection devices 3, 3’, from the inactive mode to an active mode.

[0062] The central unit 22 is in wireless communication with the first detection device 3 and the second detection device 8, as is illustrated by the flashes 25. The second detection device 8 is configured to be in communication with the first detection device 3, either directly or via the central unit 22. The wireless communication may be radio communication or IR communication. Alternatively, the communication may be communication by wire as is illustrated by the dashed lines 26. The first detection device 3 may also be in direct communication with the second detection device 3’.

[0063] The first detection device 3 transmits information on the direction of the first optical axis 6 and the first distance D1 to the second detection device 3’. The first detection device has also at some point transmitted the position of the first detection device 3 to the second detection device 3’. The second transmitter 9’ is configured to remote control the intervention UAV 10 to intervene with the intruding UAV 2, using the first direction defined by the direction of the first optical axis 6, the first distance D1 , the second direction defined by the second optical axis 6’, and the second distance D2. In the system of Figure 1 , the central unit 22, the first detection device 3, and the second detection device 3’, are separate units. If the first detection device 3 is at a distance from the second detection device 8, the direction to the intruding UAV 2 is different for the first detection device 3 and the second detection device 8. The second transmitter 9’ may then be configured to remote control the intervention UAV 10 to intervene with the intruding UAV 2, using also the position of the first detection device 3 and the position of the second detection device 3’. The position of the first detection device 3 and the second detection device 3’ may be known in advance to the first detection device 3.

[0064] The second transmitter 9’ may remote control the invention UAV using infrared, IR, light or radio signals as is illustrated by the flash 27. The second identification device 8 activates one of the intervention UAVs 10 in a group of inactivated intervention UAVs 10’. If the second transmitter 9’ uses IR light, the second detection device 3’ first direct the second camera 4’ towards the group of inactivated intervention UAVs 10’. The second detection device 3’ remote control, using the second transmitter 9’ the intervention UAV 10 to intervene with the intruding UAV 2. The intervention UAV 10 may intervene in many different ways. The intervention UAV 10 may comprise an explosive charge. When the intervention UAV is sufficiently close to the intruding UAV the explosive charge is detonated. Alternatively, the intervention UAV 10 may comprise a net or lines hanging down from the intervention UAV 10. According to this alternative the intervention UAV 10 is controlled to pass above the intruding UAV 2 to jam the propellers of the intruding UAV 2. In both examples the intervention UAV is lost during the intervention. As an alternative, the intervention drone may be configured to release a chemical substance that intervenes with the intruding UAV. The intervention UAV 10 used by the system may be produced at a very low cost as it does not need to have any navigation system of its own. Except for a hull, electric motors, rotors, and a battery, the intervention UAV 10 only has to have a receiver to receive the control signals from the transmitter and drive electronics for the motors.

[0065] As an alternative to the wireless communication described above, the system may comprise a base station 14 for 5G WiFi communication, wherein the central unit communicates with the first detection device and or the second detection device using the base station. The transmitters 9, 9’, may also communicate with the intervention drone 10 using the base station 14. The base station 14 may be movable. The movability may be provided by arranging the base station 14 as a UAV.

[0066] The first detection device 3, and the second detection device 3’ may be movable and comprise geolocation devices 28, 28’, for determination of the position of the first detection device and the position of the second detection device. The movability may be provided by arranging the detection devices 3, 3’, as UAVs.

[0067] Figure 2 shows an image registered by the first digital camera 4. The image of an intruding UAV 2 is in the upper right quadrant in Figure 2. The centre of the intruding UAV 2 is imaged a distance X from the centre C in the horizontal direction and a distance Y from the centre C in the vertical direction. With information on the focus length of the lens, the size of the sensor of the first digital camera and the distances X, Y, and the distance D1 to the intruding UAV, it is possible to determine a first angular deviation of the direction to the intruding UAV in relation to the first direction based on the position of the intruding UAV. A second angular deviation of the direction to the intervention UAV may be determined from a similar image registered with the second digital camera. The transmitter is configured to remote control the intervention UAV to intervene with the intruding UAV also based on the first angular deviation and the second angular deviation.

[0068] Figure 3 shows schematically a system comprising a plurality of central units 22, 22’, and microphone arrays 15, 15’, 15”, a plurality of detection devices 3, 3’, 3”, 3’”, and a plurality of groups of intervention UAVs 10, 10’, 10”, 10’”. The central units 22, 22’, 22”, and detection devices 3, 3’, 3”, 3’”, are in wireless communication with each other in a mesh net as is indicated by the dashed lines in Figure 3. Information is sent within the mesh net so that at least all detection devices 3, 3’, 3”, 3’”, have all information relevant to them. The communication in the mesh net is preferably made using IR radiation or by wire to avoid detection. If the detection devices are movable the communication is preferably wireless and by IR. Alternatively, the communication may be based on 5G WiFi communication using a base station as mentioned above in relation to the description of Figure 1 .

[0069] In some embodiments the central units only have to transmit information. The sound of an intruding drone 2 is detected by the first microphone array 15 and the second microphone array 15’. The corresponding first central unit 22 and second central unit 22’, analyses the detected sound and determines that the sound is from an intruding UAV. A first intrusion direction 11 from the first microphone array 15 is determined and a second intrusion direction I2 from the second microphone array 15’ is determined. When two intrusion directions 11 , I2, have been determined it is possible to use triangulation to determine a position of the intruding UAV 2, without any measurement of the distance from the respective microphone arrays 15, 15’. When the first detection device 3 receives the intrusion directions it may autonomously determine that it is most suitable to track the intruding UAV. The determination is based on information on the positions of all microphone arrays 15, 15’, 15”, and detection devices 3, 3’, 3”, 3’”.

[0070] Correspondingly, the second detection device may determine that it is most suitable for remote control of an intervention UAV. An intervention UAV 10 with intervention means 30 in the form of lines is also shown. Microphones are passive devices and for that reason the position of the microphone array is very difficult to detect. Microphones work also for detection when it is dark, when it is raining or snowing and when it is foggy.

[0071] The analysing of the sound signal may be based on analysation of the frequency of the sound. UAVs are often propelled by rotors which emit sound with specific frequency spectra. The frequency spectra are recognisable.

[0072] By communicating by wire or by IR in the mesh net, the system is not sensitive to jamming.

[0073] The intervention unit may be an autonomous UAV. The UAV may be a kamikaze UAV equipped with night sight and possibly be equipped with an explosive charge. The autonomous UAV may be equipped with night sight and one of the following a) minor explosive charge that ejects fishing lines or similar that jams the propellers on intruding UAVs. b) minor explosive charge that ejects fishing net or similar and possibly comprising a small parachute for reducing risk for people on the ground. c) a directed energy weapon (DEW) that destroys electrical circuits of intruding UAVs.

[0074] By the detection devices having an inactive mode of the battery life of the detection device is extended. The intervention UAVs may also be configured with an active mode and an inactive mode.

[0075] The described embodiments may be amended in many ways without departing from the scope of the invention, which is limited only by the appended claims.

Claims

CLAIMS1. A system (1 ) for controlling an intervention unmanned aerial vehicle, UAV, (10) to intervene with an intruding UAV (2) wherein the system (1 ) comprises at least two detection devices (3, 3’), each comprising:- a digital camera (4, 4’) for imaging of the intruding UAV (2) or an intervention UAV (10), the digital camera (4, 4’) having a lens (5, 5’) with an optical axis (6, 6’) defining a direction,- a rangefinder (7, 7’) configured to measure a distance from the rangefinder (7, 7’) to the intruding UAV (2) or the intervention UAV (10),- a transmitter (9, 9’) for remote control of the intervention UAV (10), wherein the detection devices (3, 3’) are configured to track the intruding UAV (2) or the intervention UAV (10) by adjustment of the direction, and wherein the detection devices (3, 3’) are configured to be in communication with each other, wherein the system (1 ) is configured to assign a first detection device (3) to track the intruding UAV (2) and a second detection device (10) to track the intervention UAV (10), wherein the second detection device (3’) is configured to control the transmitter (9’) to remote control the intervention UAV (10) to intervene with the intruding UAV (2), using the direction of the digital camera (4) of the first detection device (3), the distance measured by the rangefinder (7) of the first detection device (3), the direction of the digital camera (4’) of the second detection device (3’) and the distance measured by the rangefinder (7’) of the second detection device (3’).

2. The system (1 ) according to claim 1 , comprising a microphone array (15) and a central unit (22) with a processor (23) configured to be in communication with the microphone array (15), the first detection device (3) and the second detection device (3’), wherein the microphone array (15) comprises a plurality of directional microphones (16-21 ), wherein each microphone (16-21 ) is configured for detection of sound from a specific solid angle in a specific direction from the microphone array (15), wherein the central unit (22) is configured to- analyse with the processor (23) the detected sound, to identify an intruding UAV (2),- when the intruding UAV (2) has been identified, determine with the processor (23) an intrusion direction corresponding to a direction from the microphone array (15) to the intruding UAV (2),- transmit a first initiation signal to at least the first detection device (3), such that the first detection device (3) may direct the optical axis (6) of the digital camera (4) towards the intruding UAV (2) based on the determined intrusion direction (11 ), and- transmit a second initiation signal to at least the second detection device (3’), such that the second detection device (3’) may deploy an intervention UAV (10) and control the optical axis (6’) of the digital camera (4’) to be directed towards the intervention UAV (10).

3. The system (1 ) according to claim 2, wherein the processor (23) is configured to identify an intruding UAV (2) based on an analysation of the frequency spectrum of the detected sound.

4. The system (1 ) according to claim 2 or 3, wherein the central unit (22) is integrated with the microphone array (15).

5. The system (1 ) according to claim 2, 3 or 4, wherein the central unit (22), the first detection device (3), and the second detection device (3’), are separate units, wherein the transmitter (9, 9’) is configured to remote control the intervention UAV (10) to intervene with the intruding UAV (2), using also the position of the first detection device (3) and the position of the second detection device (3’).

6. The system (1 ) according to claim 5, wherein the central unit (22) is in communication by wire with the first detection device (3) and the second detection device (3’).

7. The system (1 ) according to claim 5, wherein the central unit (22) is in wireless communication with the first detection device (3) and the second detection device (3’).

8. The system (1 ) according to claim 7, comprising a base station (14) for 5G WiFi communication, wherein the central unit (22) communicates with the first detection device (3) and / or the second detection device (3’) using the base station (14).

9. The system (1 ) according to claim 8, wherein the base station (14) is movable.

10. The system (1 ) according to claim 8 or 9, wherein the transmitter (9, 9’) communicates with the intervention drone (10) using the base station (14).11 . The system (1 ) according to any one of claims 7-10, wherein the first detection device (3) and the second detection device (3’) are movable.

12. The system (1 ) according to any one of claims 1-11 , wherein the central unit (22), the first detection device (3) and the second detection device (3’) comprises geolocation devices (28, 28’) for determination of the position of the first detection device (3) and the position of the second detection device (3’).

13. The system (1 ) according to any one of claims 2-12, wherein the first detection device (3), and the second detection device (3’), are configured to be in one of at least an active mode and an inactive mode, and configured to switch from the inactive mode to an active mode at receipt of an activation signal, wherein the central unit (22) is configured to transmit an activation signal when an intruding UAV (22) has been identified, to put the first detection device (3) and the second detection device (3’) in the active mode.

14. The system (1 ) according to any one claims 2-13, wherein- the first detection device (3) is configured to provide information on a first angular deviation of the direction to the intruding UAV (2) in relation to the direction of the digital camera (4) of the first detection device (3) based on the position of the intruding UAV (2) in an image from the digital camera (4) of the first detection device (3), and- the second detection device (3’) is configured to provide information on a second angular deviation of the direction to the intervention UAV (2) in relation to the direction of the digital camera (4’) of the second detection device (3’) based on the position of the intervention UAV (10) in an image from the digital camera (4’) of the second detection device (3’), and wherein the transmitter (9’) is configured to remote control the intervention UAV (10) to intervene with the intruding UAV (2) also based on the first angular deviation and the second angular deviation.

15. The system (1 ) according to any one of the preceding claims, wherein the lenses (5, 5’) of the detection devices (3, 3’) are zoom lenses and each detection device (3, 3’) is configured to control adjustment of the zoom of the lens (5, 5’) of the detection device (3, 3’).

16. The system (1 ) according to any one of the preceding claims, wherein the digital cameras (4, 4’) are night vision cameras.

17. The system (1 ) according to any one of the preceding claims, wherein the transmitter (9, 9’) is configured to transmit light, preferably infrared, IR, light.

18. The system (1 ) according to any one of the preceding claims, comprising at least one intervention UAV (10), wherein the intervention UAV (10) comprises a receiver (29) for reception of a remote control signal from the transmitter (9’), wherein theintervention UAV (10) comprises an intervention means configured to be triggered at the receipt of a trigger signal by the receiver.

19. The system (1 ) according to claim 18, wherein the intervention means are chosen from, an explosive charge, lines, nets, and chemical substances.

20. A method for controlling a remote control intervention unmanned aerial vehicle, UAV (10), to intervene with an intruding, UAV (2), comprising the steps of- receiving a first direction from a first detection device (3) comprising a first digital camera (4) which has a first lens (5) with a first optical axis (6) defining the first direction, wherein the first detection device (3) images and tracks an intruding UAV (2) by adjustment of the first direction (11 ), and,- receiving a first distance (D1 ) from a first rangefinder (7) which measures the first distance (D1 ) from the first rangefinder (7) to the intruding UAV (2),- receiving a second direction from a second detection device (3’) comprising a second digital camera (4’) which has a second lens (5’) with a second optical axis (6’) defining the second direction, wherein the second detection device (3’) images and tracks the intervention UAV (10) by adjustment of the second direction,- receiving a second distance (D2) from a second rangefinder (7’) which measures the second distance (D2) from the second rangefinder (7’) to the intervention UAV (10), -determining, using the first direction, the first distance (D1 ), the second direction and the second distance (D2), the necessary instructions to be provided to the intervention drone (10) to make the intervention drone (10) to intervene with the intruding UAV (2), and- controlling a transmitter (9, 9’) to transmit the necessary instructions to the intervention UAV (10), such that the intervention UAV (10) intervenes with the intruding UAV (2).

Images