JP7020652B2 - Abnormal water level notification system - Google Patents

Description

The present invention relates to an abnormal water level notification system that notifies the occurrence of an abnormal water level caused by heavy rain and urges residents to evacuate.

In recent years, the occurrence of abnormal heavy rains such as torrential rains and guerrilla rainstorms has increased, and the damage caused by floods and debris flows tends to increase. In the event of an abnormal heavy rain, the Japan Meteorological Agency, the Ministry of Land, Infrastructure, Transport and Tourism, and related organizations of prefectures will evacuate residents in areas at risk of flooding based on the results of observing the river water level and flow rate at predetermined points. Recommendations and evacuation orders have been issued to reduce human damage. As described above, as a technique related to a system for issuing an alarm about the danger of flood to the inhabitants, those of Patent Documents 1 to 3 are conventionally known.

Patent Document 1 describes an abnormal water level warning device for warning a passing vehicle on a bridge such as a river or a lake, which is capable of transmitting a microwave question signal and receiving a response signal. Abnormal water level equipped with a responder installed at the water surface position to be detected and returning a microwave response signal when the question signal of the interrogator is received, and a determination unit for determining the water level based on the presence or absence of the response signal of the interrogator. An alarm device is described (Patent Document 1, Claim 1). This abnormal water level alarm device is a water level detection device that transmits / receives data using microwaves by utilizing the property that microwaves are absorbed by water (仝 [0011]). The interrogator and responder are powered by a built-in battery and are installed near the surface of the water you want to detect. The responder is not normally flooded, but is installed in a position where it is flooded by flooding (see FIGS. 8 and 9 in the literature). When the responder is not submerged, the responder receives the question signal transmitted by the interrogator, and the responder returns the response signal according to the stored data. Therefore, the response signal can be received by the interrogator, and the determination unit determines that the water level is not abnormal. When the water level rises due to the flood and the responder is submerged, the microwave interrogation signal transmitted by the interrogator is absorbed by the water and cannot be received by the responder, and the response signal is not returned to the interrogator. As a result, the determination unit determines that the water level is not abnormal (仝 [0022]-[0025]).

The river water level warning unit described in Patent Document 2 measures the river water level with a water level measurement sensor installed on a bridge or the like (Fig. 2 of Patent Document 2), compares the measured water level with the water level judgment standard, and determines the absolute water level. In response to each condition such as rising or sudden increase in water, an alarm is issued by the rotating light, buzzer, message output, etc. provided in the unit (Patent Specification Paragraph [0026], FIG. 1), and the wireless communication line is connected. The alarm result is transmitted to the central management device via the above (Patent specification paragraph [0027]).

The flood warning system described in Patent Document 3 includes the foundation of a house, a gate, a stone wall, a block wall (Patent Document 3 specification paragraph [0022], Fig. 1) and various places corresponding to the land height level from a river. 0037], a flood occurrence warning device is installed in FIG. 4), and each flood occurrence warning device detects the water level and issues an alarm with an alarm buzzer or an alarm lamp (仝 [0034]), and by means of transmission in the device. , A flood warning is sent to the warning management center (仝 [0038]). Here, the flood occurrence warning device includes a main circuit section provided with a float switch for detecting water, and a sub circuit section provided with warning means (warning buzzer and warning lamp) for issuing an alarm, and the main circuit section includes a main circuit section. The float switch is electrically connected with an operating relay, the float switch is electrically arranged with a first set relay, and the sub-circuit section is electrically connected with an alarm means. A second set relay is arranged in. When the float switch detects water and turns on, the operation relay is urged to urge the 1st and 2nd set relays, and the urging of the 1st set relay keeps the operation relay in the urged state. , The alarm means is activated by energizing the second set relay (仝 [0028]-[0034]). As a result, it has been devised to detect the occurrence of floods for a long period of time while suppressing power consumption as much as possible (仝 [0019]).

Japanese Unexamined Patent Publication No. 2000-298055 Japanese Unexamined Patent Publication No. 2010-170190 Japanese Unexamined Patent Publication No. 2013-109558

Japan Automatic Identification Systems Association, "Familiar RFID", Revised 2nd Edition, Japan, Ohmsha Co., Ltd., June 20, 2014.

Since the river water level warning unit of Patent Document 2 is attached to a bridge and measures the height from the bridge to the water surface of the river with a water level measurement sensor, it is basically attached to the river. However, in recent floods, it is not uncommon for water to overflow from culverts and irrigation canals to make it difficult to evacuate. Insufficient to apply as a reporting system.

On the other hand, in the flood occurrence warning system of Patent Document 3, an alarm device is provided inside a house such as a house (see FIG. 1 of Patent Document 3), and a float type water level detection switch installed on the side of the house or on the bank of a river is used. It detects an abnormal water level and issues an alarm. Therefore, even when water overflows from an underdrain or an irrigation canal to a road other than a river, an abnormal water level can be detected and an alarm can be issued. However, the float-type water level detection switch is prone to malfunction due to clogging with dust and clogging due to nesting of organisms such as ants, spiders, and mud bees unless maintenance is performed for a long period of time. And there is a problem in terms of maintenance cost.

Further, in the flood occurrence warning system of Patent Document 3 (Fig. 4), when an abnormal water level is detected by the water level detection switch of each flood occurrence warning device (106), an alarm buzzer or an alarm attached to the flood occurrence warning device is used. Along with issuing an alarm with a lamp, a flood occurrence signal is transmitted wirelessly or by wire to the alarm management center on a hill (仝 [0038], [0041]), and a warning or alarm is issued from the alarm management center. Then, flood warning information and flood warning information are issued by alarm output means (152) such as loudspeakers installed in various places (仝 [0042]). However, the introduction of such a large-scale system requires a large amount of equipment cost, and it is difficult for local governments with weak financial power to introduce this system. Further, in recent years, flood damage caused by heavy rain often occurs in mountainous areas where the population density is small, and it is not realistic to introduce equipment such as an alarm management center in each of such mountainous areas. In addition, during heavy rains, there have been many reports of cases where the sound from alarm output means such as loudspeakers does not reach the surrounding residents due to the sound of rain, and in terms of the transmissibility of evacuation information. There's a problem.

Regarding the reliability and maintenance cost related to the operation guarantee of the water level sensor mentioned in the above-mentioned problem in Patent Document 3, the water level sensor using the microwave interrogator and the responder described in Patent Document 1 is applied. Can be considered. However, even in this case, there still remain problems regarding the problem of system introduction cost, the problem of difficulty in applying in mountainous areas, and the problem of transmissibility of evacuation information.

Therefore, an object of the present invention is that the reliability of abnormal water level detection is high, the maintenance cost can be suppressed, the system introduction cost is low, and the system can be easily introduced voluntarily and easily in general households and small business establishments other than the government. The purpose is to provide an abnormal water level notification system that can be used.

Another object of the present invention is to provide an abnormal water level notification system capable of reliably transmitting evacuation information to residents even during heavy rain and providing information for making an appropriate evacuation decision. To do.

The first configuration of the abnormal water level notification system according to the present invention is an abnormal water level notification system that detects and notifies the occurrence of an abnormal water level due to rainfall.
Center nodes installed inside the building and
One or more router nodes installed indoors or outdoors around the center node,
A leaf node to be installed one or more in the vicinity of each router node is provided.
The router node is
A router node position output means that detects router position information that represents self-position by a global positioning satellite system or outputs router position information that represents self-position recorded in advance in position information storage means.
A response receiving means for receiving a leaf response signal transmitted from each leaf node intermittently with respect to a question signal wirelessly transmitted to the surrounding space for each leaf node or at predetermined time intervals.
Based on the presence or absence of the leaf node whose transmission of the leaf response signal is interrupted, or based on the intensity change of the leaf response signal, the presence or absence of water approach or inundation is determined, and the presence or absence of water approach or inundation is determined. A water level detection means that generates water level detection information for which a value indicating water level detection is valid when it is determined, and
A water level detection signal transmission means for wirelessly transmitting the water level detection information output by the water level detection means to the center node together with the router position information is provided.
The leaf node is
A leaf ID storage means for storing a leaf ID which is an identification code of the leaf node, and a leaf ID storage means.
When the interrogation signal transmitted from the router node is received, or intermittently at predetermined time intervals, the leaf response signal including the leaf ID stored in the leaf ID storage means is generated and wirelessly transmitted to the surrounding space. Equipped with a leaf node response means to send
The center node is
A communication interface that communicates with the outside via a public communication line,
A center node receiving means for receiving the water level detection information and the router position information wirelessly transmitted from the router node, and
When the center node receiving means receives the water level detection information and the router position information, if the value indicating the water level detection of the water level detection information is valid, the occurrence of the abnormal water level is notified to the surroundings by voice or display. 1 abnormality notification means and
When the center node receiving means receives the water level detection information and the router position information, and the value indicating the water level detection of the water level detection information is valid, the water level detection information and the router position information are transmitted to the public communication. It is characterized by being provided with an abnormal water level information transmission means for transmitting to an external flood information collection / distribution server via a line.

According to this configuration, when introducing an abnormal water level detection system in each household, each household needs to introduce only the center node independently. Since the router node and leaf node are shared by each center node, they can be installed at the joint expense of households that have introduced the abnormal water level detection system or at the expense of the local government as public equipment, and are introduced as a whole. The cost can be suppressed. In addition, in this system, each router node transmits abnormal water level detection information, and the center node notifies the surroundings of the occurrence of an abnormality by voice or display in the building based on the abnormal water level detection information transmitted by each router node. Ru. Therefore, for example, it is not necessary to introduce equipment such as an alarm management center on a hill as in Patent Document 3, and each household or each business establishment can easily introduce the system independently. Therefore, it can be applied even in mountainous areas where the population density is low and scattered in various places. In addition, the detection of abnormal water level determines the approach of water due to the change in electromagnetic waves transmitted by the leaf node and the presence or absence of inundation. It is expensive and easy to install and maintain. Further, since RFID or Bluetooth (registered trademark) beacon can be used for the leaf node, it is inexpensive, and if a large number of leaf nodes are installed around the router node, the detection accuracy can be improved as much as possible. Further, the abnormal water level is detected depending on whether or not the leaf node in the vicinity of each router node is submerged, and the router node is suitable for wireless communication and can be installed in a high place where there is little risk of submersion. As a result, the distance between the router node and the center node that can be wirelessly communicated can be extended, and the abnormal water level can be detected in a wide range centering on the center node. Further, even after the vicinity of the router node is flooded, the router node can continuously transmit the detection information of the abnormal water level as long as the router node is not submerged. Therefore, by installing a plurality of leaf nodes at different heights in the vicinity of the router node, it is possible to detect the inundation depth in the vicinity of the router node. Further, since each router node is equipped with a router node position output means, the position can be grasped by the center node and the flood information collection / distribution server side only by installing the router node. Therefore, when installing the router node, it is not necessary to set the position on the flood information collection / distribution server side, and the router node can be easily added.

Here, "Global Navigation Satellite System (GNSS)" is a general term for satellite positioning systems such as GPS (Global Positioning System), GLONASS, Galileo, and Quasi-Zenith Satellite (QZSS). The "self-position recorded in advance in the position information storage means" means that the router node is written and recorded in a position information storage means such as a rewritable memory built in the router node when the router node is installed. Position information. The "leaf response signal transmitted from each leaf node to the question signal wirelessly transmitted to the surrounding space to each leaf node or intermittently at predetermined time intervals" is the "leaf" in the leaf node. As the transmission method of "response signal", when the router node responds to the inquiry signal wirelessly transmitted to the surrounding space to each leaf node from each leaf node (question response method), it depends on the inquiry signal. However, it means that each leaf node intermittently transmits a leaf response signal at a predetermined time interval (push method). Here, the "predetermined time interval" includes not only a fixed time interval but also a case such as a random time sequentially determined by a random number at an interval of 5 to 10 minutes at a leaf node (Example 1, 1. See FIG. 10).

The second configuration of the abnormal water level notification system according to the present invention includes a plurality of the center nodes arranged in various buildings in the first configuration.
It is equipped with a flood information collection and distribution server connected to the center node via a public communication line.
The flood information collection and distribution server is
A flood map database that manages flood damage transaction information, which is transaction information for displaying abnormal water level occurrence information on a map, and
A server-side receiving means for receiving the water level detection information and the router position information transmitted from each center node, and
A map information acquisition means for acquiring map information from a map distribution server via a public communication line or from a map database provided in the flood information collection distribution server.
A flood damage occurrence map generation means that generates the flood damage occurrence transaction information and stores it in the flood damage map database based on the received water level detection information, the router position information, and the map information.
Map information in a predetermined range centered on the designated position specified by the location information by the map information acquisition means in response to the map distribution request and location information transmitted from the outside via the public communication line (hereinafter, """Designated location area map information") is acquired, and flood damage occurrence information is displayed in the designated position area map information based on the flood damage occurrence transaction information related to the designated position area map information extracted from the flood damage map database. A map distribution means that generates the flood damage occurrence map information and distributes the flood damage occurrence map information,
It is characterized by being equipped with.

With this configuration, the flood information collection and distribution server collects water level detection information transmitted from router nodes installed in various locations via the center node and distributes flood damage map information to the area where flood damage has occurred. Residents or residents, and related organizations such as local governments that have jurisdiction over the area can easily and accurately grasp the occurrence of flood damage in real time. Residents or residents of the area where the flood has occurred can know the status of the flood without going through the administration, so they can evacuate quickly and accurately.

The third configuration of the abnormal water level notification system according to the present invention is that, in the second configuration, the leaf nodes are installed in the vicinity of the router nodes at different heights. The leaf ID storage means of each leaf node stores the leaf ID including height information assigned according to the height of each leaf node.
The router node includes a leaf list storage means for generating and storing a list of the leaf IDs included in the leaf response signal received in the router node in normal times.
The water level detecting means of the router node extracts the leaf ID of the leaf node from which the reply of the leaf response signal is interrupted to the question signal from the leaf IDs stored in the leaf list storage means. , The water level detection information including the height information included in the extracted leaf ID is generated.
The flood damage occurrence map generation means of the flood damage information collection / distribution server determines the occurrence position of the abnormal water level and the occurrence position thereof based on the water level detection information including the received water level information, the router position information, and the map information. It is characterized in that it generates flood damage occurrence map information showing the water level on a map.

With this configuration, for example, when the water level becomes very high due to flooding and the router node itself is submerged, or when the router node itself is submerged or washed away due to the occurrence of a sudden water level rise such as when a landslide or a levee breaks. In addition, it is possible to accurately detect the abnormal water level at the installation point of the router node.

The fourth configuration of the abnormal water level notification system according to the present invention is the second or third configuration, in which the flood damage occurrence map generation means indicates the router position information based on the received router position information. Elevation data around the position is acquired from the map information, the estimated inundation range around the position indicated by the position information is extracted based on the acquired elevation data, and the position where the abnormal water level occurs and the estimated inundation range are determined. It is characterized in that it generates the flood damage occurrence map information shown on the map.

With this configuration, when residents or residents in the inundated area evacuate, the location of the abnormal water level and the estimated inundation range can be grasped on the map, and it is possible to judge whether to evacuate or stay. It is possible to accurately determine which evacuation route to evacuate.

The fifth configuration of the abnormal water level notification system according to the present invention is the second or third configuration, in which the flood damage occurrence map generation means indicates the router position information based on the received router position information. Elevation data around the position and road route information are acquired from the map information, the estimated inundation range around the position indicated by the position information is extracted, and the estimated inundation road range is the road range included in the estimated inundation range. Is extracted, and the flood damage occurrence map information showing the occurrence position of the abnormal water level and the inundation estimated road range on the map is generated.

With this configuration, when residents or residents in the inundated area evacuate, the location of the abnormal water level and the estimated inundation road range can be grasped on the map, and it is possible to judge whether to evacuate or stay. , It is possible to accurately determine which evacuation route to evacuate.

The sixth configuration of the abnormal water level notification system according to the present invention is the mobile terminal device connected to the flood information collection / distribution server via a public communication line in any one of the second to fifth configurations. Prepare,
The mobile terminal device is
With the display
A mobile terminal position detection means that detects position information indicating its own position using a global positioning satellite system,
A map distribution request means for transmitting the map distribution request to the flood information collection / distribution server via a public communication line together with the position information detected by the mobile terminal position detection means.
A map receiving means for receiving the flood damage occurrence map information transmitted from the flood damage information collection and distribution server via a public communication line in response to the map distribution request.
A map display means for displaying the flood damage occurrence map information received by the map receiving means on the display, and a map display means.
It is characterized by being equipped with.

With this configuration, flood damage map information is displayed on a map on a mobile terminal device, so that the range of abnormal water levels can be grasped on the map even while residents or residents in the inundated area are evacuating. It is possible to accurately determine which evacuation route to evacuate.

The seventh configuration of the abnormal water level notification system according to the present invention is the configuration of any one of the second to six, wherein each router node is a router that stores a router ID that is an identification code of the router node. Equipped with ID storage means
The water level detection signal transmission means of each router node wirelessly transmits the water level detection information output by the water level detection means to the center node as water level detection information together with the router position information and the router ID. ,
Each of the router nodes includes a roof-side router node installed on the side of the building where the center node is installed or near the ground indoors, and peripheral router nodes installed at various locations away from the building where the center node is installed. The router ID of the shop-side router node includes the shop-side node identification information for identifying the shop-side router node.
The first abnormality notification means of the center node is
When the center node receiving means receives the water level detection information and the router ID wirelessly transmitted from the router node,
When the router ID indicates that the node identification information on the shop side is a peripheral router node, a caution alarm indicating that an abnormal water level has been detected around the building is notified to the surroundings.
When the router ID indicates that the shopside node identification information is the shopside router node, it is characterized in that it notifies the surroundings of an emergency evacuation warning indicating that an abnormal water level has been detected just before the building. And.

With this configuration, the inhabitants or residents of the area where the inundation has occurred can grasp how much inundation is occurring in the surrounding area.

The eighth configuration of the abnormal water level notification system according to the present invention is the seventh configuration, wherein the flood information collection / distribution server is used.
When the server-side receiving means receives the water level detection information and the router position information transmitted from the center node.
Based on the map information, among the buildings in which the center nodes are installed, the buildings that are presumed to be affected by flood damage to the position specified by the router position information are extracted.
A flood warning information transmission means for transmitting flood warning information via a public communication line to each of the center nodes installed in the extracted building is provided.
The first abnormality notification means of the center node indicates that an abnormal water level is detected upstream of the building when the flood warning information transmitted from the flood information collection / distribution server is received via a public communication line. It is characterized in that it notifies the surroundings of the flood damage warning to be shown.

With this configuration, residents or residents in the vicinity of the inundated area or in the downstream area can grasp that the flood has occurred in the upstream area, which can lead to early evacuation and caution.

Here, the "building that is presumed to be affected by flood damage to the position specified by the router position information" is a building in the downstream area of the position (specific position) specified by the router position information, or the building. A building within a predetermined range around a specific location. Extraction of "buildings that are presumed to be affected by flood damage to the location specified by the router location information" is a predetermined rule (for example, an area lower than the specific location in the downstream area of the specific location). (Select a building within a certain distance from a specific location, a building in an area where flood damage is estimated from the hazard map around the specific location, etc.).

The ninth configuration of the abnormal water level notification system according to the present invention is characterized in that, in any one of the first to eighth configurations, a part of the router node is a mobile terminal device.

The tenth configuration of the abnormal water level notification system according to the present invention is the configuration of any one of the first to nine, and the water level detecting means indicates the water level detection for a part or all of the router nodes. It is characterized in that it is provided with a second abnormality notification means for notifying the surroundings of the occurrence of an abnormal water level by voice or display when the water level detection information for which is valid is generated.

As described above, according to the abnormal water level notification system of the present invention, each household can directly detect inundation in the neighborhood, so that it is possible to make an evacuation decision by oneself without waiting for an evacuation advisory or instruction. You can evacuate by helping each other. Furthermore, the introduction cost as a whole can be suppressed, and each household or each business establishment can easily introduce the system independently. Therefore, it can be applied not only to cities but also to mountainous areas where the population density is low and scattered in various places. In addition, since the abnormal water level is detected by wirelessly detecting the approach of water due to the electromagnetic wave change of the leaf node and the presence or absence of inundation by the router node, dirt, foreign matter adhesion, and deterioration over time are caused because no mechanical mechanism is used. The detector is highly reliable and easy to install and maintain. In addition, the leaf node can be configured at low cost, and a large number of leaf nodes can be installed around the router node to improve the detection accuracy. In addition, abnormal water level detection can extend the distance between the router node and the center node by installing the router node at a high place that is suitable for wireless communication and has a low risk of submersion. Abnormal water level can be detected in a wide range centering on the node. In addition, by installing a plurality of leaf nodes at different heights in the vicinity of the router node, it is possible to detect the inundation depth in the vicinity of the router node. In addition, the position can be grasped on the center node and the flood information collection and distribution server side just by installing each router node, and when the router node is installed, the position is set on the flood information collection and distribution server side. There is no need, and router nodes can be easily added.

It is a figure which shows the whole structure of the abnormal water level notification system which concerns on Example 1 of this invention. It is a figure which showed an example of the installation of a router node 3 and a leaf node 4. It is a block diagram which showed the functional structure of the abnormal water level notification system of FIG. It is a flowchart which shows the initialization process of each router node. It is a flowchart which shows the operation of the detection and notification of the occurrence of the abnormal water level in the abnormal water level notification system of FIG. It is a flowchart which shows the update process of the flood damage information database 17 and the flood damage occurrence map database 18 in the abnormal water level notification system of FIG. It is a flowchart which shows the operation of the distribution processing of the flood damage occurrence map information in the abnormal water level notification system of FIG. It is a flowchart which shows the operation of the distribution processing of the flood damage occurrence map information in the abnormal water level notification system of FIG. It is a flowchart which shows the operation of the delivery process of the flood warning in the abnormal water level notification system of FIG. It is a flowchart which shows the example of the case where the transmission method of the leaf response signal by the push method is applied to the abnormal water level notification system of FIG. It is a figure which shows the whole structure of the abnormal water level notification system which concerns on Example 2 of this invention. It is a block diagram which showed the functional structure of the abnormal water level notification system which concerns on Example 3 of this invention. It is a figure which shows the transmission path of the leaf response signal from a leaf node 4 to a router node 3. It is a figure which shows the electromagnetic wave incident on the receiving point B. This is the result of calculating the relationship between the time averages U _Ep ^(ave) and U _Es ^(ave) of the relative energy densities of the electric field components of the electromagnetic waves received at the receiving point B and the height y _A0 of the water surface. This is the result of calculating the relationship between the time averages U _Ep ^(ave) and U _Es ^(ave) of the relative energy densities of the electric field components of the electromagnetic waves received at the receiving point B and the height y _A0 of the water surface. This is the result of measuring the change in reception intensity due to the change in the distance between the transmission point A and the water surface using an active beacon actually in the laboratory. It is a figure which shows the measurement condition of the measurement of FIG. It is a figure which shows the change of the intensity reflectance R _p , R _s of water with respect to the incident angle θ _C at a frequency f = 2.4GHz. It is a figure which shows the whole structure of the abnormal water level notification system which concerns on Example 4 of this invention. It is a block diagram which showed the functional structure of the abnormal water level notification system of FIG. It is a figure which shows the whole structure of the abnormal water level notification system which concerns on Example 5 of this invention. It is a figure which shows the whole structure of the abnormal water level notification system which concerns on Example 6 of this invention.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[1] System Configuration FIG. 1 is a diagram showing an overall configuration of an abnormal water level notification system according to a first embodiment of the present invention. The abnormal water level notification system of this embodiment includes a flood information collection / distribution server 1, a center node 2, a router node 3, a leaf node 4, and a mobile terminal device 5. Here, the "node" means a device such as a contact point, a branch point, or a relay point of a network.

The flood information collection and distribution server 1 is a server that collects and distributes information related to the occurrence of abnormal water levels transmitted from center nodes 2 installed in various places, and is a general-purpose computer such as a general personal computer or a rack mount server computer. It is composed of. The flood information collection / distribution server 1 may be installed in a remote location as a cloud virtual environment because it may be connected to a management center (regardless of the location where the management center is installed. It may be connected by a communication line) that collects and distributes flood information. It is installed in.) And is connected to a public communication line 6 such as a fixed telephone line and a mobile telephone line. The flood information collection and distribution server 1 can connect to the Internet through the public communication line 6.

The center node 2 has water level detection information (information regarding the presence / absence of detection of abnormal water level), router position information (information regarding the position of the router node 3), and a router transmitted from each router node 3 within the communicable range. A signal including an ID (identification code of router node 3) (hereinafter referred to as "router signal") is received, and an alarm is notified to the surroundings based on the water level detection information and the shopside node identification information in the router ID. It is a node that transmits the water level detection information and the router position information to the flood information collection / distribution server 1. The center node 2 is installed inside a building B such as a house, various business establishments, and a river management office. The center node 2 is connected to the public communication line 6 via a generally widely used LAN router, and can be connected to the Internet. The center node 2 can also be configured by a smartphone or a personal computer (hardware) and an application (software).

Here, the alarm notified by the center node 2 in this embodiment has the following three levels of alarm levels.
(Level L1) Warning: There is a point where an abnormal water level is detected in the area that causes the area such as the upstream area of Building B to be affected by flood damage.
(Level L2) Warning required: There is a point where an abnormal water level is detected around Building B.
(Level L3) Emergency evacuation warning: Water is approaching or flooding building B.

In the center node 2, warnings and alarms according to the level are notified by an alarm lamp, and are notified by voice or an alarm sound from a speaker.

The router node 3 detects its own position information (router position information) by the Global Navigation Satellite System (GNSS) and transmits it to the center node 2, and each of the router nodes 3 is installed in the vicinity of the router node 3. Water level detection information (leaf node approached or flooded) is detected by detecting the approach of water and the presence or absence of inundation due to the change in electromagnetic waves transmitted by each leaf node 4 by short-range communication with the leaf node 4 using electromagnetic waves such as microwaves. 4 is a node that transmits the router position information and the router position information to the center node 2 as a router signal. The router node 3 is installed indoors in the building B of each center node 2 or outdoors around the building B. The center node 2 and the router node 3 are capable of wireless communication within the reach of their respective radio waves (assuming about 100 m to 10 km in this embodiment). In addition, the identification code (leaf ID) of each leaf node 4 in the vicinity of itself is read by anti-collision (multiple batch reading), similar to the RFID (radio frequency identifier) currently widely used. Will be. The router node 3 can also be configured by a smartphone or an embedded computer (hardware) and an application (software).

The leaf node 4 is a node that receives a question signal transmitted from the router node 3, generates a leaf response signal including the leaf ID of the leaf node 4, and wirelessly transmits to the surrounding space. The leaf node 4 is installed at a position lower than the router node 3 in the vicinity of each router node 3. The leaf node 4 is composed of wireless devices such as a passive RF tag, an active RF tag, and a Bluetooth® beacon, and is installed in the vicinity of each router node one or more. The router node 3 and the leaf node 4 can perform wireless communication within the reach of their respective radio waves (in this embodiment, it is assumed to be about several m to 30 m). By configuring the router node 4 in a mesh shape by ad hoc communication, the distance can be further extended and the area can be monitored in a plane.

The mobile terminal device 5 is a portable terminal device that displays information such as a point where an abnormal water level has occurred, a water level, and a flooded road as map information. The mobile terminal device 5 is used to distribute reference information on an evacuation route when a resident evacuates when an abnormal water level occurs. Since reference information on the evacuation route is also required during evacuation, this system employs a mobile terminal device 5 that can be carried independently of the center node 2 during evacuation. The mobile terminal device 5 is composed of a terminal device having a display such as a smartphone or a tablet and a communication function, and is connected to a public communication line 6 such as a mobile phone line. From the mobile terminal device 5, it is possible to connect to the Internet through the public communication line 6. Further, the mobile terminal device 5 and the center node 2 can communicate with each other by short-range wireless communication such as Bluetooth (registered trademark).

FIG. 2 is a diagram showing an example of installation of a router node 3 and a leaf node 4. As shown in FIG. 2A, the router node 3 has a roof-side router node 3a installed on the side of the building B where the center node 2 is installed or near the ground indoors, and a center node 2. It is categorized into peripheral router nodes 3b installed in various places away from the building B. The roof-side router node 3a is installed on or near the outer wall or inner wall of the building B. Further, the leaf node 4 in the vicinity of the roof-side router node 3a is installed near the ground of a structure such as a foundation or a wall of the building B or a wall in the vicinity of the building B at a position lower than the roof-side router node 3a. .. In this case, since the object to which the leaf node 4 is attached is a non-metal such as concrete, it is preferable to use a passive RFID for the leaf node 4 if the distance is about 1 m. Any number of leaf nodes 4 in the vicinity of the roof-side router node 3a may be installed as long as they can communicate with the shop-side router node 3a.

On the other hand, the peripheral router node 3b is attached to a structure fixed to the ground such as a street light, as shown in FIG. 2B, for example. The peripheral router node 3b should be installed as high as possible so that it can communicate with the center node 2 even when it is flooded by heavy rain. Further, by installing the peripheral router node 3b at a high place, the communication distance with the center node 2 can be extended. The leaf node 4 installed in the vicinity of the peripheral router node 3b is composed of an RF device such as a passive RF tag or an active RF tag and a Bluetooth® beacon. As shown in FIG. 2B, the leaf node 4 is located at a position lower than the peripheral router node 3b, such as a street light P, a guardrail G, a road sign, a signal tower, and a pedestal box (underground line / electric wire utility tunnel). It is attached to a fixed structure such as a storage box for ground equipment). For the leaf node 4, it is preferable to use an RF device containing a passive RF tag if the attached fixed structure is non-metal and a distance of about 1 m, and an RF device containing a metal or an active RF tag if the distance is long. be. Further, as shown in FIG. 2C, for example, the peripheral router node 3b is attached to a fixed structure such as a sign, a floodgate, or a bridge on the upper part of the river embankment T of the river R, and the leaf node 4 is attached to the periphery thereof. It is fixedly installed on piles on the slope of the river surface of the river embankment T or fixed structures such as stones, piers, and floodgates. In this case, since the distance between the peripheral router node 3b and each leaf node 4 is relatively large, it is preferable to use an active RF tag for the leaf node 4.

When a plurality of leaf nodes 4 are installed in the vicinity of the router node 3, it is preferable to install the leaf nodes 4 at different heights as shown in FIG. As a result, it is possible to detect the occurrence of an abnormal water level and also to detect the current water level.

When an abnormal water level occurs and water overflows to the ground and the leaf node 4 is flooded, electromagnetic waves such as microwaves used for communication due to the water around the leaf node 4 are attenuated in correlation with the frequency and water depth due to the dielectric loss of water. Energy is attenuated according to the characteristics, and electromagnetic waves such as microwaves used for communication are reflected at the interface between flooded water and the atmosphere, and communication power is reduced in wireless communication between the router node 3 and the leaf node 4. As a result, the communication state changes from the normal state to the interrupted state due to the increase in the error rate during communication. It is possible to detect that the leaf node 4 is flooded in the router node 3 and detect the occurrence of an abnormal water level based on the transition of the error rate and the final interruption state. At this time, by installing a plurality of leaf nodes 4 so as to have different heights, communication is interrupted in order from the lower leaf node 4 as the water level rises, so that the inundation depth at the time of the occurrence of an abnormal water level can be determined. It can also be detected at the router node 3.

FIG. 3 is a block diagram showing a functional configuration of the abnormal water level notification system of FIG. In FIG. 3, the same components as those in FIG. 1 are designated by the same reference numerals. The flood information collection and distribution server 1 includes a map database 10, a server-side receiving unit 11, a map information acquisition unit 12, a flood damage occurrence map generation unit 13, a map distribution unit 14, a flood caution information transmission unit 15, a line communication interface 16, and flood information. It includes a database 17, a flood map database 18, a measurement point correction database 19, and a center node list storage unit 20. The line communication interface 16 is an interface for exchanging data with and from the public communication line 6. The map database 10 is a database for storing electronic map data. The flood information database 17 is a database that manages and stores water level detection information and router position information sent from each center node 2. Water level detection information and router position information are accumulated in the flood information database 17. The flood damage map database 18 is a database that manages and stores flood damage occurrence map information showing the inundation status on a map based on the water level detection information and router position information sent from each center node 2. Specifically, the flood damage occurrence map information takes the form of transaction data for displaying the flood damage occurrence information on the map. This flood damage map information is updated in real time every moment. The measurement point correction database 19 is a database that manages and stores information related to position correction of the router node 3. For example, in the cases shown in FIGS. 2A and 2B, the altitude at the position of the router node 3 is the same as the altitude of the leaf node 4 adjacent to the router node 3, so that the position correction of the router node 3 is performed. However, in the case shown in FIG. 2 (c), the altitude at the position of the router node 3 and the altitude of each leaf node 4 for measuring the water level are significantly different, so that the position of the router node 3 is measured at the water level. It is necessary to correct the position of the point that becomes the reference altitude. "Information regarding position correction" refers to information for correcting the position of such a router node 3. The measurement point correction database 19 stores the corrected position information only for the router node 3 that needs to be corrected. The center node list storage unit 20 stores a list of center node-related information including identification numbers (center node IDs), network addresses on the network, and location information of center nodes 2 installed in buildings B in various places. ..

The center node 2 includes a center node receiving unit 21, an abnormality notification unit 22, an abnormal water level information transmitting unit 23, a line communication interface 24, a long-distance communication interface 25, a long-distance communication antenna 26, a short-range communication interface 27, a speaker 29, and an alarm. It includes a lamp 30 and a router list storage unit 31. The router list storage unit 31 stores a list of router IDs (hereinafter referred to as “router list”) of the router node 3 within the reception range of the center node 2. The line communication interface 24 is an interface for exchanging data with and from the public communication line 6. The telecommunications interface 25 and the telecommunications antenna 26 are interfaces and antennas for wireless communication with the router node 3. For the long-distance communication interface 25, it is preferable to adopt an interface using spectral diffusion communication in order to increase the communication distance. As the telecommunications antenna 26, an antenna provided in the center node 2 may be used, or an external antenna such as a television antenna may be connected to the center node 2 for use. The short-range communication interface 27 is an interface for performing short-range communication with the mobile terminal device 5 using radio waves or infrared rays, and for example, a short-range wireless communication method such as Bluetooth (registered trademark) can be used. As the alarm lamp 30, a red lamp or a rotating lamp, which is generally used for a fire alarm, is used.

The router node 3 includes a position detection module 41, a router ID storage unit 42, a leaf list storage unit 43, an initialization unit 44, an initialization switch 44a, a question transmission unit 45, a response reception unit 46, a water level detection unit 47, and a water level detection signal. It includes a transmitter 48, a long-distance communication interface 49, a long-distance communication antenna 50, a short-range communication interface 51, and a short-range communication antenna 52. The position detection module 41 is a module that detects router position information indicating its own position by GNSS, and can use a GPS (Global Positioning System) receiving module or the like that is widely used in general. The router ID storage unit 42 stores the router ID, which is the identification code of the router node 3. The router ID includes the shop-side node identification information for the router node 3 to identify the shop-side router node 3a or the peripheral router node 3b. For example, the code of the router ID is set to "YWWWWWW" (Y: shop side node identification information, WWWWWWW: router number). The "storey node identification information" is information indicating the classification of the storeside router node 3a or the peripheral router node 3b, for example, the storeside router node 3a is Y = 0 and the peripheral router node 3b is Y = 1. Is set to. The "router number" is an identification field number uniquely assigned to each router node 3. The router ID can be written in the field using a wireless reader / writer when the router node 3 is installed, or can be set in the field only for the "store side node identification information" using the DIP switch. .. Non-volatile memory such as EPROM, EEPROM, flash memory, MRAM, and ReRAM is used for the leaf list storage unit 43. The telecommunications interface 49 and the telecommunications antenna 50 are interfaces and antennas for wireless communication with the center node 2. The short-range communication interface 51 and the short-range communication antenna 52 are interfaces and antennas that perform wireless communication with each leaf node 4 in the vicinity of the router node 3 by microwaves or the like. The initialization switch 44a is a push switch used when the initialization process of the router node 3 is performed.

In this embodiment, an example in which the "position detection module 41" that detects the router position information by GNSS is used as the "router node position output means" of the router node 3 is shown, but in the present invention, the "router node position" is shown. As the "output means", instead of the "position detection module 41", a configuration including a "position storage memory 41'" that can be rewritten from the outside using a writer or the like may be provided. In this case, when the router node 3 is installed at the site, the position of the installation site (router position information) is measured by GNSS or the like, and the router position information measured by the writer is written in advance in the position storage memory 41'. To. The position storage memory 41'outputs the router position information written in advance in response to the request.

The leaf node 4 includes a leaf ID storage unit 61, a leaf node receiving unit 62, a leaf node response unit 63, a short-range communication interface 64, and a short-range communication antenna 65. The short-range communication interface 64 and the short-range communication antenna 65 are interfaces and antennas that perform wireless communication with a router node 3 in the vicinity of the leaf node 4 by microwaves or the like. The leaf ID storage unit 61 stores the leaf ID, which is the identification code of the leaf node 4. This leaf ID includes height information assigned according to the height at which the leaf node 4 is installed. For example, the code of the leaf ID is set to "XXXXXZZZZZZ" (XXXXX: height information, ZZZZZZZZ: leaf number). "Height information" is information indicating the inundation depth (height from the ground to the water surface of the inundation area) at that point, and is, for example, "0 to 0.5 m (0 to 0.5 m) along the inundation depth specified by the Ministry of Land, Infrastructure, Transport and Tourism. Underfloor flooding (uses up to the knees of adults) "," 0.5-1.0m (floods above the floor (uses up to the waist of adults)) "," 1.0-2.0m (uses up to the eaves on the first floor) "," 2.0-5.0 It may be set at stages such as "m (flooding to the bottom of the eaves on the 2nd floor)" and "5.0m ~ (flooding above the roof on the 2nd floor)", or the inundation depth divided in more detail is set independently. May be good. Numerical codes are assigned to each inundation depth in ascending order of inundation depth, and this is referred to as "height information". The "leaf number" is an identification field number uniquely assigned to each leaf node 4. The leaf ID can be written in the field using a wireless reader / writer when the leaf node 4 is installed.

The mobile terminal device 5 includes a touch panel display 71, a position detection module 72, a map distribution request unit 73, a map reception unit 74, a map display unit 75, a line communication interface 76, and a line communication antenna 77. The line communication interface 76 and the line communication antenna 77 are interfaces and antennas for exchanging data with and from the public communication line 6. The touch panel display 71 is an electronic component that combines a display device such as a liquid crystal panel and a position input device such as a touch pad, and is an input / display device that operates a device by pressing a display on the screen. The position detection module 72 is a module that detects the position information of the mobile terminal representing the self-position by GNSS, and can use a GPS receiving module or the like that is widely used in general.

The detailed functions of the above components will be collectively described in the operation description described later.

[2] System operation The operation of the abnormal water level notification system of this embodiment configured as described above will be described below.

(1) Initialization of Router Nodes FIG. 4 is a flowchart showing an initialization process of each router node. The initialization process of the router node is performed immediately after installing each router node 3 and each leaf node 4 in the vicinity thereof, when a new leaf node 4 is installed in the vicinity of the router node 3, or a leaf node in the vicinity of the router node 3. It is carried out only once when 4 is removed or replaced.

First, the router node 3 waits until the initialization switch 44a provided in the router node 3 is pressed (S101). Here, the initialization switch 44a is a push switch provided in the router node 3. The installer of the router node 3 presses the initialization switch 44a with a finger to turn it on, and releases the finger to turn it off.

When it is detected that the initialization switch 44a is pressed in step S101, the initialization unit 44 of the router node 3 clears the leaf list stored in the leaf list storage unit 43 (clears the data in the list). .. Here, the "leaf list" is a list of leaf IDs included in the leaf response signal received in normal times at the router node 3. The "leaf response signal" is a signal transmitted from the leaf node 4 in the vicinity of the router node 3 with respect to the question signal that the question transmitting unit 45 of the router node 3 wirelessly transmits to the surrounding space. It is a signal including the information of the leaf ID of the leaf node 4.

Next, when the question transmitting unit 45 of the router node 3 wirelessly transmits a question signal to each leaf node 4 in the vicinity thereof to the surrounding space, and the leaf node receiving unit 62 of each leaf node 4 in the vicinity receives the question signal, the question signal is received. The leaf node response unit 63 generates a leaf response signal including the leaf ID stored in the leaf ID storage unit 61 and wirelessly transmits it to the surrounding space, and the response reception unit 46 of the router node 3 transmits from each leaf node 4 in the vicinity. By performing a series of operations of receiving the incoming leaf response signal, the router node 3 performs a process of reading the leaf ID of each leaf node 4 in the vicinity thereof. In this process, when there are a plurality of leaf nodes 4 in the vicinity, collision of leaf response signals occurs. Therefore, anti-collision techniques such as a time slot method and a bit collision method (for example, 47 to 50 of Non-Patent Document 1) See page). The initialization unit 44 of the router node 3 stores the leaf ID of each leaf node 4 in the vicinity of the reception as a leaf list in the leaf list storage unit 43 (S103, S210).

Finally, the initialization unit 44 of the router node 3 receives the router signal transmitted by the other router node 3 for a certain period of time by the long-distance communication interface 49 and the long-distance communication antenna 50, and the other router node 3 transmits. The transmission timing and transmission channel that do not collide with the router signal to be used are determined (S104). Subsequent transmission of the router signal from the router node 3 is executed using the transmission timing and transmission channel determined here by the initialization unit 44.

By the initialization processing operation of the router node 3 described above, the leaf ID of the leaf node 4 installed in the vicinity of the router node 3 is stored in the leaf list storage unit 43 as a leaf list. Subsequent determination of communication blackout of each leaf node 4 will be made by referring to this leaf list. At the same time, the transmission timing and transmission channel when the router node 3 transmits the router signal to the center node 2 are determined, and collision avoidance with the router signal with another router node 3 is set.

(2) Notification of abnormal water level (2.1) Detection and notification of abnormal water level Next, the operation of detecting and notifying the occurrence of abnormal water level will be described. FIG. 5 is a flowchart showing the operation of detecting and notifying the occurrence of an abnormal water level in the abnormal water level notification system of FIG.

First, the router node 3 determines whether or not the detection timing time has been reached by the internal timer, and waits until the detection timing time is reached (S111). The "detection timing time" means a time when the abnormal water level is detected, and is set at a fixed time interval (for example, every 5 minutes).

When the detection timing time is reached, the question transmission unit 45 of the router node 3 then wirelessly transmits a question signal to each leaf node 4 in the vicinity thereof to the surrounding space, and the leaf node reception unit of each leaf node 4 in the vicinity thereof. When 62 receives the inquiry signal, the leaf node response unit 63 generates a leaf response signal including the leaf ID stored in the leaf ID storage unit 61 and wirelessly transmits it to the surrounding space, and the response reception unit 46 of the router node 3 receives the inquiry signal. By performing a series of operations of receiving a leaf response signal transmitted from each leaf node 4 in the vicinity, a process of reading the leaf ID of each leaf node 4 in the vicinity is performed in the router node 3 (S112, S211). This process is executed using anti-collision as in the case of the initialization process of the router node. At this time, the response receiving unit 46 also simultaneously detects the received signal strength (hereinafter referred to as “RSS”) when the leaf response signal transmitted from each leaf node is received, and together with the leaf ID, it is inside. Save to memory.

Next, the water level detection unit 47 of the router node 3 collates the leaf ID of each leaf response signal received by the response reception unit 46 with the leaf list stored in the leaf list storage unit 43, and communication is interrupted. The leaf ID (Communication Disruption Leaf-node's ID: hereinafter referred to as “CDLID”) of the leaf node 4 is detected (S113).

Here, when the CDRID is not detected (S114), the water level detection unit 47 inspects the RSS of the leaf response signal of each leaf node 4 for which the leaf response signal is received, and determines the magnitude of the RSS and the RSS. The water level around the leaf node 4 is detected by the magnitude of the variance (or standard deviation) of the sampling values (S115a). Specifically, the water level detection unit 47 distributes the average value U _ave (i) (i is the index of each leaf node 4) and the RSS sampling value of the RSS of the leaf response signal of each leaf node 4 in fine weather. The average value (normal variance value) σ ² _Uave (i) of the value is stored in the internal memory in advance. Then, in the time interval [t-Δt, t] at each time t, the RSS interval average U (i; t-) of the leaf response signal of each leaf node 4 received in that time interval [t-Δt, t]. Ratio of Δt, t) to normal average value U _ave (i) Ur (i; t-Δt, t) = U (i; t-Δt, t) / U _ave (i) value (ratio RSS), And the ratio of the interval dispersion value σ ² _U (i; t-Δt, t) of the RSS sampling value of the time interval [t-Δt, t] to the normal dispersion value σ ² _Uave (i) σ ² _Ur (i; t-Δt, t) = σ ² _U (i; t-Δt, t) / σ ² _Uave (i) value (ratio RSS variance) is calculated, and this ratio RSS Ur (i; t-Δt, t) And the water level around the leaf node 4 is detected by the magnitude of the ratio RSS dispersion σ ² _Ur (i; t-Δt, t). When the water surface approaches the lower part of the leaf node 4 to some extent, the ratio RSS dispersion σ ² _Ur (i; t-Δt, t) gradually increases, and when the water surface approaches the lower part of the leaf node 4, the ratio RSS Ur (i; t) gradually increases. -Δt, t) begins to decrease. Then, when the leaf node 4 is flooded, the ratio RSS Ur (i; t-Δt, t) drops sharply, and when the flooding becomes deep, communication is interrupted. Therefore, some ratio RSS thresholds Urth (n) (n represents the ratio RSS determination level, n = 1,2, ...; Urth (1)> Urth (2)> ...) and the ratio RSS variance threshold σ ² rth (m) (m represents the ratio RSS dispersion determination level, m = 1,2, ...; σ ² rth (1) <σ ² rth (2) <...) is set, and the water level detection unit 47 sets. , The ratio RSS Ur (i; t-Δt, t) is below each threshold, or the RSS variance σ ² _Ur (i; t-Δt, t) is above each threshold. , It becomes possible to detect the water level around the leaf node 4. Here, the "water level" is a value obtained by gradually dividing the detected water level according to its height. For example, if m is set to 2 levels of 0,1 and n is set to 4 levels of 0,1,2,3.
(0) Water level level (n, m) = (0, 0) (Ur (i; t-Δt, t)> Urth (1) ∩ σ ² _Ur (i; t-Δt, t) <σ ² rth ( 1)) is "water level not detected",
(1) Water level level (n, m) = (0, 1) (Ur (i; t-Δt, t) ＞ Urth (1) ∩ σ ² _Ur (i; t-Δt, t) ≧ σ ² rth ( 1)) is "water level detection",
(2) Water level level n = 1 (Urth (1) ≧ Ur (i; t-Δt, t) ＞ Urth (2)) is “approaching the water surface”,
(3) Water level level n = 2 (Urth (2) ≧ Ur (i; t-Δt, t) ＞ Urth (3)) is “flooded” (leaf node 4 is flooded),
(4) Water level level n = 3 (Urth (3) ≧ Ur (i; t-Δt, t)) is “communication disruption due to submersion” (communication disruption due to flooding of leaf node 4),
The water level is detected as in. Instead of the ratio RSS variance σ ² _Ur (i; t-Δt, t), the ratio RSS standard deviation σ _Ur (i; t-Δt, t), the mean deviation of RSS, or the mean value of similar RSS. You may use a statistic that represents the dispersion for.

The relationship between the ratio RSS Ur (i; t-Δt, t) and the ratio RSS dispersion σ ² _Ur (i; t-Δt, t) of the leaf response signal and the water level will be described in more detail in Example 3. do. In addition to this, as a method of determining the water level of the leaf response signal from RSS, determination is performed by a machine learning method such as deep learning using a neural network based on the pattern of time change of RSS. You can also.

When it is determined by this water level detection that the water level is not detected in all the leaf nodes 4, the water level detection unit 47 outputs the water level detection information in which the value indicating the water level detection (water level detection flag value) is invalid. On the other hand, when the water level is detected in any of the leaf nodes 4, the water level detection unit 47 represents the height at which the "height information" is the largest among the leaf nodes 4. , The one with the largest inundation depth (maximum water level) among the water level levels n detected in each leaf node 4 is obtained, and the effective water level detection flag value, the detected height information, and the water level detection information including the maximum water level level are obtained. Is output. For example, in a certain router node 3, when three leaf nodes 4 (hereinafter referred to as Lf1, Lf2, Lf3) are registered in the leaf list, the height information of the leaf nodes Lf1, Lf2, Lf3 is 0. , 1, 1 (The inundation depth is larger in the height information 1 than in the height information 0, that is, the height information 1 represents a higher place than the height information 0), and is detected by the leaf node Lf1. If the water level level is 2 (inundation), the water level detected in leaf node Lf2 is 1 (close to the water surface), and the water level detected in leaf node Lf3 is 2 (inundation), the one with the largest inundation depth is , The water level level 2 detected in the leaf node Lf3 of the height information 1. Therefore, the height information and the maximum water level level included in the water level detection information are (height information, water level level) = (1, 2). Then, the water level detection signal transmission unit 48 transmits the router signal including the water level detection information, the router position information output by the position detection module 41, and the router ID stored in the router ID storage unit 42, as a long-distance communication interface. Radio transmission to the surrounding space is performed by the 49 and the long-distance communication antenna 50 (S115b).

On the other hand, when CDLID is detected in step S113 (S114), the water level detection unit 47 outputs water level detection information including a valid water level detection flag value. At this time, the water level detection unit 47 also adds the "height information" extracted from the CDLID to the water level detection information, which has the largest inundation depth, and adds the maximum water level level (S116). For example, when the "height information" included in the CDLID is 0 and 1 (the inundation depth is larger in the height information 1 than in the height information 0) as the CDLID, the water level detection information. Is added with 1 as "height information" and the maximum water level as the water level (for example, water level 3 (communication interruption due to submersion)). Then, the water level detection signal transmission unit 48 transmits the router signal including the water level detection information, the router position information output by the position detection module 41, and the router ID stored in the router ID storage unit 42, as a long-distance communication interface. Radio transmission to the surrounding space is performed by the 49 and the long-distance communication antenna 50 (S117). After the processing of step S115 or steps S116 and S117, the router node 3 returns to step S111 again and repeats the same operation.

On the other hand, the center node 2 installed indoors in each building B transmits the router signal transmitted from each router node 3 within the receivable range via the telecommunications antenna 26 and the telecommunications interface 25. It waits until the center node receiving unit 21 receives the signal (S301). Here, the router signal transmitted from each router node 3 includes "water level detection information", "router position information", and "router ID" as described above.

When the router signal is received by the center node receiving unit 21, the abnormality notification unit 22 of the center node 2 determines whether the water level detection flag value of the "water level detection information" included in the router signal is valid or invalid, and the water level detection information. It is determined whether or not the maximum water level detected in is the level (level 0) of "water level not detected" (S302), and if the water level detection flag value is valid or other than the maximum water level level level 0, the process proceeds to the next step S303. If the water level detection flag value is invalid and the maximum water level level is 0, the "water level detection information", "router position information", and "router ID" of the router signal are transmitted to the flood information collection / distribution server 1 (S304). ), Return to the above step S301.

When the water level detection flag value of the "water level detection information" in the router signal is valid or the maximum water level level is equal to or higher than a certain level (for example, a value or higher indicating "flooding") in step S302, the abnormality notification unit 22 raises the abnormal water level. The occurrence of the abnormal water level is notified to the surroundings by turning on or blinking the alarm lamp 30 while an alarm sound and a warning sound are notified by the speaker 29 (S303). Here, the abnormality notification unit 22 refers to the shopside node identification information Y of the “router ID” included in the received router signal, and the shopside node identification information Y indicates a value indicating the peripheral router node 3b (for example, Y). In the case of = 1), the alarm level is L2, and in the case where the shopside node identification information Y is a value indicating the shopside router node 3a (for example, Y = 0), the warning level is L3. Then, in the case of the alarm level L2, the abnormality notification unit 22 notifies the surroundings by the speaker 29 of an "attention required alarm" indicating that an abnormal water level has been detected around the building. In the case of the alarm level L3, the abnormality notification unit 22 notifies the surroundings by the speaker 29 of an "emergency evacuation warning" indicating that an abnormal water level has been detected just before the building.

Then, the abnormal water level information transmission unit 23 uses the "water level detection information", "router position information" and "router ID" included in the router signal as "abnormal water level information", and uses the line communication interface 24 to make a public communication line. It is transmitted to the flood information collection and distribution server 1 via 6 (S304), and the operation returns to the operation of the above step S301.

As described above, the router signal is periodically transmitted from the router node 3 within the receivable range of the center node 2 at a fixed time interval TR. Therefore, the center node 2 stores in advance the router ID and the position information included in the router signal that is periodically received in normal times in the router list storage unit 31 as a router list. Then, when a router node 3 whose router ID is registered in the router list is detected in which the router signal is not received for a certain threshold time Tth (> TR) or more (S301), the router of the router node 3 is detected. It is determined that the signal is interrupted (S305). This is because, for example, the water level becomes very high due to a flood and the router node 3 itself is submerged, or the router node 3 itself is submerged or washed away due to a sudden rise in water level such as when a debris flow or a levee breaks. It corresponds to the case. If the router node 3 itself is submerged or washed away, the transmission of the router signal from the router node 3 to the center node 2 is interrupted, so that the center node 2 cannot determine the abnormal water level by the router signal. Therefore, the center node 2 determines that the router node 3 itself is submerged or washed away when the transmission of the router signal is interrupted, and issues an alarm. When it is determined in step S305 that the router signal is interrupted, the abnormality notification unit 22 notifies the surroundings of the occurrence of the abnormal water level by the speaker 29 and the alarm lamp 30 (S306), and the abnormality water level information transmission unit 23 communicates. The "water level detection information", "router position information" and "router ID" of the router node 3 that has been interrupted are transmitted to the flood information collection and distribution server 1 as "abnormal water level information" (S307), and the operation returns to the operation of step S301. .. The operation of step S306 is the same as that of step S303. Further, in step S307, the "water level detection information" of the router node 3 in which communication is interrupted is assumed to have the "water level detection flag value" enabled and a value indicating the maximum inundation depth added as "height information". It is transmitted to the flood information collection and distribution server 1 together with the "router position information" of the router node 3 in which communication is interrupted.

As described above, when an abnormal water level (inundation) is detected in the router node 3 around the center node 2, the speaker 29 and the alarm lamp 30 notify the surroundings of an alarm to the residents in the building B or the residents in the building B. It is possible to encourage the evacuation of residents. In addition, this abnormal water level notification system automatically notifies residents when an abnormal water level is actually detected, like a fire alarm that is generally used, without going through the judgment of the government. Alternatively, the resident can make a quick evacuation decision, and at the same time, the disaster prevention organization such as the government can grasp the situation of the area in real time.

In this embodiment, each leaf node 4 receives a question signal from the router node 3 and returns a leaf response signal, but in addition to this, an internal power supply (battery) is used as the leaf node 4. Using the active leaf node 4 having the leaf node 4, the leaf node 4 can be configured to periodically transmit a leaf response signal at regular time intervals without receiving a question signal. In this case, in step S112, the process in which the question transmission unit 45 of the router node 3 transmits a question signal is omitted, and the question transmission unit 45 may be omitted in the router node 3.

(2.2) Distribution of flood damage information collection server flood damage occurrence map information distribution When an abnormal water level occurs around building B and center node 2 notifies the surroundings of an alarm, the residents or residents of that building B are the buildings. It is necessary to evacuate from B. In this case, it is very useful if there is information on the location where the abnormal water level around the building B occurs and the roads that can be passed. Therefore, this section describes the distribution processing of flood damage occurrence map information showing information on the points where abnormal water levels occur and roads that can be passed.

FIG. 6 is a flowchart showing an update process of the flood damage information database 17 and the flood damage occurrence map database 18 in the abnormal water level notification system of FIG. First, the flood information collection and distribution server 1 waits until "abnormal water level information" is transmitted from the center node 2 (S401). As described above, the "abnormal water level information" is information including "water level detection information", "router position information", and "router ID". When the server-side receiving unit 11 of the flood information collection and distribution server 1 receives the "abnormal water level information" transmitted from the center node 2, the "water level detection information" and "router position information" included in the "abnormal water level information" , And the reception time of the "abnormal water level information" are stored in the flood information database 17 (S402).

Next, the map information acquisition unit 12 receives the "router position information" included in the "abnormal water level information" from the map distribution server or the map database 10 connected to the flood information collection and distribution server 1 via the public communication line. Acquire map information of the surrounding area (S403). Here, the map database 10 stores an electronic map such as an electronic national land map provided by the Geographical Survey Institute. Further, the "map distribution server connected to the flood information collection distribution server 1 via a public communication line" is, for example, an electronic map distribution server distributed on the Internet.

Next, the flood damage occurrence map generation unit 13 of the flood information collection and distribution server 1 is based on the received "water level detection information" and "router position information" and the extracted map information, and the position indicated by the router position information. The estimated inundation range around the water is extracted (S404). The extraction of the inundation estimation range is performed according to a predetermined rule based on the elevation data of each point of the map information and the hazard map data stored in the map database 10 in advance. At this time, if there is "information on position correction" for the "router ID" included in the "abnormal water level information" in the measurement point correction database 19, when extracting the inundation estimation range, The "router position information" corrected based on the "information on position correction" is used. If the water level detection flag value in the "water level detection information" is an invalid value, it means that no abnormal water level has occurred around the router node 3 in the "router position information". There is no estimation range (NULL).

Next, the flood damage occurrence map generation unit 13 extracts roads (including roadways, walking roads, and garden roads) included in the extracted inundation estimation range, and sets the extracted road range as the estimated inundation road range (S405). ).

Then, the flood damage occurrence map generation unit 13 displays the water level information, the inundation estimation range, and the estimated inundation road range information at the position indicated by the "router position information" on the map from the inundation estimation range and the estimated inundation road range. Transaction data (hereinafter referred to as “flood damage occurrence transaction data”) is generated, associated with the “router ID” included in the “abnormal water level information”, and stored in the flood damage map database 18 (S406). Here, if the flood damage map database 18 has a record (existing record) related to the same "router ID" as the "router ID", the flood damage occurrence transaction data of that record is used as the new flood damage occurrence created here. Update to transaction data. Further, when an existing record having the same "router ID" exists and there is no inundation estimation range (NULL), the existing record is deleted. After updating the flood damage map database 18 in this way, the operation returns to the operation of step S401.

By the above operation, in the flood information database 17, "abnormal water level information" sequentially transmitted from each center node 2 is accumulated in the flood information database 17, and information on the inundation range that changes from moment to moment is displayed on the map. It is stored in the flood damage map database 18 as transaction data for display (flood damage occurrence transaction data), and the flood damage occurrence transaction data in the flood damage map database 18 is updated in real time.

FIG. 7 is a diagram showing an example of flood damage occurrence map information displayed using the flood damage occurrence transaction data generated by the flood damage occurrence map generation unit 13. In FIG. 7, the points indicated by "○", "△", and "×" are the positions indicated by "router position information", "○" is no inundation, "△" is inundation below the knee, and "×" is above the knee. It represents the inundation depth of the above inundation. In addition, the inundation area above the knee and the inundation area below the knee are shown in blue and light blue on the map, the road range in the inundation above the knee is shown in red, and the road range in the inundation area below the knee is shown in orange. (Since FIG. 7 is a black-and-white shade image, the color information is grayscale-converted). Further, the house mark represents the position of the building B in which the center node 2 is installed (determined from the "store side node identification information" included in the "router ID"). The flood damage transaction data is a command sequence for displaying symbols such as "○", "△", "×", road lines in the flooded area, and displaying the flooded area on the map.

FIG. 8 is a flowchart showing the operation of the distribution processing of the flood damage occurrence map information in the abnormal water level notification system of FIG. The flood damage occurrence map information is distributed to the mobile terminal device 5 owned by the resident or the resident in the building B via the public communication line 6.

First, in the mobile terminal device 5, the user inputs an instruction to display a flood damage occurrence map from the touch panel display 71 (S500). When the display instruction is input, the map distribution request unit 73 detects the position information indicating the self-position by the position detection module 72 (S501). Next, the map distribution request unit 73 transmits a map distribution request to the flood information collection / distribution server 1 via a public communication line together with the position information of its own position (S502).

When the flood information collection distribution server 1 receives the map distribution request and the location information transmitted from the mobile terminal device 5 (S421), first, the map distribution unit 14 receives the map database 10 or public communication by the map information acquisition unit 12. From the map distribution server connected to the flood information collection distribution server 1 via the line, map information in a predetermined range centered on the designated position specified by the position information (hereinafter referred to as "designated position surrounding map information") is obtained. Acquire (S422). Next, the map distribution unit 14 extracts the flood damage occurrence transaction information related to the designated position surrounding map information from the flood damage map database 18 (S423). Here, the "flood damage occurrence transaction information related to the designated position surrounding map information" is the flood damage occurrence transaction information that displays the abnormal water level occurrence information at the points on the map within the range of the designated position surrounding map information. be. Next, the map distribution unit 14 generates flood damage occurrence map information in which the flood damage occurrence information is displayed in the map of the designated position surrounding map information based on the extracted flood damage occurrence transaction information (S424). This can be done by executing the transaction of the extracted flood damage occurrence transaction information with respect to the map information around the designated position. Then, the map distribution unit 14 distributes the generated flood damage occurrence map information to the mobile terminal device 5 that has transmitted the map distribution request and the location information (S425).

When the map receiving unit 74 receives the flood damage occurrence map information transmitted from the flood damage information collection distribution server 1 in response to the map distribution request in the mobile terminal device 5 (S503), the map display unit 75 receives the flood damage occurrence map. Information is displayed on the touch panel display 71 (S504). The flood damage occurrence map information displayed on the touch panel display 71 is, for example, a flood damage occurrence map as shown in FIG. 7.

In this way, the resident or resident in the building B browses the flood damage occurrence map information from the mobile terminal device 5, so that the resident or the resident can grasp the flood damage occurrence situation around the building B in real time. Can be done. As a result, residents or residents can accurately determine whether to evacuate or stay, and when evacuating, the mobile terminal device 5 confirms the flood damage situation in real time while evacuating the evacuation route. You can choose.

(2.3) Collection and distribution of wide area water level detection information on the flood information collection and distribution server The abnormal water level detection and notification operation described in (2.1) above is the abnormal water level around the building B where the center node 2 is installed. It detects and notifies the narrow area water level detection information in which the above occurred. On the other hand, although no abnormal water level has occurred around the building B, the abnormal water level is in the area that causes the area where the building B is located, such as the upstream area of the area where the building B is located, when it is estimated that the area is affected by the flood. If this occurs, it is highly likely that an abnormal water level will occur in the area around the building B. Therefore, it is considered useful to notify the wide area water level detection information including the upstream area of the area where the building B is located. Therefore, in this section, the collection and distribution of wide area water level detection information and the notification processing will be described.

FIG. 9 is a flowchart showing the operation of the flood warning distribution process in the abnormal water level notification system of FIG. First, "abnormal water level information" is transmitted from one of the center nodes 2 installed in the buildings B in various places to the flood information collection and distribution server 1. As described above, the "abnormal water level information" includes the "router position information" and "router ID" of the router node 3 that has detected the abnormal water level, and the "water level detection information". When the flood warning information transmitting unit 15 of the flood information collection distribution server 1 receives the "abnormal water level information" (S431), the "router" is based on the "router position information" included in the "abnormal water level information". The map information acquisition unit 12 acquires a predetermined range around the "location information" and map information of the downstream area downstream of the "router location information". The peripheral and downstream areas of the "router position information" extracted here are referred to as "flood warning issuance areas". Next, the flood warning information transmitting unit 15 extracts the center node-related information whose position information is included in the flood warning issuing area from the center node-related information stored in the center node list storage unit 20. (S433), a "flood warning" is transmitted to the network address of the extracted center node-related information via the public communication line 6 (S434). Here, the "flood warning" is information for notifying that there is a flooded area in the upstream area of the building B, and is the information of the warning level L1 (see the section of "[1] System configuration" above). be.

The abnormality notification unit 22 of the center node 2 that received the "flood damage warning" transmitted from the flood information collection distribution server 1 (S321) detected an abnormal water level upstream of the building by the speaker 29 and the alarm lamp 30. The "flood damage warning" indicating the above is notified to the surroundings (S322).

By the above operation, it is possible to notify the wide area water level detection information including the upstream area of the area where the building B is located in the building B in each place where the center node 2 is installed.

In this embodiment, the leaf node 4 receives a question signal wirelessly transmitted from the router node 3 to the surrounding space, and transmits a leaf response signal to the question signal (question response method). Although steps S111 to S113 and S211 in FIG. 5 have been described), the method of transmitting the leaf response signal in the leaf node 4 is different from that of the interrogation signal from the router node 3, and each leaf node. It can also be configured by the case where 4 intermittently transmits a leaf response signal at predetermined time intervals (push method). In this case, the parts of steps S111 to S113 and S211 in FIG. 5 may be changed as shown in FIG. 10, for example.

In FIG. 10, the leaf node 4 transmits a leaf response signal once during a fixed cycle time Tc. First, the leaf node response unit 63 of the leaf node 4 resets the internal timer (S211), determines the transmission timing Ts (S222), and starts the internal timer (S223). The "transmission timing" is the time Ts from the start of the internal timer to the transmission of the leaf response signal, and is randomly determined by a random number in the range of 0 <Ts <Tc. Here, the transmission timing Ts is randomly determined in order to prevent the leaf response signal of the leaf node 4 from colliding with the leaf response signal of another leaf node 4 in the router node 3. When the time t of the internal timer reaches the transmission timing Ts (S224), the leaf node response unit 63 of the leaf node 4 generates a leaf response signal including the leaf ID and wirelessly transmits it to the surrounding space (S225). Then, after waiting until the clock time t of the internal timer reaches the cycle time Tc (S226), the process returns to step S221. As a result, the leaf response signal is transmitted once from one leaf node 4 during one cycle time Tc.

On the other hand, in the router node 3, a list (leaf list) of leaf IDs of leaf nodes 4 in the vicinity of which the leaf response signal is transmitted in normal times is registered in the leaf list storage unit 43 in advance. In this state, the internal timer is started, and during one cycle time Tc, the response receiving unit 46 receives the leaf response signal transmitted from each leaf node 4, and the leaf ID included in the received leaf response signal. And a list of reception strengths of the leaf response signal (reception leaf list) is generated (S111', S112'). When the clock time t of the internal timer reaches one cycle time Tc, the water level detection unit 47 collates the received leaf list with the leaf list stored in the leaf list storage unit 43, and each leaf in the vicinity of the router node 3 is collated. It is determined whether or not the transmission of the leaf response signal is interrupted among the nodes 4 (S113'). The following continues to step S114 described above, as in FIG. In this way, the leaf response signal is transmitted by the leaf response signal spontaneously transmitted by each leaf node 4 in the vicinity once every 1 cycle time Tc, regardless of the question signal of the question transmission unit 45. It is also possible to detect the interrupted leaf node 4 in the router node 3 to detect the occurrence of an abnormal water level and the inundation depth.

FIG. 11 is a diagram showing the overall configuration of the abnormal water level notification system according to the second embodiment of the present invention. The abnormal water level notification system of this embodiment is different from that of the first embodiment in that a relay node 7 is newly added. The relay node 7 is a node that relays the transmission when the router signal is transmitted from the router node 3 to the center node 2. The relay node 7 includes a relay node ID storage unit (not shown) that stores the relay node ID that is its own identification code. When the relay node 7 receives the router signal transmitted from the router node 3 or another relay node 7, the relay node 7 adds the relay node ID stored in the relay node ID storage unit to the router signal as routing information. Make a wireless call to the surrounding space. At this time, if the own relay node ID is added to the router signal as routing information, the router signal is discarded and wireless transmission to the surrounding space is not performed. This prevents the router signal from infinitely circulating between the plurality of relay nodes 7. By introducing the relay node 7 in this way, each center node 2 can receive a router signal from a wider range of router nodes 3 and notify the occurrence of an abnormal water level in a wider range. In particular, in mountainous areas, it is often difficult to install many center nodes 2 because the surrounding mountains make it difficult for radio waves to reach far away, and buildings such as private houses and business establishments are sparse. In such a case, by using the relay node 7 to expand the abnormal water level detection area covered by one center node 2, it is possible to accurately notify the abnormal water level.

In this embodiment, an example in which the water level detection from RSS U (i, t) of the leaf response signal of each leaf node 4 communicating with each router node 3 is performed in each center node 2 will be described. It is assumed that the overall configuration of the abnormal water level notification system in this embodiment is the same as that in FIG. FIG. 12 is a block diagram showing a functional configuration of the abnormal water level notification system according to the third embodiment. Compared with FIG. 3 of the first embodiment, the difference is that the water level detection unit 32 is newly added to the center node 2.

The operation of the abnormal water level notification system of the third embodiment is basically the same as that of the first embodiment, but in the present embodiment, in step S115a of FIG. 5, the water level detection unit 47 of the router node 3 has each leaf. The leaf response signal (leaf ID, RSS, height information) of the node 4 is used as the water level detection information, and in step S115b, the water level detection signal transmission unit 48 uses the water level detection information and the router position output by the position detection module 41. The router signal including the information and the router ID stored in the router ID storage unit 42 is wirelessly transmitted to the surrounding space by the long-distance communication interface 49 and the long-distance communication antenna 50.

Further, in step S116 of FIG. 5, the water level detection unit 47 enables the water level detection flag value, extracts the "height information" extracted from the CDLID with the largest inundation depth, and is an effective water level detection flag. The value, the detected height information, and the information (leaf ID, RSS, height information) of each received leaf response signal are output as water level detection information. Then, the water level detection signal transmission unit 48 transmits the router signal including the water level detection information, the router position information output by the position detection module 41, and the router ID stored in the router ID storage unit 42, as a long-distance communication interface. Radio transmission to the surrounding space is performed by the 49 and the long-distance communication antenna 50 (S117).

That is, in this embodiment, the router node 3 does not perform the estimation of the water level from the RSS of each leaf response signal, and the RSS information itself is used as the center node together with the "height information" of the leaf node 4 related to the leaf response signal. Send to 2.

In the center node 2, the water level detection unit 32 acquires the RSS of the leaf response signal of the leaf node 4 around the router node 3 from the router signal sent from each router node 3, and the leaf node 4 Detect the water level in the surroundings. This water level detection is the same as the method described in step S115a of Example 1. Then, when the abnormality notification unit 22 has a water level level higher than a certain level (for example, a value indicating "inundation" or higher) among the water level levels detected by the water level detection unit 32, or "water level detection information" in the router signal. If the water level detection flag value of "" is valid, the occurrence of an abnormal water level is notified by a speaker 29 with an alarm sound and a warning voice, and the alarm lamp 30 is turned on or blinked to generate an abnormal water level. Is notified to the surroundings.

In this way, it is also possible to configure the center node 2 to concentrate the detection of the water level around each leaf node 4 instead of the router node 3.

Finally, the relationship between the RSS U (i, t) of the leaf response signal received at the router node 3 and the water level level will be described. Consider the case where the water surface exists below the leaf node 4 when the leaf response signal is transmitted from the leaf node 4 to the router node 3. Here, for the sake of simplification of the principle explanation, it is assumed that the water surface is a still water surface without any waves. In this case, the transmission path of the leaf response signal is as shown in FIG. In FIG. 13, assuming that the leaf node 4 is the transmission point A and the router node 3 is the reception point B and the points A and B are on the hydrostatic surface, as shown in FIG. 13, in the vertical plane including the points A and B. Set the xy coordinate system with the x-axis in the horizontal direction and the y-axis in the vertical direction. Let the coordinates of the transmission point A be (0, y _A ), the coordinates of the reception point B be (x _B , y _B ), and the water surface be y = y ₀ . Assuming that the electromagnetic wave (leaf response signal) emitted from the transmission point A is a spherical wave spreading radially, the path of the electromagnetic wave reaching the reception point B is (1) directly from the transmission point A to the reception point B. Path p _AB , (2) Reflected from transmission point A at reflection point C on the water surface, and route to reception point B p _ACB , (3) Refraction from transmission point A at refraction point D on water surface into water It is conceivable that the path p _ADECB , etc., which enters, is reflected at the reflection point E on the bottom surface of the water, is refracted at the refraction point C on the water surface, and reaches the reception point B. The frequency of electromagnetic waves currently assumed is the frequency band (900 MHz to several GHz) used in RFID, Bluetooth (registered trademark), etc. In this frequency band, the reflectance of electromagnetic waves on the water surface is large, and underwater. Since it is considered that the electromagnetic wave is greatly attenuated in, only the paths p _AB and p _{AC B} are considered here. Let y _A0 be the distance from the water surface to the transmission point A, y _B0 be the distance from the water surface to the reception point B, and h _BA = y _B -y _A. At this time, at the path length l _AB of the route p _AB , the path length l _ACB of the route p _ACB , the x coordinate x _C of the reflection point C of the route p _ACB , the incident / reflection angle θ _C of the reflection point C, and the reception point B. The angle θ _B formed by the paths p _AB and p _AC B is expressed as follows, respectively.

Further, the electric field components of the electromagnetic wave incident on the receiving point B through the paths p _AB and p _ACB are set to E ₁ and E ₂ , respectively, and the components (p-polarized component) in the xy plane of the electric fields E ₁ and E ₂ are taken. ) Is E _1p , E _2p , the component in the direction perpendicular to the xy plane (s polarization component) is E _1s , E _2s , and E _1p , E _2p , E _1s , E _2s are expressed as follows. (See FIG. 14).

ここで、i₁, i₂は、其々、電場E₁, E₂の向きを表す単位ベクトル、i_zはx-y平面に垂直な向きの単位ベクトル、ωは電磁波の角周波数、φ₁, φ₂は、其々、受信点Ｂにおける送信点Ａに対する電磁波E₁, E₂の位相シフト量である。

Here, i ₁ and i ₂ are unit vectors representing the directions of the electric fields E ₁ and E ₂ , respectively, i _z is a unit vector in the direction perpendicular to the xy plane, ω is the angular frequency of the electromagnetic wave, φ ₁ , φ. ₂ is the phase shift amount of the electromagnetic waves E ₁ and E ₂ with respect to the transmission point A at the reception point B, respectively.

At this time, the time averages U _Ep ^(ave) and U _Es ^(ave) of the energy densities of the p-polarized electric field and the s polarized electric field at the receiving point B are expressed as follows, respectively.

If the wavelength of the electromagnetic wave is λ, the phase shift amounts φ ₁ and φ ₂ are expressed as follows.

Now, since it is assumed that the electromagnetic wave emitted from the transmission point A is a spherical wave, if the optical path length from the transmission point A is l, the energy density of the electromagnetic wave is attenuated in proportion to 1 / l ² . Therefore, assuming that the magnitudes of the p-polarization and s-polarization of the electric field component of the electromagnetic wave at the transmission point A are E _0p and E _0s , E _10p , E _20p , E _10s and E _20s are expressed as follows, respectively. ..

ここで、R_p, R_sは、其々、ｐ偏光，ｓ偏光の水面における強度反射率であり、水の屈折率をn（周波数2.4GHzではn=8.94（水温10℃））とすると次のように表される。

Here, R _p and R _s are the intensity reflectances of p-polarized and s-polarized water on the water surface, respectively, and if the refractive index of water is n (n = 8.94 (water temperature 10 ° C) at a frequency of 2.4 GHz), then It is expressed as.

From each of the above equations, the time average U _Ep ^(ave) of the relative energy density of the electric field component of the electromagnetic wave received at the receiving point B (the value obtained by dividing the electric field energy density of the receiving point B by the electric field energy density of the transmitting point A). , U _Es ^(ave) and the height of the water surface y _A0 are calculated as shown in FIGS. 15 and 16. Here, h _BA = 1 m, x _B = 1 m in FIG. 15, and x _B = 10 m in FIG. From FIGS. 15 and 16, as the water surface approaches the transmission point A, the interference between the direct wave and the reflected wave increases, so that it depends on the change in y _A0 of the relative energy density of the electric field component of the electromagnetic wave received at the reception point B. The vibration becomes large. Since the actual water surface vibrates in a pseudo-random manner, it is observed as a phenomenon in which the dispersion of the electromagnetic wave reception intensity at the reception point B increases as the water surface approaches the transmission point A.

FIG. 17 shows the results of measuring the change in reception intensity due to the change in the distance between the transmission point A and the water surface using an active beacon actually in the laboratory. In FIG. 17, the horizontal axis represents time and the vertical axis represents reception intensity (dB). Further, FIG. 18 is a diagram showing measurement conditions for the measurement of FIG. For measurement, poles are installed in the water tank, active beacons are installed by changing the height at 125 cm intervals, and the reception strength of the signal transmitted from each beacon by the receiver outside the water tank while pouring water into the water tank. Was carried out by observing. The measurement results of (a), (b), and (c) of FIG. 17 represent the reception strength of the signal from the beacons of (a), (b), and (c) of FIG. 18, respectively.

From FIG. 17, when water starts to be injected into the water tank, the dispersion of the reception intensity starts to increase, and the dispersion of the reception intensity increases as the water surface approaches each beacon. This is because as the water surface approaches the beacon, the influence of the interference between the direct wave propagating from the beacon to the receiving antenna and the reflected wave increases (FIGS. 15 and 16), and the change in reception intensity due to the shaking of the water surface increases. It is understood that it is because of. When the water surface approaches the beacon further, the average value of the reception intensity starts to gradually decrease and the effective sampling number (the number of signals successfully received) of the received signal starts to decrease from the point where the water surface approaches to 10 cm or less. This is because when the water surface is very close to the beacon, the angle of incidence of the reflected wave on the water surface approaches the brewer angle, so that the reflection of the p-polarized wave does not occur so much, and the overall reception intensity decreases by that amount. It is understood that it is because of. FIG. 19 is a diagram showing changes in the intensity reflectances R _p and R _s of water with respect to the incident angle θ _C at a frequency f = 2.4 GHz. From FIG. 19, at the frequency f = 2.4 GHz, the brewer angle of the reflection between air and water is about 84 degrees, and the reflectance of the p-polarized wave suddenly increases from the vicinity where the incident angle θ _C exceeds 60 degrees. It can be seen that it is decreasing.

Then, when the beacon is submerged, the reception intensity drops sharply. It is understood that this is because the radio waves emitted from the underwater beacon are reflected and refracted on the water surface. Since the refraction coefficient is large at the frequency f = 2.4GHz, the refraction angle of the electromagnetic wave incident on the water surface from the water is about 90 degrees, and most of the refracted waves propagate along the water surface, so that they are separated from the water surface. It is considered that the strength of the radio wave reaching the receiving antenna at the position is greatly weakened. Further, when the water depth of the beacon becomes large after being submerged, the radio waves emitted from the underwater beacon are greatly attenuated in the water, so that the reception intensity further drops sharply, leading to communication blackout.

Therefore, it can be seen that it is possible to detect that inundation has started by observing an increase in the variance of the signal reception intensity from the transmission point (leaf node 4) at the reception point (router node 3). .. Further, it can be seen that it is possible to detect that the transmission point (leaf node 4) is close or submerged by observing a decrease in the average value of the reception intensity.

FIG. 20 is a diagram showing the overall configuration of the abnormal water level notification system according to the fourth embodiment of the present invention. The abnormal water level notification system of this embodiment has basically the same configuration as that of the first embodiment, but the mobile terminal device 5 is configured to also function as a router node 3 (hereinafter, “portable”). Terminal devices 5, 3 "). That is, the mobile terminal devices 5 and 3 include the touch panel display 71, the position detection module 72, the map distribution request unit 73, the map receiving unit 74, the map display unit 75, the line communication interface 76, and the line communication antenna 77 shown in FIG. As shown in FIG. 21, the position detection module 41, the router ID storage unit 42, the leaf list storage unit 43, the initialization unit 44, the initialization switch 44a, the question transmission unit 45, the response reception unit 6, and the water level. It also has the functions of a detection unit 47, a water level detection signal transmission unit 48, a long-distance communication interface 49, a long-distance communication antenna 50, a short-range communication interface 51, and a short-range communication antenna 52. Further, in the mobile terminal devices 5 and 3, when the water level detection unit 47 generates the water level detection information for which the value indicating the water level detection is valid, the abnormality notification that the occurrence of the abnormal water level is notified to the surroundings by voice or display. A unit 78 and a speaker 79 are provided. Here, as the mobile terminal device 5, a smartphone or tablet can be used.

In this way, by making the mobile terminal devices 5 and 3 also function as the router node 3, if the resident or the resident always carries the mobile terminal devices 5 and 3, the resident or the resident can use the abnormal water level notification system. No matter where you are, you can receive the signal from the leaf node 4 and know the occurrence of abnormal water level in real time, which leads to the quick evacuation of residents or residents.

In this embodiment, among the router nodes 3, only the mobile terminal devices 5 and 3 are provided with the abnormality notification unit 78 and the speaker 79, but all the router nodes 3 are provided with the abnormality notification unit 78 and the speaker. It can also be configured to include 79.

FIG. 22 is a diagram showing the overall configuration of the abnormal water level notification system according to the fifth embodiment of the present invention. The abnormal water level notification system according to the fifth embodiment is basically the same as the abnormal water level notification system of the fourth embodiment, but each router node 3 and each center node 2 are ad hoc networks (multi-hop wireless networks). The difference is that they are connected by. In this case, one of the center nodes 2 is in charge of the role of the network coordinator. Such an ad hoc network configuration can be easily realized by, for example, Bluetooth (registered trademark). By connecting each router node 3 and each center node 2 by an ad hoc network in this way, each router node 3 and each center node 2 also have a function as a relay node 7. Therefore, even if a part of the router node 3 or the center node 2 is submerged in water and the communication is interrupted, the router node 3 or the center node 2 in which the communication is not interrupted by the multipath routing protocol can be used. It becomes possible to continuously perform network communication via the system, and it is possible to improve the communication robustness of the entire system.

FIG. 23 is a diagram showing the overall configuration of the abnormal water level notification system according to the sixth embodiment of the present invention. The abnormal water level notification system according to the sixth embodiment is basically the same as the abnormal water level notification system of the fifth embodiment, except that the center node 2 and the roof side router node 3a are combined. That is, the center nodes 2 and 3 in FIG. 23 also have the functional configurations of the router node 3a on the shop side. By doing so, the network configuration can be simplified and the system can be introduced at a lower cost. As the center nodes 2 and 3, it is also possible to use smart meters that are currently becoming widespread.

1 Flood damage information collection and distribution server 10 Map database 11 Server side receiver 12 Map information acquisition unit 13 Flood damage occurrence map generation unit 14 Map distribution unit 15 Flood damage caution information transmission unit 16 Line communication interface 17 Flood damage information database 18 Flood damage map database 19 Measurement points Correction database 20 Center node list storage 2 Center node 21 Center node receiver 22 Abnormality notification unit 23 Abnormal water level information transmission unit 24 Line communication interface 25 Long-distance communication interface 26 Long-distance communication antenna 27 Short-range communication interface 29 Speaker 30 Alarm lamp 31 Router list storage unit 32 Water level detection unit 3 Router node 3a Shopside router node 3b Peripheral router node 41 Location detection module 42 Router ID storage unit 43 Leaf list storage unit 44 Initialization unit 44a Initialization switch 45 Question transmission unit 46 Response reception 47 Water level detection unit 48 Water level detection signal transmission unit 49 Long-distance communication interface 50 Long-distance communication antenna 51 Short-range communication interface 52 Short-range communication antenna 4 Leaf node 61 Leaf ID storage unit 62 Leaf node receiver 63 Leaf node response unit 64 Short-range communication interface 65 Short-range communication antenna 5 Portable terminal device 71 Touch panel display 72 Position detection module 73 Map distribution request unit 74 Map receiver 75 Map display unit 76 Line communication interface 77 Line communication antenna 6 Public communication line 7 Relay node B building

Claims (10)

It is an abnormal water level notification system that detects and notifies the occurrence of abnormal water level due to rainfall.
A center node consisting of a smartphone or computer installed indoors in a building or loaded with an app and executed .
One or more router nodes installed indoors or outdoors around the center node, or composed of smartphones or computers on which the app is loaded and executed .
A leaf node to be installed one or more in the vicinity of each router node is provided.
The router node is
A router node position output means that detects and outputs router position information that represents self-position by a global positioning satellite system, or outputs router position information that represents self-position recorded in advance in a position information storage means.
A response receiving means for receiving a leaf response signal transmitted from each leaf node intermittently with respect to a question signal wirelessly transmitted to the surrounding space for each leaf node or at predetermined time intervals.
Based on the presence or absence of the leaf node whose transmission of the leaf response signal is interrupted, or based on the intensity change of the leaf response signal, the presence or absence of water approach or inundation is determined, and the presence or absence of water approach or inundation is determined. A water level detection means that generates water level detection information for which a value indicating water level detection is valid when it is determined, and
A water level detection signal transmission means for wirelessly transmitting the water level detection information output by the water level detection means to the center node together with the router position information is provided.
The leaf node is
A leaf ID storage means for storing a leaf ID which is an identification code of the leaf node, and a leaf ID storage means.
When the interrogation signal transmitted from the router node is received, or intermittently at predetermined time intervals, the leaf response signal including the leaf ID stored in the leaf ID storage means is generated and wirelessly transmitted to the surrounding space. Equipped with a leaf node response means to send
The center node is
A communication interface that communicates with the outside via a public communication line,
A center node receiving means for receiving the water level detection information and the router position information wirelessly transmitted from the router node, and
When the center node receiving means receives the water level detection information and the router position information, if the value indicating the water level detection of the water level detection information is valid, the occurrence of the abnormal water level is notified to the surroundings by voice or display. 1 abnormality notification means and
When the center node receiving means receives the water level detection information and the router position information, and the value indicating the water level detection of the water level detection information is valid, the water level detection information and the router position information are transmitted to the public communication. Abnormal water level information transmission means to be transmitted to an external flood information collection and distribution server via a line,
An abnormal water level notification system characterized by being equipped with.



With the multiple center nodes placed in various buildings,
It is equipped with a flood information collection and distribution server connected to the center node via a public communication line.
The flood information collection and distribution server is
A flood map database that manages flood damage transaction information, which is transaction information for displaying abnormal water level occurrence information on a map, and
A server-side receiving means for receiving the water level detection information and the router position information transmitted from each center node, and
A map information acquisition means for acquiring map information from a map distribution server via a public communication line or from a map database provided in the flood information collection distribution server.
A flood damage occurrence map generation means that generates the flood damage occurrence transaction information and stores it in the flood damage map database based on the received water level detection information, the router position information, and the map information.
Map information in a predetermined range centered on the designated position specified by the location information by the map information acquisition means in response to the map distribution request and location information transmitted from the outside via the public communication line (hereinafter, """Designated location area map information") is acquired, and flood damage occurrence information is displayed in the designated position area map information based on the flood damage occurrence transaction information related to the designated position area map information extracted from the flood damage map database. A map distribution means that generates the flood damage occurrence map information and distributes the flood damage occurrence map information,
The abnormal water level notification system according to claim 1, wherein the system is provided with. A plurality of the leaf nodes are installed in the vicinity of the router nodes at different heights from each other, and the leaf ID storage means of the leaf nodes are assigned heights according to their respective heights. The leaf ID including the information is stored,
The router node includes a leaf list storage means for generating and storing a list of the leaf IDs included in the leaf response signal received in the router node in normal times.
The water level detecting means of the router node extracts the leaf ID of the leaf node from which the reply of the leaf response signal is interrupted to the question signal from the leaf IDs stored in the leaf list storage means. , The water level detection information including the height information included in the extracted leaf ID is generated.
The flood damage occurrence map generation means of the flood damage information collection / distribution server determines the occurrence position of the abnormal water level and the occurrence position thereof based on the water level detection information including the received water level information, the router position information, and the map information. The abnormal water level notification system according to claim 2, wherein the flood damage occurrence map information showing the water level on a map is generated. The flood damage occurrence map generation means acquires the altitude data around the position indicated by the router position information from the map information based on the received router position information, and the position information based on the acquired surrounding altitude data. 2. The described abnormal water level notification system. The flood damage occurrence map generation means acquires elevation data and road route information around the position indicated by the router position information from the map information based on the received router position information, and obtains the route information of the road at the position indicated by the location information. The inundation estimation road range, which is the road range included in the inundation estimation range, is extracted as well as the surrounding inundation estimation range, and the flood damage occurrence map information showing the location of the abnormal water level and the inundation estimation road range on the map. The abnormal water level notification system according to claim 2 or 3, wherein the abnormal water level notification system is produced. It is equipped with a mobile terminal device connected to the flood information collection and distribution server via a public communication line.
The mobile terminal device is
With the display
A mobile terminal position detection means that detects position information indicating its own position using a global positioning satellite system,
A map distribution request means for transmitting the map distribution request to the flood information collection / distribution server via a public communication line together with the position information detected by the mobile terminal position detection means.
A map receiving means for receiving the flood damage occurrence map information transmitted from the flood damage information collection and distribution server via a public communication line in response to the map distribution request.
A map display means for displaying the flood damage occurrence map information received by the map receiving means on the display, and a map display means.
The abnormal water level notification system according to any one of claims 2 to 5, wherein the abnormal water level notification system is provided. Each router node includes a router ID storage means for storing a router ID which is an identification code of the router node.
The water level detection signal transmission means of each router node wirelessly transmits the water level detection information output by the water level detection means to the center node as water level detection information together with the router position information and the router ID. ,
Each of the router nodes includes a roof-side router node installed on the side of the building where the center node is installed or near the ground indoors, and peripheral router nodes installed at various locations away from the building where the center node is installed. The router ID of the shop-side router node includes the shop-side node identification information for identifying the shop-side router node.
The first abnormality notification means of the center node is
When the center node receiving means receives the water level detection information and the router ID wirelessly transmitted from the router node,
When the router ID indicates that the node identification information on the shop side is a peripheral router node, a caution alarm indicating that an abnormal water level has been detected around the building is notified to the surroundings.
When the router ID indicates that the shopside node identification information is the shopside router node, it is characterized in that it notifies the surroundings of an emergency evacuation warning indicating that an abnormal water level has been detected just before the building. The abnormal water level notification system according to any one of claims 2 to 6. The flood information collection and distribution server is
When the server-side receiving means receives the water level detection information and the router position information transmitted from the center node.
Based on the map information, among the buildings in which the center nodes are installed, the buildings that are presumed to be affected by flood damage to the position specified by the router position information are extracted.
A flood warning information transmission means for transmitting flood warning information via a public communication line to each of the center nodes installed in the extracted building is provided.
The first abnormality notification means of the center node indicates that an abnormal water level is detected upstream of the building when the flood caution information transmitted from the flood information collection / distribution server is received via a public communication line. The abnormal water level notification system according to claim 7, wherein the flood warning is notified to the surroundings. The abnormal water level notification system according to any one of claims 1 to 8, wherein a part of the router node is a mobile terminal device. Part or all of the router node
The water level detecting means is provided with a second abnormality notifying means for notifying the surroundings of the occurrence of an abnormal water level by voice or display when the water level detecting means for which a value indicating the water level detection is valid is generated. The abnormal water level notification system according to any one of claims 1 to 9, wherein the abnormal water level notification system is characterized.

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