DEVICE AND METHOD FOR BLOWING AVALANCHES

Description

[0001] The invention relates to a device and a method for blasting avalanches.

[0002] Snow avalanches pose a danger to people in the area of ​​a potential avalanche cone. Avalanches also destroy infrastructure such as power poles or roads, or block them for extended periods.

[0003] To limit the danger of such snow avalanches, which will be referred to simply as avalanches below, it is known to trigger avalanches in a controlled manner using blasting. This ensures that no one is in the avalanche zone and is injured during the avalanche. Furthermore, if the avalanche is triggered early, it can be ensured that the destructive potential of the avalanche is so low that infrastructure facilities are not damaged. If, for example, one were to wait during a persistent snowfall, the potential amount of snow that could be swept away by an avalanche would increase, causing unwanted destruction.

[0004] There are different devices and methods for blasting avalanches.

[0005] In places where avalanches frequently have to be blasted, there are permanently installed devices such as blasting cable cars, blasting masts or blasting tubes.

[0006] A blasting cableway consists of a cable that is permanently installed above a blasting site. A carriage is mounted on the cable for movement. An explosive charge is suspended from the carriage by a cord. The explosive charge is equipped with a detonator that automatically detonates after a predetermined time after the active position.

[0007] The sled is moved with the explosive device over the blasting site in the area where the explosive charge ignites and triggers the avalanche.

[0008] The blasting tubes are designed to open above the snowpack, with the opening slightly angled downward. The gaseous explosive charge is remotely detonated inside the tube, so that a hot gas stream hits the snowpack and triggers an avalanche.

[0009] The disadvantage of using blasting tubes is that the hot gas stream melts the snow in the surrounding area. The melted snow cover freezes and hardens again. This is especially the case if the blasting does not trigger an avalanche. Repeated blasting can create a very stable ice sheet. This can render further avalanche blasting ineffective, as the gas stream cannot trigger another avalanche, even if unstable snow patches exist in the immediate vicinity.

[0010] With a blasting mast, an explosion can be triggered via radio.

[0011] It is also known to drop explosives from a helicopter, which explode in the snow cover and thus trigger an avalanche.

[0012] These different methods have different advantages and disadvantages.

[0013] Blasting cable cars, blasting masts, and blasting tubes only make sense when avalanches need to be blasting regularly at specific locations. This is the case, for example, in ski resorts to ensure that no ski runs are buried. Depending on the weather conditions and, in particular, the prevailing wind direction during snowfall, avalanche danger can exist on different slopes. It is practically impossible to equip all slopes with blasting equipment.

[0014] If the explosive charge is dropped from a helicopter, such avalanche blasting can be tailored much more individually to the current avalanche situation. If an avalanche danger exists, for example, only on south-facing slopes, then avalanches will be triggered only on south-facing slopes.

[0015] However, dropping explosives from a helicopter also has disadvantages. If the snow cover is hard, the explosive device can slide and detonate in a completely different location. It should be noted that, according to legal regulations, the explosive device may not detonate until two minutes after being dropped from the helicopter. The helicopter must have sufficient opportunity to move away from the detonation site. If the snow cover is hard, it may happen that the explosive charge has already slid a large part of its way down towards the valley before it explodes.

[0016] Furthermore, once an explosive device has been dropped from a helicopter and activated, it can no longer be defused.

[0017] Another major problem with avalanche blasting using helicopters is misfires. The blasting must be performed by a demolition expert. The demolition expert is responsible for ensuring that any unexploded explosives are removed. If an unexploded explosive device is located on a potentially avalanche-prone slope, there is a risk of being caught in an avalanche during recovery.

[0018] The biggest problem, however, is that it is not possible to fly to a blasting site in bad weather. This is particularly critical during a long period of bad weather, for example two to three weeks, with heavy rainfall. In these cases, blasting equipment can become completely covered in snow, making it unusable. Such weather conditions, however, are the ones that can trigger avalanches with the potential for great destruction, even in places where there is usually no avalanche danger. In such locations, permanently installed avalanche blasting equipment, such as a blasting cable car or a blasting tube, are usually not provided, as an avalanche is not expected there. However, such avalanches can cover roads, topple power poles, or even hit houses.

[0019] A further disadvantage is that an explosive charge dropped from a helicopter explodes in the snow, and the pressure wave is significantly dampened by the snow cover. It is much more efficient if the explosive device is detonated some distance above the snow cover, as is the case with a blasting cable car or a blasting mast. However, a blasting cable car cannot be flexibly reached anywhere. Furthermore, it is sometimes difficult to correctly coordinate the movement of the blasting cable car's sled and the moment of detonation of the explosive charge. There is therefore a significant need to develop a device and method for blasting avalanches that can be used to trigger avalanches at different locations, even during persistently bad weather.

[0020] European Patent 2 977 318 B1 discloses the use of a drone to transport an explosive charge for triggering an artificial avalanche. The explosive charge is arranged outside the aircraft via a cable. The aircraft includes a triggering device that generates an electric current flowing along the cable to ignite the explosive charge. The triggering device can be arranged directly on the drone or directly on the explosive charge. A pyrotechnic explosive material is used as the explosive material.

[0021] US 2014 / 0353422 A1 discloses the use of a drone to drop explosive devices at predetermined locations. This is used to blast through hard-to-reach paths or to remove snow mounds in the mountains.

[0022] Other blasting devices for blasting avalanches are disclosed, for example, in WO 80 / 01511 A1, FR 2 964 732 A1 and US 2011 / 0139029 A1.

[0023] The invention is based on the object of developing a device with a drone and a method for blasting avalanches in such a way that unstable snow masses can be triggered reliably, regardless of the weather and at different locations, while also ensuring the highest possible safety for the users.

[0024] The problem is solved by the subject matter of the independent patent claims. Advantageous embodiments are specified in the respective subclaims.

[0025] According to the invention, the device for blasting avalanches comprises a drone, an explosive device which is freely suspended from the drone by means of a cord, and an ignition mechanism for detonating the explosive device, wherein the ignition mechanism is designed to be remotely controlled or automatically triggered.

[0026] This device is characterized by the fact that the ignition mechanism on the cord is positioned at a distance from the drone and the explosive device in such a way that the ignition mechanism cannot be misfired by the drone's electrical elements and is not damaged if the explosive device is detonated. This eliminates a significant risk of false triggering. This is particularly advantageous because an explosive device is used, rather than a pyrotechnic explosive, which has a significantly lower explosive effect. Explosives within the meaning of the present invention are explosives of hazardous materials class 1.1 D, i.e., detonating explosive substances or black powder capable of mass explosion (a mass explosion is an explosion that affects almost the entire charge practically simultaneously).

[0027] The ignition mechanism is attached to the cord. The ignition mechanism can be connected to the explosive device with a thin ignition cable.

[0028] The drone can be used to fly the explosive device to any location in the mountains, allowing the user to freely choose the location for triggering an avalanche. Because the explosive device is attached to the drone with a cord at a safe distance, it can be detonated while still hanging freely from the drone. It is not necessary to drop the explosive device. This makes it possible to detonate the explosive device slightly above the snow cover, which is significantly more efficient than dropping it. The remote-controlled or automatic triggering of the detonation mechanism allows the device operator, who is usually a demolition expert, to remain outside of any danger zone.

[0029] The drone can also be flown in bad weather. Firstly, the drone can simply be transported close to the area of ​​operation by vehicle, meaning that long flights are generally not necessary; instead, the operation or destination can be reached in a relatively short flight. This is much easier to accomplish in bad weather than with a helicopter. Secondly, there is no risk of human injury if the drone crashes. Therefore, a much higher flight risk can be accepted with a drone flight than with a helicopter flight. If there is a risk of infrastructure damage, the costs for a drone, which usually amount to several tens of thousands of euros, are comparatively low compared to the costs that can be caused by avalanche damage.

[0030] The distance between the drone and the firing mechanism is at least 5 m and preferably at least 10 m.

[0031] The distance between the ignition mechanism and the explosive device is at least 5 m, in particular at least 10 m and preferably at least 15 m.

[0032] The cord is at least 10 m or at least 20 m, preferably at least 30 m, and in particular at least 35 m or at least 40 m long, with one end of the cord attached to the drone and the other end connected to the explosive device. The length of the cord between the drone and the explosive charge must be dimensioned according to the explosive effect of the explosive device. The greater the explosive effect of the explosive device, the longer the cord must be to ensure that the drone is not damaged when the explosive device detonates. It may therefore be quite expedient to provide the cord with a length of at least 30 m and in particular at least 50 m.

[0033] The cord has an explosive section which is directly connected to the explosive device and is connected to the rest of the cord by means of a detachable clamp.

[0034] This makes it possible for the drone to not have to land after detonating an explosive device to attach another one. Instead, it simply lowers far enough for a user to activate the clamp, detach the remaining section of the explosive device after the last detonation, and attach a new explosive device containing a new explosive device. This allows for the drone to be loaded with another explosive device very quickly. Multiple detonations can be completed in a short period of time.

[0035] The explosive section has a length such that the detachable clamp is sufficiently far away from the explosive device so as not to be destroyed during detonation. Tests with conventional explosive devices have shown that the explosive section is generally destroyed over a length of around 1.5 to 2 m. It is therefore advantageous for the explosive section to be at least 2 m, or at least 3 m, and in particular at least 3.5 m long. If an electrical ignition mechanism is used, the explosive section contains a corresponding electrical line, and the clamp is designed to form an electrical connection between the explosive sections and the remaining area of ​​the cord leading to the ignition mechanism. The clamp can preferably be released and re-fastened using a click mechanism, allowing the explosive section to be replaced quickly.

[0036] The device comprises a device for detecting whether the explosive device is resting on a surface and an altitude measuring device for measuring the height of the drone.

[0037] This makes it possible to determine when the explosive device has touched down on the ground and to measure the height of the drone at that moment or in that state, so that the drone can be raised to a predetermined height and the explosive device can be detonated at the predetermined height above the ground.

[0038] Any altimeter can be used for this purpose. However, an altimeter that uses radio signals to determine the altitude or location of the drone in a three-dimensional coordinate system is preferred. Such an altimeter can determine altitude regardless of the weather, which is not the case for altimeters that use a laser beam. Such altimeters do not work reliably in precipitation or fog.

[0039] The impact of the explosive device on the ground can be determined by monitoring the power supplied to the motors that drive the drone's rotors. If the power decreases while the drone maintains approximately the same altitude, this means that the load being held by the drone is decreasing. This occurs when the explosive device is impacting the ground. Scales can also be provided that measure the load hanging from the drone's tether. If the weight hanging from the drone decreases, this can be interpreted as the explosive device touching the ground. The scales do not need to be calibrated to a predetermined weight scale. A simple force sensor is sufficient as a scale to monitor the force exerted on the tether and, above all, to detect changes in this force or in the weight hanging on the tether.

[0040] A brief placement of the explosive device on the ground can also be used to prevent the explosive device from swinging around on the drone.

[0041] The device preferably has a location sensor. The location sensor is, in particular, a radio location sensor. A radio location sensor is a location sensor that determines its location using radio signals. Two main classes of location sensors are distinguished here: satellite location sensors and location sensors that use mobile phone signals for location. A satellite location sensor receives radio signals from satellites that contain location and time information. Using this information, the location sensor can calculate its location in a three-dimensional spatial coordinate system. Such satellite location sensors are known, for example, as GPS sensors. Location sensors that work with mobile phone signals calculate their location using triangulation of the mobile phone signals. Using one of these location sensors, the drone can automatically determine its location.

[0042] With such a radio-location sensor, the relative altitude of the drone can be determined very precisely, even in bad weather. After the explosive device has been placed on the ground as described above, the height of the explosive device above the ground achieved by lifting it can be determined very precisely using the radio-location sensor.

[0043] The device can have a control unit that allows the device to fly automatically to a specific location based on location coordinates determined by the location sensor. This allows the location to which the drone is to fly to to be stored in advance in the flight control unit, allowing the drone to fly to this location independently, without requiring a human to control its flight. Upon reaching the target location, all that is needed is to trigger the detonation mechanism to detonate the explosive device.

[0044] However, the ignition mechanism can also be triggered automatically, for example when it is automatically detected that the drone and thus the entire device is at the desired destination.

[0045] The device can be equipped with a visible-light camera and / or an infrared camera. These cameras are directed downward or diagonally downward, allowing the ground to be optically scanned as the drone flies. The infrared camera, also known as a thermal imaging camera, is used to determine whether living beings are present in the area where the explosive device is to be detonated and / or the avalanche is to occur.

[0046] Preferably, a radio device is provided for transmitting sensor signals and / or camera signals. This radio device can be used, for example, to transmit the location coordinates detected by the positioning sensor and / or the image signals detected by the camera and / or altitude values ​​detected by the height measuring device.

[0047] When transmitting location coordinates, a user can control the drone's flight based on the received location coordinates. This is particularly useful when no target coordinates are known and the target location is to be reached remotely. This data can be received by a remote control and / or a server.

[0048] Using the image signals, the drone can be used to scan the potential avalanche cone before blasting to determine whether there are any people, animals, or objects within it that could be caught in the avalanche. This is particularly possible using image signals from a thermal imaging camera (a camera that detects infrared radiation), which allows living creatures to be seen with high contrast against the cold background of a snowpack.

[0049] The cord can be attached to the drone via a remote-controlled release device. If, for example, the cord gets caught on a tree, it can be released from the drone, preventing it from being lost. Preferably, the location of the device is recorded when the cord and thus the explosive device are released, making it much easier to locate the explosive device later.

[0050] By transmitting the elevation values ​​and location coordinates to a server, the server can determine the thickness of the snow cover by comparing the elevation values ​​above the snow cover with stored elevation values ​​from a measurement taken at the same location at a time when no snow was present. This allows a profile of the snow cover to be automatically calculated by recording multiple elevation values ​​and the corresponding location coordinates. Such snow cover profiles can also be recorded regularly over predetermined intervals of a few days or weeks, allowing a progression of the snow cover profile to be recorded. This data can be used to estimate the avalanche danger. This is particularly true when this data is linked to corresponding weather data, particularly the temperature and wind during the respective snowfall.This allows the server to make a very precise assessment of the avalanche danger, as the actual snow depths are included in the assessment.

[0051] The system can be designed in such a way that an optimal blasting location is calculated based on this assessment of the avalanche danger. This optimal blasting location can be transmitted to the drone, which then automatically carries out the blasting at this location. This system represents an independent concept that can also be used for other types of avalanche blasting using drones, such as avalanche blasting in which an explosive device is dropped from the drone. The avalanche danger assessment is based on a large database, which preferably includes a model of the slope in which the contours of the slope are modeled. Furthermore, the nature of the slope surface (e.g. meadow, bushes, trees, rocks) can be included in the database. The database can contain extensive weather data, which describes not only the current weather, but also the weather of the last few days or weeks.This database is compared with the current snow depth measurement, with the snow depth measurement preferably capturing a profile of the snow cover over a specific area, meaning that multiple spatially distributed snow depth measurement points are available. This combination of a large database and the current snow depth measurement, or snow cover thickness, allows for a significantly more precise assessment of the avalanche danger than with conventional systems for estimating local avalanche danger, enabling a very precise determination of the blasting location and thus the control of the drone to the blasting location.

[0052] When determining the blasting location, a simulation of the expected avalanche can also be considered. For example, if the artificially induced avalanche is too large and there is a risk of causing damage, it may be advisable to first blast the avalanche in a lower section of the slope, allowing only a portion of the snow load to slide off, and then to blast the upper section of the slope with a second blasting.

[0053] Since the avalanche danger can vary considerably between individual locations due to the varying contours of mountain slopes, varying weather conditions, and varying snow conditions, while similar conditions repeatedly occur at the same locations, this system can preferably be implemented with a self-learning computer system, such as a neural network, which learns the local conditions regarding avalanche danger over time during a learning mode. In such a learning mode, the relevant data are entered which are intended to determine the avalanche danger, as explained above, along with additional data which document the success of the avalanche triggering. This data describing the success of the avalanche triggering can be recorded manually by the user and / or automatically by scanning the avalanche path and / or the avalanche cone with a camera.

[0054] The transmission of sensor signals and / or camera signals also serves to document the success of the blasting operation and to secure evidence. After the avalanche has been detonated, the drone can fly over the avalanche cone, and the corresponding image data can be captured, transmitted, and recorded. Even in poor visibility conditions, where it is not possible to determine from a distance whether and how the avalanche has occurred, meaningful information can be collected due to the drone's proximity to the avalanche cone. The drone can be equipped with collision protection, which uses an ultrasonic and / or radar sensor to determine the distance to an obstacle, allowing it to fly close to potential obstacles (trees, rocks, etc.) even in poor visibility conditions. It may be advisable to limit the flight speed to ensure that the collision protection functions effectively. For example, while the collision protection is in use,The maximum flight speed should be limited to 5 m / s or 3 m / s. This allows data to be collected to document the avalanche, particularly image data showing the avalanche break and / or the avalanche cone, even in poor weather conditions.

[0055] Furthermore, a search transmitter, in particular a passive search transmitter such as that sold by Recco, can be arranged on the cord and / or the explosive device to facilitate subsequent searching.

[0056] Instead of a remotely triggered release device, a fastening mechanism can also be installed that releases automatically upon reaching a certain moment of force. This moment is greater than the weight hanging from the cord, so that the freely hanging cord containing the explosive device and, if applicable, the detonation mechanism can be securely held, and smaller than the maximum moment of force exerted by the drone, so that it can release automatically if the cord becomes caught in a tree or other object.

[0057] The device preferably has a height measuring device for measuring the height relative to the ground. This height measuring device can be arranged on the drone and / or on the tether. The height measuring device can be, for example, a laser scanner, with which the distance to the ground can be determined very precisely.

[0058] Based on the altitude value determined by the altimeter, the drone's target location can be automatically corrected and the distance from the snow surface can be automatically adjusted. Since the snow cover height changes during snowfall, the altimeter can be used to adjust the blasting location to the changing snow cover thickness.

[0059] In a method for blasting an avalanche, a device as described above can be used, comprising a drone, an explosive device suspended freely from the drone by a cord, and a firing mechanism for detonating the explosive device. The drone is flown to a blasting location, which can also be referred to as the target location. The explosive device is positioned above a snow cover to be detonated, and the firing mechanism is triggered either remotely or automatically.

[0060] The target location is preferably determined so that the explosive device is located at least 0.1 m, in particular at least 0.5 m, in particular at least 1 m, or even at least 2 m above the snow cover. This prevents the blast from being dampened by the snow, as would be the case if the explosive device were to detonate within the snow cover.

[0061] Preferably, the target location is positioned so that the explosive device is no more than 10 m, especially no more than 8 m, and preferably no more than 5 m above the snow cover. The greater the distance of the explosive device from the snow cover, the greater the range, but the smaller the impact on the snow cover. The actual distance of the explosive device must therefore be selected by the on-site explosives expert.

[0062] The height of the explosive device above the ground can be determined, for example, by lowering the drone at the target location until the explosive device touches the ground, and then using the height measuring device to measure the drone's height when the explosive device touches the ground. The drone is then raised by a predetermined height so that the explosive device is positioned at this predetermined height above the ground. The explosive device is detonated at the predetermined height above the ground. This allows the height of the explosive device above the ground to be precisely adjusted.

[0063] The impact of the explosive device on the ground can be determined by monitoring the power supplied to the motors driving the drone's rotors. It is also possible to determine the impact of the explosive device on the ground using a scale that measures the weight hanging from the string.

[0064] The drone preferably flies to the blasting site autonomously. In this case, the target location is stored in the flight control system using location coordinates. This allows the target location to be reached reliably even under difficult flight conditions.

[0065] The drone's flight can also be controlled remotely. This is particularly useful when flying to destinations whose coordinates are unknown.

[0066] Multiple devices can be used to detonate avalanches, each comprising a drone, an explosive device suspended freely from the drone by a cord, and a firing mechanism for detonating the explosive device. The firing mechanism can be remotely controlled or automatically triggered. These devices are used simultaneously to fly to an area, each with an explosive device, in which an artificial avalanche is to be triggered. The firing mechanisms for detonating the explosive devices are synchronized with each other. This synchronization can mean that all firing mechanisms are triggered simultaneously, so that several explosive devices detonate simultaneously in a predetermined area and trigger one or more avalanches. However, it is also possible for the individual explosive devices to be synchronized so that they are triggered with a time offset.This time offset can, for example, correspond to the time it takes for the sound waves from a first explosion to reach the range of the nearest second drone. Accordingly, the detonations of the explosive devices of the additional drones located even further away from the first drone can be delayed, so that a wave front spreads approximately continuously along the line on which the drones are arranged and is repeatedly amplified by further detonations.

[0067] The synchronized firing mechanisms can be triggered with a single radio signal. If they are triggered simultaneously, all firing mechanisms will fire immediately upon receipt of the radio signal. If the firing mechanisms are to be synchronized such that the individual firings occur at different times, then additional information containing the time offset is preferably transmitted with the firing signal to each device or firing mechanism. The time offset can also be determined by calculating the distance between the drones. For this purpose, the location of the individual drones is recorded and transmitted to the remote control 8. The distances between the drones 2 and thus the time offsets are calculated at the remote control 8.

[0068] The time offsets can also be preset in the ignition mechanisms 5, so that all ignition mechanisms 5 are triggered with a common radio signal and ignite with a time offset from one another.

[0069] In principle, it is advisable to provide two ignition mechanisms that are designed independently of each other. So-called HU detonators are preferably used as ignition mechanisms, which are highly insensitive and firedamp-proof.

[0070] Instead of an electrical ignition mechanism, a mechanical ignition mechanism can also be provided. This is, for example, a so-called demolition detonator. The cord is made of two sections, with each section connected to the demolition detonator at one end and attached to the drone at the other end. One of the two sections is slightly shorter and forms a so-called shed section. This shed section is preferably made of a thin hemp rope, which is shed upon ignition and can decompose.

[0071] The cord consisting of the two sections forms a loop, with the demolition fuse located slightly above a lower end area of ​​the loop.

[0072] When the loosing section is released from the drone, the demolition fuse drops slightly until the other section of the cord is stretched. This abruptly slows the demolition fuse's movement, causing it to detonate.

[0073] With such a mechanical detonator, it is not necessary for the explosive device to be detonated electrically. This type of mechanical detonation mechanism is particularly reliable in the weather conditions (cold, snowfall) common during avalanche blasting.

[0074] The invention is explained in more detail below using the drawings. The drawing shows schematically: Figure 1 shows a device for blasting an avalanche in a side view according to a first embodiment, Figure 2 shows a drone which is a component of this avalanche blasting device, in a block diagram, Figure 3 shows a device for blasting an avalanche in a side view according to a second embodiment, Figure 4 shows a device for blasting an avalanche in a side view according to a second embodiment, which is slightly modified, and Figure 5 shows a device for blasting an avalanche in a side view according to a third embodiment.

[0075] An embodiment of a device for blasting avalanches, which is also referred to below as an avalanche blasting device 1, comprises a drone 2 and an explosive device 3, which is freely suspended from the drone 2 by means of a cord 4. An ignition mechanism 5 for igniting the explosive device 3 is attached to the cord 4. The ignition mechanism 5 is connected to the explosive device 3 by an ignition cable 6.

[0076] The ignition mechanism 5 is designed for remote-controlled and / or automatic triggering. For remote-controlled triggering, the ignition mechanism 5 has a radio receiver (not shown) to receive a radio signal to ignite the ignition charge.

[0077] Cord 4, for example, is a rope with a diameter of 1 mm to 3 mm. It can have a load-bearing capacity of 100 kg to 300 kg.

[0078] Preferably, the section of the cord between the drone 2 and the detonation mechanism 5 is thicker than the section of the cord between the detonation mechanism 5 and the explosive device 3. The thicker section of the cord has, for example, a thickness of at least 3 mm and preferably at least 4 mm, and the thinner section is preferably thinner than 3 mm. This is particularly advantageous when taking off and landing the drone 2, since the thicker section of the cord 4 is less likely to be stirred up by the air vortices generated by the drone and become tangled with a propeller of the drone.

[0079] The thick section of cord 4 is, for example, 5 m to 15 m long, and the thin section is, for example, 25 m to 40 m long. The total length of cord 4 in the present embodiment is approximately 40 m to 65 m.

[0080] Explosive device 3 may contain an explosive charge weighing several kilograms. The explosive charge can weigh up to 10 kg. Typically, an explosive charge weighing 2 kg to 5 kg is used.

[0081] The drone 2 is preferably a hexacopter or an octocopter, with all flight-relevant parts being provided redundantly so that in the event of a single part failure, the drone 2 can continue to fly safely.

[0082] The drone has an antenna 7 for transmitting and receiving a radio signal. The drone 2 can be controlled by a remote control 8, which, with its own antenna 9, can receive the radio signals from the drone 2 and transmit corresponding radio signals for controlling the drone 2. The remote control 8 has input elements 10 for inputting control signals. In the present embodiment, the input elements 10 are two operating levers and several buttons. The remote control 8 is equipped with a screen 11 on which signals received from the drone 2 can be displayed.

[0083] The Drone 2 ( Figure 2 ) has several motors 12, each driving a propeller 13. In the present embodiment, the drone is an octocopter with eight motors 12, each driving one of the propellers 13 (for simplicity, only two motors and two propellers are shown in the figures).

[0084] The drone 2 is equipped with a central control device 14. The central control device 14 is connected to a transmitting / receiving device 15, which is designed to transmit and receive a radio signal via the antenna 7.

[0085] The drone 2 also has a positioning sensor 16, which in the present embodiment is a satellite sensor, in particular a GPS sensor. The positioning sensor 16 is equipped with an antenna 17 for receiving satellite signals. In principle, other positioning sensors, such as those that perform positioning using radio or telephone signals, can also be used. However, for use in the mountains, a positioning sensor that receives satellite signals is recommended, as these are available everywhere.

[0086] The power supply of the drone 2 is provided by an accumulator 18.

[0087] In addition to the positioning sensor 16, the drone 2 can also include additional sensors, such as a visible light camera 19, an infrared camera (= thermal imaging camera) 20, and an altitude measuring device 21. The altitude measuring device 21 can be a laser scanner that can determine the distance between the altitude measuring device 21 and the nearest object to within a few centimeters, with a total distance corresponding to the length of the cord 4. However, the positioning sensor can also be used as the altitude measuring device. A radio positioning sensor can be used reliably even in poor weather conditions. While absolute altitude cannot usually be measured with the accuracy of a laser scanner using a radio positioning sensor, relative altitude can also be determined very precisely using a radio positioning sensor.

[0088] The sensors 19, 20, and 21 are each arranged on the drone 2 with their viewing direction or detection direction oriented vertically downwards. The sensors 19, 20, and 21 are preferably pivotably mounted on the drone 2, so that they automatically maintain their vertically downward viewing direction regardless of the tilt of the drone 2. Such mountings are known in the field of camera technology.

[0089] The drone has a release device 22 to which the cord 4 is attached. The release device 22 can be opened automatically, so that the cord 4 is released from the drone 2. In the present embodiment, the release device comprises a hook that can be pivoted sideways so that the cord can slide off the hook 23.

[0090] The central control device 14 contains several modules, each implemented by a program unit. These modules include an autopilot flight module a remote control flight module a communications module.

[0091] The communication module reads the sensor signals from the location sensor 16, the visible light camera 19, the thermal imaging camera 20, and / or the height measuring device 21 and either makes these sensor signals available to the other modules and / or transmits the sensor signals to the remote control 8 via the transceiver 15. The image signals generated by the cameras 19, 20 can be displayed on the screen 11. The location coordinates can be shown as text on the screen 11.

[0092] The autopilot flight module can automatically fly to a destination whose location coordinates are stored in advance. By continuously comparing the location coordinates detected by the positioning sensor 16 with the target coordinates, the destination can be flown to automatically.

[0093] The destination can be reached solely based on the location coordinates provided by the location sensor 16.

[0094] A drone with an autopilot flight module can also be permanently stationed at a base station on a specific mountain. The base station features a system for automatically charging the drone's battery and automatically loading it with an explosive device. From the base station, the drone flies to individual detonation points, which are predetermined or determined using an avalanche risk assessment system. A detonation process, and thus a drone flight, can be triggered remotely by a user, e.g., via the internet or another communications network.

[0095] An optional height measuring device 21 is provided, which can be used to correct the height of the target location. The height measuring device 21 measures the distance between the drone 2 and the ground directly vertically below the drone 2. Since the thickness of the snow layer increases during snowfall, the height of the ground can vary. As a result, the distance to the ground can change between the target location defined using pre-stored location coordinates. However, if it is desired that the explosive device be positioned at a specific height above the ground or above the surface of the snow cover when it is detonated, the height of the target location can be corrected using the distance measurement by the height measuring device 21 during the flight of the drone 2, and thus the explosive device 3 can be positioned at the exact desired height above the surface of the snow cover or above the ground.This can be done completely automatically using the autopilot flight module. Upon reaching the target location, if legally permitted, the explosive device 3 can be automatically detonated by the central control unit 14. For this purpose, a corresponding detonation signal must be transmitted from the central control unit 14 to the detonation mechanism 5. This can be done via radio or a wired transmission.

[0096] However, the detonation mechanism can also be triggered remotely. If the detonation mechanism receives a detonation signal, the explosive device 3 is detonated without delay and explodes above the snowpack, triggering an avalanche.

[0097] The autopilot flight module then automatically flies Drone 2 back to the takeoff location from which Drone 2 took off.

[0098] Within the scope of the invention, it is also possible for the autopilot flight module to be configured such that the drone flies in a meandering pattern across the potential avalanche cone from the launch site to the target site, and the image signals from the cameras 19, 20 are transmitted to the screen 11, allowing the user of this device to determine whether there are people or animals in the potential avalanche cone. If this is the case, the blasting process can be aborted and the drone 2 can return without performing the blasting.

[0099] With the remote control flight module, a user, in particular a demolition expert, can control the flight of the drone 2 using the remote control 8 and remotely trigger the detonation using a radio signal from the remote control 8 to the detonation mechanism 5. Here, too, the user can first fly over the potential avalanche cone and use the cameras 19, 20 to scan for people and / or animals.

[0100] To secure predetermined structures, such as roads, villages, or ski slopes, it can be useful to fly to potential target locations in summer. A cord 4 is attached to the drone 2 with a weight so that the position of the explosive device 3 relative to a respective triggering location can be easily simulated. The cord 4 can also be somewhat longer than for blasting operations to simulate snow cover. The location coordinates of these target locations are saved during this simulation so that they can be automatically and reliably flown to when snow cover is present. In principle, any number of target locations can be saved and then flown to as needed. This allows a specific structure to be reliably protected by triggering avalanches at many different locations in a timely manner. This is also possible when weather conditions are so bad that a helicopter cannot fly.By detonating explosive device 3 in a position at a distance from the surface of the snowpack, avalanche blasting can be reliably carried out repeatedly at different target locations. There is no risk of the explosive device sliding off the snowpack and exploding elsewhere.

[0101] When approaching a destination with an existing snow cover, the thickness of the snow cover can be measured by comparing the stored location coordinates and the altitude measurement using the altitude measuring device 21. This is relevant information for assessing the avalanche danger. The location coordinates for describing a mountain slope are preferably stored in the control device 14 and / or in the remote control 8, so that a profile of the snow cover thickness can be determined by comparing the current location coordinates of the drone 2 and the simultaneously recorded altitude values. Such a snow cover measurement can also be carried out independently of an avalanche blasting operation to estimate the avalanche danger. If such a snow cover measurement is carried out repeatedly at intervals, the thicknesses of the individual snow layers can be determined.Combining this data with the relevant weather data, especially temperature and wind during a given snowfall, allows for a very accurate assessment of avalanche danger. This can also be done automatically using a self-learning system, particularly a neural network, which can be trained to estimate avalanche danger for specific areas.

[0102] The self-learning system is trained by feeding the snowpack thickness values ​​and corresponding avalanche events on that slope into the self-learning system during a learning phase. Preferably, the relevant weather data for the slope are also fed in. After the learning phase, the self-learning system can then estimate the avalanche danger based on the snowpack thickness values ​​and, if applicable, the weather data. This allows for an individual assessment of the avalanche danger for a slope, which can be based on a large database and is thus significantly more reliable than conventional avalanche danger assessment methods.

[0103] A second embodiment of the device 1 for blasting avalanches is explained below ( Figure 3The second embodiment again comprises a drone 2, an explosive device 3, which is freely suspended from the drone by means of a cord 4, and an ignition mechanism 5 for detonating the explosive device 3. In the second embodiment, the same parts are designated by the same reference numerals as in the first embodiment. The above explanations regarding the individual components of the avalanche blasting device apply equally to the second embodiment, unless otherwise stated below.

[0104] In this embodiment, the cord 4 is formed from two sections, a permanent section 24 and a loosing section 25. The firing mechanism 5 is a mechanical firing mechanism designed as a breakaway detonator. The firing mechanism 5 is suspended from the drone 2 by the loosing section 25. The explosive device 3 is suspended from the drone 2 by means of the permanent section 24. The explosive device 3 and the firing mechanism 5 are connected by a fuse 28, which joins the two sections 24, 25 of the cord 4 to form a loop that sags slightly below the firing mechanism 5 and the explosive device 3. The sections 24, 25 of the cord 4 are each attached to the drone 2 by a latch 26, 27.

[0105] The loosing section 25 of the cord 4 is a thin hemp rope that is separated from the drone 2 and ejected when the ignition mechanism 5 is triggered by releasing the latch 27. This causes the ignition mechanism 5 to drop slightly until the fuse 28 is stretched. A part of the ignition mechanism connected to the loosing section 25 separates from the other part of the ignition mechanism 5 and is sacrificed together with the loosing section 25. The ignition is triggered mechanically, and the explosive device 3 is detonated via the fuse 28. As is known to those skilled in the art, the fuse is not ignited directly, but rather by means of a detonator (not shown) arranged on the explosive device.

[0106] The lost section is a hemp rope that is sacrificed. The hemp rope decomposes without harming the environment.

[0107] This mechanical ignition mechanism 5 is very simple and reliable and can be used reliably even in adverse weather conditions.

[0108] According to a modification of the second embodiment ( Fig. 4 ) the ignition mechanism 5 is suspended from the drone 2 by means of the permanent section 24 and the explosive device 3 by means of the loss section 25. The permanent section 24 and the fuse 28 are connected to the detonator 5 by means of a bypass loop 29.

[0109] To trigger the detonation, the latch 26 is released, causing the loosing section to separate from the drone 2 and the explosive device 3 to fall slightly downward until the fuse is extended. This separates a part of the ignition mechanism connected to the loosing section 25 from the other part of the ignition mechanism 5, triggering the ignition mechanism. The fuse 28 and the permanent section 24 are held together by the bypass loop 29. The explosive device 3 is detonated via the fuse 28.

[0110] A third embodiment is designed to create a separation edge in a snow cover by distributing several explosive charges 3 / 1 - 3 / 4 across a slope ( Fig. 5a to 5b ). This third embodiment essentially corresponds to the second embodiment as shown in Fig. 4is shown, whereby only the bypass loop 29 is omitted here. Furthermore, instead of a single explosive device 3, several explosive devices 3 / 1 - 3 / 4 are provided, which are each connected to one another by means of a detonating cord 30. The detonating cord 30 differs from the fuse 28 in that the ignition flame propagates much more quickly here. Conventional detonating cords, such as the one known under the brand name Detonex, have an ignition flame propagation speed of 6000 m / s. As a result, the explosive devices connected to the detonating cord detonate virtually simultaneously. The fuse 28 can be used to set a predetermined time period of several seconds to several tens of seconds between the triggering of the ignition mechanism 5 and the detonation.

[0111] Because no bypass loop 29 is provided, when the latch 26 is released, not only is the loosing section 25 detached from the drone 2, but when the ignition mechanism 5 is triggered, it is separated into two parts, so that all explosive devices 3 / 1 - 3 / 4 and the fuse 28 are separated from the drone or the permanent section 24 of the cord 4.

[0112] The explosive charges 3 / 1 - 3 / 4 can be placed across a slope along a line, with the lowest charge 3 / 4 being placed on the ground first, followed by the charges 3 / 3 - 3 / 1 arranged above it, placed sequentially. These charges form a so-called cutting charge to cut a separation edge into the snow cover. When charge 5 is triggered, thus completely dropping the charges 3 / 1 - 3 / 4, the fuse 28 is ignited, which causes the charges 3 / 1 - 3 / 4 to detonate.

[0113] With such a cutting charge, avalanches on a wide slope and snow cornices can be blasted very efficiently.

[0114] Such a device 1 for blasting avalanches can also have an electrical detonation mechanism instead of a mechanical detonation mechanism 5. However, in this case, a separating device for separating the explosive devices from the drone must be provided. The separating device is preferably provided in the area below the detonation mechanism 5, so that it remains with a drone and can be reused.

[0115] Since the present device and method do not require fixed installations or the use of a helicopter, the technical effort and thus the costs involved are significantly lower than with conventional avalanche blasting devices.

[0116] One of the most significant advantages of the device and method according to the invention is that avalanches can be triggered even in situations where this was previously impossible. Such situations occur primarily when it snows continuously for several days, especially over several weeks. These situations do not occur often, but they are the ones with the greatest potential danger. Certain wind conditions can lead to very specific avalanche hazards that no one had anticipated beforehand. List of reference symbols

[0117] 1 Avalanche blasting device 2 Drone 3 Explosive device 4 Cord 5 Firing mechanism 6 Firing lever 7 Antenna 8 Remote control 9 Antenna 10 Input element 11 Screen 12 Motor 13 Propeller 14 Central control device 15 Transmitting / receiving device 16 Positioning sensor 17 Antenna 18 Accumulator (short: battery) 19 Camera for visible light 20 Camera for infrared rays 21 Height measuring device 22 Release device 23 Hook 24 Permanent section 25 Loss section 26 Latch 27 Latch 28 Fuse 29 Bypass loop 30 Detonating cord

Claims

1. A device (1) for avalanche blasting, comprising a drone (2), an explosive charge (3) which is attached to the drone (2) so as to hang freely by means of a cord (4), and a firing mechanism (5) for firing the explosive charge (3), the firing mechanism (5) being designed to be triggered remotely or automatically, characterized in that the firing mechanism (5) is arranged on the cord (4) at a distance from the drone (2) and at a distance from the explosive charge (3) such that the firing mechanism (5) cannot be misfired by electrical elements of the drone (2), on the one hand, and is not damaged when the explosive charge (3) is detonated, on the other hand.

2. The device (1) according to claim 1, characterized in that the distance between the drone (2) and the firing mechanism (5) is at least 5 m and preferably at least 10 m and / or the distance between the firing mechanism (5) and the explosive charge (3) is at least 5 m, in particular at least 10 m and preferably at least 15 m.

3. The device (1) according to claim 1 or 2, characterized in that the cord (4) comprises an explosive section which is directly connected to the explosive charge (3) and to the remaining cord (4) by means of a releasable clamp.

4. The device (1) according to any one of claims 1 to 3, characterized in that the device (1) comprises an equipment for detecting whether the explosive charge (3) touches down on a ground and an altitude measuring equipment (21) for measuring the altitude of the drone (2).

5. The device (1) according to claim 4, characterized in that the altitude measuring equipment (21) determines the altitude and / or the location of the drone (2) in a three-dimensional coordinate system by means of radio signals and / or the altitude measuring equipment (21) is provided to measure the distance to the ground.

6. The device (1) according to any one of claims 1 to 5, characterized in that the cord (4) has a length of at least 10 m and preferably at least 20 m, one end of the cord (4) being attached to the drone (2) and the other end of the cord (4) being connected to the explosive charge (3), and / or the cord (4) is attached to the drone (2) by means of a drop device (22) which is designed to be triggered by remote control.

7. The device (1) according to any one of claims 1 to 6, characterized in that the device (1) comprises a location sensor (16) and / or the device (1) comprises a camera (19) for visible light and / or a camera (20) for infrared radiation and / or a radio equipment (15) is provided for transmitting sensor signals and / or image signals.

8. The device (1) according to claim 7, characterized in that the device (1) comprises a control equipment (14) by means of which the device (1) can fly automatically to a specific target location based on location coordinates determined by the location sensor (16).

9. A method for avalanche blasting, wherein a device (1) according to any one of claims 1 to 8 is used and the drone (2) is flown to a target location such that the explosive charge (3) is located above a snow cover to be detonated and the firing mechanism (5) is triggered by remote control or automatically.

10. The method according to claim 9, characterized in that the drone (2) flies to the target location automatically and / or the flight of the drone (2) is controlled remotely.

11. The method according to claim 9 or 10, characterized in that a device (1) according to claim 5 and in particular a device (1) according to claim 6 is used, wherein the drone (2) is lowered at the target location so far until the explosive charge (3) touches down on the ground and the altitude measuring equipment (21) measures the altitude of the drone (2) when the explosive charge (3) is placed on the ground, the drone (2) is then raised by a predetermined height so that the explosive charge (3) is located above the ground by this predetermined height, and the explosive charge (3) is detonated at the predetermined height above the ground.

12. The method according to claim 11, characterized in that the touchdown of the explosive charge (3) on the ground is determined by monitoring a drive power supplied to motors (12) for driving rotors (13) of the drone (2), or by means of a scale which measures the weight hanging on the cord (4).

13. The method according to any one of claims 9 to 12, characterized in that the drone (2) is used to fly over a slope covered with a snow cover and the distance between the altitude measuring equipment (21) and the surface of the snow cover is measured using the altitude measuring equipment (21) provided on the drone (2) and, at the same time, the location of the altitude measuring equipment (21) or the drone (2) is detected using the location sensor (16) and, on the basis of this measurement data, the thickness of the snow cover and in particular a thickness profile is determined by means of a comparison with data describing the surface of the slope without snow cover.

14. The method according to claim 13, characterized in that the measurement data is supplied to a self-learning system so that the risk of an avalanche is estimated on the basis of this measurement data.

15. The method according to any one of claims 9 to 14, characterized in that several devices (1) for avalanche blasting, each comprising a drone (2), an explosive charge (3) which is attached to the drone (2) so as to hang freely by means of a cord (4), and a firing mechanism (5) for igniting the explosive charge (3), the firing mechanism (5) being designed to be triggered remotely or automatically, are used simultaneously, and the firing mechanisms (5) are triggered synchronously with one another to fire the explosive charges (3), the devices (1) preferably being designed according to any one of claims 1 to 9.