JP2022037172A - Water surface condition monitoring system and water surface condition monitoring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water surface condition monitoring system capable of monitoring the condition of a flow in a view of flooding, and a water surface condition monitoring method.

SOLUTION: The water surface condition monitoring system includes: a water surface altitude calculation unit that calculates the altitude of the water surface based on a distance measurement signal received by a float floating on the surface of the water from a positioning satellite; and an altitude difference calculation unit that calculates the difference between the altitude of the top and the altitude of the water surface based on the altitude of the top of an embankment and the altitude of the water surface. The operation interval of the float is changed based on the difference calculated by the altitude difference calculation unit.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a water surface condition monitoring system for monitoring the water surface condition and a water surface condition monitoring method.

In recent years, abnormal weather such as torrential rain has been increasing, and flooding of water areas including rivers, ponds, and lakes has been increasing, such as water flowing out beyond the top of the embankment due to flooding. In order to suppress the occurrence of human damage due to the flooding of the water area, it is desirable to measure the condition of the water area so that appropriate evacuation guidance can be provided.

In Patent Document 1, the altitude of the riverbed is measured based on the distance measurement signal from the positioning satellite, and the altitude of the water surface of the river is measured based on the distance measurement signal from the positioning satellite. A system for calculating the altitude difference with is proposed.

Japanese Unexamined Patent Publication No. 11-257957

However, the above-mentioned conventional system calculates the altitude from the riverbed to the water surface, and even if the altitude from the riverbed to the water surface is known, it is not easy to determine whether or not the river overflows. This is not limited to rivers, but also to other bodies of water such as ponds or lakes.

The present invention has been made in view of the above, and an object of the present invention is to obtain a water surface condition monitoring system capable of monitoring the water surface condition from the viewpoint of flooding of the water area.

In order to solve the above-mentioned problems and achieve the object, the water surface condition monitoring system of the present invention is a water surface altitude calculation unit that calculates the altitude of the water surface based on the distance measurement signal received from the positioning satellite by the float floating on the water surface. And an altitude difference calculation unit that calculates the difference between the altitude of the top and the altitude of the water surface based on the altitude of the top of the embankment and the altitude of the water surface, and the operation interval of the float is calculated by the altitude difference calculation unit. It will be changed based on the difference made.

According to the present invention, there is an effect that the state of the water area can be measured from the viewpoint of the flooding of the water area.

The figure which shows the schematic structure of the water surface condition monitoring system which concerns on Embodiment 1. The figure which shows the configuration example of the water surface condition monitoring system which concerns on Embodiment 1. The figure which shows the arrangement example of the float and the outdoor apparatus which concerns on Embodiment 1. The figure which shows the relationship of the float, the outdoor apparatus, the cloud server, and the information providing server which concerns on Embodiment 1. The figure which shows an example of the specific structure of the float which concerns on Embodiment 1. The figure which shows an example of the installation state of the float which concerns on Embodiment 1. A flowchart showing an example of processing of the float processing unit according to the first embodiment. A flowchart showing an example of the operation interval determination process of the float processing unit according to the first embodiment. The figure which shows an example of the structure of the outdoor device which concerns on Embodiment 1. A flowchart showing an example of processing of the processing unit of the outdoor device according to the first embodiment. The figure which shows an example of the configuration of the cloud server which concerns on Embodiment 1. The figure which shows the screen example which is displayed on the display part of the terminal apparatus which concerns on Embodiment 1. The figure which shows the screen example which is displayed on the display part of the terminal apparatus which concerns on Embodiment 1. A flowchart showing an example of processing of the processing unit of the cloud server according to the first embodiment. The figure which shows an example of the hardware configuration of the float, the outdoor apparatus, and the cloud server which concerns on Embodiment 1. The figure which shows the configuration example of the water surface condition monitoring system which concerns on Embodiment 2. The figure which shows an example of the specific structure of the float which concerns on Embodiment 2. A flowchart showing an example of processing of the float processing unit according to the second embodiment. The figure which shows an example of the structure of the outdoor device which concerns on Embodiment 2. A flowchart showing an example of processing of the processing unit of the outdoor device according to the second embodiment. The figure which shows the configuration example of the water surface condition monitoring system which concerns on Embodiment 3. The figure which shows an example of the structure of the outdoor device which concerns on Embodiment 3. A flowchart showing an example of processing of the processing unit of the outdoor device according to the third embodiment. The figure which shows an example of the configuration of the cloud server which concerns on Embodiment 3. A flowchart showing an example of processing of the processing unit of the cloud server according to the third embodiment. The figure which shows an example of the specific structure of the float which concerns on Embodiment 4. The figure which shows an example of the installation state of the float which concerns on Embodiment 4. The figure which shows the arrangement example of the outdoor apparatus which concerns on Embodiment 5.

Hereinafter, the water surface condition monitoring system and the water surface condition monitoring method according to the embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited to this embodiment.

Embodiment 1.
FIG. 1 is a diagram showing a schematic configuration of a water surface condition monitoring system according to the first embodiment of the present invention. In the following, a river will be taken as an example of the water area, but the water area for monitoring the water surface condition by the water surface condition monitoring system may be a lake, a dam lake, or the ocean.

As shown in FIG. 1, the water surface condition monitoring system according to the first embodiment calculates the difference Δh between the altitude hf of the water surface and the altitude hlc of the top of the embankment based on the position of the float floating on the water surface of the river. , The altitude difference information indicating the calculated difference Δh is output. In the following, the difference Δh may be referred to as the altitude difference Δh.

As described above, in the configuration of the water surface condition monitoring system according to the first embodiment, the difference Δh between the altitude hf of the water surface and the altitude hlc of the top of the embankment is calculated. Can be measured. Then, based on the information indicating the altitude difference Δh, it is possible to easily grasp how high the water surface is until the river overflows.

Hereinafter, the configuration and processing of the water surface condition monitoring system will be specifically described. FIG. 2 is a diagram showing a configuration example of the water surface condition monitoring system according to the first embodiment.

As shown in FIG. 2, the water surface condition monitoring system 100 according to the first embodiment includes a plurality of floats 1 ₁ to 1 _n , a plurality of outdoor devices 2 ₁ to 2 _m , a cloud server 3, and an information providing server 4. And. In the following, floats 1 ₁ to 1 _n may be collectively referred to as float 1, and outdoor devices 2 ₁ to 2 _m may be collectively referred to as outdoor device 2. Further, n and m are integers of 1 or more.

Information can be transmitted and received between the float 1 and the outdoor device 2 by wireless communication. The outdoor device 2 can communicate with the cloud server 3 via the base station ₆₁ and the network 5 by wireless communication. The cloud server 3 and the information providing server 4 can communicate with each other via the network 5. The cloud server 3 and the information providing server 4 can communicate with the terminal device 7 via the network 5, and can communicate with the terminal device 8 via the network ₅ and the base station 62. The network 5 is the Internet, but may be a WAN (Wide Area Network) other than the Internet.

FIG. 3 is a diagram showing an arrangement example of the float 1 and the outdoor device 2, and FIG. 4 is a diagram showing the relationship between the float 1, the outdoor device 2, the cloud server 3, and the information providing server 4.

As shown in FIGS. 3 and 4, the float 1 is a device that floats on the water surface 92 of the river 90, and the outdoor device 2 is a device that is arranged on the embankment 91. The float 1 is movably attached to the pole 80 in the extending direction of the pole 80 via an attachment portion (not shown). The float 1 may have the function of a water rescue buoy. When the float 1 has the function of a water rescue buoy, it has a buoyancy such that a part of the float 1 comes out on the water surface 92 when a person clings to the float 1.

Each outdoor device 2 targets a plurality of floats 1 for communication, and wirelessly communicates with the plurality of floats 1 to transmit and receive information. In the example shown in FIG. ₃ , the outdoor device 2 ₁ wirelessly communicates with the floats _{1 1} to 13 and the outdoor device 2 ₂ wirelessly communicates with the floats 14 to ₁₆ .

Further, in the example shown in FIG. ₃ , a plurality of floats ₁ , 1, ₂ , and 13 are arranged along the width direction of the river 90, which is the direction crossing the water flow of the river 90, and similarly, the width of the river 90. A plurality of floats 1 ₄ , 1 ₅ and ₁₆ are arranged along the direction.

The reason why the plurality of floats 1 are arranged along the width direction of the river 90 in this way is that the flow rate of the river 90 differs in the width direction of the river 90 depending on the shape of the river 90, and the water surface 92 in the width direction of the river 90. This is because the altitude hf may be different. For example, in a curved or meandering region of river 90, due to the influence of centrifugal force, the flow rate on the outside of the curve of river 90 is larger than that on the inside of the curve, and the flow rate is larger on the outside of the curve than on the inside of the curve of river 90. The altitude hf of the water surface 92 is higher.

In the water surface condition monitoring system 100 according to the first embodiment, since a plurality of floats 1 are arranged along the width direction of the river 90, the altitude difference Δh at a plurality of measurement points in the direction crossing the river flow can be obtained. It becomes possible to measure.

The float 1 receives a plurality of ranging signals transmitted from the plurality of positioning satellites 98a and the quasi-zenith satellite 98b and an error correction signal transmitted from the quasi-zenith satellite 98b, and receives the ranging signal and the error correction signal. Based on the above, the altitude hf of the water surface 92 is calculated. The float 1 outputs the water level altitude information indicating the calculated altitude hf of the water surface 92 to the outdoor device 2. The positioning satellite 98a is a GNSS (Global Navigation Satellite System) satellite, and the quasi-zenith satellite 98b is a QZSS (Quasi-Zenith Satellite System) satellite. The error correction signal, also called a QZSS reinforcement signal or an L6 signal, includes error correction information which is information for performing centimeter-class error correction. The quasi-zenith satellite 98b has a function as a positioning satellite, and in the following, the positioning satellite 98a and the quasi-zenith satellite 98b may be collectively referred to as a satellite 98.

The outdoor device 2 receives a plurality of distance measurement signals transmitted from the plurality of satellites 98 and an error correction signal transmitted from the quasi-zenith satellite 98b, and based on the received distance measurement signal and the error correction signal, The altitude hlc of the top 93 of the embankment 91 is calculated.

The outdoor device 2 receives the water surface altitude information from the float 1. The outdoor device 2 calculates the altitude difference Δh, which is the difference between the altitude hf of the water surface 92 and the altitude hlc of the top 93, based on the calculated altitude hlc of the top 93 and the received water surface altitude information. The outdoor device 2 transmits the altitude difference information indicating the calculated altitude difference Δh to the cloud server 3.

As described above, the water surface condition monitoring system 100 according to the first embodiment calculates the altitude hf of the water surface 92 and the altitude hlc of the top end 93 based on the distance measurement signal and the error correction information, so that the altitude difference is obtained. Δh can be calculated accurately.

Further, in the water surface condition monitoring system 100 according to the first embodiment, the altitude hhf of the water surface 92 and the zenith 93 are based on the plurality of distance measurement signals from the same plurality of satellites 98 and the error correction information from the quasi-zenith satellite 98b. Calculate the altitude hlc of. Since the calculation result of the altitude hf of the water surface 92 and the calculation result of the altitude hlc of the top end 93 have the same error, the altitude difference Δh can be calculated accurately.

The cloud server 3 is a server constructed on the network 5. The cloud server 3 generates altitude change information indicating a change in altitude difference Δh based on the altitude difference information acquired from the outdoor device 2, and predicts altitude difference Δh based on the change in altitude difference Δh. Generates predictive information that indicates the change in.

The cloud server 3 can transmit at least one of altitude difference information, altitude change information, and prediction information in response to a request from the terminal device 8. Further, the cloud server 3 determines the altitude difference information, the altitude change information, and the prediction when the altitude difference Δh becomes equal to or less than the first threshold value or when the change amount of the altitude difference Δh becomes equal to or more than the second threshold value. At least one piece of information can be sent. This makes it possible to provide the user of the terminal device 8 with information indicating the state of the river 90.

The cloud server 3 transmits altitude difference information, altitude change information, and prediction information to the information providing server 4. The information providing server 4 can provide information indicating the state of the river 90 to the terminal device 7 based on the altitude difference information, the altitude change information, and the prediction information.

The information providing server 4 is a server operated by a local government such as a municipality. The information providing server 4 can generate alarm information for each area based on altitude difference information, altitude change information, and prediction information, and can output alarm information from an alarm device provided for each area. The warning information includes at least one of altitude difference information, altitude change information, prediction information, and evacuation information indicating an evacuation site. As a method of notifying the alarm information by the alarm device, there is a method of notifying the alarm information by at least one of voice and light in a predetermined range area. Further, the information providing server 4 can transmit alarm information to the disaster prevention information homepage managed by the local government and display the alarm information on the disaster prevention information homepage. Further, the information providing server 4 can also transmit alarm information to an application installed in an information terminal owned by an individual and display the alarm information on the information terminal owned by the individual.

Hereinafter, the configurations and processes of the float 1, the outdoor device 2, and the cloud server 3 will be described in more detail in order. FIG. 5 is a diagram showing an example of a specific configuration of the float 1.

As shown in FIG. 5, the float 1 includes a float unit 10, a housing unit 11, a receiving antenna unit 12, a communication antenna unit 13, a solar panel 14, a secondary battery 15, and a processing unit 16. To prepare for.

The float portion 10 is composed of a resin member having buoyancy. The resin member is a foamed resin or a urethane resin, and the foamed resin is a member obtained by foaming polyethylene, polypropylene, or styrene. The float portion 10 may be made of a member having buoyancy, and the member constituting the float portion 10 is not limited to the resin member. Further, by using the existing buoy in the river 90 as the float portion 10, the installation cost of the float 1 can be reduced.

The housing unit 11 has a storage space for accommodating the receiving antenna unit 12, the communication antenna unit 13, the solar panel 14, the secondary battery 15, and the processing unit 16 so that water does not enter the storage space. In addition, the housing portion 11 has a waterproof structure.

The configuration of the float portion 10 and the housing portion 11 is not limited to the example shown in FIG. The housing portion 11 shown in FIG. 5 is inserted into the hollow portion of the float portion 10 formed in an annular shape and attached to the float portion 10, but the float portion 10 is not provided with the hollow portion and is mounted on the float portion 10. The housing portion 11 may be arranged, or may be an integral structure with the float portion. In the case of an integral structure, the float portion does not have to be limited to the resin member.

The receiving antenna unit 12 is an example of a float-side receiving antenna unit, and has an antenna that receives a plurality of ranging signals transmitted from a plurality of satellites 98 and an error correction signal transmitted from the quasi-zenith satellite 98b. The receiving antenna unit 12 may have a configuration in which an antenna for receiving the ranging signal and an antenna for receiving the error correction signal are separately provided.

The communication antenna unit 13 has an antenna for wireless communication. The float 1 can transmit and receive wireless communication of a wireless PAN (Personal Area Network) or a wireless signal of a wireless LAN (Local Area Network) via the communication antenna unit 13.

The wireless PAN is a ZigBee or Bluetooth® compliant with the communication standard defined in IEEE802.154. Further, the wireless PAN includes LPWA (Low Power Wide Area). The float 1 is not limited to the wireless PAN and the wireless LAN, and may be configured to communicate with the outdoor device 2 by wireless communication other than the wireless PAN and the wireless LAN, and the outdoor device 2 may be wired instead of wireless. It may be configured to communicate with.

The solar panel 14 converts sunlight into electric power and outputs it to the secondary battery 15. If the remaining amount of the secondary battery 15 is larger than a predetermined value, the electric power of the solar panel 14 may be directly output to the processing unit 16. In the example shown in FIG. 5, the solar panel 14 is arranged in the storage space of the housing portion 11, but when the solar panel 14 has a waterproof structure, it may be arranged outside the storage space of the housing portion 11. good.

The secondary battery 15 is charged by the electric power from the solar panel 14, and supplies electric power to the processing unit 16. The secondary battery 15 is, for example, a lithium ion battery, a nickel hydrogen battery, or a lead storage battery. The processing unit 16 is driven by power supply from the solar panel 14, but the processing unit 16 may have a configuration in which power is supplied by wire from the ground. Since the processing unit 16 has a configuration in which power is supplied by wire from the ground, the voltage drop due to power consumption in the float 1 can be suppressed, so that the processing cycle for positioning can be shortened and the positioning accuracy of the float 1 can be improved. can.

The processing unit 16 includes a position calculation processing unit 17 and a communication processing unit 18. The position calculation processing unit 17 is an example of the water surface altitude calculation unit, and calculates the altitude hf of the water surface 92 based on a plurality of distance measurement signals and error correction signals received by the receiving antenna unit 12.

The range-finding signal of each satellite 98 includes information indicating the time when each satellite 98 transmitted the range-finding signal and information indicating the position of the satellite 98. The position calculation processing unit 17 calculates an observed value of the distance between satellite floats, which is the distance between each satellite 98 and the float 1, from the distance measurement signal of the satellite 98.

In GNSS positioning, due to multiple factors including the clock error of satellite 98, the orbital error of satellite 98, the ionospheric delay error which is the delay error of the ionospheric signal due to the ionosphere, and the convection zone delay error which is the delay error of the distance measurement signal due to the convection zone. The positioning accuracy obtained from the ranging signal is about 10 m.

Therefore, the position calculation processing unit 17 corrects the error of the observed value of the distance between satellite floats obtained from the ranging signal based on the error correction information included in the error correction signal transmitted from the quasi-zenith satellite 98b. Calculates highly accurate position information.

The error correction information includes a plurality of error values including a clock error value of the satellite 98, an orbital error value of the satellite 98, an ionospheric delay error value, and a tropospheric delay error value. The clock error value of satellite 98 and the orbital error value of satellite 98 are region-independent errors.

The ionospheric delay error value and the tropospheric delay error value are region-dependent errors and are calculated for each grid point. The grid points are virtual measurement points arranged at predetermined intervals in each of the latitude direction and the longitude direction. Each outdoor device 2 is set so that a plurality of floats 1 existing in the same grid are communication targets. This makes it possible to improve the measurement accuracy of the altitude difference Δh.

The position calculation processing unit 17 calculates the position of the float 1 by correcting the error included in the observed amount of the distance between satellite floats based on the error correction information included in the error correction signal. The position information indicating the position of the float 1 is information including the longitude, latitude, and altitude of the float 1.

FIG. 6 is a diagram showing an example of the installation state of the float 1. As shown in FIG. 6, the float 1 is attached to the pole 80 via the attachment portion 81, and is movable in the extending direction of the pole 80. The mounting portion 81 has an annular member 85 inserted through the pole 80 and a member 86 connecting the float 1 and the annular member 85. The float 1 is rotatably attached to the pole 80 about the pole 80 by an annular member 85. Since the flow of the river 90 is from the upstream to the downstream, the float 1 is located on the downstream side of the pole 80, and the latitude and longitude of the float 1 can be regarded as a fixed state.

Floats 1 ₁ to 13 shown in FIG. ₃ are attached to a bridge 94 built across the river 90. Specifically, the floats _{1 1} to 13 are attached to a pole 80 whose upper end is fixed to a side edge portion on the downstream side of the bridge 95 of the bridge 94 via a mounting portion 81. Since the pole 80 is fixed to the bridge 95 in this way, the float 1 is installed on the bridge 95 of the bridge 94 erected on the river 90, so that the installation cost of the float 1 can be reduced, and the pole can be reduced. 80 can be stably fixed. The side edge portion of the bridge 95 is, for example, the side end portion of the balustrade in the bridge 95. Further, the lower end of the pole 80 can be fixed to the bottom of the river 90.

Since the floats _{1 1} to 13 are attached to the side edges of the bridge 95 as described above, they are located downstream of the bridge 95 due to the flow of water in the river 90. Therefore, it is possible to prevent the bridge 94 from becoming an obstacle between the floats 1 ₁ to ₁₃ and the quasi-zenith satellite 98b, and it is possible to suppress a decrease in the reception level of the error correction signal in the floats _{1 1} to 13. ..

Further, since the extending direction of the pole 80 is a direction along the vertical direction which is the altitude direction, the positions of the float 1 in the latitude direction and the longitude direction can be constrained. Therefore, the accuracy of the position calculated by the position calculation processing unit 17 can be improved, and the load of the calculation processing can be reduced. Hereinafter, the processing of the position calculation processing unit 17 will be described more specifically.

Immediately after activation, the position calculation processing unit 17 calculates a plurality of values including latitude, longitude, and altitude, a clock error of float 1 which is a receiver, and a carrier phase ambiguity between each satellite 98. Using the Kalman filter as the state quantity, the position of the float 1 is estimated from the distance measurement signals and the error correction information received continuously. The initial values of latitude, longitude, and altitude are set to the approximate latitude, longitude, and altitude at the installation location of the float 1, and the initial standard deviation value is, for example, 10 [m] in each direction. ] Is set.

The float 1 is attached to a pole 80 extending in the altitude direction so as to be movable in the altitude direction, and can be regarded as being fixed in the latitude direction and the longitude direction. Therefore, when the Kalman filter is used, the latitude and longitude process noise values can be set to 0, and the latitude and longitude process noise can be treated as a static state quantity.

In order to take into account changes in the latitude and longitude of the pole 80 due to crustal movements or vibrations, the standard deviation value of the latitude and longitude process noise is set to a small value such as 0.00001 [m / s], and the latitude and longitude process. Noise can also be treated as a quasi-static state quantity.

Further, the altitude of the float 1 changes with time due to the altitude change of the water surface 92 of the river 90. Therefore, when the Kalman filter is used, a large value is given as a standard deviation value of the high-level process noise as compared with the latitude and longitude process noise. As an example of the standard deviation value of such a high degree of process noise, a value such as 0.02 [m / s] can be given.

The estimated values of latitude and longitude have converged after a sufficient time has elapsed from the start of the altitude calculation of the float 1 in the position calculation processing unit 17. Therefore, after the set time has elapsed, the position calculation processing unit 17 regards the latitude and longitude values as fixed values and removes them from the state quantity. The set time is a time longer than the time when the estimated values of latitude and longitude converge and can be regarded as fixed values, for example, one week.

After the set time has elapsed, the position calculation processing unit 17 uses fixed values of latitude and longitude to determine the altitude, the clock error of the receiver, and the carrier phase ambiguity between each satellite 98. Using the Kalman filter, the altitude is estimated from the distance measurement signals and error correction information that are continuously received. As a result, the accuracy of the position calculated by the position calculation processing unit 17 can be improved, and the load of the calculation processing can be reduced.

The position calculation processing unit 17 regards the latitude and longitude process noise as a quasi-static state quantity even after the set time has elapsed, as before the set time has elapsed, and the latitude and longitude process noise. The standard deviation value of can be continuously reduced to a small value.

Further, since the error of the altitude hf of the water surface 92 obtained by the calculation and the error of the altitude hlc of the calculated top end 93 include an error of the same degree, the calculated altitude hf of the water surface 92 and the calculated altitude of the top end 93 are included. By obtaining the difference from the hlc, the error of the altitude hf of the water surface 92 and the error of the altitude hlc of the top end 93 are offset, so that the detection error of the difference Δh can be reduced.

The position calculation processing unit 17 generates water level altitude information indicating the altitude hf of the water surface 92 of the river 90 based on the calculated altitude information, and outputs the water surface altitude information to the communication processing unit 18. The communication processing unit 18 transmits a radio signal including water surface altitude information acquired from the position calculation processing unit 17 from the communication antenna unit 13.

In the float 1 shown in FIG. 5, when the float 1 is floated on the river 90, the receiving antenna unit 12 is arranged at an altitude corresponding to the altitude hf of the water surface 92 of the river 90. Therefore, the position calculation processing unit 17 outputs the calculated altitude information to the communication processing unit 18 as water surface altitude information indicating the altitude hf of the water surface 92. Note that "matching the altitude hwf" means that the difference between the height of the receiving antenna unit 12 and the altitude hf of the water surface 92 is less than the resolution in the altitude estimation calculation by the position calculation processing unit 17.

When the float 1 is floated on the river 90, the float 1 may arrange the receiving antenna unit 12 at an altitude that does not match the altitude fwf of the water surface 92 of the river 90. In this case, the position calculation processing unit 17 corrects the calculated altitude value by the difference between the altitude of the receiving antenna unit 12 and the altitude hp of the water surface 92, and the corrected value indicates the altitude whf of the water surface 92. It can be output to the communication processing unit 18 as water surface altitude information.

The communication processing unit 18 can receive altitude difference information indicating the altitude difference Δh from the outdoor device 2. The processing unit 16 changes at least a part of the operation interval of the processing executed by the processing unit 16 based on the altitude difference information notified from the outdoor device 2 and at least one of the battery remaining amount P of the secondary battery 15. be able to.

The "operation interval" is an interval of operation periods, which is a period during which the processing unit 16 executes processing. In the processing of the processing unit 16, the position calculation processing unit 17 generates the water surface altitude information, the communication processing unit 18 outputs the water surface altitude information to the communication antenna unit 13, and the communication processing unit 18 is the communication antenna unit 13. It includes the process of acquiring altitude difference information from. When the operation interval is changed depending on the remaining battery level P, the processing of the processing unit 16 may not include the processing of acquiring altitude difference information from the communication antenna unit 13.

When the altitude difference Δh is less than the threshold value hth, the processing unit 16 shortens the operation interval Tc as compared with the case where the altitude difference Δh is equal to or more than the threshold value hth. As a result, when the possibility that the river 90 is flooded is low, the operation interval Tc becomes long, so that the decrease in the battery remaining amount P can be suppressed. Further, the processing unit 16 can lengthen the operation interval Tc as the altitude difference Δh increases. As a result, the lower the possibility that the river 90 is flooded, the longer the operation interval Tc becomes, and the decrease in the battery remaining amount P can be suppressed.

Further, when the battery remaining amount P is less than the threshold value Pth, the processing unit 16 lengthens the operation interval Tc as compared with the case where the battery remaining amount P is equal to or more than the threshold value Pth. Therefore, when the battery remaining amount P is small, the operation interval Tc becomes long, and it is possible to suppress a decrease in the battery remaining amount P. Further, the processing unit 16 can lengthen the operation interval Tc as the remaining battery level P decreases. As a result, the smaller the battery remaining amount P is, the longer the operation interval Tc is, and the decrease in the battery remaining amount P can be suppressed.

The processing unit 16 can change the operation interval Tc based on the score Sc, which is a value obtained by weighting and adding the altitude difference Δh and the reciprocal of the battery remaining amount P, respectively. When the score Sc is equal to or greater than the threshold value Sth, the processing unit 16 can increase the operation interval Tc as compared with the case where the score Sc is less than the threshold value Sth. Further, the processing unit 16 can lengthen the operation interval Tc as the score Sc increases.

Further, the processing unit 16 can change the operation interval Tc based on the amount of power generation of the solar panel 14 instead of the battery remaining amount P. The processing unit 16 can shorten the operation interval Tc when the amount of power generation of the solar panel 14 is large, and increase the operation interval Tc when the amount of power generation of the solar panel 14 is small.

Further, instead of the above processing, the processing unit 16 sets the operation interval Tc to the basic time interval T0, which is an instruction value from the cloud server 3, when the cloud server 3 gives an instruction to set the operation interval, and the cloud server. The process of step S16 can also be performed when there is no instruction for setting the operation interval from 3.

In this case, the cloud server 3 notifies the float 1 of the operation interval setting instruction directly or via the outdoor device 2. When the wireless signal including the operation interval setting instruction is received by the communication antenna unit 13, the processing unit 16 can determine that the operation interval setting instruction is given from the cloud server 3.

Here, when the cloud server 3 does not instruct the operation interval setting, the processing unit 16 sets the operation interval Tc to the basic time interval T0, which is an instruction value from the cloud server 3, and sets the operation interval from the cloud server 3. If there is an instruction in, the process of step S16 can also be performed.

Further, the communication processing unit 18 outputs the water surface altitude information indicating the altitude hf of the water surface 92 via the communication antenna unit 13, and also acquires the water surface altitude information indicating the altitude hf of the water surface 92 from the other float 1. Can be done. The position calculation processing unit 17 can correct the calculation result of the altitude hf of the water surface 92 of the river 90 based on the water surface altitude information generated by the other float 1 from the communication processing unit 18.

Here, the altitude hf calculated by the floats 1 ₁ to 13 is set to the altitudes hwf ₁ to hwf ₃ , and the position calculation processing unit 17 of the float 1 ₁ indicates the altitude hf ₂ and the water surface altitude information indicating the _{hwf 3 .} And is obtained. When the variation of the altitudes hp ₁ to hp ₃ or the variation of the amount of change of the altitudes hp ₁ to hp ₃ is equal to or more than the threshold value, the position calculation processing unit 17 corrects the altitude hp f ₁ so as to reduce the variation. It is possible to generate water surface altitude information indicating the corrected altitude _hp1 .

The position calculation processing unit 17 can correct the altitude hp ₁ by adding or subtracting a correction amount for reducing the difference between the average value of the altitudes hp ₁ to hp ₃ and the altitude hp ₁ to the altitude hp ₁ . Further, the position calculation processing unit 17 adds or subtracts a correction amount for reducing the difference between the average value of the changes in the altitudes hwf ₁ to hwf ₃ and the change in the altitude hwf ₁ to the altitude hwf ₁ to increase the altitude hwf ₁ . It can be corrected. The position calculation processing unit 17 can also correct the altitude hhf ₁ by weighting according to the position of the float 1 in the width direction of the river 90.

Further, in the above-mentioned example, the error correction signal is described as being transmitted from the quasi-zenith satellite 98b, but the error correction signal is a float 1 and an outdoor device from a ground device (not shown) which is a device installed on the ground. It may be transmitted to 2 wirelessly or by wire.

Next, the processing of the processing unit 16 of the float 1 will be described with reference to the flowchart. FIG. 7 is a flowchart showing an example of the processing of the processing unit 16 of the float 1 according to the first embodiment, and the processing is repeatedly executed by the processing unit 16.

As shown in FIG. 7, the processing unit 16 determines whether or not the operation period has arrived (step S10). The processing unit 16 determines that the operation period has arrived when the time of the operation interval Tc has elapsed after the end of the previous operation period and the current operation period has arrived.

When the position calculation processing unit 17 of the processing unit 16 determines that the operation period has come (step S10: Yes), the position calculation processing unit 17 receives a plurality of ranging signals from the plurality of satellites 98 from the receiving antenna unit 12 (step S11). Further, the error correction signal of the quasi-zenith satellite 98b is received from the receiving antenna unit 12 (step S12).

The position calculation processing unit 17 calculates the position of the float 1 based on the distance measurement signal and the error correction signal (step S13). The position calculation processing unit 17 generates water surface altitude information based on the position of the float 1, and the communication processing unit 18 of the processing unit 16 communicates a transmission signal including the water surface altitude information generated by the position calculation processing unit 17. Output to the antenna unit 13 (step S14).

Further, the communication processing unit 18 acquires altitude difference information via the communication antenna unit 13 (step S15), and executes an operation interval determination process (step S16). When the processing of step S16 is completed, or when it is determined that the operation period has not arrived (step S10: No), the processing unit 16 ends the processing shown in FIG. 7.

FIG. 8 is a diagram showing an example of the operation interval determination process in step S16. As shown in FIG. 8, the processing unit 16 determines whether or not the altitude difference Δh is less than the threshold value hth (step S20). When the processing unit 16 determines that the altitude difference Δh is less than the threshold value hth (step S20: Yes), the processing unit 16 sets the operation interval Tc to the first time T1 (step S21).

When the processing unit 16 determines that the altitude difference Δh is not less than the threshold value hth (step S20: No), the processing unit 16 determines whether or not the battery remaining amount P is less than the threshold value Pth (step S22). When the processing unit 16 determines that the remaining battery level P is less than the threshold value Pth (step S22: Yes), the processing unit 16 sets the operation interval Tc to the second time T2, which is longer than the first time T1 (step S23). ..

When the processing unit 16 determines that the remaining battery level P is not less than the threshold value Pth (step S22: No), the operation interval Tc is set to the third time T3 which is longer than the first time T1 and shorter than the second time T2. Set (step S24). When the processing of steps S21, S23, and S24 is completed, the processing unit 16 ends the processing shown in FIG.

Next, the configuration and processing of the outdoor device 2 will be described. FIG. 9 is a diagram showing an example of the configuration of the outdoor device 2 according to the first embodiment. As shown in FIG. 9, the outdoor device 2 according to the first embodiment includes a receiving antenna unit 20, a first communication antenna unit 21, a second communication antenna unit 22, a processing unit 23, and a storage unit 24. Be prepared.

The receiving antenna unit 20 is an example of a receiving antenna unit on the embankment side, and has an antenna that receives a plurality of ranging signals transmitted from a plurality of satellites 98 and an error correction signal transmitted from the quasi-zenith satellite 98b. The receiving antenna unit 20 may have a configuration in which an antenna for receiving the ranging signal and an antenna for receiving the error correction signal are separately provided.

The first communication antenna unit 21 has an antenna for wireless communication. The outdoor device 2 can transmit and receive a wireless signal to and from the float 1 via the first communication antenna unit 21. The outdoor device 2 may be configured to communicate with the float 1 by wire instead of wirelessly.

The second communication antenna unit 22 has an antenna for wireless communication. The outdoor device 2 communicates with the cloud server 3 via the base station ₆₁ and the network 5 by transmitting and receiving radio signals via the second communication antenna unit 22. The outdoor device 2 may be configured to communicate with the cloud server 3 by wire instead of wirelessly.

The processing unit 23 includes a first communication processing unit 31, a position calculation processing unit 32, an altitude difference calculation unit 33, and a second communication processing unit 34. The first communication processing unit 31 acquires water surface altitude information included in the radio signal received by the first communication antenna unit 21. The first communication processing unit 31 outputs the acquired water surface altitude information to the altitude difference calculation unit 33.

The position calculation processing unit 32 is an example of the top end altitude calculation unit, and calculates the altitude hlc of the top end 93 of the embankment 91 based on a plurality of distance measurement signals and error correction signals received by the receiving antenna unit 20. do. The advanced calculation process in the position calculation processing unit 32 is performed in the same manner as the advanced calculation process in the position calculation processing unit 17. The position calculation processing unit 32 outputs the top end altitude information indicating the calculated altitude hlc of the top end 93 to the altitude difference calculation unit 33.

The receiving antenna unit 20 is arranged at an altitude corresponding to the altitude hlc of the top end 93. Therefore, the position calculation processing unit 32 outputs the calculated altitude information to the altitude difference calculation unit 33 as the top end altitude information indicating the altitude hlc of the top end 93. Note that "matching the altitude hlc" means that the difference between the height of the receiving antenna unit 20 and the altitude hlc of the top end 93 is less than the resolution in the altitude estimation calculation by the position calculation processing unit 32.

The receiving antenna unit 20 may be arranged at an altitude that does not match the altitude hlc of the top end 93. In this case, the position calculation processing unit 32 corrects the calculated altitude value by the difference between the altitude of the receiving antenna unit 20 and the altitude hlc of the top end 93, and the corrected value is the altitude hlc of the top end 93. It can be output to the altitude difference calculation unit 33 as the top altitude information indicating.

The altitude difference calculation unit 33 determines the altitude hlc of the top end 93 and the water surface 92 based on the water surface altitude information acquired from the first communication processing unit 31 and the top end altitude information acquired from the position calculation processing unit 32. The difference Δh from the altitude hpf is calculated. The altitude difference calculation unit 33 stores the altitude difference information indicating the calculated difference Δh in the storage unit 24.

The altitude difference calculation unit 33 is based on the water surface altitude information transmitted from the plurality of floats 1 set as communication targets and the top height information acquired from the position calculation processing unit 32. The difference Δh between the altitude hlc and the altitude hf of the water surface 92 is calculated for each float 1. As a result, it is possible to calculate the difference Δh of the measurement points where each float 1 set as the communication target is arranged.

The altitude difference calculation unit 33 can correct a difference Δh of 1 or more based on the difference Δh of each measurement point. Here, the altitude hf of the water surface 92 calculated by the floats 1 ₁ to 13 is defined as the altitudes hp _{1 to hp 3, and the difference Δh between the altitudes hp 1 to hp 3} and the altitude _hlc is defined as the difference Δh ₁ to Δh ₃ .

When the variation of the difference Δh ₁ to Δh ₃ or the variation of the amount of change of the difference Δh ₁ to Δh ₃ is equal to or more than the threshold value, the altitude difference calculation unit 33 has the difference Δh ₁ to Δh ₃ so as to reduce the variation. A difference Δh of 1 or more can be corrected. Thereby, the calculation error of the difference Δh can be reduced. The altitude difference calculation unit 33 may also perform weighting according to the position of the float 1 in the width direction of the river 90 to correct a difference Δh of one or more of the differences Δh ₁ to Δh ₃ .

Further, when the altitude difference calculation unit 33 cannot acquire the altitude hwf ₂ among the altitudes hwf ₁ to hwf ₃ due to the failure of the float 1 ₂ , the altitude difference calculation unit 33 obtains the altitude hwf ₂ by interpolation processing based on the altitudes hwf ₁ and hwf ₃ . Can be calculated. The altitude difference calculation unit 33 can, for example, set the average value of the altitudes hwf ₁ and hwf ₃ to the altitude hwf ₂ .

The second communication processing unit 34 is an example of an output unit, and the altitude difference information indicating the difference Δh of each measurement point is read from the storage unit 24, and the radio signal including the read altitude difference information is read from the second communication antenna unit 22. Send to the cloud server 3.

When a radio signal including information other than altitude difference information such as flow rate is transmitted from float 1, the first communication processing unit 31 passes from the float 1 via the first communication antenna unit 21 to other than altitude difference information such as flow rate. Information can be acquired and the acquired information can be stored in the storage unit 24. Then, the second communication processing unit 34 can read out information such as the flow rate stored in the storage unit 24, and can transmit a radio signal including the information such as the read flow rate from the second communication antenna unit 22 to the cloud server 3. ..

The outdoor device 2 may have a solar panel and a secondary battery as in the float 1. In this case, the processing unit 23 of the outdoor device 2 operates by the electric power from the secondary battery, similarly to the processing unit 16 of the float 1. In order to suppress power consumption, the processing unit 23 has an operation interval Tm of the position calculation processing unit 32 and the altitude difference calculation unit 33 and an altitude difference information transmission interval Ts to the cloud server 3 based on the difference Δh of each measurement point. Can be changed.

Specifically, in the processing unit 23, when the average value Δhav or the maximum value Δhmax of the difference Δh of the plurality of measurement points is the threshold value hth1 or more, the processing unit 23 is compared with the case where the average value Δhav or the maximum value Δhmax is less than the threshold value hth1. , The operation interval Tm and the transmission interval Ts can be lengthened. Further, the processing unit 23 can lengthen the operation interval Tm and the transmission interval Ts as the average value Δhav or the maximum value Δhmax increases.

Further, when the battery remaining amount P of the secondary battery is less than the threshold value Pth, the processing unit 23 may lengthen the operation interval Tm and the transmission interval Ts as compared with the case where the battery remaining amount P is equal to or more than the threshold value Pth. The smaller the battery level P is, the longer the transmission interval Ts can be. Further, the processing unit 23 can change the operation interval Tm and the transmission interval Ts based on the amount of power generation of the solar panel instead of the battery remaining amount P.

Further, in the above-mentioned example, the processing unit 23 acquires the error correction information from the error correction signal received by the receiving antenna unit 20, but acquires the error correction information from the float 1 to obtain the altitude hlc of the top end 93. It may be configured to calculate. In this case, the processing unit 16 of the float 1 transmits a wireless signal including error correction information from the communication antenna unit 13, and the processing unit 23 of the outdoor device 2 is included in the wireless signal acquired by the first communication antenna unit 21. Get the error correction information.

Next, the processing of the processing unit 23 of the outdoor device 2 will be described with reference to the flowchart. FIG. 10 is a flowchart showing an example of the processing of the processing unit 23 according to the first embodiment, and the processing is repeatedly executed by the processing unit 23.

As shown in FIG. 10, the first communication processing unit 31 of the processing unit 23 acquires the water surface altitude information from the float 1 (step S30). Further, the position calculation processing unit 32 of the processing unit 23 receives a plurality of ranging signals from the plurality of satellites 98 from the receiving antenna unit 20 (step S31), and further, an error of the quasi-zenith satellite 98b from the receiving antenna unit 20. The correction signal is received (step S32).

The position calculation processing unit 32 calculates the altitude hlc of the top end 93 based on the distance measurement signal and the error correction signal acquired in steps S31 and S32 (step S33). Then, the altitude difference calculation unit 33 of the processing unit 23 is based on the altitude hf of the water surface 92 included in the water surface altitude information acquired in step S30 and the altitude hlc of the top end 93 calculated in step S33. The difference Δh is calculated (step S34).

The second communication processing unit 34 of the processing unit 23 outputs the altitude difference information indicating the altitude difference Δh calculated by the altitude difference calculation unit 33 (step S35). In the process of step S35, the second communication processing unit 34 reads the altitude difference information indicating the difference Δh of each measurement point from the storage unit 24, and the radio signal including the read altitude difference information is clouded from the second communication antenna unit 22. Send to server 3.

When the first communication processing unit 31 of the processing unit 23 determines that the cloud server 3 has instructed the operation interval setting, the first communication processing unit 31 sends a wireless signal including the operation interval setting instruction from the cloud server 3 to the float 1. 1 It is possible to output from the communication antenna 21, and at the same time, it is possible to change the operation interval and the transmission interval of the own device to the indicated values from the cloud server 3. In such processing, when the second communication processing unit 34 receives a wireless signal including an operation interval setting instruction from the cloud server 3, the first communication processing unit 31 receives an operation interval setting instruction from the cloud server 3. It can be determined that the server has been used.

Next, the configuration and processing of the cloud server 3 will be described. FIG. 11 is a diagram showing an example of the configuration of the cloud server 3 according to the first embodiment. As shown in FIG. 11, the cloud server 3 according to the first embodiment includes a first communication unit 40, a second communication unit 41, a processing unit 42, and a storage unit 43.

The first communication unit 40 is a communication unit for acquiring altitude difference information from the outdoor device 2 via the network 5. The second communication unit 41 is a communication unit for providing water surface status information to the information providing server 4 and the terminal device 8 via the network 5. The first communication unit 40 and the second communication unit 41 may be configured by one communication unit.

The processing unit 42 includes an altitude difference information acquisition unit 50, a water surface condition information generation unit 51, and an information provision processing unit 52. The altitude difference information acquisition unit 50 acquires altitude difference information transmitted from the outdoor device 2 from the first communication unit 40, and stores the acquired altitude difference information in the storage unit 43. The storage unit 43 stores the history information of the altitude difference Δh including the altitude difference information acquired in the past.

The water surface condition information generation unit 51 predicts altitude change information, which is information indicating a change in altitude difference Δh at each measurement point, and prediction of each measurement point, based on the history information of altitude difference Δh stored in the storage unit 43. It is possible to generate prediction information indicating a change in the altitude difference Δh. The water surface condition information generation unit 51 stores the generated altitude change information and prediction information in the storage unit 43. The water surface condition information generation unit 51 can generate altitude change information and prediction information at different positions in the width direction of the river 90.

The information providing processing unit 52 reads at least one of the altitude difference information, the altitude change information, and the predicted information from the storage unit 43, and transfers the read information from the second communication unit 41 to the information providing server 4 via the network 5. Send. Further, the information providing processing unit 52 provides altitude difference information, altitude change information, when the altitude difference Δh becomes equal to or less than the first threshold value, or when the amount of change in the altitude difference Δh becomes equal to or more than the second threshold value. And at least one of the prediction information can be transmitted to the information providing server 4. The information providing server 4 can provide the information acquired from the cloud server 3 to the terminal device 7.

Further, the information providing processing unit 52 can transmit at least one of altitude difference information, altitude change information, and prediction information in response to a request from the terminal device 8. Further, the information providing processing unit 52 provides altitude difference information, altitude change information, when the altitude difference Δh becomes equal to or less than the first threshold value, or when the amount of change in the altitude difference Δh becomes equal to or more than the second threshold value. And at least one of the prediction information can be transmitted to the terminal device 8. This makes it possible to provide the user of the terminal device 8 with information indicating the state of the river 90.

12 and 13 are diagrams showing screen examples displayed on the display units of the terminal devices 7 and 8 based on the information provided by the information providing processing unit 52. As shown in the screen 70 shown in FIG. 12, the information providing processing unit 52 provides screen information including a graph showing changes in the altitude difference Δh at a plurality of measurement points including the A point and the B point to the information providing server 4 and the terminal device. Can be provided to 8.

Further, as shown in the screen 71 shown in FIG. 13, the information providing processing unit 52 provides screen information including a graph showing a change in the past altitude difference Δh and a change in the altitude difference Δh predicted in the future to the information providing server 4 and the information providing server 4. It can be provided to the terminal device 8. In the screen 71 shown in FIG. 13, the hatched portion indicates the change in the altitude difference Δh predicted in the future, and “%” shown in FIG. 13 indicates the prediction probability.

The information provided by the information providing processing unit 52 is not limited to the above-mentioned information, and it is possible to process the information transmitted from the outdoor device 2 and provide various information to the information providing server 4 and the terminal device 8. can.

Next, the processing of the processing unit 42 of the cloud server 3 will be described with reference to the flowchart. FIG. 14 is a flowchart showing an example of the processing of the processing unit 42 according to the first embodiment, and the processing is repeatedly executed by the processing unit 42.

As shown in FIG. 14, the altitude difference information acquisition unit 50 of the processing unit 42 performs altitude difference information reception processing (step S50). In the process of step S50, the altitude difference information acquisition unit 50 acquires the altitude difference information transmitted from the outdoor device 2 from the first communication unit 40, and stores the acquired altitude difference information in the storage unit 43.

Next, the water surface condition information generation unit 51 of the processing unit 42 performs the water surface condition information generation processing (step S51). In the process of step S51, the water surface condition information generation unit 51 generates various information including altitude difference information, altitude change information, and prediction information based on the history information of the altitude difference Δh stored in the storage unit 43. , The generated information is stored in the storage unit 43.

Next, the information provision processing unit 52 of the processing unit 42 performs information provision processing (step S52). In the process of step S52, as described above, the information providing processing unit 52 provides at least one of a plurality of information including the altitude difference information, the altitude change information, and the prediction information to the information providing server 4 or the terminal device 8. can do. The processing unit 42 of the cloud server 3 can transmit a wireless signal including the above-mentioned operation interval setting instruction from the first communication unit 40 to the float 1 or the outdoor device 2.

FIG. 15 is a diagram showing an example of the hardware configuration of the float 1, the outdoor device 2, and the cloud server 3 according to the first embodiment. As shown in FIG. 15, the float 1 is a computer including a processor 101, a memory 102, an HDD 103, and an interface circuit 104. The processor 101, the memory 102, the HDD 103, and the interface circuit 104 can send and receive data to and from each other by the bus 105. The receiving antenna unit 12 and the communication antenna unit 13 are realized by the interface circuit 104.

The processor 101 executes the function of the processing unit 16 by reading and executing the OS and the processing program stored in the HDD 103. It should be noted that a part or all of the processing unit 16 may be configured by hardware represented by an ASIC (Application Specific Integrated Circuit) and an FPGA (Field Programmable Gate Array). That is, the processing circuit that realizes a part or all of the processing unit 16 may be dedicated hardware.

Further, the processor 101 transmits an OS and a processing program from one or more storage media of a magnetic disk, a USB (Universal Serial Bus) memory, an optical disk, a compact disk, and a DVD (Digital Versatile Disc) via an interface (not shown). It can also be stored in the read HDD 103 and executed.

Similarly, the outdoor device 2 is a computer including a processor 101, a memory 102, an HDD 103, and an interface circuit 104. The receiving antenna unit 20, the first communication antenna unit 21, and the second communication antenna unit 22 are realized by the interface circuit 104. Further, the storage unit 24 is realized by the memory 102 and the HDD 103. The processor 101 executes the function of the processing unit 23 by reading and executing the OS and the processing program stored in the HDD 103. It should be noted that a part or all of the processing unit 23 may be configured by hardware typified by ASIC and FPGA. That is, the processing circuit that realizes a part or all of the processing unit 23 may be dedicated hardware.

Similarly, the cloud server 3 can use a computer including a processor 101, a memory 102, an HDD 103, and an interface circuit 104. Further, the cloud server 3 may be realized by a plurality of servers connected to each other. When the cloud server 3 includes a plurality of servers, the process executed by the cloud server 3 can be virtually regarded as one server by executing the processes by the plurality of servers. The first communication unit 40 and the second communication unit 41 are realized by the interface circuit 104. Further, the storage unit 43 is realized by the memory 102 and the HDD 103. The processor 101 executes the function of the processing unit 42 by reading and executing the OS and the processing program stored in the HDD 103.

As described above, the water surface condition monitoring system 100 according to the first embodiment includes an altitude difference calculation unit 33 and a second communication processing unit 34, which is an example of an output unit. The altitude difference calculation unit 33 calculates the difference Δh between the altitude hf of the water surface 92 and the altitude hlc of the top end 93 of the embankment 91 based on the position of the float 1 floating on the water surface 92. The second communication processing unit 34 outputs information indicating the difference Δh calculated by the altitude difference calculation unit 33. In this way, the water surface condition monitoring system 100 calculates the altitude difference Δh between the altitude hf of the water surface 92 and the altitude hlc of the top end 93 of the embankment 91, so that the state of the river 90 is measured from the viewpoint of the flooding of the river 90. can do. Therefore, based on the information indicating the altitude difference Δh, it is possible to easily grasp how high the altitude of the water surface 92 is until the river 90 overflows. This also applies to lakes, dam lakes, or oceans other than river 90.

Compared to the ocean, the river 90 can be equipped with an outdoor device 2 that is not affected by waves in the vicinity of the float 1, for example, within a few kilometers. Therefore, by canceling each position measurement error when calculating the altitude difference Δh, , The accuracy of the altitude difference Δh can be improved.

Further, the water surface condition monitoring system 100 includes a receiving antenna unit 12 and a position calculation processing unit 17 which is an example of the water surface altitude calculation unit. The receiving antenna unit 12 is provided on the float 1 and receives the ranging signal transmitted from the satellite 98. The position calculation processing unit 17 calculates the altitude hf of the water surface 92 based on the distance measurement signal received by the reception antenna unit 12. The altitude difference calculation unit 33 calculates the difference Δh based on the altitude hf of the water surface 92 calculated by the position calculation processing unit 17. As described above, since the water surface condition monitoring system 100 calculates the altitude hf of the water surface 92 by the distance measuring signal transmitted from the satellite 98, the receiving antenna unit 12 for receiving the distance measuring signal is provided on the float 1. The altitude hf of the water surface 92 can be easily obtained.

Further, the water surface condition monitoring system 100 includes a receiving antenna unit 20 and a position calculation processing unit 32 which is an example of the top altitude calculation unit. The receiving antenna unit 20 is arranged on the embankment 91 and receives the ranging signal transmitted from the satellite 98. The position calculation processing unit 32 calculates the altitude hlc of the top end 93 based on the distance measurement signal received by the reception antenna unit 20. The altitude difference calculation unit 33 calculates the difference Δh based on the altitude hf of the water surface 92 calculated by the position calculation processing unit 17 and the altitude hlc of the top end 93 calculated by the position calculation processing unit 32. As described above, the water surface condition monitoring system 100 calculates the altitude hlc of the crown 93 by the distance measuring signal transmitted from the satellite 98, similarly to the altitude hf of the water surface 92.

Further, the position calculation processing unit 17 and the position calculation processing unit 32 are based on error correction information for correcting an altitude error transmitted from the quasi-zenith satellite 98b or a ground device (not shown) and obtained from the ranging signal. Corrects the altitude error obtained by the ranging signal. Therefore, it is possible to obtain the water surface altitude information indicating the altitude hf of the water surface 92 and the altitude information of the crown indicating the altitude hlc of the top end 93 with high accuracy.

Further, the position calculation processing unit 17 is provided in the float 1, and the position calculation processing unit 32 is provided in the outdoor device 2. Therefore, in the float 1, it is possible to obtain the water surface altitude information indicating the altitude hf of the water surface 92 with high accuracy.

At least one operation interval of the position calculation processing unit 17, the position calculation processing unit 32, the altitude difference calculation unit 33, and the second communication processing unit 34 is when the difference Δh calculated by the altitude difference calculation unit 33 is relatively small. , The difference Δh is shorter than when it is relatively large. As a result, power consumption in the water surface condition monitoring system 100 can be suppressed in a state where the difference Δh is large and the water area does not overflow.

Further, the water surface condition monitoring system 100 includes a plurality of position calculation processing units 32 that calculate the altitude of the water surface based on the positions of floats 1 that are different from each other. Based on the altitude hf of the water surface 92 calculated by each of the plurality of position calculation processing units 32, the altitude hf of the water surface 92 calculated by at least one position calculation processing unit 32 among the plurality of position calculation processing units 32 is corrected. .. As a result, even when a large error is momentarily generated in a part of the plurality of position calculation processing units 32 due to multipath or obstacles, it is possible to obtain an altitude hf of the water surface 92 in which the error is suppressed.

Further, the water surface condition monitoring system 100 includes a pole 80 and a mounting portion 81. The pole 80 is installed in the body of water. The mounting portion 81 mounts the float 1 on the pole 80 so as to be movable in the extending direction of the pole 80. By making the extending direction of the pole 80 along the vertical direction, the float 1 can be regulated in the latitude direction and the longitude direction, so that the accuracy of the position calculated by the position calculation processing unit 17 can be improved, and further. , The load of arithmetic processing can be reduced.

Further, the float 1 may have a function of a water rescue buoy. In this case, by installing the float 1 at the place where the water rescue buoy is arranged, it is possible to avoid a state in which a large number of floats having different purposes float in the river 90.

Embodiment 2.
In the first embodiment, the float 1 uses the error correction information to generate high-precision water surface altitude information, but in the second embodiment, the outdoor device uses the error correction information to generate high-precision water surface altitude information. In that respect, it differs from the first embodiment. In the following, the components having the same functions as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted, and the differences from the water surface condition monitoring system 100 of the first embodiment will be mainly described.

FIG. 16 is a diagram showing a configuration example of the water surface condition monitoring system according to the second embodiment. As shown in FIG. 16, the water surface condition monitoring system 100A according to the second embodiment includes a plurality of floats _1A 1-1A _n , a plurality of outdoor devices 2A _{1-2A m} , a cloud server 3, and an information providing server 4. And. In the following, floats 1A ₁ to 1A _n may be collectively referred to as float 1A, and outdoor devices 2A ₁ to 2 _Am may be collectively referred to as outdoor devices 2A.

FIG. 17 is a diagram showing an example of a specific configuration of the float 1A. As shown in FIG. 17, the float 1A includes a float unit 10, a housing unit 11, a receiving antenna unit 12A, a communication antenna unit 13, a solar panel 14, a secondary battery 15, and a processing unit 16A. To prepare for.

The receiving antenna unit 12A has an antenna that receives a plurality of ranging signals transmitted from the plurality of satellites 98. The processing unit 16A includes a position calculation processing unit 17A and a communication processing unit 18A. The position calculation processing unit 17A calculates an observed value of the distance between satellite floats based on a plurality of distance measurement signals received by the reception antenna unit 12A.

The communication processing unit 18A transmits a radio signal including GNSS positioning information indicating the observed value of the distance between satellite floats calculated by the position calculation processing unit 17A from the communication antenna unit 13. The GNSS positioning information may be information based on a plurality of ranging signals and may be information that can be corrected by the error correction information in the outdoor device 2A.

FIG. 18 is a flowchart showing an example of processing of the processing unit 16A of the float 1A according to the second embodiment. The processes of steps S10, S11, S15, and S16 shown in FIG. 18 are the same as the processes of steps S10, S11, S15, and S16 shown in FIG. 7, and are omitted below.

As shown in FIG. 18, GNSS positioning information is generated (step S13A) based on a plurality of ranging signals received by the receiving antenna unit 12A of the processing unit 16A, and the generated GNSS positioning information is transmitted from the communication antenna unit 13. Output to the outdoor device 2 (step S14A).

Next, the configuration and processing of the outdoor device 2A will be described. FIG. 19 is a diagram showing an example of the configuration of the outdoor device 2A according to the second embodiment. As shown in FIG. 19, the outdoor device 2A according to the second embodiment includes a receiving antenna unit 20, a first communication antenna unit 21, a second communication antenna unit 22, a processing unit 23A, and a storage unit 24. Be prepared.

The processing unit 23A includes a first communication processing unit 31A, a position calculation processing unit 32A, an altitude difference calculation unit 33, and a second communication processing unit 34. The first communication processing unit 31A acquires the GNSS positioning information included in the radio signal received by the first communication antenna unit 21. The first communication processing unit 31A outputs GNSS positioning information to the position calculation processing unit 32A.

Similar to the position calculation processing unit 32, the position calculation processing unit 32A calculates the altitude hlc of the top end 93 of the embankment 91 based on the plurality of distance measurement signals received by the receiving antenna unit 20 and the error correction signal. .. The position calculation processing unit 32A outputs the top end altitude information indicating the altitude hlc of the top end 93 to the altitude difference calculation unit 33.

Further, the position calculation processing unit 32A is based on the GNSS positioning information acquired by the first communication processing unit 31A and the error correction signal received by the reception antenna unit 20 by the same processing as the position calculation processing unit 17. , Calculate the altitude hf of the water surface 92. The position calculation processing unit 32A outputs the water surface altitude information indicating the altitude hf of the water surface 92 to the altitude difference calculation unit 33. The position calculation processing unit 32A is an example of the water surface altitude calculation unit and the crown altitude calculation unit.

The altitude difference calculation unit 33 calculates the difference Δh between the altitude hlc of the top end 93 and the altitude hf of the water surface 92 based on the water surface altitude information and the top end altitude information acquired from the position calculation processing unit 32A, and calculates. The altitude difference information indicating the difference Δh is stored in the storage unit 24.

The second communication processing unit 34 is an example of an output unit, and the altitude difference information indicating the difference Δh of each measurement point is read from the storage unit 24, and the radio signal including the read altitude difference information is read from the second communication antenna unit 22. Send to the cloud server 3.

As described above, in the water surface condition monitoring system 100A, the outdoor device 2A can generate high-precision water level information, and in the float 1A, the process of generating high-precision water level information is not performed. Therefore, since the configuration for performing the error correction processing becomes unnecessary in the float, the water surface condition monitoring system 100A and the float 1A can be provided at a lower cost than in the case where the error correction processing using the error correction signal is performed in each float 1A. Can be done.

FIG. 20 is a flowchart showing an example of processing of the processing unit 23A of the outdoor device 2A according to the second embodiment. The processes of steps S31 to S35 shown in FIG. 20 are the same as the processes of steps S31 to S35 shown in FIG. 10, and are omitted below.

As shown in FIG. 20, the processing unit 23A acquires the GNSS positioning information included in the radio signal received by the first communication antenna unit 21 (step S30A). Further, after the processing in step S32, the processing unit 23A calculates the altitude hf of the water surface 92 based on the GNSS positioning information acquired in step S30A and the error correction signal received in step S32 (step S36A). ).

The processing unit 23A calculates the altitude difference Δh based on the altitude hf of the water surface 92 calculated in step S36A and the altitude hlc of the top end 93 calculated in step S33 (step S34).

The hardware configuration example of the float 1A and the outdoor device 2A according to the second embodiment is the same as that of the float 1 and the outdoor device 2 shown in FIG.

As described above, the water surface condition monitoring system 100A according to the second embodiment is an outdoor device 2 in which the position calculation processing unit 32A, which is an example of the water surface altitude calculation unit and the crown altitude calculation unit, is installed on the embankment 91. It is provided in. Therefore, since the float 1A does not have a configuration for executing high-precision altitude information, the cost of the float 1A can be reduced.

Embodiment 3.
In the first and second embodiments, high-precision altitude information is generated by the float 1 and the outdoor devices 2 and 2A using the error correction information, but in the third embodiment, the error correction information is used by the cloud server to generate high-precision altitude information. It differs from the first and second embodiments in that the altitude information of the above is generated. In the following, the components having the same functions as those of the second embodiment are designated by the same reference numerals and the description thereof will be omitted, and the differences from the water surface condition monitoring system 100A of the second embodiment will be mainly described.

FIG. 21 is a diagram showing a configuration example of the water surface condition monitoring system according to the third embodiment. As shown in FIG. 21, the water surface condition monitoring system 100B according to the third embodiment includes a plurality of floats _1A 1-1A _n , a plurality of outdoor devices 2B _{1-2B m} , a cloud server 3B, and an information providing server 4. And an error correction signal distribution device 9. The cloud server 3B can also use a signal transmitted from a ground device (not shown) as an error correction signal. In the following, floats 1A ₁ to 1A _n may be collectively referred to as float 1A, and outdoor devices 2B ₁ to 2B _m may be collectively referred to as outdoor devices 2B.

The error correction signal distribution device 9 periodically generates an error correction signal including the same error correction information as the error correction signal transmitted from the quasi-zenith satellite 98b, and transfers the generated error correction signal to the cloud server 3B via the network 5. And deliver. As a result, the error correction information can be acquired in the cloud server 3B.

FIG. 22 is a diagram showing an example of the configuration of the outdoor device 2B according to the third embodiment. As shown in FIG. 22, the outdoor device 2B includes a receiving antenna unit 20, a first communication antenna unit 21, a second communication antenna unit 22, and a processing unit 23B. The processing unit 23B includes a first communication processing unit 31B, a position calculation processing unit 32B, and a second communication processing unit 34B.

The first communication processing unit 31B acquires the GNSS positioning information included in the radio signal received by the first communication antenna unit 21. The first communication processing unit 31B outputs the GNSS positioning information as the first GNSS positioning information to the second communication processing unit 34B.

The position calculation processing unit 32B calculates an observed value of the distance between satellite floats based on a plurality of distance measurement signals received by the reception antenna unit 20. The position calculation processing unit 32B outputs the GNSS positioning information indicating the calculated observed value of the distance between satellite floats to the second communication processing unit 34B as the second GNSS positioning information. The first GNSS positioning information and the second GNSS positioning information may be information based on a plurality of ranging signals and can be corrected by the error correction information in the cloud server 3B.

The second communication processing unit 34B transmits a radio signal including the first GNSS positioning information and the second GNSS positioning information from the second communication antenna unit 22 to the cloud server 3B.

FIG. 23 is a flowchart showing an example of processing of the processing unit 23B of the outdoor device 2B according to the third embodiment. The processing of steps S30A and S31 shown in FIG. 23 is the same as the processing of S30A and S31 shown in FIG. 20, and is omitted below.

As shown in FIG. 23, the position calculation processing unit 32B of the processing unit 23B generates GNSS positioning information based on a plurality of ranging signals received by the receiving antenna unit 20 (step S37B). Then, the position calculation processing unit 32B outputs the GNSS positioning information acquired in step S30A and the GNSS positioning information generated in step S37B to the cloud server 3B (step S38B).

FIG. 24 is a diagram showing an example of the configuration of the cloud server 3B according to the third embodiment. As shown in FIG. 24, the cloud server 3B according to the third embodiment includes a first communication unit 40, a second communication unit 41, a processing unit 42B, and a storage unit 43.

The processing unit 42B includes a water surface condition information generation unit 51, an information provision processing unit 52, an information acquisition unit 53B, a position calculation processing unit 54B, and an altitude difference calculation unit 55B. The information acquisition unit 53B acquires GNSS positioning information including the first GNSS positioning information and the second GNSS positioning information from the outdoor device 2B via the first communication unit 40. Further, the information acquisition unit 53B acquires the error correction information included in the error correction signal from the error correction signal distribution device 9 via the first communication unit 40.

The position calculation processing unit 54B is an example of the water surface altitude calculation unit and the crown altitude calculation unit, and the altitude hf and the top end 93 of the water surface 92 are based on the GNSS positioning information and the error correction information acquired by the information acquisition unit 53B. Calculates the altitude hlc of. Specifically, the position calculation processing unit 54B calculates the altitude hf of the water surface 92 based on the first GNSS positioning information and the error correction information, similarly to the position calculation processing unit 32A. Further, the position calculation processing unit 54B calculates the altitude hf of the water surface 92 based on the second GNSS positioning information and the error correction information, similarly to the position calculation processing unit 32A.

The altitude difference calculation unit 55B calculates the difference Δh between the altitude hlc of the top end 93 and the altitude hf of the water surface 92, similarly to the altitude difference calculation unit 33. The altitude difference calculation unit 55B stores the altitude difference information indicating the calculated difference Δh in the storage unit 43.

The information providing processing unit 52 is an example of an output unit, reads at least one of altitude difference information, altitude change information, and prediction information from the storage unit 43, and transfers the read information to the information providing server 4 or the terminal device 8. Send.

FIG. 25 is a flowchart showing an example of the processing of the processing unit 42B of the cloud server 3B according to the third embodiment, and the processing is repeatedly executed by the processing unit 42B. The processes of steps S64 and S65 shown in FIG. 25 are the same as the processes of steps S51 and S52 shown in FIG. 14, and are omitted below.

As shown in FIG. 25, the information acquisition unit 53B of the processing unit 42B acquires GNSS positioning information from the outdoor device 2B (step S60). Further, the information acquisition unit 53B receives an error correction signal from the error correction signal distribution device 9 (step S61).

The position calculation processing unit 54B calculates the altitude hf of the water surface 92 and the altitude hlc of the top end 93 based on the GNSS positioning information and the error correction signal (step S62). The altitude difference calculation unit 55B calculates the difference Δh between the altitude hlc of the top end 93 and the altitude hf of the water surface 92 (step S63). The processing unit 42B of the cloud server 3 can transmit a wireless signal including altitude difference information and an instruction for setting an operation interval from the first communication unit 40 to the float 1 or the outdoor device 2.

The hardware configuration example of the outdoor device 2B and the cloud server 3B according to the third embodiment is the same as the outdoor device 2 and the cloud server 3 shown in FIG.

Further, in the above example, the processing unit 16A of the float 1A transmits the GNSS positioning information to the outdoor device 2B, but the processing unit 16A of the float 1A uses the GNSS positioning information as the first GNSS positioning information as the first GNSS positioning information in the cloud server by wire or wirelessly. It can also be sent directly to 3B. The processing unit 42B of the cloud server 3B calculates the altitude hf of the water surface 92 and the altitude hlc of the top 93 based on the first GNSS positioning information acquired from the float 1A and the second GNSS positioning information acquired from the outdoor device 2B. can do.

As described above, in the water surface condition monitoring system 100B according to the third embodiment, the position calculation processing unit 54B, which is an example of the water surface altitude calculation unit and the crown altitude calculation unit, is provided in the cloud server 3B. Therefore, since the float 1A and the outdoor device 2B do not perform the process of generating the water surface altitude information with high accuracy, the cost of the float 1A and the outdoor device 2B can be reduced.

Embodiment 4.
The fourth embodiment is different from the first to third embodiments in that a point of calculating the flow rate of water flowing through the river 90 in the float is added. In the following, the components having the same functions as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted, and the points added from the float 1 of the first embodiment will be mainly described. It can also be applied to the float 1A of the forms 2 and 3.

FIG. 26 is a diagram showing an example of a specific configuration of the float in the water surface condition monitoring system 100C according to the fourth embodiment. As shown in FIG. 26, the float 1C according to the fourth embodiment includes a float unit 10, a housing unit 11, a receiving antenna unit 12, a communication antenna unit 13, a solar panel 14, and a secondary battery 15. And a processing unit 16C.

The processing unit 16C includes a position calculation processing unit 17, a communication processing unit 18C, and a flow rate calculation unit 19. The flow rate calculation unit 19 calculates the flow rate of water flowing in the river 90 based on the magnitude of the tension detected by the tension sensor 83. FIG. 27 is a diagram showing an example of the installation state of the float 1C.

As shown in FIG. 27, the float 1C is attached to the pole 80 via the attachment portion 81 and is movable in the extending direction of the pole 80. A tension sensor 83 is attached to the attachment portion 81, and the tension sensor 83 detects the magnitude of the tension applied to the attachment portion 81.

The flow rate calculation unit 19 has table or calculation formula information showing the relationship between tension, water surface altitude, and flow rate, and estimates the flow rate of water flowing in the river 90 based on the tension detection result by the tension sensor 83. Then, the flow rate information indicating the estimated flow rate is output to the communication processing unit 18C. The communication processing unit 18C transmits a radio signal including water surface altitude information and flow rate information from the communication antenna unit 13.

The float 1C may have a configuration in which a pressure sensor is attached to the outer peripheral side surface of the housing portion 11 instead of the tension sensor 83. The flow rate calculation unit 19 estimates the flow rate of water flowing in the river 90 based on the magnitude of the pressure detected by the pressure sensor, and transmits a radio signal including flow rate information indicating the estimated flow rate from the communication antenna unit 13. be able to.

The hardware configuration example of the float 1C according to the fourth embodiment is the same as that of the float 1 shown in FIG.

As described above, the float 1C of the water surface condition monitoring system 100C according to the fourth embodiment estimates the flow rate of the water flowing in the river 90 and generates the flow rate information indicating the estimated flow rate. As a result, the water surface condition monitoring system 100C can provide the flow rate information in addition to the altitude difference information to the information providing server 4 and the terminal devices 7 and 8 via the cloud server 3B. Therefore, the state of the river 90 can be measured from the viewpoint of the flooding of the river 90, and the measured information can be provided to the user.

Embodiment 5.
The fifth embodiment differs from the first embodiment in that the outdoor device 2 is provided on the pole 80 instead of the embankment 91. In the following, the components having the same functions as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted, and the differences from the water surface condition monitoring system 100 of the first embodiment will be mainly described. The outdoor devices 2A and 2B of the embodiments 2 and 3 may also be attached to the pole 80.

FIG. 28 is a diagram showing an arrangement example of the outdoor device 2D of the water surface condition monitoring system 100D according to the fifth embodiment. As shown in FIG. 28, the outdoor device 2D according to the fifth embodiment is attached to the pole 80. The outdoor device 2D has the same configuration as the outdoor device 2.

The water surface condition monitoring systems 100, 100A to 100D of the above-described embodiments 1 to 5 calculate the altitude hlc of the top end 93 based on the GNSS positioning information and the error correction information, but the present invention is not limited to this example. .. The water surface condition monitoring systems 100, 100A to 100D can also store the altitude hlc of the top end 93 in advance and calculate the altitude difference Δh based on the stored altitude hlc of the top end 93.

As a result, the outdoor device 2 can be provided at any place other than the place where the top altitude is measured, so that the cost can be reduced and the workability can be improved by consolidating the outdoor devices 2.

The configuration shown in the above-described embodiment shows an example of the content of the present invention, can be combined with another known technique, and is one of the configurations as long as it does not deviate from the gist of the present invention. It is also possible to omit or change the part.

1,1 1-1n, _1A , _{1A 1-1A n ,} 1B, 1C float, 2,2 _{1-2 m} , 2A, 2A _{1-2A m} , 2B, 2B _{1-2B m} , 2D outdoor equipment, 3 , 3B cloud server, 4 information providing server, 5 network, 6 ₁ , 6 ₂ base station, 7, 8 terminal device, 9 error correction signal distribution device, 10 float part, 11 housing part, 12, 12A, 20 receiving antenna Unit, 13 Communication antenna unit, 14 Solar panel, 15 Secondary battery, 16, 16A, 16C, 23, 23A, 23B, 42, 42B processing unit, 17, 17A, 32, 32A, 32B, 54B Position calculation processing unit , 18, 18A, 18C communication processing unit, 19 flow calculation unit, 21 first communication antenna unit, 22 second communication antenna unit, 24,43 storage unit, 30 poles, 31, 31A, 31B first communication processing unit, 33 , 55B altitude difference calculation unit, 34, 34B second communication processing unit, 40 first communication unit, 41 second communication unit, 50 altitude difference information acquisition unit, 51 water surface condition information generation unit, 52 information provision processing unit, 53B information Acquisition part, 80 poles, 81 mounting part, 83 tension sensor, 90 rivers, 91 embankments, 92 water surface, 93 tops, 94 bridges, 95 bridges, 98 satellites, 98a positioning satellites, 98b quasi-zenith satellites, 100, 100A-100D Water surface condition monitoring system.

Claims (10)

A water surface altitude calculation unit that calculates the altitude of the water surface based on the distance measurement signal received from the positioning satellite by the float floating on the water surface.
It is equipped with an altitude difference calculation unit that calculates the difference between the altitude of the top and the altitude of the water surface based on the altitude of the top of the embankment and the altitude of the water surface.
A water surface condition monitoring system characterized in that the operation interval of the float is changed based on the difference calculated by the altitude difference calculation unit. The operation interval is
The water surface condition monitoring system according to claim 1, wherein the change is made based on the remaining battery level of the float and the difference calculated by the altitude difference calculation unit. The operation interval is
The water surface condition monitoring system according to claim 1, wherein the change is made based on the amount of power generated by the float solar panel and the difference calculated by the altitude difference calculation unit. A plurality of the water surface altitude calculation units for calculating the altitude of the water surface based on the positions of floats different from each other are provided.
The claim is characterized in that the altitude of the water surface calculated by at least one of the plurality of water surface altitude calculation units is corrected based on the altitude of the water surface calculated by each of the plurality of water surface altitude calculation units. The water surface condition monitoring system according to any one of 1 to 3. With the pole installed in the water area,
The water surface condition monitoring system according to any one of claims 1 to 4, further comprising a mounting portion for mounting the float on the pole so as to be movable in the extending direction of the pole. The float is
The water level condition monitoring system according to any one of claims 1 to 5, which has a function of a water rescue buoy. A receiving antenna unit on the embankment side, which is arranged on the embankment and receives the ranging signal transmitted from the positioning satellite,
A crown altitude calculation unit for calculating the altitude of the crown based on the ranging signal received by the embankment side receiving antenna unit is provided.
The altitude difference calculation unit is
Claims 1 to 6, wherein the difference is calculated based on the altitude of the water surface calculated by the water surface altitude calculation unit and the altitude of the crown calculated by the crown altitude calculation unit. The water surface condition monitoring system described in any one. The water surface altitude calculation unit and the crown altitude calculation unit
The altitude is calculated based on the error correction information transmitted from the quasi-zenith satellite or the ground device, which is the error correction information for correcting the altitude error obtained from the distance measurement signal, and the distance measurement signal. The water level condition monitoring system according to claim 7, wherein the water level condition monitoring system is characterized. The water level condition monitoring system according to claim 7 or 8, wherein the water surface altitude calculation unit and the crown altitude calculation unit are provided in a cloud server. Based on the distance measurement signal received from the positioning satellite by the float floating on the water surface, the water surface altitude calculation step for calculating the altitude of the water surface and the water surface altitude calculation step.
An altitude difference calculation step for calculating the difference between the altitude of the top and the altitude of the water surface based on the altitude of the top of the embankment and the altitude of the water surface.
A water surface condition monitoring method comprising: an operation interval change step in which the operation interval of the float is changed based on the difference calculated by the altitude difference calculation step.

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