Disaster monitoring devices

Abstract

To continue disaster monitoring.SOLUTION: A water immersion monitoring device comprises a plurality of transmitters and a water immersion detection device. The water immersion detection device comprises a receiver and a server. The transmitter comprises a battery and a transmission circuit. The transmission circuit transmits information indicating whether or not a disaster occurs and a radio signal containing identification information. A reception device comprises a receiver control device. In the case where a time when the radio signal cannot be received exceeds a threshold value, the receiver control device determines that a remaining amount of the battery of the transmitter transmitting the radio signal which cannot be received is exhausted. The plurality of transmitters comprise: a first transmitter that transmits the radio signal at a first transmission interval; and a second transmitter that transmits the radio signal at a second transmission interval longer than the first transmission interval.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a disaster monitoring device.

Background Art

[0002] A disaster monitoring device monitors the occurrence of a disaster based on the detection results of sensors. The disaster monitoring device disclosed in Patent Document 1 monitors the water level. The disaster monitoring device disclosed in Patent Document 1 includes a plurality of water pressure sensor devices, a repeater, and a server. The water pressure sensor device includes a water pressure sensor, a battery, and a wireless communication unit. The wireless communication unit wirelessly transmits the water pressure measured by the water pressure sensor and the identification information to the repeater. The battery supplies power to the water pressure sensor device. The repeater calculates the water level for each water pressure sensor device based on the water pressure measured by the water pressure sensor and the atmospheric pressure. The repeater transmits the calculated water level to the server.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the remaining amount of the battery of the water pressure sensor device runs out, the measurement of the water pressure by the water pressure sensor device stops. As a result, it becomes impossible to monitor the water level at the position where the water pressure sensor device with the depleted battery is provided. In particular, when a plurality of water pressure sensor devices with depleted batteries occur, it becomes impossible to monitor the water level in the range where the plurality of water pressure sensor devices are provided.

Means for Solving the Problems

[0005] A disaster monitoring device that solves the above problems comprises a plurality of transmitters and a determination device, each of the plurality of transmitters comprising a battery, a sensor for determining whether or not a disaster has occurred, and a transmission circuit for transmitting a wireless signal including information indicating whether or not a disaster has occurred and identification information set individually for each of the plurality of transmitters, the determination device comprising a receiving circuit for receiving the wireless signal and a control device for the determination device, the control device for the determination device recognizes whether or not a disaster has occurred at the location of the transmitters based on the information indicating whether or not a disaster has occurred, and if there is a transmitter for which the time for which the wireless signal cannot be received exceeds a threshold, it determines that the battery of that transmitter has run out, and the plurality of transmitters comprises a first transmitter that transmits the wireless signal at a first transmission interval and a second transmitter that transmits the wireless signal at a second transmission interval that is longer than the first transmission interval.

[0006] The second transmitter transmits radio signals at a longer transmission interval than the first transmitter. Therefore, the second transmitter's battery lasts longer than the first transmitter's battery. If the first transmitter's battery runs out, the second transmitter can continue monitoring the disaster until the first transmitter's battery is replaced. While the first transmitter's battery is still functional, it can maintain real-time disaster monitoring; if the first transmitter's battery runs out, the second transmitter can continue disaster monitoring.

[0007] With respect to the disaster monitoring device described above, the number of second transmitters may be less than the number of first transmitters. Regarding the disaster monitoring device described above, the determination device may include a command transmission circuit that, when the control device for the determination device determines that the battery charge of the first transmitter has run out, transmits a command to the second transmitter to shorten the transmission interval of the wireless signal.

[0008] Regarding the disaster monitoring device described above, the determination device may include a command transmission circuit that, when the control device for the determination device recognizes that the disaster has occurred at the first location based on the wireless signal transmitted from the transmitter located at the first location, transmits a command to the second transmitter located at the second location, which is linked to the first location, to shorten the transmission interval of the wireless signal. [Effects of the Invention]

[0009] According to the present invention, disaster monitoring can be continued. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram showing an example of a flood monitoring device. [Figure 2] This is a schematic diagram of the flood monitoring system. [Figure 3] This is a time chart showing the first transmission interval and the second transmission interval. [Figure 4] This flowchart shows the flood monitoring and control performed by the flood detection device. [Figure 5] This flowchart shows the battery level determination control performed by the receiver control device. [Figure 6] This flowchart shows an example of a change to the battery level determination control. [Modes for carrying out the invention]

[0011] The following describes one embodiment of a disaster monitoring device. As shown in Figure 1, the flood monitoring device 10 comprises a plurality of transmitters 11 and a flood detection device 30. The flood detection device 30 comprises a receiver 21 and a server 31. The flood monitoring device 10 monitors flooding as a disaster. The flood monitoring device 10 is an example of a disaster monitoring device.

[0012] <Transmitter> The transmitter 11 may be a dedicated device used only for the flood monitoring device 10, or it may be a device that can also be used as an air pressure sensor for measuring tire pressure.

[0013] The transmitter 11 is positioned at a predetermined location. This predetermined location is a location where flooding may occur. The transmitter 11 is installed, for example, near a waterway or near a river. The transmitter 11 is attached to a structure. The structure includes a wall ST1, a pile ST2, a utility pole ST3, and a building ST4. In the example shown in Figure 1, two transmitters 11 are attached to the wall ST1. One transmitter 11 is attached to each of the pile ST2, the utility pole ST3, and the building ST4. Two placement positions P1 and P2 are set on the wall ST1. One placement position P3 is set on the pile ST2. One placement position P4 is set on the utility pole ST3. One placement position P5 is set on the building ST4. The two placement positions P1 and P2 are the same in the horizontal direction but differ in the height direction. Placement position P1 will be referred to as the first placement position P1, and placement position P2 as the second placement position P2, as appropriate. The first placement position P1 is lower than the second placement position P2.

[0014] The multiple transmitters 11 include a first transmitter 11A and a second transmitter 11B. Transmitters 11 located at positions P1, P3, P4, and P5 are the first transmitters 11A. Transmitters 11 located at the second position P2 are the second transmitters 11B. The number of second transmitters 11B is less than the number of first transmitters 11A. The hardware configuration of the first transmitters 11A and the hardware configuration of the second transmitters 11B are identical to each other.

[0015] As shown in Figure 2, the transmitter 11 is equipped with a pressure sensor 12. The pressure sensor 12 is equipped with a pressure receiving section 12a. The pressure sensor 12 measures the pressure applied to the pressure receiving section 12a. The pressure receiving section 12a is provided to be exposed to the outside air. The pressure sensor 12 is a sensor for determining whether or not a disaster has occurred.

[0016] The transmitter 11 includes a control device 13 for the transmitter. The control device 13 for the transmitter includes, for example, a processor 14 and a storage unit 15. Examples of the processor 14 include an MPU (Micro Processing Unit), a CPU (Central Processing Unit), and a DSP (Digital Signal Processor). The storage unit 15 includes a RAM (Random Access Memory) and a ROM (Read Only Memory). The storage unit 15 stores program codes or instructions configured to cause the processor 14 to execute processing. The storage unit 15, that is, the computer-readable medium, includes any available medium accessible by a general-purpose or dedicated computer. The control device 13 for the transmitter may be constituted by a hardware circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The control device 13 for the transmitter, which is a processing circuit, may include one or more processors operating according to a computer program, one or more hardware circuits such as an ASIC or an FPGA, or a combination thereof. The storage unit 15 stores identification information. The identification information is individually set for each of the plurality of transmitters 11.

[0017] The transmitter 11 includes a transmission circuit 16. The transmission circuit 16 performs modulation according to the frame input from the control device 13 for the transmitter. The frame is constituted by data in a format defined by a protocol. The frame includes pressure data and identification information. The pressure data is the measurement result of the pressure sensor 12. The identification information is information for identifying each of the plurality of transmitters 11. The identification information is, for example, an ID code set for each transmitter 11.

[0018] The transmitter 11 includes a transmission antenna 17. The transmission circuit 16 transmits the modulated radio signal from the transmission antenna 17. This radio signal is a signal including information indicating pressure data and information indicating identification information.

[0019] The transmitter 11 includes a receiving antenna 18. The receiving antenna 18 receives a radio signal transmitted from the receiver 21. The radio signal transmitted from the receiver 21 includes a command for the transmitter 11.

[0020] The transmitter 11 includes a receiving circuit 19. The receiving circuit 19 demodulates the radio signal transmitted from the receiver 21 to obtain a command. The receiving circuit 19 outputs the command to the transmitter control device 13. The transmitter control device 13 operates the transmitter 11 according to the command.

[0021] The transmitter 11 includes a battery 20. The battery 20 serves as a power source for the transmitter 11 by supplying power to the transmitter 11. The battery 20 is, for example, a primary battery or a secondary battery.

[0022] As shown in FIG. 3, the transmitter 11 transmits a radio signal periodically. The first transmitter 11A and the second transmitter 11B have different transmission intervals of the radio signal. In the first transmitter 11A, a radio signal is transmitted at a first transmission interval T1. Specifically, in the first transmitter 11A, an acquisition process is performed in which the transmitter control device 13 acquires the measurement result of the pressure from the pressure sensor 12 every first transmission interval T1. In the acquisition process, pressure data is acquired from the pressure sensor 12 a plurality of times. The number of times the pressure data is acquired in the acquisition process can be arbitrarily set, for example, within a range of 6 to 10 times. The transmitter control device 13 transmits a radio signal including pressure data indicating the measurement result of the pressure and identification information. The first transmission interval T1 can be arbitrarily set. The first transmission interval T1 can be arbitrarily set, for example, within a range of one minute to two minutes.

[0023] In the second transmitter 11B, a radio signal is transmitted at a second transmission interval T2. More specifically, in the second transmitter 11B, the transmitter control device 13 performs an acquisition process to acquire the pressure measurement result from the pressure sensor 12 at each second transmission interval T2. This acquisition process is the same as the acquisition process performed in the first transmitter 11A. The transmitter control device 13 transmits a radio signal containing pressure data indicating the pressure measurement result and identification information. The second transmission interval T2 is longer than the first transmission interval T1. The transmission frequency of the radio signal of the second transmitter 11B is lower than the transmission frequency of the radio signal of the first transmitter 11A. The second transmission interval T2 can be set arbitrarily. For example, the second transmission interval T2 can be set arbitrarily within a range of three minutes to several tens of minutes.

[0024] The transmission interval of transmitter 11 varies depending on the software stored in the memory unit 15. Therefore, whether transmitter 11 functions as the first transmitter 11A or the second transmitter 11B depends on the software stored in the memory unit 15. For example, the function of transmitter 11 as the first transmitter 11A or the second transmitter 11B may be selected by writing the software to the memory unit 15 during the manufacturing of transmitter 11. Alternatively, the software may be written to the memory unit 15 using an external tool after transmitter 11 has been placed at positions P1 to P5. In this case, the software itself may be written by the external tool. Software for transmitting transmitter 11 as the first transmitter 11A and software for transmitting transmitter 11 as the second transmitter 11B may be stored in the memory unit 15 in advance, and selection information for which software to execute may be written using an external tool. When writing is performed using an external tool, transmitter 11 is equipped with a receiving circuit that receives a wireless signal from the external tool. Furthermore, writing using an external tool may be performed by connecting the external tool and the transmitter 11 via a wired connection.

[0025] <Receiver> As shown in Figure 1, the receiver 21 is mounted on a structure. The receiver 21 is positioned to receive radio signals from the transmitters 11. The receiver 21 is capable of receiving radio signals transmitted from multiple transmitters 11. The number of receivers 21 is less than the number of transmitters 11. The receiver 21 is an example of a determination device.

[0026] As shown in Figure 2, the receiver 21 includes a receiver control device 22. The hardware configuration of the receiver control device 22 is, for example, the same as that of the transmitter control device 13. The receiver control device 22 includes, for example, a processor 23 and a storage unit 24. The receiver control device 22 is an example of a control device for a determination device.

[0027] The receiver 21 includes a receiving circuit 25. The receiving circuit 25 demodulates the radio signal transmitted from the transmitter 11 to obtain the data contained in the frame. The receiving circuit 25 outputs the data to the receiver control device 22. As a result, the receiver control device 22 obtains pressure data, which is the measurement result of the pressure sensor 12, and identification information of the transmitter 11 that transmitted the radio signal.

[0028] The receiver 21 is equipped with a receiving antenna 26. The receiving antenna 26 receives the radio signal transmitted from the transmitter 11. The radio signal received by the receiving antenna 26 is input to the receiving circuit 25. The receiving circuit 25 receives the radio signal via the receiving antenna 26.

[0029] The receiver 21 includes a communication device 27. The communication device 27 is a network device equipped with a communication control unit, ports, etc., and capable of sending and receiving information via a communication network NW. The communication device 27 is connected to the server 31 via the communication network NW.

[0030] The receiver 21 includes a transmission circuit 28. The transmission circuit 28 modulates according to the frame input from the receiver control device 22. The frame consists of data in a format specified by the protocol. The frame includes a command to the transmitter 11 and identification information of the destination transmitter 11. The transmission circuit 28 is an example of a command transmission circuit.

[0031] The receiver 21 is equipped with a transmitting antenna 29. The transmitting circuit 28 transmits a modulated radio signal from the transmitting antenna 29. This radio signal is a signal that includes a command. <server> Server 31 includes a server control device 32. The hardware configuration of the server control device 32 is, for example, the same as that of the transmitter control device 13. The server control device 32 includes, for example, a processor 33 and a storage unit 34.

[0032] The memory unit 34 stores a correspondence between the identification information of the transmitter 11 and the location of the transmitter 11. The location of the transmitter 11 is expressed as a position in an absolute coordinate system. For example, the location of the transmitter 11 is expressed as latitude and longitude.

[0033] The server 31 is equipped with a communication device 35. The communication device 35 is similar to, for example, the communication device 27. The communication device 35 is connected to the receiver 21 via a communication network NW. This allows the server 31 and the receiver 21 to send and receive information from each other.

[0034] The server 31 can provide information to the user terminal 40. For example, the server 31 provides information to the user terminal 40 via a communication network NW. The user terminal 40 is, for example, a smartphone, a tablet device, or a personal computer.

[0035] <Flood monitoring and control performed by flood detection devices> The flood monitoring and control performed by the flood detection device 30 will now be described. The flood monitoring and control is performed repeatedly at a predetermined control cycle.

[0036] As shown in Figure 4, in step S1, the receiver control device 22 acquires pressure data. More specifically, when the receiving antenna 26 receives a radio signal from the transmitter 11, the receiver control device 22 acquires pressure data when the radio signal is demodulated in the receiving circuit 25. In step S1, the receiver control device 22 acquires pressure data that has been acquired multiple times through the acquisition process. The receiver control device 22 acquires pressure data each time the receiver 21 receives a radio signal from one of the multiple transmitters 11 from which it can receive radio signals.

[0037] Next, in step S2, the receiver control device 22 determines whether the pressure fluctuation is greater than or equal to a predetermined value from the pressure indicated by the pressure data acquired multiple times in step S1. In other words, the receiver control device 22 determines whether there has been a fluctuation of greater than or equal to a predetermined value in the pressure measured by the pressure sensor 12 during the acquisition process. Whether the pressure fluctuation is greater than or equal to a predetermined value can be determined by various methods. The receiver control device 22 may determine that the pressure fluctuation is greater than or equal to a predetermined value if the difference between the highest pressure value and the lowest pressure value is greater than or equal to a predetermined value. The receiver control device 22 may calculate the standard deviation of the pressure and determine that the pressure fluctuation is greater than or equal to a predetermined value if the standard deviation is greater than or equal to a predetermined value. The receiver control device 22 may calculate the difference between each of the multiple measured pressures and the previous value and determine that the pressure fluctuation is greater than or equal to a predetermined value if the difference from the previous value is greater than or equal to a predetermined value. As a predetermined value, for example, it is set so that the determination result in step S2 does not become affirmative due to pressure fluctuations caused by fluctuations in atmospheric pressure. The processing in step S2 is performed individually for each piece of identification information. As a result, the receiver control device 22 determines for each transmitter 11 whether the pressure fluctuation is above a predetermined value. If the determination result in step S2 is positive, the receiver control device 22 performs the process in step S3. If the determination result in step S2 is negative, the receiver control device 22 performs the process in step S4.

[0038] In step S3, the receiver control device 22 recognizes that the location of the transmitter 11 equipped with the pressure sensor 12, where the pressure has fluctuated above a predetermined value, is submerged in water. After completing the process in step S3, the receiver control device 22 proceeds with the process in step S5.

[0039] In step S4, the receiver control device 22 recognizes that the locations where the transmitter 11 is equipped with a pressure sensor 12 whose pressure does not fluctuate above a predetermined value are not flooded. In this way, the receiver control device 22 uses pressure data to determine whether or not flooding has occurred, and recognizes from this determination whether or not flooding has occurred at locations P1 to P5. Pressure data is an example of information that indicates whether or not a disaster has occurred. After completing the processing in step S4, the receiver control device 22 proceeds to the processing in step S5.

[0040] In step S5, the receiver control device 22 transmits data to the server 31 that associates the determination result of whether or not the device is submerged in water with the identification information. Next, in step S6, the server control device 32 provides the user terminal 40 with information indicating the location where the receiver control device 22 has determined to be submerged. From the determination result transmitted in step S5, the server control device 32 can recognize the identification information of the transmitter 11 located at the submerged location. The server control device 32 recognizes the submerged location using the correspondence stored in the storage unit 34. At this time, the server control device 32 may determine that a predetermined range based on the submerged location P1 to P5 is submerged.

[0041] The server control device 32 provides the user terminal 40 with information indicating the location of the flooded area via a web browser and / or an application. The information indicating the location of the flooded area may be provided as text or as an image. If the information indicating the location of the flooded area is provided as text, the place name of the flooded area may be displayed on the user terminal 40. If the information indicating the location of the flooded area is provided as an image, an image depicting the flooded area on a map may be displayed on the user terminal 40.

[0042] <Battery level detection control> The battery level determination control performed by the receiver control device 22 will now be described. The battery level determination control is a control that determines whether or not the battery 20 of the transmitter 11 has run out of charge. The battery level determination control is performed repeatedly at a predetermined control cycle.

[0043] As shown in Figure 5, in step S11, the receiver control device 22 determines whether or not there is a transmitter 11 whose duration of inability to receive a wireless signal exceeds a threshold. The receiver control device 22 can determine from the identification information obtained by demodulating the radio signal which of the five transmitters 11 has failed to receive a radio signal for a period exceeding a threshold. The receiver control device 22 measures the elapsed time since the last reception of a radio signal for each piece of identification information. If the elapsed time exceeds the threshold, it can determine that the time during which the radio signal from the transmitter 11 of the identification information that exceeded the threshold has not been received has exceeded the threshold. The threshold is set to a value that allows the receiver to determine whether or not the transmitter 11 is transmitting a radio signal. Even if the transmitter 11 is transmitting a radio signal, the receiver 21 may not be able to receive the radio signal due to the communication environment. For this reason, it is preferable that the threshold be the time during which the transmitter 11 can transmit a radio signal multiple times. The threshold may be the same value for the first transmitter 11A and the second transmitter 11B. If the threshold is the same value for the first transmitter 11A and the second transmitter 11B, the threshold is set to a time that is at least longer than the second transmission interval T2. The threshold values ​​may differ for the first transmitter 11A and the second transmitter 11B. In this case, the threshold for the first transmitter 11A is set to a time that is at least longer than the first transmission interval T1. The threshold for the second transmitter 11B is set to a time that is at least longer than the second transmission interval T2.

[0044] If the transmitter 11 is not transmitting a wireless signal, it is assumed that the battery 20 has run out of power. Therefore, if there is a transmitter 11 for which the time during which a wireless signal cannot be received exceeds a threshold, the receiver control device 22 determines that the battery 20 of that transmitter 11 has run out of power.

[0045] If the result of step S11 is negative, the receiver control device 22 terminates the battery level determination control. If the result of step S11 is positive, the receiver control device 22 performs the process in step S12.

[0046] In step S12, the receiver control device 22 notifies the server 31 that the battery 20 has run out, along with identification information. This allows the server 31 to recognize which of the multiple transmitters 11 has run out of battery 20. The server 31 then notifies the administrator that the battery 20 has run out. This notification can be made by any method. For example, the server 31 may display a message indicating that the battery 20 has run out on its display unit, or it may send a command to a mobile terminal held by the administrator to display the message on the mobile terminal. In this case, the server 31 will notify the administrator which of the multiple transmitters 11 has run out of battery 20. For example, the coordinates of the transmitter 11 whose battery 20 has run out may be displayed, or the location of the transmitter 11 whose battery 20 has run out may be displayed on a map.

[0047] Next, in step S13, the receiver control device 22 determines whether the battery 20 has run out in the first transmitter 11A or not. For example, the receiver control device 22 determines whether the transmitter 11 whose battery 20 has run out is the first transmitter 11A or not based on correspondence data that associates the identification information with either the first transmitter 11A or the second transmitter 11B. Alternatively, the identification information for the first transmitter 11A and the second transmitter 11B may be different to determine whether the transmitter 11 whose battery 20 has run out is the first transmitter 11A or not. For example, a specific bit in the bits representing the identification information may be set to "1" if it is the first transmitter 11A and to "0" if it is the second transmitter 11B.

[0048] If the result of step S13 is negative, the receiver control device 22 terminates the battery level determination control. If the result of step S13 is positive, the receiver control device 22 performs the process in step S14.

[0049] In step S14, the receiver control device 22 sends a command from the transmission circuit 28 to the second transmitter 11B to shorten the second transmission interval T2. As a result, the transmission interval of the radio signal of the second transmitter 11B becomes shorter than the second transmission interval T2. When the second transmitter 11B receives the command, it may set the second transmission interval T2 to the first transmission interval T1, or it may set the second transmission interval T2 to be longer than the first transmission interval T1 and shorter than the second transmission interval T2.

[0050] [Effect of the Embodiment] As shown in Figure 1, when the placement locations P1 to P5 of the transmitter 11 are submerged in water, pressure from the water F is applied to the pressure receiving part 12a of the pressure sensor 12. Due to the pressure from the water F applied to the pressure receiving part 12a of the pressure sensor 12, the pressure sensor 12 acquires pressure data multiple times, and the pressure fluctuation exceeds a predetermined value. The receiver control device 22 determines that the placement locations P1 to P5 of the transmitter 11 are submerged in water when the pressure fluctuation measured by the pressure sensor 12 exceeds a predetermined value.

[0051] If the battery 20 of the transmitter 11 is depleted, the transmitter 11 will not function. Therefore, if water ingress occurs and the battery 20 of the transmitter 11 is depleted, the receiver control device 22 will not be able to recognize the occurrence of water ingress. In particular, if there are multiple transmitters 11 with depleted batteries 20, the receiver control device 22 will not be able to recognize the occurrence of water in the area where the multiple transmitters 11 are located. Since the hardware configuration of the transmitters 11 is the same, the full capacity of the battery 20 is the same for all transmitters 11. If all transmitters 11 transmit radio signals at the same transmission interval, the battery 20 of all transmitters 11 may be depleted in a short period of time.

[0052] In contrast, the second transmitter 11B transmits radio signals at a second transmission interval T2 that is longer than the first transmission interval T1, so the battery 20 of the second transmitter 11B is less likely to run out of charge than the battery 20 of the first transmitter 11A. If the battery 20 of the first transmitter 11A runs out of charge, the second transmitter 11B can monitor for water ingress until the battery 20 of the first transmitter 11A is replaced. This prevents all the batteries 20 of the transmitters 11 from running out of charge in a short period of time.

[0053] [Effects of the Embodiment] (1) The second transmission interval T2 is longer than the first transmission interval T1. As long as the battery 20 of the first transmitter 11A is not depleted, the first transmitter 11A can ensure real-time monitoring of flooding, and when the battery 20 of the first transmitter 11A is depleted, the second transmitter 11B can continue monitoring of flooding.

[0054] (2) The number of second transmitters 11B is less than the number of first transmitters 11A. Reducing the number of first transmitters 11A among the multiple transmitters 11 reduces the real-time capability of flood monitoring. Reducing the number of second transmitters 11B to less than the number of first transmitters 11A can suppress the reduction in the real-time capability of flood monitoring.

[0055] (3) The receiver 21 is equipped with a transmission circuit 28. When the receiver control device 22 determines that the battery 20 of the first transmitter 11A is depleted, it sends a command to the second transmitter 11B to shorten the second transmission interval T2. When the battery 20 of the first transmitter 11A is depleted, the real-time performance of flood monitoring decreases. By sending a command to the second transmitter 11B to shorten the second transmission interval T2, the decrease in real-time performance of flood monitoring caused by the depletion of the battery 20 of the first transmitter 11A can be compensated for.

[0056] [Example of changes] The embodiment can be implemented with the following modifications. The embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0057] As shown in Figure 6, the process in step S13 may be replaced with the process in step S23. The process in step S14 may be replaced with the process in step S24. In step S23, the receiver control device 22 determines whether or not flooding has occurred at the first placement location P1. The receiver control device 22 associates the identification information of the transmitter 11 placed at the first placement location P1 with the first placement location P1, and associates the identification information of the transmitter 11 placed at the second placement location P2 with the second placement location P2, and determines whether or not flooding has occurred at the first placement location P1 based on this data. The receiver control device 22 determines that flooding has occurred at the first placement location P1 if the identification information of the transmitter 11 whose battery 20 has run out matches the identification information of the transmitter 11 placed at the first placement location P1. If the determination result in step S23 is negative, the receiver control device 22 terminates the battery level determination control. If the determination result in step S23 is positive, the receiver control device 22 performs the processing in step S24.

[0058] In step S24, the receiver control device 22 sends a command from the transmission circuit 28 to the second transmitter 11B located at the second position P2 to shorten the second transmission interval T2. That is, the first position P1 and the second position P2 are linked so that if the receiver control device 22 recognizes that flooding has occurred at the first position P1 due to a radio signal transmitted from the transmitter 11 located at the first position P1, the second transmission interval T2 of the second transmitter 11B located at the second position P2 will be shortened. As a result, the transmission interval of the radio signal from the second transmitter 11B located at the second position P2 becomes shorter than the second transmission interval T2. When the second transmitter 11B receives the command, it may set the second transmission interval T2 to the first transmission interval T1, or it may set the second transmission interval T2 to be longer than the first transmission interval T1 and shorter than the second transmission interval T2.

[0059] If flooding occurs at the first placement location P1, it may be desirable to quickly detect that flooding has also occurred at the second placement location P2. For example, if two placement locations P1 and P2 are set up so that their horizontal positions are the same but their vertical positions are different, as in the embodiment, the water level can be predicted based on whether or not the second placement location P2 is flooded. Furthermore, the rate at which the water level rises can be predicted from the time between the flooding of the first placement location P1 and the flooding of the second placement location P2. If flooding occurs at the first placement location P1, the flooding of the second placement location P2 can be detected quickly by shortening the transmission interval of the second transmitter 11B located at the second placement location P2.

[0060] The first and second placement locations are not limited to just two locations; they just need to be linked in such a way that if flooding occurs at the first placement location, the transmission interval of the second transmitter 11B located at the second placement location is shortened. Let's take three placement locations P1, P2, and P3 as an example. Assume that the first transmitter 11A is located at placement location P1, the second transmitter 11B is located at placement location P2, and the second transmitter 11B is located at placement location P3. In this case, if flooding occurs at placement location P1, the receiver control device 22 may send a command to shorten the second transmission interval T2 of the second transmitter 11B located at placement location P2. Furthermore, if flooding occurs at placement location P2, the receiver control device 22 may send a command to shorten the second transmission interval T2 of the second transmitter 11B located at placement location P3. In this case, the correspondence between placement location P1 and placement location P2 is such that placement location P1 is the first placement location and placement location P2 is the second placement location. The correspondence between placement position P2 and placement position P3 is such that placement position P2 is the first placement position and placement position P3 is the second placement position. Preferably, the first placement position is a location where flooding is expected to occur before the second placement position.

[0061] There may be multiple first placement locations. In the example described above, if flooding occurs at either of the two placement locations P1 or P3, the receiver control device 22 may send a command to shorten the second transmission interval T2 of the second transmitter 11B located at placement location P2. In this case, placement locations P1 and P3 are the first placement locations, and placement location P2 is the second placement location.

[0062] There may be multiple second placement locations. In the example described above, if flooding occurs at placement location P1, the receiver control device 22 may send a command to shorten the second transmission interval T2 of the second transmitters 11B located at placement locations P2 and P3. In this case, placement location P1 is the first placement location, and placement locations P2 and P3 are the second placement locations.

[0063] A second transmitter 11B may be placed in the first placement position. In step S13, the receiver control device 22 may determine whether the battery 20 has run out for a specific first transmitter 11A among the first transmitters 11A. For example, the receiver control device 22 may determine whether the battery 20 of the first transmitter 11A located at the first placement position P1 has run out. The receiver control device 22 may then determine the result of step S13 to be positive if the battery 20 of the first transmitter 11A located at the first placement position P1 has run out, and negative if the battery 20 of the first transmitter 11A located at the first placement position P1 has not run out.

[0064] In step S13, the receiver control device 22 may determine whether the number of first transmitters 11A whose batteries 20 have run out is equal to or greater than a predetermined number. The predetermined number is an integer of 2 or more. If the number of first transmitters 11A whose batteries 20 have run out is equal to or greater than the predetermined number, the receiver control device 22 may affirm the result of the determination in step S13. If the number of first transmitters 11A whose batteries 20 have run out is less than the predetermined number, the receiver control device 22 may deny the result of the determination in step S13.

[0065] The determination of whether or not the placement locations P1 to P5 are submerged may be performed by the server control device 32. In this case, the receiver control device 22 may transmit data to the server 31 that associates identification information with the pressure data acquired from the transmitter 11. Alternatively, if the transmitter 11 is equipped with a communication device that can transmit data to the server 31 via a communication network NW, the transmitter 11 may transmit data to the server 31 that associates identification information with the pressure data. In this case, the communication device equipped in the transmitter 11 is the transmission circuit. The server 31 is the determination device. The server control device 32 is the control device for the determination device. The communication device 35 equipped in the server 31 is the receiving circuit and the command transmission circuit. If the transmitter 11 is equipped with a communication device, the submersion monitoring device 10 does not need to be equipped with a receiver 21.

[0066] The receiver control device 22 may provide the user terminal 40 with information indicating the location of the flooding. The receiver 21 may be equipped with a display unit. In this case, the receiver control device 22 may display the location of the flooding on the display unit when flooding occurs. In this case, the flood monitoring device 10 does not need to be equipped with a server 31.

[0067] The information indicating whether or not a disaster has occurred may also be the result of a determination of whether or not a disaster has occurred. In this case, the transmitter control device 13 may determine whether or not a disaster has occurred.

[0068] The disaster monitoring device may also be a device that monitors rockfalls and landslides as disasters. In this case, the transmitter 11 is equipped with an acceleration sensor as a sensor in place of, or in addition to, the pressure sensor 12. The acceleration sensor detects acceleration acting in a direction along the detection axis. The transmitter control device 13 transmits a wireless signal that includes acceleration data in place of, or in addition to, the pressure data. The acceleration data indicates the detection result of the acceleration sensor. The acceleration data is information indicating whether or not a disaster has occurred.

[0069] In areas where there is a risk of rockfalls or landslides, fences are installed as a countermeasure against rockfalls and landslides. The transmitter 11 is installed on the fence. When rocks from a rockfall or soil from a landslide hit the fence, the fence tilts. As the fence tilts, the detection axis also tilts, so the acceleration detected by the acceleration sensor is different before and after the fence tilts. The receiver control device 22 can detect that a rockfall or landslide has occurred from the change in acceleration detected by the acceleration sensor.

[0070] In the first transmitter 11A, the acquisition process may be performed at intervals shorter than the first transmission interval T1. In the second transmitter 11B, the acquisition process may be performed at intervals shorter than the second transmission interval T2.

[0071] The flood monitoring device 10 may be equipped with multiple second transmitters 11B. In this case, the second transmission interval T2 of the radio signal may be the same for all of the multiple second transmitters 11B. The second transmission interval T2 of the radio signal may be different for all of the multiple second transmitters 11B. That is, the second transmission interval T2 only needs to be longer than the first transmission interval T1, and when multiple second transmitters 11B are provided, the second transmission interval T2 may be the same for all of them or may be different for all of them.

[0072] The number of first transmitters 11A and the number of second transmitters 11B may be the same. The number of first transmitters 11A may be less than the number of second transmitters 11B. The full capacity of the battery 20 may differ between the first transmitter 11A and the second transmitter 11B. [Explanation of Symbols]

[0073] P1...First placement position, P2...Second placement position, 10...Flood monitoring device which is a disaster monitoring device, 11...Transmitter, 11A...First transmitter, 11B...Second transmitter, 12...Pressure sensor which is a sensor, 16...Transmission circuit, 20...Battery, 21...Receiver, 22...Control device for receiver which is a control device for judgment device, 25...Receiving circuit, 28...Transmission circuit which is a command transmission circuit.

Claims

1. Multiple transmitters, A determination device is provided, Each of the aforementioned plurality of transmitters is Battery and A sensor to determine whether or not a disaster has occurred, The system includes a transmitting circuit that transmits a wireless signal containing information indicating whether or not the aforementioned disaster has occurred, and identification information individually set for each of the multiple transmitters, The determination device is A receiving circuit that receives the aforementioned wireless signal, The device comprises a control device for a determination device, The control device for the determination device is Based on information indicating whether or not the aforementioned disaster has occurred, the system recognizes whether or not the aforementioned disaster has occurred at the location where the transmitter is positioned. If there is a transmitter for which the time during which it is unable to receive the aforementioned wireless signal exceeds a threshold, it is determined that the battery of that transmitter has run out of power. The aforementioned multiple transmitters are, A first transmitter that transmits the wireless signal at a first transmission interval, A disaster monitoring device comprising: a second transmitter that transmits the wireless signal at a second transmission interval longer than the first transmission interval.

2. The disaster monitoring device according to claim 1, wherein the number of second transmitters is less than the number of first transmitters.

3. The disaster monitoring device according to claim 1 or 2, wherein the determination device includes a command transmission circuit that transmits a command to the second transmitter to shorten the transmission interval of the wireless signal when the control device for the determination device determines that the battery charge of the first transmitter has run out.

4. The disaster monitoring device according to claim 1 or 2, wherein the determination device includes a command transmission circuit that, when the control device for the determination device recognizes that the disaster has occurred at the first location based on the radio signal transmitted from the transmitter located at the first location, transmits a command to the second transmitter located at the second location, which is associated with the first location, to shorten the transmission interval of the radio signal.

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