METHOD FOR EARLY DETECTION OF FOREST FIRE AND FOREST FIRE EARLY DETECTION SYSTEM

Abstract

The invention relates to a method for early detection of a forest fire using an end device having a sensor unit, the sensor unit performing signal detection in a first signal detection mode and in a second signal detection mode, and to a forest fire early detection system for performing the method.

Claims

1. Method for early detection of a forest fire using an end device (ED) with a sensor unit (S), characterised in that the sensor unit (S) performs the signal acquisition in a first signal acquisition mode (SM1) and in a second signal acquisition mode (SM2).

2. Method for the early detection of a forest fire according to claim 1 characterised in that the signals acquired when performing the first signal acquisition (SM1) are analysed.

3. Method for the early detection of a forest fire according to claim 1 characterised in that performing a first signal acquisition in a first signal acquisition mode (SM1) of the sensor unit (S) is repeated in a time interval.

4. Method for the early detection of a forest fire according to claim 1, characterised in that the execution of a second signal acquisition in a second signal acquisition mode (SM2) of the sensor unit (S) is started event-controlled, whereas the event starting the second signal acquisition in a second signal acquisition mode (SM2) is based on the acquired signals of the first signal acquisition (SM1) and/or their analysis, whereas the event that starts the second signal acquisition in a second signal acquisition mode (SM2) is the exceeding of a threshold value (SW1) of the analysed data from the signals acquired in the first signal acquisition (SM1).

5. Method for the early detection of a forest fire according to claim 1, characterised in that the acquired second signals of the second signal acquisition (SM2) are evaluated.

6. Method for the early detection of a forest fire according to claim 1, characterised in that a message is sent from the end device (ED) to a first gateway (G1), whereas the notification signal is generated in the sensor unit (S) when the data analysed from the detected second signals (SM2) exceeds a second threshold value (SW2).

7. Method for the early detection of a forest fire according to claim 1, characterised in that the second signal acquisition mode (SM2) comprises a gas analysis.

8. Method for the early detection of a forest fire according to claim 1, characterised in that the first signal acquisition mode (SM1) is based on a different physical principle than the second signal acquisition mode (SM2).

9. Method for the early detection of a forest fire according to claim 8 characterised in that the first signal detection mode (SM1) is based on optical smoke detection.

10. Method for the early detection of a forest fire according to claim 8 characterised in that the first signal detection mode (SM1) is based on gas detection.

11. An early forest fire detection system (10) comprising an end device (ED), wherein the end device (ED) comprises a sensor unit (S), characterised in that the sensor unit (S) comprises a sensor operable in a first signal acquisition mode (SM1) and a second signal acquisition mode (SM2)

12. Forest fire early detection system (10) according to claim 11, characterised in that the first signal acquisition mode (SM1) is different from the second signal acquisition mode (SM2).

13. Forest fire early detection system (10) according to claim 11, characterised in that the end device (ED) comprises an evaluation unit (C) suitable and intended for evaluating the acquired signals and for controlling the signal acquisition.

14. An early forest fire detection system (10) according to claim 11, characterised in that the first signal acquisition mode (SM1) and the second signal acquisition mode (SM2) can be controlled separately, whereas the first signal acquisition mode (SM1) can be repeated periodically and/or the second signal acquisition mode (SM2) can be activated.

15. An early forest fire detection system (10) according to claim 11, characterised in that the sensor unit (S) has a first sensor element (S1), whereas the first sensor element (S1) is a gas sensor, whereas the measuring principle of the first sensor element (S1) is based on electrical signal detection or optical signal detection, whereas the sensor unit (S) has a second sensor element (S2).

16. An early forest fire detection system (10) according to claim 11, characterised in that the end device (ED) is intended for off-grid use and has a self-sufficient energy supply (E) whereas the stand-alone energy supply (E) has an energy conversion device (EK) and/or an energy storage device (ES).

17. An early forest fire detection system (10) according to claim 11, characterised in that the end device (ED) comprises a communication unit (K1) adapted to send and receive LPWAN messages.

Description

[0036] Showing:

[0037] FIG. 1: Basic principle of the procedure for early detection of a forest fire

[0038] FIG. 2: Further development of the method for early detection of a forest fire

[0039] FIG. 3: Further embodiment of the method for early detection of a forest fire

[0040] FIG. 4 a: End device with one sensor

[0041] FIG. 4 b: End device with a sensor and an energy conversion device

[0042] FIG. 4 c: End device with two sensors

[0043] FIG. 5: Forest fire early detection system network

[0044] FIG. 6: Detailed view of the forest fire early detection system network

[0045] FIG. 1 shows an example of the method according to the invention. In the first step of the method, a first acquisition and a second acquisition of signals are performed by a sensor unit S of a sensor ED in two different sensor modes SM1, SM2. In this embodiment example, the acquisition of signals in two different signal modes SM1, SM2 takes place simultaneously. Another possibility is the acquisition in complementary time periods. In a first time period, acquisition is performed in the first signal mode SM1, while acquisition is not performed in the second signal mode SM2, as well as vice versa. The acquisition in the sensor modes SM1, SM2 is performed continuously or in a time interval such that the acquisition is constantly repeated. This increases accuracy and reliability through redundancy of acquisition by using two independent sensor modes SM1, SM2 for acquisition. The signals acquired by the sensor unit S are analyzed in the microprocessor unit C of the end device ED. If a fire is detected based on the analysis A of the data, a message is generated and sent VM. The procedure is then restarted.

[0046] Another example of the method according to the invention is shown in FIG. 2. Here, the sensor modes SM1, SM2 are not operated in parallel, the sensor unit S initially operates in the first sensor mode SM1. The sensor unit S detects the scattered light of an infrared LED scattered by smoke by means of a photodiode and operates in the first sensor mode SM1 like a conventional smoke detector. The detection in the first sensor mode SM1 is continuous and is repeated in certain time intervals t. If a first event SW1 is detected by means of the first sensor mode SM1—i.e. smoke is detected or a threshold value is reached or exceeded—the evaluation unit C controls the sensor unit S in such a way that the sensor unit S detects signals in the second sensor mode SM2. For this purpose, the sensor unit S has two sensor elements S1, S2 whose measuring principle differs. While the first sensor element S1 is an optical smoke detector, the second sensor element S2 is a detector which detects gas by means of electrical and/or electrochemical methods, e.g. a semiconductor gas detector. Accuracy and reliability of detection are thus also increased. The signals detected by the sensor unit S are analysed in the microprocessor unit C of the end device ED A. If a fire is detected on the basis of the analysis of both the data detected in the first and second sensor modes SM1, SM2, a message is generated and sent VM.

[0047] FIG. 3 shows a further example of the method according to the invention. Here the sensor modes SM1, SM2 are also not operated in parallel, the sensor unit S initially operates in the first sensor mode SM1. The sensor unit S also continuously detects the scattered light of an infrared LED scattered by smoke by means of a photodiode and records sensor data in the first sensor mode SM1. If a first event SW1 is detected by means of the first sensor mode SM1—i.e. smoke is detected—the evaluation unit C controls the sensor unit S in such a way that the sensor unit S detects signals in the second sensor mode SM2. For this purpose, the sensor unit S has two sensor elements S1, S2 whose measuring principle differs.

[0048] The signals detected by the sensor unit S are analysed in the microprocessor unit C of the end device ED. If, based on the analysis of the data acquired in sensor mode SM2, a fire is detected, for example by exceeding a threshold value SW2—i.e. a second event is detected, a message is generated and sent. The sensor unit S then continues to record data in the second sensor mode SM2 until no event (fire) is detected. A message is also generated and sent as long as an event is detected. However, if no more fire is detected based on the analysis of the data acquired in sensor mode SM2, the sensor unit S acquires sensor data in the first sensor mode SM1.

[0049] Three variants of an end device ED for detecting a forest fire are shown in FIG. 4. The end device ED is a sensor for detecting a forest fire. In order to be able to install and operate the end device ED even in inhospitable and especially rural areas far away from energy supply, the sensor ED is equipped with a self-sufficient energy supply E. In the simplest case, the energy supply E is a battery, which can also be rechargeable (FIG. 4 a). However, it is also possible to use capacitors (FIG. 4 c), especially supercapacitors. The use of solar cells (FIG. 4 b) is somewhat more complex and cost-intensive, but offers a very long service life of the sensor ED. In addition to the energy conversion EK by the solar cell, a memory ES and power electronics are also arranged in the sensor ED. Furthermore, a sensor ED has the actual sensor unit S (FIG. 4 a, b), which detects a forest fire, e.g. by means of optical and/or electronic processes. The sensor unit S can also have two sensor elements S1, S2 (FIG. 4 c). In this case, the two sensor elements S1, S2 differ from each other with regard to the measuring principle: In this embodiment example, the first sensor element S1 is a gas sensor which registers the scattered light of an infrared LED by means of a photodiode. The second sensor element is a semiconductor gas detector.

[0050] The end device ED has a microprocessor unit C for analysing the data supplied by the sensor unit S and for generating a message. The sensor ED also has the communication port K1. By means of the communication port K1, messages from the end device ED, in particular measurement data, are sent as a data packet wirelessly via the antenna A by means of a single-hop connection FSK via LoRa (chirp frequency spread modulation) or frequency modulation to a gateway G1, FGD, MDG. All of the above-mentioned components are arranged in a housing for protection against the effects of weather.

[0051] An embodiment of a forest fire early detection system 10 according to the invention is shown in FIG. 5. The forest fire early detection system 10 has a mesh gateway network 1 that uses the technology of a LoRaWAN network 1. The LoRaWAN network 1 has a star-shaped architecture in which message packets are exchanged between the sensors ED and a central internet network server NS by means of gateways.

[0052] The forest fire early detection system 10 has a plurality of sensors ED connected to gateways G via a single-hop connection FSK. The gateways G1 are usually front-end gateways FGD. The front-end gateways FGD are connected to each other and partly to border gateways G2. A border gateway G2 can also be combined with a front-end gateway FGD to form a mesh gateway device MDG in one device. The border gateways G2 are connected to the internet network server NS, either via a wired connection WN or via a wireless connection using internet protocol IP.

[0053] The front-end gateways FGD and the border gateways G2 are connected to each other via a meshed multi-hop communication network MHF, so that a front-end gateway FGD does not require a direct connection to the Internet network server NS. This achieves a range extension of LoRaWAN networks by interconnecting a multi-hop network by means of front-end gateways FGD, thus achieving full compatibility with the LoRaWAN specification.

[0054] A detailed view of a forest fire early detection system 10 according to the invention is shown in FIG. 6. The forest fire early detection system 10 has a plurality of sensors ED, with eight sensors ED each being connected to a gateway G1 via a single-hop connection FSK. The gateways G1 are front-end gateways FGD. The front-end gateways FGD are connected to each other and to border gateways G2. The border gateways G2 are connected to the internet network server NS, either via a wired connection WN or via a wireless connection using internet protocol IP.

REFERENCE LIST

[0055] 1 Mesh gateway network [0056] 10 Forest fire early detection system [0057] ED, EDn1 End devices/sensors [0058] G1 Gateway [0059] G2 Border gateway [0060] NS Internet network server [0061] IP Internet Protocol [0062] FGD, FGDn Front-end gateways [0063] MHF Multi-hop communication network [0064] MDG, MDGn Mesh gateways [0065] FSK FSK modulation [0066] WN Wired connection [0067] W Forest [0068] S Sensor [0069] S1, S2 Sensor element [0070] E Energy supply [0071] ES Energy storage [0072] EK Energy conversion [0073] K1 Communication port [0074] C Microprocessor unit [0075] SM1 Sensor mode 1 [0076] SM2 Sensor mode 2 [0077] VM Dispatch message [0078] A Antenna [0079] SW1 First threshold value [0080] SW2 Second. threshold value