WO2025202294A1 - Method and device for forest fire fighting and/or forest fire early detection - Google Patents

Abstract

The invention relates to a method for forest fire fighting and/or forest fire early detection using a drone, comprising the method steps of receiving, in the navigation unit of the drone, first position data relating to a possible forest fire, calculating a first flight route of the drone in relation to the position data by means of the navigation unit of the drone, starting the drone, navigating the drone in relation to the position data, the flying altitude for part of the calculated flight route being beneath the treetop of the forest, and to a device for forest fire fighting and/or forest fire early detection.

Description

Method and device for forest fire fighting and/or early forest fire detection

The invention describes methods for forest fire fighting and/or early detection of forest fires using a drone, comprising the method steps of receiving first position data of a possible forest fire in the navigation unit of the drone, calculating a first flight route of the drone to the position data by the navigation unit of the drone, starting the drone, navigating the drone to the position data, wherein the flight altitude for part of the calculated flight route runs below the treetop of the forest, as well as a device for forest fire fighting and/or early detection of forest fires.

State of the art

The larger a forest fire, the more difficult it is to determine its direction and speed of spread. Weather, wind, soil conditions, and vegetation determine its path and speed of spread, which can change within a short period of time. It is therefore very important to detect a forest fire very early in order to minimize damage and keep the fire manageable, as well as to give the fire department a decisive time advantage.

During a wildfire, the complex thermal decomposition processes (distillation, pyrolysis, charring, and the oxidation of the resulting gas products during flame combustion) occur simultaneously and often in close proximity to one another. The thermal decomposition of fuels occurs in front of and along the fire line, while pockets of intermittent open flame often persist far behind the flame front.

Flame combustion is generally between 800°C - 1200°C. Smoldering ground fires are between 300°C - 600°C. Combustible gases, especially volatile Volatile organic compounds (VOCs) are formed more quickly at temperatures above 200°C, reaching their peak at 320°C. VOCs are the collective term for organic, carbon-containing substances that evaporate into the gas phase at room temperature or higher temperatures, particularly terpenes. Various organic compounds are also formed, such as methanol, carbon dioxide, carbon monoxide, and molecular hydrogen. Flaming combustion only begins at 425°C to 480°C. Flame temperatures of 700°C to 1300°C are most common. In this temperature range, carbon dioxide, nitrogen oxides, and volatile sulfur-containing compounds (VSCs), particularly sulfur dioxide, are mainly formed. Smoldering fires spread slowly, at around 3 cm/h, and can produce ground temperatures above 300°C for several hours, with peak temperatures of 600°C.

Drones have already proven to be a proven aid in detecting wildfires. In the event of a fire, drones are tasked with locating the source of the fire and, if necessary, searching for people. Drones used to locate and suppress wildfires typically have two cameras: a visual image camera and a thermal imaging camera. The visual image camera can observe and detect various situations in real time. The thermal imaging camera searches for fire sources or the heat signature of a person.

Drones fly lower than helicopters, providing a more detailed picture of the situation, and can navigate in confined or dangerous spaces. Thermal imaging capabilities allow them to pinpoint fire hotspots within seconds and detect people trapped even in areas of thick smoke. Thanks to the information collected from the air by drones, incident commanders can make appropriate decisions.

Drones carrying extinguishing agents can be used to additionally combat identified fires, especially in their initial stages when the fire's extent is limited. This can prevent the fire from spreading and thus causing a large-scale forest fire with immense damage to people and nature. Another option for detecting forest fires is to install a network of gas sensors directly in the forest. These sensors detect gases released during the development of forest fires, thus enabling early detection of forest fires before they can be detected by optical systems from a distance. However, due to the varying vegetation types and soil composition in forests, different gases and gas concentrations are produced, making accurate detection very difficult. Furthermore, the increasing temperatures during the different phases of forest fire development also result in different gases and gas concentrations.

It is therefore an object of the present invention to provide a method for early detection and/or fighting of forest fires which has improved detection accuracy, is expandable as required and is cost-effective to install and maintain.

It is also an object of the invention to provide a forest fire early detection and suppression system which has improved detection accuracy, is expandable as required and is cost-effective to install and maintain.

It is also an object of the invention to provide a drone station for early detection and/or fighting of forest fires for improved supply of a drone in parking position.

It is also an object of the invention to provide a drone for early detection and/or fighting of forest fires, which enables improved detection and fighting of a fire source.

Description of the invention

This object is achieved by means of the method according to the invention for detecting a forest fire. Advantageous embodiments of the invention are also set forth in the subclaims. This object is achieved by means of the inventive method for forest fire fighting and/or early forest fire detection using a drone. Advantageous embodiments of the invention are also set forth in the subclaims.

The method according to the invention for fighting forest fires and/or early detection of forest fires using a drone comprises four method steps: In the first method step, initial position data of a possible forest fire are received in the navigation unit of the drone.

A drone (UAV) as defined in this document is an unmanned aerial vehicle without a crew on board. The drone is controlled and navigated either remotely, along a pre-programmed flight path, and/or completely autonomously.

For the purposes of this patent specification, early forest fire detection refers to the detection of a forest fire and/or, in particular, the detection of a fire source, e.g., a smoldering fire, in the monitored area. In this specification, early forest fire detection includes not only the detection of a forest fire and/or fire source, but also the determination of the location of a forest fire and/or fire source.

Furthermore, for the purposes of this patent specification, forest fire fighting is understood to mean the detection, localization, containment, and/or extinguishing of a forest fire. Detection includes the recognition of a forest fire and/or the detection of a fire source in the monitored area. In this specification, the localization of forest fires includes not only the detection of a forest fire and/or the fire source, but also the determination of the position of a forest fire and/or the fire source.

The drone's navigation unit receives position data of a possible forest fire, e.g. from a forest fire early detection system, e.g. from a satellite system, a monitoring system using high-altitude surveillance towers and/or from drones. In the second step, the drone's navigation unit calculates an initial flight path for the drone based on the position data. The drone's flight path takes into account, in particular, the drone's takeoff point and the position of the potential forest fire, which is the end point of the flight path.

The third step involves launching the drone. When idle, the drone is typically located in a weather-protected area, such as a drone base, where it can be serviced and supplied with fuel.

In the fourth step, the drone navigates to the position data, with the flight altitude for part of the calculated flight route in the forest area being below the tree canopy of the forest. In particular, the drone moves to the position data by flying. The tree canopy of the forest within the meaning of the invention is the part of the tree formed by the branches, which as a whole has a more or less expansive shape. The tree canopy also has leaves and needles. The tree trunk connects the roots and the tree canopy. The distance from the lower edge of the tree canopy to the ground is referred to as the clear height. The tree canopy itself has a vertical dimension referred to as the crown height. The vertical tree height is therefore composed of the clear height and the crown height. The tree canopy of the forest has an average distance (clear height) of the tree canopy of all trees in the forest to the ground. According to the invention, the drone navigates below the forest canopy for part of its flight path at a distance from the ground that is less than the distance from the lower edge of the forest canopy to the ground. The drone navigates below the lower edge of the forest canopy, particularly during takeoff and/or optionally during the final approach to the forest fire's position data.

This enables precise localization of the forest fire and/or the source of the fire, as the distance between the drone and the fire is so close that optional sensors installed on the drone can detect the source of the fire. Likewise, targeted extinguishing of the forest fire and/or the source of the fire is achieved, as the drone can efficiently apply the extinguishing agent thanks to the precise localization of the fire and/or the source of the fire. In a further development of the invention, the drone is launched in a forested area. Due to the short distance to the fire source, the drone requires only a short time to fly along the calculated flight path to the fire source's position data, thus enabling effective localization and extinguishing of the forest fire.

In a further aspect of the invention, the drone is launched below the treetop. In its idle state, the drone is usually parked in a weather-protected area, e.g., a drone station, where it can be serviced and supplied with fuel. The drone's parking position is therefore usually located below the forest canopy. The drone's launch to navigate to the forest fire location data also usually takes place below the forest canopy.

In an advantageous embodiment of the invention, the drone is launched autonomously. Within the scope of the invention, a method and/or device is referred to as "autonomous" if it can reach a given target independently and adapted to the situation without human control or detailed programming. Autonomous methods and/or systems can operate without direct human instruction, make decisions, optionally learn independently, and react to unforeseen events. The drone is launched autonomously to navigate to the location data of the forest fire, without direct human command.

In a further embodiment of the invention, obstacle detection methods are performed by the drone during its flight. For this purpose, the drone optionally has navigation sensors for detecting objects in the environment. The navigation sensors detect, in particular, obstacles that may occur during the drone's movement.

In a further embodiment of the invention, collision avoidance procedures are carried out by the drone during its flight. For this purpose, the drone optionally has navigation sensors for detecting objects in the environment. The navigation sensors have, for example, one or a plurality of cameras and/or The drone uses sensors based on time-of-flight measurement to detect obstacles as the drone moves. A control unit located within the drone detects, recognizes, analyzes, and converts these obstacles into control commands so that the drone avoids a collision with a detected obstacle during its flight.

Based on this information, once an obstacle is detected, collision avoidance can be activated as a consequence of the detected object. In its simplest form, obstacle detection ensures that a moving drone stops in front of the obstacle and does not touch it. If the drone is merely hovering, collision avoidance ensures that the drone cannot move in the direction of the obstacle at all. For this purpose, specific distances can be optionally set in the navigation unit.

In a further embodiment of the invention, the collision avoidance method includes calculating and/or executing an evasive maneuver around the detected obstacle. For this purpose, the drone optionally has navigation sensors for detecting objects in the environment. The navigation sensors comprise, for example, one or more cameras and/or time-of-flight sensors that detect obstacles while the drone is moving. The obstacles are detected, recognized, analyzed, and converted into control commands by a control unit arranged in the drone such that the drone automatically avoids the obstacles during its flight.

In a further development of the invention, the collision avoidance method includes calculating and/or executing a new flight route. The drone is equipped with a navigation unit that determines the alternative route based on the detected obstacles, the current position of the drone, and position data of the forest fire. The advanced stage of collision avoidance involves proactively changing the flight path around the obstacle. To do this, the drone autonomously calculates a new flight path that passes to the side, above, or below the obstacle.

In a further embodiment of the invention, the flight route runs in the forest area at least 5%, preferably at least 10%, particularly preferably at least 15% and Particularly preferably at least 25% and/or at least 5 m, preferably at least 10 m, particularly preferably at least 25 m, and especially preferably at least 50 m below the treetop. The drone navigates below the forest canopy, particularly during takeoff. After takeoff, the drone optionally navigates its flight path to the fire and/or fire source at a flight altitude above the treetop in order to avoid as few obstacles as possible, or ideally no obstacles at all, during its flight. During the final approach to the position data of the forest fire, the drone's flight path optionally runs below the forest canopy.

This enables precise localization of the forest fire and/or the source of the fire, as the distance between the drone and the fire is so close that optional sensors installed on the drone can detect the source of the fire. Likewise, targeted extinguishing of the forest fire and/or the source of the fire is achieved, as the drone can efficiently apply the extinguishing agent thanks to the precise localization of the fire and/or the source of the fire.

In a further embodiment of the invention, the approach to the forest fire occurs within the last 0.5%, preferably within the last 1%, particularly preferably within the last 5%, and especially preferably within the last 10% of the flight path below the forest canopy. This enables precise localization of the forest fire and/or the source of the fire, because the distance between the drone and the source of the fire is so short that optional sensors arranged in the drone can detect the source of the fire. Likewise, targeted extinguishing of the forest fire and/or the source of the fire is achieved, as the exact localization of the fire and/or the source of the fire allows the drone to efficiently apply the extinguishing agent.

In a further embodiment of the invention, sensor data is collected by the drone to locate the source of the fire. The drone is equipped with suitable sensors for this purpose, e.g., a camera in the optical spectral range (visual image) and optionally a camera in the IR range. A visible image camera can detect smoke, in particular, while the IR camera can detect the source of the fire based on the heat generated. The sensor data is optionally evaluated in the navigation unit. In a further embodiment of the invention, the sensor data allows for an accurate determination of the position of the Fire source of less than 10m, preferably less than 5m, particularly preferably less than 2m and especially preferably less than 1m.

In a further aspect of the invention, firefighting is carried out by the drone from a distance of less than 25 m, preferably less than 15 m, more preferably less than 10 m, and especially preferably less than 5 m from the source of the fire. Different extinguishing agents can be used. The extinguishing agent can, for example, be a foam extinguishing agent filled in a plurality of droppable containers. One or more containers are dropped by the drone onto the source of the fire; the heat generated causes the plastic wall of the container to burst, and the extinguishing agent is applied. Another possibility is the use of water-filled containers. Alternatively, the drone can have an acoustic cannon as an extinguishing agent, which fights the source of the fire using air pressure fluctuations caused by sound pressure. The shorter the distance between the drone and the source of the fire at the moment of firefighting, the more effectively the extinguishing agent is applied, increasing its effectiveness.

In a further embodiment of the invention, the drone flies autonomously. The drone flies to its target, the fire source, without direct programming and without direct human instructions. A direct connection to a central control unit and/or a human operator is therefore unnecessary.

In a further embodiment of the invention, the location of the forest fire's source is located autonomously. The drone locates the fire source without direct programming and without direct human instructions. A direct connection to a central control unit and/or a human operator is therefore not necessary.

In a further embodiment of the invention, the forest fire is extinguished autonomously. The drone fights the fire with a suitable extinguishing agent without direct programming and without direct human instructions. A direct connection to a central control unit and/or a human operator is therefore unnecessary. In a further embodiment of the invention, the drone locates the source of the forest fire. The drone is equipped with suitable sensors for this purpose, e.g., a camera in the optical spectral range (visual image) and, optionally, an IR camera. A visual image camera can detect smoke, in particular, while the IR camera can detect the source of the fire based on the heat generated. The sensor data is optionally evaluated in the navigation unit.

In a further embodiment of the invention, the drone flies above the treetops when locating the source of the forest fire. After takeoff, the drone navigates its flight path to the fire and/or source of the fire at an altitude above the treetops in order to avoid as few or no obstacles as possible during its flight. Avoiding obstacles would increase the flight time.

In a further embodiment of the invention, the drone performs the localization using an IR sensor. A sensor located in the drone that is sensitive to IR radiation can detect and locate the source of the fire based on the heat generated.

In an advantageous development of the invention, the method is carried out with two or more drones. A plurality of drones locates the source of the fire and/or performs extinguishing operations. This allows for more effective and faster localization and, in particular, extinguishing of the source of the fire.

In a further embodiment of the invention, the first drone locates the source of the fire. In particular, the first drone locates the source of the fire without the first drone actually fighting the fire. Instead, the first drone optionally flies at a safe altitude above the fire and locates the source of the fire while the second drone extinguishes the fire.

Optionally, the first drone flies above the treetop when locating the fire source. After takeoff, the drone navigates its flight path to the fire and/or fire source at a height above the treetop in order to Avoiding obstacles as little as possible, or even none at all. Avoiding obstacles would extend the drone's flight time.

In a further embodiment of the invention, the first drone transmits position data of the fire source to a second drone. The second drone receives position data of the fire source, optionally continuously during its flight on its flight route to the fire source. For this purpose, the first drone is optionally directly connected wirelessly to the second drone.

Communication between the first and second drones optionally takes place via a mesh network. A mesh network has a star-shaped architecture in which message packets are exchanged between the first and second drones, and optionally between a network server and the drones, via gateways distributed throughout the forest. Such a mesh network is infinitely expandable and resilient to the failure of individual gateways.

In a further embodiment of the invention, the second drone flies part of its flight route below the treetops. The second drone navigates below the forest canopy, particularly during takeoff. After takeoff, the second drone optionally navigates its flight route to the fire and/or source of the fire at an altitude above the treetops in order to avoid as few, and ideally no, obstacles as possible during its flight. During the final approach to the position data of the forest fire, the flight path of the second drone runs below the forest canopy. This enables precise localization of the forest fire and/or source of the fire because the distance between the second drone and the source of the fire is so short that optional sensors arranged in the second drone can detect the source of the fire. Likewise, targeted extinguishing of the forest fire and/or source of the fire is achieved because the more precise localization of the fire and/or source of the fire allows the second drone to efficiently apply the extinguishing agent.

In a further embodiment of the invention, the second drone carries out firefighting. Different extinguishing agents (e.g., water, foam) can be used, which are arranged in containers on the second drone. By means of the first The first drone continuously updates the location of the fire source, which is then sent to the second drone. Firefighting by the second drone is therefore very efficient.

The problem is further solved with the forest fire early detection and/or fire fighting system according to the invention.

The forest fire early detection and/or suppression system according to the invention comprises a drone station and a drone, wherein the drone is suitable for locating and/or suppressing a forest fire. Each drone station comprises at least one drone. A drone station is a weatherproof station for accommodating the drone. A drone station is configured to accommodate the drone and has all-round weather protection that can be opened or closed. The drone station comprises an energy conversion device (e.g., by means of solar cells). Additionally, an energy storage device (battery) is optionally arranged, which is charged with electrical energy by the energy conversion device.

In the parked position, the drone is connected to a drone station. While connected to the drone station, the drone can be loaded with extinguishing agent and refueled, data and information can be exchanged, and a software update can be performed if necessary. The drone can be supplied with electrical power via a power supply located in the drone station.

The drone is equipped with suitable sensors for locating a forest fire and/or fire source, e.g., a camera with an optical spectral range (visual image) and, optionally, an IR camera. A visible image camera can detect smoke, in particular, while the IR camera can detect the fire source based on the heat generated. In addition, the drone optionally carries extinguishing agents (e.g., water, foam) in suitable containers, which are preferably dropped onto the fire source.

According to the invention, the forest fire early detection and/or fire suppression system is located directly in the forest. The drone's flight path from the drone station to the fire source is The flight time is therefore short, and the flight duration is also short. The drone can therefore reach the source of the fire in a very short time, locate the source of the fire, and begin firefighting.

In a further development of the invention, the forest fire early detection and/or extinguishing system comprises multiple drone stations and/or multiple drones. A plurality of drones locates the source of the fire and/or performs extinguishing operations. This allows for more effective and faster localization and, in particular, extinguishing of the source of the fire.

In a further embodiment of the invention, the drone station and/or drones are arranged below the forest canopy. When idle, the drone is parked in the drone station, where it can be serviced and supplied with fuel. The drone station is arranged below the forest canopy to allow for maintenance and repairs if necessary. The drone's parking position is therefore also generally located below the forest canopy. The drone's launch to navigate to the forest fire location data therefore also generally takes place below the forest canopy.

In a further embodiment of the invention, the forest fire early detection and/or suppression system comprises a mesh network. A mesh network has a star-shaped architecture in which message packets are exchanged between the first and second drones, and optionally between a network server and the drones, via gateways distributed throughout the forest. Such a mesh network is infinitely expandable and resilient to the failure of individual gateways.

The object is further achieved with the drone station according to the invention for early detection and/or suppression of forest fires. Further advantageous embodiments of the invention are set forth in the subclaims.

The drone station according to the invention for early detection and/or suppression of forest fires is located directly in the forest. The drone station has at least one drone in a parked position. Furthermore, the drone station has facilities for supplying the drone with power and, optionally, extinguishing agents. The drone's flight path The distance from the drone station to the fire is therefore short, and the flight time is also short. The drone can therefore reach the fire in a very short time, locate the fire, and begin firefighting.

In a further embodiment of the invention, the drone station is located below the forest canopy. When idle, the drone is parked in the drone station, where it can be serviced and supplied with fuel. The drone station is located below the forest canopy to allow for maintenance and repairs if necessary. The drone's parking position is therefore also generally located below the forest canopy. The drone's launch to navigate to the forest fire location data also generally takes place below the forest canopy.

In a further embodiment of the invention, the drone station is part of a network of drone stations in this forest. The drone stations are optionally connected to each other, e.g., via a mesh network. A plurality of drones locates the source of the fire and/or performs extinguishing operations. This enables more effective and faster localization and, in particular, extinguishing of the source of the fire.

In a further embodiment of the invention, the drone station is part of a forest fire early detection and/or firefighting system with a mesh network. A mesh network has a star-shaped architecture in which message packets are exchanged between the first and second drones, and optionally between a network server and the drones, via gateways distributed throughout the forest. Such a mesh network is infinitely expandable and resilient to the failure of individual gateways.

The object is further achieved with the drone according to the invention for early detection and/or suppression of forest fires. Further advantageous embodiments of the invention are set forth in the subclaims.

The drone according to the invention for early detection and/or fighting of forest fires is located directly in the forest. The drone is in the parking position in the A drone station is located where the drone can be serviced and supplied with fuel. The drone's flight path from the drone station to the fire is therefore short, as is the flight time. The drone can therefore reach the fire in a very short time, locate the source of the fire, and begin firefighting.

In a further embodiment of the invention, the drone's parking position is located below the forest canopy. When idle, the drone is parked in the drone station, where it can be serviced and supplied with fuel. The drone station is located below the forest canopy to allow for maintenance and repairs if necessary. The drone's parking position is therefore also generally located below the forest canopy. The drone's launch to navigate to the forest fire location data also generally takes place below the forest canopy.

In a further embodiment of the invention, the drone is part of a network of drones in this forest. The drones are optionally connected to each other, e.g., via a mesh network. A plurality of drones locates the source of the fire and/or performs extinguishing operations. This allows for more effective and faster localization and, in particular, extinguishing of the fire source.

In a further embodiment of the invention, the drone is part of a forest fire early detection and/or firefighting system with a mesh network. A mesh network has a star-shaped architecture in which message packets are exchanged between the first and second drones, and optionally between a network server and the drones, via gateways distributed throughout the forest. Such a mesh network is infinitely expandable and resilient to the failure of individual gateways.

Embodiments of the method according to the invention and the forest fire early detection system according to the invention are shown schematically in simplified form in the drawings and are explained in more detail in the following description.

They show: Fig. 1 : Forest fire early detection and/or control system in a

forest area

Fig. 2: Forest fire early detection and/or control system in a

Forest area, drone flight routes

Fig. 3: Forest fire early detection and/or suppression system in a

Forest area, drone flight routes with flight altitudes

Fig. 4: Altitude profile of flight route R1

Fig. 5: Altitude profile of flight route R4

Fig. 6: Three different paths of the flight route R5

Fig. 7 a: Altitude profile of flight route R5.1

Fig. 7 b: Altitude profile of flight route R5.2

Fig. 7 c: Altitude profile of flight route R5.3

Fig. 8: Forest fire early detection and/or suppression system in a

Forest area, master drone

Fig. 9 a: Altitude profile of flight route MD, time t1

Fig. 9 b: Altitude profile of flight route R5.2, time t1

Fig. 9 c: Altitude profile of flight route MD, time t2

Fig. 9 d: Altitude profile of flight route R5.2, time t2

Fig. 9 e: Altitude profile of flight route MD, time t3

Fig. 9 f: Altitude profile of flight route R5.2, time t3

Fig. 9 g: Altitude profile of flight route MD, time t4

Fig. 9 h: Altitude profile of flight route R5.2, time t4

Fig. 10: Forest fire early detection system comprising a LoRa radio network

Fig. 11 : Example of a drone

Fig. 1 shows an exemplary embodiment of the arrangement of a forest fire early detection and/or suppression system 1 in a forest area W, which is traversed by unforested roads R and a stream B, as well as a clearing L and a lake S. The forest W itself comprises coniferous and deciduous trees (mixed forest), with the individual trees having different tree heights, clearances, crown heights, and crown widths. The forest area W is surrounded by an unforested area P. A network of eight drone stations D1, D2, D3, D4, D5, D6, D7, D8 is arranged in and around the forest area W, with the drone stations D1, D3, D7, D8 located in the unforested area P and the drone stations D2, D4, D5, D6 located in the forest area W. The individual drone stations Dn are wirelessly connected to each other and to a radio tower via a radio link (G5).

Each drone station Dn has a drone 300. A drone station Dn is a weatherproof station for accommodating the drone 300. A drone station Dn is designed to accommodate the drone 300 and has all-round weather protection, which is designed to be opened and closed on the top. The top has an energy conversion device (solar cells). An energy storage device (battery) is arranged on the bottom, which is charged with electrical energy by the energy conversion device.

In the parked position, the drone 300 is immovably coupled to a drone station Dn. By coupling it to the drone station Dn, the drone 300 can be loaded with extinguishing agent and refueled, data and information can be exchanged, and a software update can be performed if necessary. The drone 300 can be supplied with electrical power via a power supply located in the drone station Dn.

Fig. 2 shows an embodiment of the method according to the invention for forest fire fighting and/or early forest fire detection in the forest area W shown in the above embodiment (see Fig. 1). For forest fire fighting and/or early forest fire detection, each drone 300 coupled to the drone stations D1, D2, D3, D4, D5, D6, D7, D8 and located in the parked position simultaneously receives first position data of a possible fire source BH via the navigation unit 360 of the drone 300 (see Fig. 11). The first position data of the possible fire source BH are transmitted via the G5 radio network. A first flight route of the drone 300 based on the position data is then calculated by the navigation unit 360 of the drone 300, wherein the flight route also includes the respective flight altitude of a drone 300. After that, each drone 300 is launched autonomously, with the drones 300 being launched in the drone stations D1, D3, D7, D8 in the unforested area P and the drones 300 being launched in the drone stations D2, D4, D5, D6 within the forest area W. After After launch, each drone 300 also navigates autonomously to the position data of the fire source BH. A drone 300 launched from a drone station Dn navigates along a flight route Rn.

Fig. 3 shows, by way of example, the flight routes Rn to the fire seat BH of the drones launched from all drone stations D1, D2, D3, D4, D5, D6, D7, D8, with one drone 300 being launched from each drone station D1, D2, D3, D4, D5, D6, D7, D8. The flight routes Rn each have different flight directions and, on a flight route Rn, different flight altitudes, i.e., a drone 300 also changes its flight altitude on its flight route Rn depending on the topography and vegetation of the ground. The respective flight routes Rn run at least 50%, preferably at least 30%, particularly preferably at least 20%, and especially preferably at least 10% below the treetops.

The drone 300, launched from the drone station D1, flies on its way to the fire source BH on the flight path R1, with the flight altitude on the section R1a being above the unforested area P at the height of the treetops of the forest area W. On the section R1b, the flight altitude is below the treetops of the forest area W.

The drone 300 launched from the drone station D2 flies on its way to the fire source BH on the flight route R2, the flight altitude is below the treetop of the forest area W on the entire flight route R2.

Drone 300, launched from drone station D3, is flying on its way to the fire site BH on flight route R3 at an altitude above the treetops of forest area W.

Drone 300, launched from drone station D4, is flying along flight path R4 on its way to the fire site BH. On section R4a, the flight altitude is below the treetops of forest area W, and on section R4b, the flight altitude is above the treetops of forest area W.

Drone 300, launched from drone station D5, is flying on its way to the fire site BH on flight route R5 at an altitude below the treetops of forest area W. Drone 300, launched from drone station D6, is flying along flight path R6 on its way to the fire site BH. On section R6a, the flight altitude is above the treetops of forest area W, and on section R6b, the flight altitude is below the treetops of forest area W.

Drone 300, launched from drone station D7, is flying along flight path R7 on its way to the fire site BH. On section R7a, the flight altitude is above the treetops of forest area W, and on section R7b, the flight altitude is below the treetops of forest area W.

Drone 300, launched from drone station D8, is flying along flight path R8 on its way to the fire site BH. On section R8a, the flight altitude is above the treetops of forest area W, and on section R8b, the flight altitude is below the treetops of forest area W.

The approach to the forest fire BH takes place on the last 0.5%, preferably on the last 1%, particularly preferably on the last 5% and especially preferably on the last 10% of the distance of the respective flight route Rn below the tree canopy of the forest W.

Fig. 4 shows a flight altitude profile of the flight route R1 of the drone 300 launched from the drone station D1 on its way to the fire source BH. In this and the following figures (see Fig. 5, Fig. 7, Fig. 9), the y-axis shows the height H above the ground. The height H1 denotes a height below the treetop of the forest W, the second height H2 a height of the treetop, the height H3 a height above the treetop of the forest W. The height Ku denotes the average height of the underside of the treetop of the forest W (clear height), the height Ko the average height of the top of the treetop of the forest W. The distance Ku-Ko is therefore the average treetop height of the forest W. The x-axis shows the distance traveled by a drone 300 from its starting point at the drone station Dn to the fire source BH. Drone 300 takes off from drone station D1 in the unforested area P and flies in section R1a at altitude H2. In the forested area W on section R1b, the drone flies at altitude H1 below the treetops of forest W.

During the flight of the drone 300 along the flight route R1, the forest fire detection unit 300 continuously detects any obstacles that may occur using the navigation sensor 350, determines an alternative route to the target area when obstacles occur, and continues the motorized movement along the alternative route to the target area, wherein the detection of obstacles, determination of an alternative route, and motorized movement along the alternative route are continuously repeated and executed during the movement of the drone 300.

After arriving in the vicinity of the fire source BH, the drone 300 autonomously collects sensor data to locate the fire source BH and its position, wherein the sensor data allow a positioning accuracy of the fire source BH of less than 10 m. Optionally, the sensor data allow a positioning accuracy of the fire source BH of preferably less than 5 m, more preferably less than 2 m, and especially preferably less than 1 m. In addition, the fire source BH is extinguished autonomously by the drone 300 by dropping the extinguishing agent 313 from the fire source BH from a distance of less than 25 m, preferably less than 15 m, more preferably less than 10 m, and especially preferably less than 5 m. In this exemplary embodiment, the extinguishing agent 313 is a foam extinguishing agent that is filled into a plurality of droppable containers. One or more containers are dropped onto the fire source BH by the drone 300. Due to the heat generated, the plastic wall of the container bursts, and the extinguishing agent 313 is applied. Another option is the use of water-filled containers. Alternatively, the drone 300 can be equipped with an acoustic cannon as the extinguishing agent 313, which fights the fire source BH using the air pressure fluctuations caused by the sound pressure.

Fig. 5 shows an altitude profile of the flight path R4 of the drone 300 launched from the drone station D4 on its way to the fire site BH. The drone 300 launches from the drone station D4 in the wooded area W and flies in the section R4a in the Flight altitude H1 below the treetops. In the area of road R, drone 300 changes its flight altitude from H1 to H3 and flies in section R4b within the wooded area W at an altitude H3 above the treetops. In the area of stream B, drone 300 changes its flight altitude from H3 to H1 and flies in section R4c within the wooded area W at an altitude H1 below the treetops to the fire source BH. During its flight along flight path R4, drone 300 also performs obstacle detection and collision avoidance procedures.

Fig. 6 and Fig. 7 show an embodiment of the drone 300 launched from the drone station D5, which flies on three different flight routes 5.1, 5.2, 5.3 (Fig. 6) to the fire source BH. The drone 300 launches from the drone station D5 in the wooded area W. On the flight route R5.1 (Fig. 7 a), the drone 300 flies in the sub-section R5.1a in the wooded area W at a flight altitude H1 below the treetops. In the area of the road R, the drone 300 changes its flight altitude from H1 to H2 and flies in the sub-section R5.1b at a height H2 at the height of the treetops. Also in the area of the road R, the drone 300 changes its flight altitude from H2 to H1 and flies in the sub-section R5.1c at a height H1 to the fire source BH.

On flight route R5.2 (Fig. 7 b), drone 300 flies in section R5.2a in the wooded area W at altitude H1 below the treetops. In the area of road R, drone 300 changes its altitude from H1 to H3 and flies in section R5.2b at altitude H3 above the treetops. In the area of clearing L, drone 300 changes its altitude from H1 to H1 and flies in section R5.2c at altitude H1 below the treetops to the fire source BH.

On flight route R5.3 (Fig. 7 c), drone 300 flies in section R5.3a in the wooded area W at altitude H1 below the treetops. In the area of road R, drone 300 changes its altitude from H1 to H3 and flies in section R5.3b both above road R and above the wooded area W at altitude H3 above the treetops. Drone 300 changes its altitude in the area of road R from H3 to H1 and flies in section R5.3c at altitude H1 below the treetops to the fire source BH. The drone 300 approaches the fire source BH in the last 0.5%, preferably in the last 1%, particularly preferably in the last 5%, and especially preferably in the last 10% of the flight path below the treetop of the forest W. Once it arrives at the fire source BH, the drone 300 autonomously extinguishes the fire source BH.

An advantageous embodiment of a forest fire early detection and/or fire fighting system 1 according to the invention arranged in the environment already described is shown in Fig. 8. A network of eight drone stations D1, D2, D3, D4, D5, D6, D7, D8 is arranged in and around the forest area W, wherein the drone stations D1, D3, D7, D8 are arranged in the unforested area P and the drone stations D2, D4, D5, D6 are arranged in the forest area W (see Fig. 3). Each drone station Dn has a drone 300. In addition, a drone station MD, also with a drone 300, is arranged in the unforested area P. The flight routes Rn to the fire source BH of the drones 300 launched from all drone stations D1, D2, D3, D4, D5, D6, D7, D8 are described in an earlier embodiment (see Fig. 3). The drone 300 launched from the drone station MD is a master drone 300 which, in contrast to the drones 300 launched from the drone stations D1, D2, D3, D4, D5, D6, D7, D8, flies on a flight route Rn to the fire source BH, which, except during the takeoff process from the drone station MD itself, does not fly below the treetop of the forest W, but above the treetop (see Fig. 9).

The master drone 300 launched from drone station MD does not carry out any fire fighting itself, but locates the source of the fire BH by hovering at a safe height above the source of the fire BH. In addition, it is connected to all other drones 300 launched from drone stations D1, D2, D3, D4, D5, D6, D7, D8 as well as to drone stations D1, D2, D3, D4, D5, D6, D7, D8 themselves. Upon arrival at the source of the fire BH, the master drone 300 launched from drone station MD autonomously locates the source of the fire BH with an accuracy of less than 1 m. Depending on the extent of the source of the fire BH, the fire fighting of the source of the fire BH is coordinated by the drones 300 launched from drone stations D1, D2, D3, D4, D5, D6, D7, D8 using the master drone 300. Fig. 9 shows an embodiment of the flight route of the drone 300 launched from the drone station MD in comparison to the drone 300 launched from the drone station D5 on the flight route R2 (see Fig. 7 b) at four different times t1, t2, t3, t4. It is assumed that the average flight speed of a drone 300 at an altitude H1 below the treetop is 14 of the average flight speed of a drone 300 at an altitude H3 above the treetop. At an altitude H1 below the treetop, the drone 300 carries out methods for obstacle detection and evasive maneuvers, e.g. around the vegetation (trees), whereas at an altitude H3 above the treetop, the drone 300 also carries out methods for obstacle detection, but due to the lack of obstacles, e.g. trees, does not carry out any evasive maneuvers and therefore does not carry out any evasive maneuvers on its flight route.

At the first time t1, drone 300 has just taken off from drone station MD in the non-forested area P and has reached its altitude H3 above the treetop (Fig. 9 a). At the same time t1, drone 300 has also just taken off from drone station D5 in the forested area W and has reached an altitude H1 below the treetop (Fig. 9 b).

At time t2, which is later than time t1, drone 300, launched from drone station MD at altitude H3, has covered approximately 1% of its flight path Rn to fire source BH (Fig. 9 c). Drone 300, launched from drone station D5, has only covered approximately 14% of its flight path to fire source BH, reached the area of road R, and changed its flight altitude from H1 to H3 (Fig. 9 d).

At time t3, which is later than time t2, drone 300, launched from drone station MD, has reached fire source BH at altitude H3 (Fig. 9 e) and assumed a position above fire source BH at altitude H3. Drone 300, launched from drone station MD, has arrived at fire source BH and located fire source BH. Drone 300, launched from drone station D5, has only completed approximately 1/2 of its route to fire source BH (Fig. 9 f).

At time t4, which is later than time t3, the drone 300 has started from the drone station MD and is still at height H3 in a position above the The drone 300, launched from drone station D5, has also reached the fire source BH at altitude H1 (Fig. 9 h) and is beginning the extinguishing process. The drone 300, launched from drone station D5, has changed altitude from H3 to H1 over clearing L.

Fig. 10 shows an embodiment of a forest fire early detection and/or suppression system 1 according to the invention, arranged in a forest W to be monitored. The forest fire early detection and/or suppression system 1 has a mesh gateway network 10 that uses the technology of a LoRaWAN network. The LoRaWAN network 10 has a star-shaped architecture in which message packets are exchanged between the terminal devices ED and a central internet network server NS via gateways G. A terminal device ED has a sensor array for gas analysis and for recording the temperature of the gases, with which a forest fire and/or a fire source can be detected.

The mesh gateway network 10 comprises a plurality of end devices ED connected to gateways G via a single-hop connection FSK. The gateways G are typically mesh gateways. The mesh gateways G are interconnected and, in some cases, connected to border gateways G. The border gateways G are connected to the internet network server NS, either via a wired connection WN or via a wireless connection using the Internet Protocol IP.

The fire source BH is located using an initial localization. The initial localization is performed autonomously by the ED devices detecting the fire source BH. In other words, the position of the ED device detecting the forest fire marks the location of the fire source BH. Furthermore, the localization is performed using a plurality of ED devices: A plurality of ED devices each detects a signal whose source is the gases generated by the forest fire. The signals contain position data of the fire source BH and are forwarded to the network server NS via the mesh gateway network 10. The network server NS is connected via a wireless connection to the drone stations D1, D2, D3, D4, D5, D6, D7, D8, whereby each drone station D1, D2, D3, D4, D5, D6, D7, D8 has a drone 300 in a parked position. The position data of the fire source BH are sent from the network server NS to the drone stations D1, D2, D3, D4, D5, D6, D7, D8, which are distributed in and around the forest W below the treetops of the forest W.

Fig. 11 shows an embodiment of a drone 300 according to the invention for early detection and/or suppression of forest fires. The drone 300 is designed as an autonomously flight-capable drone and, for this purpose, has a drive unit 320 with a plurality of rotors 322 driven by motors 321. The motors 321 are typically electric motors and are powered by a rechargeable energy storage device (battery). The drone 300 is steered by pivoting the rotors 322 and varying the speed of the individual motors 321.

To locate a fire source BH, the drone 300 has a first forest fire detection sensor S1, which in this exemplary embodiment has four sensors S1.1, S1.2, S1.3, S1.4. The sensors S1.1, S1.2, S1.3, S1.4 are arranged at four different positions on the underside of the drone 300. The four sensors S1.1, S1.2, S1.3, S1.4 are each identically constructed infrared cameras for detecting the heat of the fire source BH. In addition, the forest fire detection unit 300 in this exemplary embodiment has a further second forest fire detection sensor S2, which in this exemplary embodiment also has four sensors S2.1, S2.2, S2.3, S2.4. The four sensors S2.1, S2.2, S2.3, S2.4 are gas sensors, which are also arranged at different positions on the drone 300.

To detect and determine the extent and position of a fire source BH, the drone 300 has the extinguishing unit 310, which has the extinguishing agent receptacle 311 for receiving the extinguishing agent 313. The extinguishing agent 313 can be released to extinguish a fire source BH using the extinguishing agent ejection device 312.

The extinguishing agent 313 in this embodiment is a foam extinguishing agent that is filled into a plurality of disposable containers. One or more containers are Drone 300 is dropped onto the fire BH to extinguish the fire. Due to the heat generated, the plastic wall of the container bursts, and the extinguishing agent 313 is applied. Another option is the use of water-filled containers. Alternatively, the drone 300 can be equipped with an acoustic cannon as the extinguishing agent 313, which extinguishes the fire using the air pressure fluctuations caused by the sound pressure. The sound waves, with a frequency of 30 to 60 Hz, trigger mechanical vibrations in the area surrounding the fire BH, which affect both the burning material and the oxygen supply. Extinguishing the fire using an acoustic cannon is particularly sustainable, produces no waste during extinguishing, requires no water or chemicals that might be harmful to forest soil, and can be carried out as long as the drone 300's energy storage system has power.

The drone 300 according to the invention also has a navigation sensor 350 that detects objects in the environment of the drone 300. The navigation sensor 350 has one or a plurality of cameras and/or time-of-flight-based sensors (e.g., radar, ultrasound, lidar) that detect obstacles during the flight of the drone 300. The obstacles are detected, recognized, and analyzed by the navigation unit 360 arranged in the drone 300 such that the drone 300 automatically avoids the obstacles during its flight. All of these components are connected to a navigation unit 360 of the drone 300 and controlled by the navigation unit 360.

LIST OF REFERENCE SYMBOLS

1 forest fire early detection and/or suppression system

10 LoRaWAN mesh gateway network

ED terminal / device for early detection of a forest fire

G Gateway

NS Internet Network Server

IP Internet Protocol

MHF multi-hop radio network

FSK FSK modulation

WN Wired connection

300 drones

310 extinguishing unit

311 recording

312 Detachable connection

313 extinguishing agents

320 Flight propulsion/propulsion unit

321 engine

322 Rotor

330 First Sensor

340 Second Sensor

350 navigation sensor

360 navigation unit

51, S1.1, S1.2, 51.3, First Sensor

S1.4

52, S2.1, S2.2, 52.3, Second Sensor

S2.4

53, S3.1, S3.2, 53.3, Third Sensor

S3.4

H Height

H1, H2, H3 1st, 2nd, 3rd height Ko Upper limit of the tree crown

Ku Lower limit of the tree crown tn nth time point

BH fire source

W forest area

L Clearing

R Street

B Bach

S Lake

P Non-forested area / plain

The drone station

Rn flight route

Rna, Rnb, Rnc section of a flight route

R5.na, R5.nb, R5.nc: Section of the nth alternative flight route of the fifth flight route or section of the fifth flight route at time tn

Claims

PATENT CLAIMS 1. Method for fighting forest fires and/or early detection of forest fires using a drone (300) comprising the following steps: • Receiving initial position data of a possible forest fire in the navigation unit (360) of the drone (300), • Calculating a first flight route (Rn) of the drone (300) to the position data by the navigation unit (360) of the drone (300), wherein the flight route (Rn) also includes the respective flight altitude, • Starting the drone (300), • Navigating the drone (300) to the position data, whereby the flight altitude (H) for part of the calculated flight route (Rn) is below the treetop of the forest (W). 2. Method for fighting forest fires and/or early detection of forest fires using a drone (300) according to claim 1, characterized in that the drone (300) is launched in the forest area (W). 3. Method for fighting forest fires and/or early detection of forest fires using a drone (300) according to claim 2, characterized in that the drone (300) is launched below the treetop. 4. Method for fighting forest fires and/or early detection of forest fires using a drone (300) according to one or more of the preceding claims, characterized in that the drone (300) is launched autonomously. 5. Method for fighting forest fires and/or early detection of forest fires using a drone (300) according to one or more of the preceding claims, characterized in that methods for detecting obstacles are carried out by the drone (300) during the flight of the drone (300). 6. Method for fighting forest fires and/or early detection of forest fires using a drone (300) according to one or more of the preceding claims, characterized in that collision avoidance methods are carried out by the drone (300) during the flight of the drone (300). 7. A method for fighting forest fires and/or early detection of forest fires using a drone (300) according to claim 6, characterized in that the method for avoiding collisions includes calculating and/or executing an evasive maneuver around the detected obstacle. 8. Method for fighting forest fires and/or early detection of forest fires using a drone (300) according to claim 6, characterized in that the method for avoiding collisions includes the calculation and/or execution of a new flight route (Rn). 9. Method for fighting forest fires and/or early detection of forest fires using a drone (300) according to one or more of the preceding claims, characterized in that the flight route (Rn) in the forest area (W) runs at least 5%, preferably at least 10%, particularly preferably at least 15% and especially preferably at least 25% and/or at least 5 m, preferably at least 10 m, particularly preferably at least 25 m and especially preferably at least 50 m below the tree crown. 10. Method for fighting forest fires and/or early detection of forest fires using a drone (300) according to one or more of the preceding claims, characterized in that the approach to the forest fire (BH) takes place on the last 0.5%, preferably on the last 1%, particularly preferably on the last 5% and especially preferably on the last 10% of the distance of the flight route (Rn) below the treetop of the forest (W). 11. Method for fighting forest fires and/or early detection of forest fires using a drone (300) according to one or more of the preceding claims, characterized in that sensor data are collected by the drone (300) to locate the source of the fire (BH). 12. Method for fighting forest fires and/or early detection of forest fires using a drone (300) according to claim 6, characterized in that the sensor data allow an accuracy of determining the position of the fire source (BH) of less than 10 m, preferably less than 5 m, particularly preferably less than 2 m and especially preferably less than 1 m. 13. Method for forest fire fighting and/or early detection of forest fires using a drone (300) according to one or more of the preceding claims, characterized in that the fire fighting is carried out by the drone (300) from a distance of less than 25 m, preferably less than 15 m, particularly preferably less than 10 m and especially preferably less than 5 m from the source of the fire (BH). 14. Method for fighting forest fires and/or early detection of forest fires using a drone (300) according to one or more of the preceding claims, characterized in that the flight of the drone (300) is autonomous. 15. Method for fighting forest fires and/or early detection of forest fires using a drone (300) according to one or more of the preceding claims, characterized in that the location of the fire source (BH) of the forest fire is carried out autonomously. 16. Method for fighting forest fires and/or early detection of forest fires using a drone (300) according to one or more of the preceding claims, characterized in that the fire source (BH) of the forest fire is fought autonomously. 17. Method for fighting forest fires and/or early detection of forest fires using a drone (300) according to one or more of the preceding claims, characterized in that the drone (300) locates the source (BH) of the forest fire. 18. Method for fighting forest fires and/or early detection of forest fires using a drone (300) according to claim 17, characterized in that the drone (300) flies above the treetop when locating the source (BH) of the forest fire. 19. Method for forest fire fighting and/or early forest fire detection using a drone (300) according to claim 17 or 18, characterized in that the drone (300) carries out the localization with the aid of an IR sensor. 20. Method for forest fire fighting and/or early forest fire detection using a drone (300) according to one or more of the preceding claims, characterized in that the method is carried out using two or more drones (300). 21. A method for fighting forest fires and/or early detection of forest fires using a drone (300) according to claim 20, characterized in that the first drone (300) locates the source of the fire (BH), the first drone (300) flying above the treetop when locating the source of the fire (BH). 22. A method for fighting forest fires and/or early detection of forest fires using a drone (300) according to claim 21, characterized in that the first drone (300) transmits position data of the source of the fire to a second drone (300), wherein the communication between the first drone (300) and the second drone (300) takes place via a mesh network (10). 23. Method for fighting forest fires and/or early detection of forest fires using a drone (300) according to one or more of claims 20 to 22, characterized in that the second drone (300) covers part of its flight route (Rn) below the treetop. 24. Method for forest fire fighting and/or early forest fire detection with a drone (300) according to one or more of claims 20 to 22, characterized in that the second drone (300) carries out the fire fighting. 25. Forest fire early detection and/or suppression system (1) comprising: • a drone station (Dn) • a drone (300) suitable for locating and/or fighting a forest fire, characterized in that the forest fire early detection and/or fighting system (1) is located directly in the forest (W). 26. Forest fire early detection and/or fire fighting system (1) according to claim 25, characterized in that the forest fire early detection and/or fighting system (1) comprises several drone stations (Dn) and/or several drones (300). 27. Forest fire early detection and/or fighting system (1) according to claim 25 or 26, characterized in that the drone station (Dn) and/or the drones (300) are arranged below the treetop of the forest (W). 28. Forest fire early detection and/or fighting system (1) according to one or more of claims 25 to 27, characterized in that the forest fire early detection and/or fighting system (1) has a mesh network (10), wherein the mesh network (10) comprises terminal devices (ED), gateways (G) and a network server (NS). 29. Drone station (Dn) for early detection and/or fighting of forest fires, characterized in that the drone station (Dn) is located directly in the forest (W). 30. Drone station (Dn) for early detection and/or fighting of forest fires according to Claim 29, characterized in that the drone station (Dn) is arranged below the treetop of the forest (W). 31. Drone station (Dn) for early detection and/or fighting of forest fires according to Claim 29 or 30, characterized in that the drone station (Dn) is part of a network of drone stations (Dn) in this forest (W). 32. Drone station (Dn) for early detection and/or fighting of forest fires according to claims 29 to 31, characterized in that the drone stations (Dn) are part of a forest fire early detection and/or fighting system (1) with a mesh network (10), wherein the mesh network (10) comprises terminal devices (ED), gateways (G) and a network server (NS). 33. Drone (300) for early detection and/or fighting of forest fires, characterized in that the drone (300) is arranged directly in the forest (W). 34. Drone (300) for early detection and/or fighting of forest fires according to Claim 33, characterized in that the parking position of the drone (300) is arranged below the treetop of the forest (W). 35. Drone (300) for early detection and/or fighting of forest fires according to Claim 33 or 34, characterized in that the drone (300) is part of a network of drones (300) in this forest (W). 36. Drone (300) for early detection and/or fighting of forest fires according to claims 33 to 35, characterized in that the drone (300) is part of a forest fire early detection and/or fighting system (1) with a mesh network (10), wherein the mesh network (10) comprises terminal devices (ED), gateways (G) and a network server (NS).