System and method for early detection of a wildfire

Abstract

The invention relates a wildfire early detection system, having a network server, a first gateway and multiple terminals, wherein the terminal has a first communication interface to a first gateway of the wildfire early detection system and a second communication interface to an external device. The invention further relates to a method for early detection of a wildfire using a wildfire early detection system, having the method steps of detection of a wildfire by the terminal, generation of a signal in a terminal, first transmission of the signal from the terminal via a first communication interface of the terminal, waiting for the receipt of a response signal at the terminal, second transmission of the signal from the terminal via a second communication interface of the terminal. The invention also relates an emergency communication terminal for a wildfire early detection system, comprising a sensor, wherein the sensor is operable to detect a wildfire, an energy supply device, a first communication interface and a second communication interface, where the first communication interface is different from the second communication interface.

Description

[0001] SYSTEM AND METHOD FOR EARLY DETECTION OF A WILDFIRE

[0002] The invention relates a wildfire early detection system, having a network server, a first gateway and multiple terminals, wherein the terminal has a first communication interface to a first gateway of the wildfire early detection system and a second communication interface to an external device. The invention further relates to a method for early detection of a wildfire using a wildfire early detection system, having the method steps of detection of a wildfire by the terminal, generation of a signal in a terminal, first transmission of the signal from the terminal via a first communication interface of the terminal, waiting for the receipt of a response signal at the terminal, second transmission of the signal from the terminal via a second communication interface of the terminal.

[0003] The invention also relates to an emergency communication terminal for a wildfire early detection system, comprising a sensor, wherein the sensor is operable to detect a wildfire, an energy supply device, a first communication interface, and a second communication interface, wherein the first communication interface is different from the second communication interface.

[0004] Prior Art

[0005] Systems for early detection of wildfires are known. For this purpose, the area to be monitored is monitored by means of optical sensors which can detect columns of smoke produced during a wildfire. These sensors are, for example, rotatable cameras, but they have the disadvantage that they are less effective at night and are susceptible to false detections, for example, in the case of dust clouds resulting from agricultural activities. In addition, optical systems can usually only detect the wildfire when the wildfire is already advanced and the smoke columns become visible over greater distances.

[0006] It makes more sense to monitor the area by means of a plurality of inexpensive, mass- producible sensors that work by means of optical smoke detection and / or gas detection.

[0007] The sensors are distributed throughout the area and deliver data to a base station via radio connection.

[0008] Such a system for early detection of wildfires is presented in the document US 2008 / 0309502 A1 . In the event of a fire alarm, a sensor delivers information to a nearby control terminal, which then triggers an alarm by means of a long-range radio frequency signal.

[0009] This system has the disadvantage that the control terminal triggers the alarm and has to have a powerful RF unit for this purpose. The sensors require a GPS unit that constantly sends a signal to the control terminal; the power consumption of the sensors is therefore high, and the service life of the energy sources (batteries) of the sensors is limited.

[0010] Object

[0011] Therefore, it is an object of the present invention to provide a wildfire early detection system and a method for early detection of a wildfire which work reliably, are expandable as desired and are inexpensive to install and maintain.

[0012] Description of the Invention

[0013] The object is achieved by means of the wildfire early detection system of claim 1. Advantageous embodiments of the invention are set forth in the dependent claims.

[0014] The wildfire early detection system according to the invention has a network server, a first gateway and multiple terminals. A terminal has a sensor unit for detection of a wildfire. The first gateways have the task of receiving data from the terminals and forwarding it to the network server. They serve as a bridge between the terminals and the network server and enable connection of term inals in the field to the back-end system . The network server is the core of the wildfire early detection system. The network server receives and processes the data packets received from the gateways. The network server enables the management of LoRa networks, the configuration of network parameters such as bandwidth, channels and transmit power. The network server communicates via different protocols (e.g., REST, MQTT, etc.) with an application which is operated as an app in the cloud, for example.

[0015] According to the invention, the terminal has a first communication interface to the first gateway and a second communication interface to an external device. For the purposes of the invention, an external device is a device which is not part of the terminal, in particular not arranged integrally with the terminal. In a development, the external device is not part of the wildfire early detection system, which has a network server, a first gateway, a second gateway and a plurality of terminals. As an example, the external device may be a receiver of a radio network, an application server, a backup server, a communication relay or a communication satellite.

[0016] By means of the first communication interface, messages may be sent to and received from a first gateway. Via the first gateway, messages may be forwarded from the terminal to the network server, optionally via a standard Internet connection and / or a wired connection.

[0017] By means of the second communication interface, a connection may be established with an external device via which the messages from the terminal may optionally be sent to the network server. By means of a connection via a communication satellite, a connection between the terminal and the external device is also possible over long spatial distances.

[0018] In a development of the invention, the second communication interface is operable to utilize a wireless communication technology. In particular, the second communication interface is operable to communicate wirelessly with the external device. The external device may therefore be arranged in a large spatial distance from the terminal; in addition, the spatial distance between the external device and the terminal does not have to be constant but may vary.

[0019] In a further embodiment of the invention, the first communication interface is different from the second communication interface of the terminal. In a further embodiment of the invention, the first communication interface is operable to utilize a communication technology different from the communication technology utilizable by the second communication interface and / or a communication protocol different from the communication protocols utilizable by the second communication interface. In a further aspect of the invention, the second communication interface is operable to communicate with a communication satellite.

[0020] By means of the first communication interface, messages may be sent to and received from gateways via a single-hop connection.

[0021] By means of the second communication interface to a communication satellite, a connection may be established with a communication satellite via which data packets may be sent from the terminal to the network server. The two communication interfaces therefore use communication protocols which are different from each other and are accordingly structured differently from each other.

[0022] In a development of the invention, the first communication interface is not operable to communicate with a communication satellite. By means of the first communication interface, messages may be sent to and received from gateways via a single-hop connection via direct radio connection.

[0023] In a further embodiment of the invention, the terminal is operable to communicate with a gateway of the wildfire early detection system or the network server via the communication satellite. Communication between the terminal and a gateway via a communication satellite is a direct one, i.e. without further intermediate stations (single-hop connection). Communication between the terminal and a network server via a communication satellite is also a direct single-hop connection.

[0024] In an advantageous embodiment of the invention, the terminal has a self-sufficient energy supply and is intended for off-grid use. To be able to install and operate the terminal even in harsh and especially rural areas far away from energy supply, the terminal is equipped with a self-sufficient energy supply. The energy supply may be provided, for example, by energy storage devices - also rechargeable ones.

[0025] In a further embodiment of the invention, the self-sufficient energy supply comprises an energy storage device and / or an energy conversion device. In particular, energy supply by means of solar cells should be mentioned, in which energy conversion from light to electrical energy takes place. The electrical energy is usually stored in an energy storage device to ensure energy supply even in times of low solar irradiation (for example at night). In a further configuration of the invention, the terminal is operated off-grid. The self-sufficient energy supply enables operation without an energy supply by external means.

[0026] In a further embodiment of the invention, the energy storage device may store more energy than is consumed by standard communication to the first gateway and by standard communication to the communication satellite. For the purposes hereof, standard communication is communication to report a wildfire. Therefore, the terminal has sufficient energy reserves to perform further communication operations, e.g., to send a further message to a gateway or the network server without the energy storage device having to be recharged by solar cells, for example.

[0027] In a development of the invention, the energy storage device may store an amount of energy which is more than twice as large as the energy needed to communicate via the second communication interface. Therefore, the terminal has sufficient energy reserves to perform other operations, in particular further communication with a network server via the second communication interface.

[0028] In a further configuration of the invention, the energy conversion device has a solar cell, a wind turbine with a generator and / or is operable to convert energy from the environment into electrical energy. The generated electrical energy is optionally stored in an energy storage device (e.g., battery, capacitor). Upon temperature changes (e.g., during day and night changes), piezo elements arranged in stacks generate an electrical voltage which may also be stored in an energy storage device.

[0029] In a further embodiment of the invention, the first communication interface is operable to send and receive LPWAN messages. LPWAN describes a class of network protocols for connecting low-power devices such as battery-operated sensors, which area arranged in a terminal, to a network server. The protocol is designed such that a long range and low energy consumption of the terminals can be achieved with low operating costs. Lo- RaWAN manages with a particularly low power consumption. The LoRaWAN networks implement a star-like architecture by means of gateway message packets between the terminals and the central network server. The gateways are coupled to the network server, while the terminals communicate with a gateway via wireless connection via LoRa.

[0030] In an advantageous embodiment of the invention, the shortest communication link leads from the terminal via the first gateway to the network server through at least one second gateway. The second gateway has a communication interface to a network server, along with communication interfaces to other gateways and / or terminals via wireless or wired connection.

[0031] In a further embodiment of the invention, the second gateway is different from the first gateway. In a development of the invention, the second gateway has different communication interfaces to the first gateway. The second gateway has a communication interface to a network server, along with communication interfaces to other gateways and / or terminals by means of wireless or wired connection. The first gateway has communication interfaces to other gateways and / or terminals by means of wireless or wired connection.

[0032] In a further embodiment of the invention, the second gateway is operable to communicate directly with the network server, the first gateway not being operable to communicate directly with the network server. The first gateway does not have a communication interface to a network server, only communication interfaces to other gateways and / or terminals by means of wireless or wired connection. In particular, the first gateways do not have a single-hop connection to a network server.

[0033] In a further configuration of the invention, the first and / or second gateways are not operable to communicate with a communication satellite. Only the termianl has a singlehop connection to a network server via a communication satellite. Communication between the gateways may be through a direct single-hop connection; a multi-hop connection is also possible. This simultaneously extends the range of the mesh gateway network because the first gateway is connected to the second gateway via a mesh multi-hop network and may thus forward the data from the terminals to the network server. The connection of the second gateway to the network server is wireless or wired.

[0034] In a further embodiment of the invention, the mesh gateway network comprises an LPWAN, the LPWAN comprising a LoRaWAN. LPWAN describes a class of network protocols for connecting low-power devices such as battery-operated sensors to a network server. The protocol is designed such that a long range and low energy consumption of the terminals can be achieved with low operating costs. LoRaWAN manages with a particularly low power consumption. The LoRaWAN networks implement a star-like architecture by means of gateway message packets between the terminals and the central network server. The gateways are coupled to the network server, while the terminals communicate with a second and / or first gateway by radio via LoRa.

[0035] In a further embodiment of the invention, the second and / or the third gateway has a communication interface which provides an Internet connection to the network server. The Internet connection is a wireless point-to-point connection, preferably by means of a standard Internet Protocol.

[0036] In an advantageous embodiment of the invention, the gateways have a self-sufficient energy supply. To be able to install and operate gateways even in harsh and especially rural areas far away from energy supply, the gateways are equipped with a self-sufficient energy supply. The energy supply may be provided, for example, by energy storage de- vices - also rechargeable ones.

[0037] In a further embodiment of the invention, the self-sufficient energy supply comprises an energy storage device and / or an energy conversion device. In particular, energy supply by means of solar cells should be mentioned, in which energy conversion from light to electrical energy takes place. The electrical energy is usually stored in an energy storage device to ensure energy supply even in times of low solar radiation (for example at night). In a further configuration of the invention, the gateways are operated off-grid. The self- sufficient energy supply enables operation without an energy supply by external means.

[0038] In a further embodiment of the invention, the first gateways have an ACK signal generation unit. For the purposes of this invention, an ACK generation unit is a sub-server unit integrated into a second gateway, which performs functionalities and tasks intended for the network server according to the LoRaWAN protocol. For the purposes of this invention, ACK signals are messages, commands, and functions stored on the first gateway or generated by a first gateway. The ACK signal (as in “acknowledgment”) generated by the ACK generation unit is a signal used in a data transmission to acknowledge receipt. This ensures that a message is sent correctly. Similarly, the terminal does not have to be active constantly. Power consumption is reduced and the lifetime of the terminal is thus increased.

[0039] In a development of the invention, the ACK signal generation unit has a processor and a memory. The processor and memory are standard components and therefore inexpensive to manufacture.

[0040] The object is further achieved by the method according to the invention for early detection of a wildfire having a wildfire early detection system. Further advantageous embodiments of the invention are also set forth in the dependent claims.

[0041] The method according to the invention for early detection of a wildfire has five method steps: the first method step includes detection of a wildfire by a terminal. For this purpose, the terminal has one or more suitable sensors.

[0042] The second method step includes generation of a signal in a terminal. The signal is generated as a data packet by means of a processor arranged in the terminal.

[0043] The third method step includes a first transmission of the signal by the terminal via a first communication interface of the terminal. The first transmission is preferably wireless, but wired transmission is also possible. The fourth method step includes waiting for receipt of a response signal at the terminal. For this purpose, the terminal has suitable interfaces and a memory on which the signal is stored.

[0044] The response signal is a message from an external device of the wildfire early detection system, e.g., a network server, to the terminal and has the content that the signal from the terminal was received by the external device. The external device generates the response signal immediately after receiving the signal from the terminal and optionally sends the response signal via a direct connection to the terminal and / or optionally also via a multi-hop connection by means of gateways of the wildfire early detection system to the terminal having sent the signal.

[0045] The fifth method step includes a second transmission of the signal by the terminal via a second communication interface of the terminal. The second transmission via the second communication interface of the terminal only takes place if the terminal does not receive a response message. This is the case, for example, if the first transmission of the signal via the first communication interface of the terminal to the external device was not successful, i.e. , the signal did not reach the external device. This may be due to a faulty first communication interface of the terminal, a faulty communication interface of the external device or a transmission failure, for example. In addition, the transmission of the response message from the external device itself may be disturbed.

[0046] That is, according to the invention, for transmission of a signal, e.g., an alarm message, upon detection of a wildfire by the terminal, the first transmission by means of the first communication interface is thus preferred. The second transmission via the second communication interface takes place only in cases where it is unclear whether the signal has reached the external device. The second transmission via the second communication interface provides a redundant possibility of sending messages from the terminal, especially in emergencies. The method according to the invention ensures that a signal from the terminal, in particular an alarm signal, reaches the external device.

[0047] In a development of the invention, the signal is sent via a first communication interface of the terminal to a first gateway of the wildfire early detection system. The first transmission of the signal from the terminal to the first gateway is via a single-hop connection. The first gateways are connected to the external device via sattelite communication or standard Internet Protocol, while the terminals communicate with the respective gateway by radio via LoRa (chirp spread spectrum modulation) or FSK (frequency modulation). Thus, the radio link is a single-hop network in which the terminals communicate directly with one or more gateways, which then forward the data traffic to the external device.

[0048] In an optional embodiment of the invention, the first transmission of the signal is via the first communication interface of the terminal to a network server of the wildfire early detection system. This allows direct communication of the terminal with the network server if communication via the gateways of the network is not possible, for example, for technical reasons.

[0049] In a further aspect of the invention, the signal contains information about a detected wildfire. In particular, the signal contains information about which device(s) detect(s) a wildfire. This enables localization of the wildfire.

[0050] In a further embodiment of the invention, the waiting for the receipt of a response signal at the terminal occurs over a specified time interval. In a development of the invention, the time interval is longer than the average duration between the first transmission of the signal and the receipt of the response signal. For this purpose, at the terminal, the time interval between each first transmission of a signal by means of the first communication interface and each receipt of a corresponding response signal at the terminal is optionally determined, the average of the time intervals is formed and stored.

[0051] In a further embodiment of the invention, the time interval between receipt of the signal and non-receipt of the response signal is greater than the duration between receipt of a signal received earlier and receipt of the response signal from the network sever associated with this signal received earlier by a factor of 2, preferably by a factor of 1.5, and particularly preferably by a factor of 1 .25. This ensures that the connection with the network server via a communication satellite is only employed if an IP connection and / or wired connection is not possible.

[0052] In an advantageous embodiment of the invention, the second transmission is via the second communication interface of the terminal, which is operable to communicate with a communication satellite. By means of the second communication interface to a communication satellite, a connection may be established with a communication satellite via which the signals from the terminal may be sent to an external device, preferably a network server. As an alternative to communication by means of the first communication interface with the network server, a connection of the terminal is also possible over large spatial distances by means of a connection via a communication satellite.

[0053] In a development of the invention, the second transmission of the signal is via the second communication interface of the terminal to a network server of the wildfire early detection system. The signal generated by the terminal is sent directly to the network server of the wildfire early detection system via the communication satellite. As an alternative to communication by means of the first communication interface with the network server, a connection of the terminal is also possible over large spatial distances by means of a connection via a communication satellite.

[0054] In a further embodiment of the invention, the response signal is an acknowledgment of receipt of the network server. The response signal from the network server acknowledges receipt of the signal from the terminal at the network server to the terminal. This ensures that the signal is sent correctly by the terminal. The response signal may be a sign for the terminal to close a download-receive time window and enter the monitoring mode. Similarly, the terminal does not have to be active all the time. Power consumption of the terminal is reduced and the lifespan of the terminal is increased.

[0055] In a further embodiment of the invention, the second transmission of the signal via the second communication interface of the terminal occurs only if the signal is an alarm signal or the energy storage device of the terminal has more energy than needed for two consecutive transmissions by means of satellite communication via the second communication interface. This ensures that sufficient energy is available in the terminal device to forward an alarm signal. In order to test the satellite communication, in addition to forwarding alarm signals, signals are also optionally sent via the second communication interface.

[0056] In an advantageous embodiment of the invention, the second transmission of the signal only takes place via the second communication interface of the terminal if the signal was previously sent by the terminal via the first communication interface. That is, for transmission of a signal, e.g., an alarm message, upon detection of a wildfire by the terminal, the first transmission by means of the first communication interface is thus preferred.

[0057] In a development of the invention, the second transmission of the signal only takes place via the second communication interface of the terminal to the network server if an acknowledgment of receipt of the transmitted signal has not been previously received from the network server at the terminal. The second transmission via the second communication interface of the terminal only takes place if the terminal does not receive an acknowledgment of receipt. This is the case, for example, if the first transmission of the signal via the first communication interface of the terminal to the network server was not successful, i.e., the signal did not reach the network server. This may be due to a faulty first communication interface of the terminal, a faulty communication interface of the external device or a transmission failure, for example. In addition, the transmission of the acknowledgment of receipt from the external device itself may be disturbed.

[0058] In a further aspect of the invention, the second transmission of the signal only takes place via the second communication interface to the network server if an acknowledgment of receipt of the transmitted signal has not been previously received from the network server via a communication interface different from the second communication interface at the terminal in advance. The second transmission via the second communication interface takes place only in cases where it is unclear whether the signal has reached the external device. The second transmission via the second communication interface provides a redundant possibility of sending messages from the terminal, especially in emergencies. The method according to the invention ensures that a signal from the terminal, in particular an alarm signal, reaches the external device.

[0059] In a further embodiment of the invention, upon detection of a wildfire, a software program for selection of the communication interface is launched. The software program runs on the terminal. For this purpose, the terminal optionally has a controller which is run as a microcomputer and is connected to a memory.

[0060] In a further aspect of the invention, the launching of a software program for selection of the communication interface takes place immediately after an analysis of the signal at the terminal. Preferably, the software program for selection of the communication interface selects a communication interface by means of which communication with the network server does not take place via a communication satellite, preferably the first communication interface. Via the first communication interface communication with the network server is preferably via multi-hop connection and / or a single-hop connection.

[0061] The object is further achieved by means of the emergency communication terminal according to the invention for a wildfire early detection system. Further advantageous embodiments of the invention are also set forth in the dependent claims.

[0062] The emergency communication terminal according to the invention comprises a sensor, wherein the sensor is operable to detect a wildfire, an energy supply device, a first communication interface and a second communication interface, wherein the first communication interface is different from the second communication interface. The sensor for detection of a wildfire is, e.g., an optical sensor, gas sensor or temperature sensor or a combination of the mentioned sensors. The power supply device enables a self-sufficient energy supply of the terminal and comprises, e.g., batteries, capacitors and / or an energy conversion by, e.g., a solar cell with an additional energy storage device.

[0063] Optionally, by means of the first communication interface, signals may be sent to and received from gateways by mean of a single-hop connection. Optionally, by means of the second communication interface, signals may preferably be sent to and received from the network server of the wildfire early detection system by means of a direct connection. The two communication interfaces use communication protocols which are different from each other and are accordingly structured differently from each other.

[0064] In a development of the invention, the first communication interface is operable to communicate with a gateway of the wildfire early detection system. By means of the first communication interface, messages may be sent to and received from a first gateway. Via the first gateway, messages may be forwarded from the terminal to the network server, optionally via a standard Internet connection and / or a wired connection.

[0065] In a further embodiment of the invention, the second communication interface is operable to communicate with a communication device outside the wildfire early detection system. As an example, the external device may be a receiver of a radio network, an application server, a backup server, a communication relay or a communication satellite.

[0066] In an advantageous embodiment of the invention, the second communication interface is operable to communicate with a communication satellite. By means of the second communication interface to a communication satellite, a connection may be established with a communication satellite via which data packets may be sent from the terminal to the network server. Therefore, the first communication interface and the second communication interface use communication protocols which are different from each other and are accordingly structured differently from each other.

[0067] In a further configuration of the invention, the emergency communication terminal has a controller which is operable to execute a software program which selects the communication interface to be used for communication. For this purpose, the terminal has the controller which is run as a microcomputer and is optionally connected to a memory.

[0068] In a further embodiment of the invention, the controller is operable to drive the communication interfaces separately. The two communication interfaces are driven such that either a signal is sent via the first communication interface at a first point in time or a signal is sent via the second communication interface at a second point in time. Both communication interfaces do not send a signal at the same time.

[0069] In a further advantageous embodiment of the invention, the energy supply means of the emergency communication terminal has an energy storage device operable to store more energy, preferably to store more than 1.5 times as much energy, and particularly preferably to store more than 2 times as much energy as is necessary for communication via the second communication interface. This ensures that sufficient energy is available in the terminal for sending a signal, in particular an alarm signal. In order to test the satellite communication, in addition to sending alarm signals, signals are also optionally sent via the second communication interface.

[0070] In a development of the invention, the signal is an alarm signal. The alarm signal is generated by a terminal equipped with one or more suitable sensors for detection of a wildfire. Therefore, the alarm signal has the content that a terminal has detected a wildfire. In a further embodiment of the invention, the signal is generated immediately after the terminal having captured sensor signals the analysis of which is indicative of a wildfire. In a further aspect of the invention, the analysis is performed at the terminal. For this purpose, the terminal has an analysis unit which analyzes the sensor signals captured for the presence of a wildfire. If the analysis shows that a wildfire is present, an alarm signal is generated immediately.

[0071] In a further configuration of the invention, in addition to the transmission of alarm signals, signals are only sent by means of satellite communication to test the satellite communication. For example, sending status messages of low priority from the terminal places an unnecessary burden on the satellite communication and generates high costs. Such status messages of low priority may also be sent via the first communication interface.

[0072] In a further embodiment of the invention, transmission of the message takes place from the terminal to the first gateway via a single-hop connection. The gateways are coupled to the network server via a multi-hop connection and the standard Internet Protocol, while the terminals communicate with the respective gateway by radio via LoRa (chirp spread spectrum modulation) or FSK (frequency modulation). Thus, the radio link is a single-hop network in which the terminals communicate directly with one or more gateways, which then forward the data traffic to the network server.

[0073] In a development of the invention, the network server has two different interfaces, via which the network server receives signals from a terminal. The different communication interfaces are operable to receive messages from the respective gateways and to send messages to the respective gateways.

[0074] Exemplary embodiments of the wildfire early detection system according to the invention and the method according to the invention for early detection of a wildfire and the emergency communication terminal according to the invention are shown in the drawings in a schematically simplified manner and are explained in more detail in the following description.

[0075] In the figures:

[0076] Fig. 1 : shows a wildfire early detection system, four second gateways, two emergency communication terminals;

[0077] Fig. 2: shows a detailed view of the wildfire early detection system according to the invention, an emergency communication terminal;

[0078] Fig. 3: shows a detailed view of the wildfire early detection system according to the invention, exchange of ACK messages;

[0079] Fig. 4: shows an exemplary embodiment of a terminal which may be utilized as an emergency communication terminal;

[0080] Fig. 5: shows a sequence diagram of the LoRa radio network;

[0081] Fig. 6: shows a sequence diagram of the LoRaWAN mesh gateway network, connection via communication satellites;

[0082] Fig. 7: shows a sequence diagram of the LoRaWAN mesh gateway network, connection via communication satellites after a time interval has passed.

[0083] An exemplary embodiment of a wildfire early detection system 10 according to the invention for early detection of a wildfire is shown in Fig. 1 . The wildfire early detection system 10 has a mesh gateway network 1 which utilizes the technology of a LoRaWAN network. The LoRaWAN network has a star-like architecture in which message packets are exchanged between the terminals ED and a central network server NS by means of gateways G1 , G2. The wildfire early detection system 10 has a plurality of terminals ED which are connected to two gateways G2 via a single-hop connection FSK. The first gateways G1 are connected to each other and partly to second gateways G2. The four second gateways G2 are connected to the network server NS, two second gateways G2 being connected to the network server NS via a wired connection WN, the other two second gateways G2 via a wireless Internet connection IP. The first gateways G1 and the second gateways G2 are connected to each other via a mesh multi-hop network such that a first gateway G1 does not require direct connection to the network MHF server NS. In this way, a range extension of LoRaWAN networks is achieved by interposing a multi-hop network by means of first gateways G1 , thus achieving complete compatibility with the LoRaWAN specification.

[0084] For early detection of a wildfire, a terminal ED first detects a wildfire by the sensor arranged in the terminal ED capturing a corresponding sensor signal. The sensor in the terminal ED is a smoke detector in all of the exemplary embodiments shown herein. The terminal ED analyzes the sensor signal. If the analysis shows that the captured sensor signal is indicative of a wildfire, the terminal ED generates a corresponding alarm signal immediately after the analysis is completed.

[0085] In a first transmission, the alarm signal is sent from the terminal ED to a first gateway G1 via a single-hop connection FSK by means of the first communication interface K1. Upon receipt of the alarm signal at the first gateway G1 , the first gateway G1 forwards the received alarm signal via a multi-hop connection MHF to a second gateway G2. At the second gateway G2, the alarm signal is also received and forwarded to the network server NS via wired connection WN or wireless Internet connection IP.

[0086] For an adjustable time interval after the first transmission of the alarm signal, the terminal ED waits for receipt of a response signal at the terminal ED. If the response signal has not been received at the terminal ED after the time interval has passed, a second transmission of the alarm signal is carried out via the second communication interface KS of the terminal ED from the terminal ED. In contrast to the first transmission of the alarm signal, the second transmission is via a satellite connection directly to the network server NS.

[0087] Optionally, the LoRaWAN mesh gateway network may have 1 mesh gateway MGDn. The mesh gateways MGDn are a combination of the second gateways G2 and the third gateways G3. The mesh gateways MGDn communicate with each other using the multihop radio network MHF, and at least one mesh gateway MGD is connected to the network server NS via the standard Internet Protocol IP.

[0088] A detailed view of a wildfire early detection system 10 according to the invention is shown in Fig. 2. The wildfire early detection system 10 has a plurality of terminals ED, with eight terminals ED each being connected to a first gateway G1 via a single-hop connection FSK. The first gateways G1 are connected to each other and to second gateways G2. The second gateways G2 are connected to the network server NS via wired connection WN or wireless Internet connection IP. A terminal ED is connected to the network server NS directly via the satellite connection SAT.

[0089] A further detailed view of the wildfire early detection system 10 according to the invention is shown in Fig. 3, in which ACK signals S-ACK are exchanged. The wildfire early detection system 10 has a plurality of terminals ED, each connected to a first gateway G1 via a single-hop connection FSK. Two terminals ED are connected to two first gateways G1 each. As an example, a terminal ED is connected to the network server NS directly via the satellite connection SAT. In contrast to the previous exemplary embodiment (see Fig. 2), here, an ACK signal is sent from first gateway G1 connected to the termianl ED to the terminals ED after the first gateway G1 has received a message from the terminal ED. The ACK signal may be a signal for the terminal ED to close a download-receive time window and enter the monitoring mode.

[0090] For this purpose, the first gateways G1 each have an ACK signal generation unit. The ACK signal (as in “acknowledgment”) is a signal used in data transmission to acknowledge receipt of a meassage from the terminal ED. This ensures that a message is sent correctly by the terminal ED. Similarly, the terminal ED does not have to be active all the time. Power consumption is reduced and the lifetime of the terminal ED is thus increased.

[0091] Fig. 4 shows an exemplary embodiment of a terminal ED which may be utilized as an emergency communication terminal ED in the wildfire early detection system 10. In this exemplary embodiment, the terminal ED has two different communication interfaces K1 , KS which utilize communication technologies which are different from each other. The first communication interface K1 is operable to send messages, in particular alarm signals, to gateways G1 , G2 and to receive messages from gateways G1 , G2 via a singlehop connection FSK. The second communication interface KS is operable to forward signals directly via satellite connection SAT to the network server NS and receive them therefrom.

[0092] The terminal ED has a sensor for detection of a wildfire, in this exemplary embodiment, a smoke detector. The controller has a microprocessor with a memory, including the software program for selection of the communication interface K1 , KS for transmission of an alarm signal to and receipt of an acknowledgment of receipt MS from a gateway G1 , G2 via the first communication interface K1 or for transmission of an alarm signal to and receipt of acknowledgment of receipt MS via satellite link SAT from the network server NS via the second communication interface KS.

[0093] The terminal ED has a self-sufficient energy supply E by means of, e.g., batteries, capacitors or energy conversion by a solar cell and an additional energy storage device. The energy storage device is dimensioned such that it may store an amount of energy greater than the energy needed to communicate via the second communication interface KS. In particular, the energy storage device may store an amount of energy that is more than twice as large as the energy needed to communicate via the second communication interface KS. In this and all of the following exemplary embodiments, the energy storage device may store an amount of energy three times as large as the energy needed to communicate via the second communication interface KS. The forwarding of the signal received from the terminal ED to the network server NS by means of satellite communication SAT only takes place if the signal received from the terminal ED is an alarm signal or the energy storage device of the terminal ED has more energy than is needed for two successive forwarding operations by means of satellite communication SAT. This ensures that sufficient energy for generating and forwarding an alarm signal is available in the terminal ED. To test satellite communication SAT, in addition to forwarding alarm signals, only test signals are sent by means of satellite communication SAT.

[0094] Fig. 5 shows a sequence diagram of a standard LoRaWAN network 1 for performing the method according to the invention according to the LoRaWAN protocol, a terminal ED being connected to a first gateway G1 via a single-hop connection FSK. The terminal ED is employed as an emergency communication terminal ED in the wildfire early detection system 10.

[0095] First, the detection e-d of a wildfire is carried out by the terminal ED. At the terminal ED, a corresponding message ME (alarm signal) is generated e-g by the controller and is sent e-s1 by the terminal ED via the first communication interface K1 to a first gateway G1. The first gateway G1 receives the message ME and forwards g1 -f this message ME to the network server NS. In this exemplary embodiment, the forwarding g1 -f by the first gateway G1 is not successful. Thus, the message ME is not received by the network server NS, and the network server NS does not generate an acknowledgment of receipt MS.

[0096] Therefore, the message ME is sent e-s2 by terminal ED for a second time, the second time via the second communication interface KS of the terminal ED directly to the network server NS, which receives n-r the message ME. Immediately upon receiving the message ME, the network server NS generates an acknowledgment of receipt MS, which is sent n-s back to the first gateway G1 . The gateway G1 in turn forwards g1 -f this acknowledgment of receipt MS to the terminal ED, at which the acknowledgment of receipt MS is received e-r.

[0097] Fig. 6 shows a sequence diagram of a LoRaWAN mesh gateway network 1 , in which the devices ED are connected to the first gateway G1 via single-hop connection FSK (see. Fig. 1 ). The terminal ED is also employed as an emergency communication terminal ED in the wildfire early detection system 10. After the detection e-d of a wildfire and the generating e-g of a message ME, a selection is made e-e by the software program for controlling the terminal ED of the communication interface K1 , KS of the terminal ED by which a first transmission e-s1 of the message ME takes place. The first transmission e-s1 of the message ME is with the first communication interface K1 to a first gateway G1. The first gateway G1 forwards g1 -f the message ME via a multi-hop connection and usually a plurality of first gateways G1 to a second gateway G2.

[0098] The second gateway G2 receives the message ME and forwards g2-f this message ME to the network server NS, wherein, in this exemplary embodiment, the forwarding g2-f is not successful, the message ME does not reach the network server NS and the network server NS does not generate an acknowledgment of receipt MS. Therefore, the message ME is sent e-s2 by terminal ED for a second time, the second time via the second communication interface KS of the terminal ED directly to the satellite S. The satellite S forwards s-f the message ME to the network server NS, which receives n-r the message ME. Immediately after receiving the message ME, the network server NS generates an acknowledgment of receipt MS, which is sent n-s to the satellite S. The satellite S receives the acknowledgment of receipt MS and forwards s-f the acknowledgment of receipt MS to the second gateway G2, which forwards g2-f the acknowledgment of receipt MS to the first gateway G1. The second gateway G2 in turn forwards g1-f this acknowledgment of receipt MS to the terminal ED, at which the acknowledgment of receipt MS is received e-r. In the star architecture of a LoRaWAN network 1 (see Fig. 1 ), this communication occurs very quickly because each terminal ED communicates with the network server NS via at least one second gateway G2.

[0099] Fig. 7 shows a sequence diagram of a LoRaWAN mesh gateway network 1 , in which, as with the previous exemplary embodiment (see Fig. 6), a message ME from the terminal ED is received via a first gateway G1 from the second gateway G2, via which the message ME is forwarded g2-f to the network server NS.

[0100] In this exemplary embodiment, this message ME is also not received at the network server NS after the first transmission e-s1 of the message ME from the terminal ED, also due to a connection failure, for example, the network server NS therefore not creating and sending n-s an acknowledgment of receipt MS to the terminal ED, which created e-g and sent the message ME by a first transmission e-s1 .

[0101] After a time interval t, between the failed forwarding g2-f and the non-receipt of an acknowledgment of receipt MS at the terminal ED, the program for selection of the communication interface K1 , KS selects e-e the satellite communication interface KS for transmission of the message ME from the terminal ED, via which the message ME is sent e- s2 from the terminal ED to the satellite S and forwarded s-f from the satellite S to the network server NS. The time interval t, is chosen such that the time interval t, between receipt of the message ME and non-receipt of the acknowledgment of receipt MS is greater than the duration between receipt n-r of a previously received message ME and receipt of the acknowledgment of receipt MS of the network server NS associated with this signal received e-r earlier at the terminal ED by a factor of 2, preferably by a factor of 1 .5 and in particular by a factor of 1 .25. In this exemplary embodiment, the time interval t, is 1 .25 times greater.

[0102] LIST OF REFERENCE NUMERALS

[0103] 1 mesh gateway network

[0104] 10 wildfire early detection system

[0105] ED, EDn terminals / sensors

[0106] G1 first gateway

[0107] G2 second gateway NS network server

[0108] IP Internet Protocol

[0109] MHF multi-hop radio network

[0110] FSK FSK modulation, single-hop connection

[0111] WN wired connection

[0112] E energy supply

[0113] K1 first communication interface

[0114] KS second communication interface I satellite communication interface

[0115] S communications satellite,

[0116] SAT satellite link

[0117] W forest e-d detecting a wildfire e-g generating a message e-s1 first message transmission from the terminal e-s2 second message transmission from the terminal e-r message receipt from the terminal g 1 — f message forwarding from the first gateway g1-e message receipt from the first gateway g2-f message forwarding from the second gateway s-f message forwarding from the satellite n-r message receipt at the network server n-s message transmission from the network server

[0118] ME message generated by the terminal

[0119] MS acknowledgment of receipt tj time interval

Claims

CLAIMS1 . A wildfire early detection system (10) having a mesh gateway network (1 ), having• a network server (NS),• a first gateway (G1 ),• multiple terminals (ED), characterized in that the terminal (ED) has a first communication interface (K1 ) to the first gateway (G1 ) and a second communication interface (KS) to an external device (S).

2. The wildfire early detection system (10) having a mesh gateway network (1 ) according to claim 1 , characterized in that the second communication interface (KS) is operable to utilize a wireless communication technology.

3. The wildfire early detection system (10) having a mesh gateway network (1 ) according to claim 1 or 2, characterized in that the first communication interface (K1 ) is different from the second communication interface (KS) of the terminal (ED).

4. The wildfire early detection system (10) having a mesh gateway network (1 ) according to claim 3, characterized in that the second communication interface (KS) is operable to utilize a communication technology different from the communication technologies utilizable by the first communication interface (K1 ) and / or a communication protocol different from the communication protocols utilizable by the first communication interface (K1 ).

5. The wildfire early detection system (10) having a mesh gateway network (1 ) ac-cording to any one or more of the preceding claims, characterized in that the second communication interface (KS) is operable to communicate with a communication satellite (S).

6. The wildfire early detection system (10) having a mesh gateway network (1 ) according to claim 5, characterized in that the first communication interface (K1 ) is not operable to communicate diretctly with a communication satellite (S).

7. The wildfire early detection system (10) having a mesh gateway network (1 ) according to claim 5 or 6, characterized in that the terminal (ED) is operable to communicate with a gateway (G1 , G2) of the wildfire early detection system (10) or the network server (NS) via the communication satellite (S).

8. The wildfire early detection system (10) having a mesh gateway network (1 ) according to any one or more of the preceding claims, characterized in that the terminal (ED) is intended for off-grid use and has a self-sufficient power supply (E).

9. The wildfire early detection system (10) having a mesh gateway network (1 ) according to claim 8, characterized in that the self-sufficient energy supply (E) has an energy conversion device (EK) and / or an energy storage device (ES).

10. The wildfire early detection system (10) having a mesh gateway network (1 ) according to claim 8 or 9,characterized in that the energy storage device (ES) can store more energy than is consumed by standard communication to the first gateway (SG) and by standard communication to the communication satellite (S).11 . The wildfire early detection system (10) having a mesh gateway network (1 ) according to claim 10, characterized in that the energy storage device (ES) can store an amount of energy that is more than twice as large as the energy needed to communicate via the second communication interface (KS).

12. The wildfire early detection system (10) having a mesh gateway network (1 ) according to any one or more of claims 8 to 11 , characterized in that the energy conversion device (EK) has a solar cell, a wind turbine and / or is operable to convert energy from the environment into electrical energy.

13. The wildfire early detection system (10) having a mesh gateway network (1 ) according to any one or more of the preceding claims, characterized in that the first communication interface (K1 ) is operable to send and receive LPWAN messages.

14. The wildfire early detection system (10) having a mesh gateway network (1 ) according to any one or more of the preceding claims, characterized in that the shortest communication link from the terminal (ED) via the first gateway (G1 ) to the network server (NS) passes through at least one second gateway (G2).

15. The wildfire early detection system (10) having a mesh gateway network (1 ) ac-cording to claim 14, characterized in that the second gateway (G2) is different from the first gateway (G1 ).

16. The wildfire early detection system (10) having a mesh gateway network (1 ) according to claim 15, characterized in that the second gateway (G2) has different communication interfaces from the first gateway (G1 ).

17. The wildfire early detection system (10) having a mesh gateway network (1 ) according to any one or more of claims 14 to 16, characterized in that the second gateway (G2) is operable to communicate directly with the network server (NS), the first gateway (G1 ) not being operable to communicate directly with the network server (NS).

18. The wildfire early detection system (10) having a mesh gateway network (1 ) according to any one or more of the preceding claims, characterized in that the first and / or second gateway (G1 , G2) is not operable for communication with a communication satellite (S).

19. The wildfire early detection system (10) having a mesh gateway network (1 ) according to any one or more of the preceding claims, characterized in that the network server (NS) has a first communication interface, wherein the first communication interface is operable to communicate with the second gateway (G1 ), and the network server (NS) has a second communication interface operable to communicate with the terminal (ED),wherein the second communication interface is not operable to communicate with the first gateway (G1 ).

20. The wildfire early detection system (10) having a mesh gateway network (1 ) according to claim 19, characterized in that the second communication interface is operable for satellite communications (SAT).

21. A method for early detection of a wildfire using a wildfire early detection system (10), with the steps of• detection (e-d) of a wildfire by a terminal (ED) of the wildfire early detection system (10),• generation (e-g) of a signal (ME) in the terminal (ED),• first transmission (e-s1 ) of the signal (ME) from the terminal (ED) via a first communication interface (K1 ) of the terminal (ED),• waiting for receipt (e-r) of a response signal (MS) at the terminal (ED),• second transmission (e-s2) of the signal (ME) from the terminal (ED) via a second communication interface (KS) of the terminal (ED).

22. The method for early detection of a wildfire using a wildfire early detection system(10) according to claim 21 , characterized in that the signal (ME) is sent (e-s1) via a first communication interface (K1 ) of the terminal (ED) to a first gateway (G1 ) of the wildfire early detection system (10).

23. The method for early detection of a wildfire using a wildfire early detection system(10) according to claim 21 or 22, characterized in that the first transmission (e-s1) of the signal (ME) takes place via the first communication interface of the terminal (ED) to a network server (NS) of the wildfire early detection sys-tem (10).

24. The method for early detection of a wildfire using a wildfire early detection system (10) according to any one or more of claims 21 to 23, characterized in that the signal (ME) contains information about the wildfire detected.

25. The method for early detection of a wildfire using a wildfire early detection system (10) according to any one or more of claims 21 to 24, characterized in that the waiting for the receipt (e-r) of a response signal (MS) at the terminal (ED) takes place over a specified time interval (t,).

26. The method for early detection of a wildfire using a wildfire early detection system (10) according to claim 25, characterized in that the time interval (t,) is longer than the average duration between the first transmission (e-s1 ) of the signal (ME) and the receipt (e-r) of the response signal (MS).

27. The method for early detection of a wildfire using a wildfire early detection system (10) according to claim 26, characterized in that the time interval (t,) between receipt (e-r) of the signal (ME) and non-receipt of the response signal (MS) is greater than the duration between receipt of a signal received earlier and receipt of the response signal from the network sever (NS) associated with this signal received earlier by a factor of 2, preferably by a factor of 1 .5, and particularly preferably by a factor of 1 .25.

28. The method for early detection of a wildfire using a wildfire early detection system (10) according to any one or more of claims 21 to 27, characterized in thatthe second transmission (e-s2) is via the second communication interface (KS) of the terminal (ED), which is operable to communicate with a communication satellite (S).

29. The method for early detection of a wildfire using a wildfire early detection system (10) according to claim 28, characterized in that the second transmission (e-s2) of the signal (ME) is via the second communication interface (K2) of the terminal (ED) to a network server (NS) of the wildfire early detection system (10).

30. The method for early detection of a wildfire using a wildfire early detection system (10) according to any one or more of claims 21 to 29, characterized in that the response signal (MS) is an acknowledgment of receipt (MS) from the network server (NS).

31. The method for early detection of a wildfire using a wildfire early detection system (10) according to any one or more of claims 21 to 30, characterized in that the second transmission (e-s2) of the signal (ME) via the second communication interface (KS) of the terminal (ED) only takes place if the signal (ME) is an alarm signal or the energy storage device (ES) of the terminal (ED) has more energy than is needed for two consecutive transmissions (e-s2) by means of satellite communication (SAT).

32. The method for early detection of a wildfire using a wildfire early detection system(10) according to any one or more of claims 21 to 31 , characterized in that the second transmission (e-s2) of the signal (ME) only takes place via the second communication interface (KS) of the terminal (ED) if the signal (ME) was previously sent (e-s1 ) by the terminal (ED) via the first communication interface (K1 ).

33. The method for early detection of a wildfire using a wildfire early detection system(10) according to any one or more of claims 21 to 32, characterized in that the second transmission (e-s2) of the signal (ME) only takes place via the second communication interface (KS) of the terminal (ED) to the network server (NS) if an acknowledgment of receipt (MS) of the transmitted signal (ME) has not been received from the network server (NS) at the terminal (ED).

34. The method for early detection of a wildfire using a wildfire early detection system (10) according to claim 33, characterized in that the second transmission (e-s2) of the signal (ME) only takes place via the second communication interface (KS) to the network server (NS) if an acknowledgment of receipt (MS) of the transmitted signal (ME) has not been received previously by the network server (NS) via a communication interface (K1 ) different from the second communication interface (KS) at the device (ED).

35. The method for early detection of a wildfire using a wildfire early detection system (10) according to any one or more of claims 21 to 34, characterized in that upon detection (e-d) of a wildfire, a software program for selection of the communication interface (K1 , KS) is launched (e-e).

36. The method for early detection of a wildfire using a wildfire early detection system (10) according to claim 35, characterized in that the launching (e-e) of the software program for selection of the communication interface (K1 , KS) takes place immediately after the analysis of the signal at the terminal (ED).

37. An emergency communication terminal (ED) for a wildfire early detection system(10), comprising:• a sensor; wherein the sensor is operable to detect a wildfire,• an energy supply device (E);• a first communication interface (K1 );• a second communication interface (KS); wherein the first communication interface (K1 ) is different from the second communication interface (KS).

38. The emergency communication terminal (ED) for a wildfire early detection system(10) according to claim 37, characterized in that the first communication interface (K1 ) is operable to communicate with a gateway (G1 , G2) of the wildfire early detection system (10).

39. The emergency communication terminal (ED) for a wildfire early detection system(10) according to claim 37 or 38, characterized in that the second communication interface (KS) is operable to communicate with a communication device outside the wildfire early detection system (10).

40. The emergency communication terminal (ED) for a wildfire early detection system(10) according to claim 39, characterized in that the second communication interface (KS) is operable to communicate with a communication satellite (S).41 . The emergency communication terminal (ED) for a wildfire early detection system(10) according to any one or more of claims 37 to 40, characterized in thatthe emergency communication terminal (ED) has a controller which is operable to execute a software program which selects the communication interface (K1 , KS) to be utilized for communication.

42. The emergency communication terminal (ED) for a wildfire early detection system (10) according to any one or more of claims 37 to 41 , characterized in that the controller is operable to control the communication interfaces (K1 , KS) separately.

43. The emergency communication terminal (ED) for a wildfire early detection system(10) according to any one or more of claims 37 to 42, characterized in that the power supply device (E) has an energy storage device which is operable to store more energy, preferably to store more than 1.5 times as much energy and particularly preferably to store more than 2 times as much energy as is needed for communication via the second communication interface (KS).

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