Water level measuring device, wireless communication terminal, water level measuring method, and program

Abstract

To provide a water level measuring device that contributes to reducing the constraints on the selection of installation locations for water level measuring devices. [Solution] The water level measuring device includes a plurality of free stations floating on the water surface of the target to be measured, and one or more fixed stations installed in a position where wireless communication with the free stations is possible and whose height from the ground is known. The device calculates the water level based on a first distance between the fixed stations and the free stations, obtained by wireless communication between the fixed stations and the free stations, and a second distance between the free stations, obtained by wireless communication between the free stations.

Description

[Technical Field]

[0001] This invention relates to a water level measuring device, a wireless communication terminal, a water level measuring method, and a program. [Background technology]

[0002] Regarding water level detection devices, the following literature can be cited.

[0003] Patent Document 1 relates to transmitting radar waves to a water surface area, receiving reflected radar waves, calculating the heights of multiple locations within the area, and calculating the water level based on these measurements. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Republished Patent No. 2023 / 003017 [Overview of the project] [Problems that the invention aims to solve]

[0005] The following analysis is provided by the inventors.

[0006] In recent years, localized heavy rains have become more frequent, leading to widespread flooding across Japan. Rising water levels worsen drainage, increasing the risk of flooding for buildings, land, and roads.

[0007] Furthermore, because a rapid rise in water levels could cause damage to escalate quickly, the importance of real-time monitoring of river water levels and disseminating disaster prevention information is increasing. For this reason, it is necessary to install water level gauges in various locations where monitoring is essential.

[0008] A hydraulic water level gauge measures the water level by installing a pressure gauge in the water and converting the water pressure into water level. However, because the device is installed underwater, it is susceptible to the influence of aquatic organisms, and installation work is difficult.

[0009] An ultrasonic water level gauge emits ultrasonic waves towards the water surface and calculates the water level from the time until the waves return. Since it is necessary to direct the ultrasonic waves at the water surface, there are restrictions on the selection of the installation location.

[0010] A water level gauge using a satellite positioning system measures the water level by measuring the height of a floating device, but there is a high possibility of errors due to environmental conditions such as waves and wind. Also, depending on the terrain, satellite signals may be blocked, so the reliability of the measured water level decreases in places such as valleys and forests.

[0011] That is, among conventional water level gauges and water level measuring devices, water level gauges of the type that submerge a measuring instrument in water are easily affected by aquatic organisms, and construction for installing the device is difficult. In water level gauges of the type that use a support or bracket to install the device and emit ultrasonic waves or radio waves onto the water surface, there are restrictions on the selection of the installation location.

[0012] Also, conventional water level gauges using a satellite positioning system measure the position of a floating device, but there is a high possibility of errors due to environmental conditions such as waves and wind. Also, depending on the terrain, satellite signals may be blocked, and in places such as valleys and forests, the reliability of the measured water level decreases, so there are restrictions on the selection of the installation location.

[0013] An object of the present invention is to provide a water level measuring device, a wireless communication terminal, a water level measuring method, and a program that contribute to reducing restrictions on the selection of the installation location of a water level measuring device.

Means for Solving the Problems

[0014] According to a first aspect of the present invention, a plurality of mobile stations floating on the water surface of an object whose water level is to be measured, including one or a plurality of fixed stations installed at a position capable of wirelessly communicating with the mobile stations and having a known height from the ground, A water level measuring device can be provided that calculates the water level based on a first distance between the fixed station and the free station, obtained by wireless communication between the fixed station and the free station, and a second distance between the free stations, obtained by wireless communication between the free stations.

[0015] According to a second aspect of the present invention, the device is installed at a position where the height from the ground is known, Multiple first wireless communication terminals floating on the water surface to be measured communicate wirelessly with each other to obtain a first distance. The plurality of first wireless communication terminals receive the second distance between the plurality of first wireless communication terminals, which has been obtained by the plurality of first wireless communication terminals performing wireless intercommunication. A wireless communication terminal can be provided that calculates the water level based on the first distance and the second distance.

[0016] According to a third aspect of the present invention, a plurality of free stations are floated on the water surface of the object to be measured, In a water level measuring device that includes one or more fixed stations installed in a location where wireless communication with the aforementioned free station is possible and whose height from the ground is known, A water level measurement method can be provided, which calculates the water level based on a first distance between the fixed station and the free station, obtained by wireless communication between the fixed station and the free station, and a second distance between the free stations, obtained by wireless communication between the free stations. This method is linked to a specific machine, a computer, which performs the above method.

[0017] According to a fourth aspect of the present invention, a computer of a wireless communication terminal installed at a known height from the ground, A process to obtain a first distance by performing wireless communication with multiple first wireless communication terminals floating on the water surface of the target water level to be measured, The process of receiving the second distance between the plurality of first wireless communication terminals, which the plurality of first wireless communication terminals have obtained through wireless mutual communication, A program can be provided that performs a process to calculate the water level based on the first distance and the second distance.

[0018] These programs can be recorded on a computer-readable storage medium. The storage medium can be non-transitory, such as semiconductor memory, hard disks, magnetic recording media, or optical recording media. The present invention can also be embodied as a computer program product. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a water level measuring device, a wireless communication terminal, a water level measuring method, and a program that contribute to reducing the constraints on the selection of installation locations for water level measuring devices. [Brief explanation of the drawing]

[0020] [Figure 1] This block diagram shows an example of the configuration of a water level measuring device according to this disclosure. [Figure 2] This block diagram shows an example of the configuration of a fixed station for a water level measuring device relating to this disclosure. [Figure 3] This block diagram shows an example of the configuration of a free station for a water level measuring device relating to this disclosure. [Figure 4] This figure shows an example of a method for measuring the distance between stations. [Figure 5] This figure shows an example of the arrangement of fixed stations and free stations when the water level measuring device according to this disclosure includes one fixed station and three free stations. [Figure 6] This figure shows an example of the operation of the water level measuring device described herein. [Figure 7] This figure shows an example of the operation of the water level measuring device described herein. [Figure 8] This figure shows an example of the arrangement of fixed stations and free stations when the water level measuring device according to this disclosure includes two fixed stations and two free stations. [Figure 9]This figure shows an example of the operation of the water level measuring device described herein. [Figure 10] This figure shows an example of the operation of the water level measuring device described herein. [Figure 11] This diagram shows the configuration of the computer that constitutes the wireless communication terminal related to this disclosure. [Modes for carrying out the invention]

[0021] In this disclosure, the drawings may be associated with one or more embodiments. Furthermore, each embodiment described below may be combined with other embodiments as appropriate, and the present invention is not limited to each embodiment.

[0022] First, an overview of one embodiment will be described with reference to the drawings. The reference numerals in the drawings attached to this overview are provided for convenience to aid understanding and are not intended to limit the present invention to the illustrated embodiment. Furthermore, the connecting lines between blocks in the drawings and other references in the following description include both bidirectional and unidirectional lines. Unidirectional arrows schematically represent the flow of the main signal (data) and do not exclude bidirectional flow.

[0023] Figure 1 is a block diagram showing an example of the configuration of a water level measuring device according to this disclosure. The water level measuring device 10 shown in Figure 1 is an example in which there is one fixed station and three free stations, but there may be one or more fixed stations. For example, the water level measuring device 10 may be configured to include two fixed stations and two free stations. Referring to Figure 1, the water level measuring device 10 includes a fixed station 101 and free stations 201, 202, and 203 connected to the fixed station 101. A server 301 may also be connected to the fixed station 101. The fixed station 101 may transmit the calculated water level information to the server 301. Note that the fixed station 101 and the free stations 201, 202, and 203 can be configured using wireless terminal devices.

[0024] Multiple free stations 201, 202, and 203 are floated on the water surface of the target water level to be measured. The fixed station 101 is installed in a location where it can communicate wirelessly with the free stations 201, 202, and 203, and its height from the ground is known. For example, the installation location may be near the water surface of the target water level to be measured.

[0025] The water level measuring device 10 calculates the water level of the target water surface based on a first distance between fixed station 101 and free stations 201, 202, and 203, which is obtained through wireless communication between fixed station 101 and free stations 201, 202, and 203, and a second distance between free stations 201, 202, and 203, which is obtained through wireless communication between free stations 201, 202, and 203.

[0026] According to one embodiment of the present invention, a configuration is provided in which multiple free stations are floated on the water surface to be measured, thereby contributing to reducing constraints on the selection of the installation location of the water level measuring device. This provides a water level measuring device, a wireless communication terminal, a water level measuring method, and a program.

[0027] [First Embodiment] Next, the first embodiment will be described in detail with reference to the drawings. Figure 1 is a block diagram showing an example of the configuration of a water level measuring device according to this disclosure. Figure 2 is a block diagram showing an example of the configuration of a fixed station of the water level measuring device according to this disclosure, and Figure 3 is a block diagram showing an example of the configuration of a free station of the water level measuring device according to this disclosure.

[0028] Referring to Figure 1, the wireless water level measuring device 10 may, for example, include free stations 201, 202, and 203 floating at any position on the water surface at the water level to be measured, and a fixed station 101 located near the water level to be measured, at a position where wireless communication with the free stations 201, 202, and 203 is possible, and at a known height. In the following description, the water level measuring device 10 will be described as including one fixed station 101 and three free stations 201, 202, and 203. Note that the fixed station 101 and the free stations 201, 202, and 203 can be configured using wireless terminal devices.

[0029] Referring to Figure 2, the fixed station 101, as an example, includes a central processing unit 111 that controls the operation of the fixed station 101, a storage device unit 121 that stores the measured distance between each station and the calculated water level at regular intervals, a data communication unit 131 for communicating with the free stations 201, 202, and 203, an analysis processing unit 141 that measures the distance to the free stations 201, 202, and 203 and calculates the water level based on the measured distance information, and a server communication unit 151 that communicates the calculated water level information to the higher-level server 301.

[0030] Referring to Figure 3, the free station 201 comprises a central processing unit 211 that controls the operation of the free station 201, a storage device unit 221 that stores the distance between the fixed station 101 and the other two free stations 202 and 203 at regular intervals, a data communication unit 231 that performs wireless communication between the fixed station 101 and the other two free stations 202 and 203, and an analysis processing unit 241 that calculates a first distance between the fixed station 101 and the other two free stations 202 and 203. The free stations 202 and 203 may have the same configuration as the free station 201, but are not limited thereto.

[0031] First, the method for measuring the distance between each station will be explained using a diagram. Figure 4 shows an example of a method for measuring the distance between each station. The distance l between the station where the distance measurement is taken, tag 401, and the station where the distance measurement is taken, anchor 402, can be determined, for example, using symmetrical double-sided two-way ranging (SDS-TWR). Here, it is assumed that fixed station 101 and free stations 201, 202, and 203 can all perform the functions of tag 401 and anchor 402. Also, it is assumed that tag 401 and anchor 402 each have an ID (Identifier).

[0032] Distance measurement using SDS-TWR will be explained in detail with reference to Figure 4. In Figure 4, the downward direction represents the direction of time progression. At time t10, tag 401 sends a distance measurement start notification msg01 to anchor 402, with the time information t10 attached.

[0033] When anchor 402 receives a notification msg01 indicating the start of distance measurement, it records the time information t21 of the time of receipt and the time information t10 contained in the received notification msg01 in the storage unit of anchor 402 (for example, if anchor 402 is a free station 201, 202, or 203, it is the storage unit 221 of each free station; if anchor 402 is a fixed station 101, it is the storage unit 121).

[0034] At time t22, anchor 402 sends a distance measurement response notification msg02 to tag 401 and records the time information t22 in the storage unit of anchor 402.

[0035] When tag 401 receives the distance measurement response notification msg02, it records the time information t12 of the time of receipt in the storage unit of tag 401.

[0036] At time t13, tag 401 sends a distance measurement completion notification msg03 to anchor 402, with time information t12 and t13 attached.

[0037] When anchor 402 receives the notification msg03 indicating the end of distance measurement, it records the time information t24 of the time of receipt and the time information t12 and t13 contained in the received notification msg03 in the storage unit of anchor 402.

[0038] Anchor 402 uses the time information t10, t12, t13, t21, t22, t24 recorded in the memory unit of anchor 402 in its analysis processing unit (for example, if anchor 402 is a free station 201, 202, 203, it is the analysis processing unit 241 for each free station, and if anchor 402 is a fixed station 101, it is the analysis processing unit 141).

number

[0039] The distance l between tag 401 and anchor 402 is given by c, where c is the speed of light.

number

[0040] At time te, anchor 402 sends a notification message msg04 to tag 401 containing the time information te and the distance measurement result including distance l.

[0041] Following the procedure described above, tag 401 can obtain the distance between itself and anchor 402.

[0042] Next, we will explain the general operation of calculating the water level in the case of a water level measuring device that includes one fixed station and three free stations. When a fixed station 101 is triggered by a preset time or a request from the server 301 to measure the water level, it becomes the tag 401 and uses free station 201 as the anchor 402 to measure the distance (first distance) using SDS-TWR and saves the result to the storage device 121. Next, following the same procedure, the fixed station 101 uses free station 202 and free station 203 as anchors 402 respectively to measure the distance (first distance) and saves the results to the storage device 121.

[0043] Next, fixed station 101 sends distance measurement requests to free stations 203, 201, and 202, respectively, requesting them to measure the distance (second distance) between free stations 203 and 201, free stations 201 and 202, and free stations 202 and 203 using SDS-TWR. Then, fixed station 101 receives the response results of the distance measurements and stores them in the storage device 121. Once fixed station 101 has collected all six pieces of distance information, it performs a water level calculation, stores the result in the storage device 121, and also sends it to server 301.

[0044] Furthermore, when independent stations 201, 202, and 203 receive a notification from fixed station 101 or another independent station to initiate an SDS-TWR distance measurement, they conduct an SDS-TWR with the source of the distance measurement (tag 401) and send the distance measurement result back to the source (tag 401) as a distance measurement result notification.

[0045] Furthermore, when independent stations 201, 202, and 203 receive a distance measurement request from fixed station 101, they become tag 401 and perform SDS-TWR with the distance measurement partner included in the distance measurement request as anchor 402. When independent stations 201, 202, and 203 (tag 401) receive a distance measurement result notification from the distance measurement partner (anchor 402), they send a distance measurement response back to fixed station 101 (the sender of the distance measurement request).

[0046] [Detailed water level measurement operation for a water level measuring device including one fixed station and three open stations] Next, as an example, the operation of measuring the water level of reservoir 701 using a water level measuring device that includes one fixed station and three open stations will be described in detail with reference to Figures 5, 6, and 7.

[0047] Figure 5 shows an example of the arrangement of fixed stations and free stations when the water level measuring device according to this disclosure includes one fixed station and three free stations. In Figure 5, H is the height from the bottom of the reservoir 701 to the ground. Fixed station 101 is at a height H from the ground. A It is assumed that the free stations 201, 202, and 203 are fixed in place and floating on the water surface at a height from the bottom of the reservoir, i.e., water level h. The height from the bottom of the free stations 201, 202, and 203, i.e., water level h, is the water level of the target water surface to be acquired as described below.

[0048] Figures 6 and 7 show an example of the operation of the water level measuring device according to this disclosure. In Figure 6, the fixed station 101 starts measuring the water level at a pre-set time or in response to a command from the server 301 and transmits wireless communication to the free station 201 (step S801).

[0049] The fixed station 101 measures the distance (the first distance) using SDS-TWR described with reference to FIG. 4, with itself becoming the "tag 401" and the "anchor 402" being the mobile station 201. The mobile station 201 calculates the inter-station distance l Aa (step S802).

[0050] The mobile station 201 transmits the current time, the obtained inter-station distance l Aa and the distance measurement completion notification msg12 to the fixed station 101 (step S803).

[0051] When the fixed station 101 receives the distance measurement completion notification msg12, it records the distance l included in the received notification msg12 Aa in the storage device unit 121 of the fixed station 101. Subsequently, the fixed station 101 and the mobile station 202 measure the distance (the first distance) using SDS-TWR. The mobile station 202 calculates the inter-station distance l Ab (step S804).

[0052] The mobile station 202 transmits the current time, the obtained inter-station distance l Ab and the distance measurement completion notification msg12 to the fixed station 101 (step S805).

[0053] When the fixed station 101 receives the distance measurement completion notification msg12, it records the distance l included in the received notification msg12 Ab in the storage device unit 121 of the fixed station 101. Subsequently, the fixed station 101 and the mobile station 203 measure the distance (the first distance) using SDS-TWR. The mobile station 203 calculates the inter-station distance l Ac (step S806).

[0054] The mobile station 203 transmits the current time, the obtained inter-station distance l Ac and the distance measurement completion notification msg12 to the fixed station 101 (step S807).

[0055] When the fixed station 101 receives the distance measurement completion notification msg12, it records the distance l included in the received notification msg12 AcThis is recorded in the storage device unit 121 of the fixed station 101. The fixed station 101 sends a distance measurement request notification msg11 to the free station 203, specifying the current time, "tag 401" as the free station 203, and "anchor 402" as the free station 203, instructing it to perform distance measurement using the SDS-TWR (step S808). Next, the operation proceeds from the circled area and symbol A in Figure 6 to the circled area and symbol A in Figure 7. The operation of the water level measuring device will be explained below with reference to Figure 7.

[0056] When free station 203 receives the distance measurement request notification msg11, it performs a distance measurement (second distance) between free station 203 and free station 201 using SDS-TWR. Free station 201 measures the inter-station distance l ca The result is calculated and transmitted to free station 203 (step S809).

[0057] Free station 203 has the current time and the calculated distance between stations l ca A message msg12 indicating the completion of distance measurement is sent to the fixed station 101 (step S810).

[0058] When the fixed station 101 receives the distance measurement completion notification msg12, it receives the distance l included in the received notification msg12. ca This is recorded in the storage device unit 121 of the fixed station 101. Subsequently, the fixed station 101 sends a distance measurement request notification msg11 to the free station 201 to perform distance measurement using SDS-TWR between the free station 201 and the free station 202, along with the current time (step S811).

[0059] When free station 201 receives the distance measurement request notification msg11, a distance measurement (second distance) is performed between free station 201 and free station 202 using SDS-TWR. Free station 202 measures the inter-station distance l ab The result is calculated and transmitted to free station 201 (step S812).

[0060] Free station 201 has the current time and the calculated distance l between stations. ab A message msg12 indicating the completion of distance measurement is sent to the fixed station 101 (step S813).

[0061] When the fixed station 101 receives the distance measurement completion notification msg12, it receives the distance l included in the received notification msg12. ab This is recorded in the storage device 121 of the fixed station 101. Subsequently, the fixed station 101 sends a distance measurement request notification msg11 to the free station 202 to perform distance measurement using SDS-TWR between the free station 202 and the free station 203, along with the current time (step S814).

[0062] When free station 202 receives the distance measurement request notification msg11, it measures the distance (second distance) between free station 202 and free station 203 using SDS-TWR. Free station 203 measures the inter-station distance l bc The result is calculated and transmitted to free station 202 (step S815).

[0063] Free station 202 has the current time and the calculated distance l between stations. bc A message msg12 indicating the completion of distance measurement is sent to the fixed station 101 (step S816).

[0064] Next, in step S817, the water level h is calculated as follows.

[0065] When the fixed station 101 receives the distance measurement completion notification msg12, it will receive the distance l included in the received notification msg12. bc The distance l between stations recorded in the storage device unit 121 of the fixed station 101 is recorded in the storage device unit 121 of the fixed station 101. Aa , l Ab , l Ac , l ca , l ab , l bc From this, we determine the water level h. The origin of the coordinate system is set to the position corresponding to the seabed directly below the fixed station 101, and the y-direction is set to the direction of the free station 201 from the Z-axis.

[0066] The coordinates of fixed station 101, free station 201, free station 202, and free station 203 are as follows:

number

[0067] The relationship between each measured distance and the coordinate is:

number

[0068] Solving these for water level h,

number

[0069] The analysis processing unit 141 of the fixed station 101 sends the calculated water level h to the central processing unit 111. The water level h sent to the central processing unit 111 is stored in the storage device unit 121 of the fixed station 101, if necessary. The central processing unit 111 may also transmit the calculated water level h to the server 301 via the server communication unit 151.

[0070] As described above, in the first embodiment of the present invention, a fixed station 101 installed at a known height and free stations 201, 202, and 203 floating on the water surface are used, and each station is equipped with a communication function. Therefore, the distance between each station can be measured at the same time, and the accurate water level can be calculated from that distance. As a result, there is no need to submerge the measuring instrument in water, so the water level measuring device is less susceptible to the influence of aquatic organisms. Furthermore, the fixed station 101 can be freely installed in a location where it can wirelessly communicate with the free stations 201, 202, and 203, and the free stations 201, 202, and 203 only need to float on the water surface, thus easing the constraints on the installation location of each station.

[0071] Accordingly, according to the first embodiment of the present invention, it is possible to provide a water level measuring device, a wireless communication terminal, a water level measuring method, and a program that contribute to reducing the constraints on the selection of the installation location of the water level measuring device.

[0072] [Second Embodiment] Next, a second embodiment will be described in detail with reference to the drawings. The second embodiment is an embodiment in which the water level measuring device includes two fixed stations and two free stations. Figure 8 is a diagram showing an example of the arrangement of fixed stations and free stations in the water level measuring device according to this disclosure, which includes two fixed stations and two free stations. Figures 9 and 10 are diagrams showing an example of the operation of the water level measuring device according to this disclosure. In Figure 8, components that are denoted by the same reference numerals as in Figure 5 will be considered to be the same components.

[0073] Referring to Figure 8, let H be the height from the bottom of the reservoir 701 to the ground. The fixed station 101 is at height H from the ground. A It is assumed that it is fixed in the position, and the fixed station 102 is at a height H from the ground. B It is assumed that the fixed stations 101 and 102 are fixed in place, while the free stations 201 and 202 are floating on the surface of the pond. The height of free stations 201 and 202 from the bottom of the pond, i.e., the water level h, is the water level to be determined as described below. Note that the fixed stations 101 and 102 and the free stations 201 and 202 can be configured using wireless terminal equipment.

[0074] Figures 9 and 10 show an example of the operation of the water level measuring device according to this disclosure. The fixed station 101 starts measuring the water level at a pre-set time or by command from the server 301 (step S901).

[0075] The distance (first distance) between fixed station 101 and free station 201 is measured using SDS-TWR. Free station 201 is station-to-station distance l Aa Calculate (step S902).

[0076] Free station 201 has the current time and the calculated distance l between stations. Aa A message msg12 indicating the completion of distance measurement is sent to the fixed station 101 (S903).

[0077] When the fixed station 101 receives the distance measurement completion notification msg12, it receives the distance l included in the received notification msg12. Aa This is recorded in the storage device 121 of the fixed station 101. Subsequently, the distance (first distance) is measured between the fixed station 101 and the free station 202 using SDS-TWR. The free station 202 measures the inter-station distance l Ab Calculate (S904).

[0078] Free station 202 has the current time and the calculated distance l between stations. Ab A message msg12 indicating the completion of distance measurement is sent to the fixed station 101 (step S905).

[0079] When the fixed station 101 receives the distance measurement completion notification msg12, it receives the distance l included in the received notification msg12. Ab This is recorded in the storage device 121 of the fixed station 101. Subsequently, the fixed station 101 sends a notification msg11 to the free station 201 requesting distance measurement, which includes the current time and the need to perform distance measurement using SDS-TWR between the free station 201 and the free station 202 (step S906).

[0080] When free station 201 receives the distance measurement request notification msg11, it measures the distance (second distance) between free station 201 and free station 202 using SDS-TWR. Free station 202 measures the inter-station distance l abCalculate and transmit to free station 201 (step S907).

[0081] Free station 201 has the current time and the calculated distance l between stations. ab A notification message msg12 indicating the completion of distance measurement is sent to the fixed station 101 (step S908). Next, the operation proceeds from the circled area and symbol B in Figure 9 to the circled area and symbol B in Figure 10. The operation of the water level measuring device will be explained below with reference to Figure 10.

[0082] When the fixed station 101 receives the distance measurement completion notification msg12, it receives the distance l included in the received notification msg12. ab This is recorded in the storage device 121 of the fixed station 101. Subsequently, the fixed station 101 sends a notification msg11 to the fixed station 102, which contains the current time and a distance measurement request to perform a distance measurement between the fixed station 102 and the free station 201 using SDS-TWR (step S909).

[0083] When fixed station 102 receives the distance measurement request notification msg11, it measures the distance (first distance) between fixed station 102 and free station 201 using SDS-TWR. Free station 201 measures the inter-station distance l Ba The result is calculated and transmitted to the fixed station 101 (step S910).

[0084] Fixed station 102 has the current time and the calculated inter-station distance l Ba A message msg12 indicating the completion of distance measurement is sent to the fixed station 101 (step S911).

[0085] When the fixed station 101 receives the distance measurement completion notification msg12, it receives the distance l included in the received notification msg12. Ba This is recorded in the storage device 121 of the fixed station 101. Subsequently, the fixed station 101 sends a notification msg11 to the fixed station 102, which contains the current time and a distance measurement request to perform a distance measurement using SDS-TWR between the fixed station 102 and the free station 202 (step S912).

[0086] When fixed station 102 receives the distance measurement request notification msg11, it measures the distance (first distance) between fixed station 102 and free station 202 using SDS-TWR. Free station 202 measures the inter-station distance l Bb The result is calculated and transmitted to the fixed station 102 (step S913).

[0087] Fixed station 102 has the current time and the calculated inter-station distance l Bb A message msg12 indicating the completion of distance measurement is sent to the fixed station 101 (message S914).

[0088] Next, in step S915, the water level h is calculated as follows.

[0089] When the fixed station 101 receives the distance measurement completion notification msg12, it receives the distance l included in the received notification msg12. Ba The distance l between stations recorded in the storage device unit 121 of the fixed station 101 is recorded in the storage device unit 121 of the fixed station 101. Aa , l Ab , l ab , l Ba , l Bb The water level h is determined from this. The origin of the coordinate system is the position corresponding to the seabed directly below fixed station 101, the y-direction is the direction from the Z-axis to fixed station 102, and the horizontal distance between fixed station 101 and fixed station 102 is Y2, so the y-coordinate of fixed station 102 is Y2.

[0090] The coordinates of fixed station 101, fixed station 102, free station 201, and free station 202 are as follows:

number

[0091] The relationship between each measured distance and the coordinate is:

number

[0092] These can be solved for the water level h (step S915).

[0093] The analysis processing unit 141 of the fixed station 101 sends the calculated water level h to the central processing unit 111. The water level h sent to the central processing unit 111 is stored in the storage device unit 121 of the fixed station 101, if necessary. The central processing unit 111 may also transmit the calculated water level h to the server 301 via the server communication unit 151.

[0094] Accordingly, according to the second embodiment of the present invention, it is possible to provide a water level measuring device, a wireless communication terminal, a water level measuring method, and a program that contribute to reducing the constraints on the selection of the installation location of the water level measuring device.

[0095] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and further modifications, substitutions, and adjustments can be made without departing from the basic technical idea of ​​the present invention. For example, the network configuration, the configuration of each element, and the message representation form shown in each drawing are examples to aid in understanding the present invention, and are not limited to the configurations shown in these drawings. Also, "A and / or B" is used to mean at least one of A or B.

[0096] Furthermore, the procedures described in the first and second embodiments above can be implemented by a program that enables a computer (9000 in Figure 11) that functions as a wireless communication terminal to be used as a fixed or mobile terminal according to the present invention to perform wireless communication terminal functions. Such a computer is exemplified by a configuration comprising a CPU (Central Processing Unit) 9010, a communication interface 9020, a memory 9030, and an auxiliary storage device 9040 as shown in Figure 11. That is, the CPU 9010 in Figure 11 executes a control program for the wireless communication terminal and performs update processing of each calculation parameter held in its auxiliary storage device 9040, etc.

[0097] Memory 9030 refers to RAM (Random Access Memory), ROM (Read Only Memory), etc.

[0098] In other words, each part (processing means, function) of the wireless communication terminal shown in the first and second embodiments described above can be realized by a computer program that causes the computer's processor to execute each of the above-described processes using its hardware.

[0099] Finally, preferred embodiments of the present invention are summarized. [First form] The water level measuring device may include multiple free stations floating on the water surface of the object whose water level is to be measured. The water level measuring device is installed in a location where it can communicate wirelessly with the aforementioned free station and may include one or more fixed stations whose height from the ground is known. The water level measuring device may calculate the water level based on a first distance between the fixed station and the free station, obtained by wireless communication between the fixed station and the free station, and a second distance between the free stations, obtained by wireless communication between the free stations. [Second form] In the water level measuring device described in the first embodiment, there is preferably one fixed station and three free stations, and the fixed station and the free stations are wireless terminal devices. [Third form] In the water level measuring device described in the first embodiment, there are two fixed stations and two free stations, and it is preferable that the fixed stations and the free stations are wireless terminal devices. [Fourth form] In the water level measuring device described in the first embodiment, it is preferable that the calculation of the water level includes using the height from the bottom of the water in the three-dimensional coordinates of each free station as a common value, and calculating the common value based on the first distance and the second distance. [Fifth form] The wireless communication terminal may be installed at a location where the height from the ground is known. A wireless communication terminal may obtain a first distance by wirelessly communicating with multiple first wireless communication terminals floating on the water surface of the target water level to be measured. The wireless communication terminal may receive the second distance between the plurality of first wireless communication terminals, which the plurality of first wireless communication terminals have obtained through wireless communication with each other. The wireless communication terminal may calculate the water level based on the first distance and the second distance. [Sixth form] In the wireless communication terminal described in the fifth embodiment, it is preferable that the calculation of the water level includes using the height of the three-dimensional coordinates of the plurality of first wireless communication terminals from the bottom of the water as a common value, and calculating the common value based on the first distance and the second distance. [Seventh form] Multiple free stations floating on the water surface to be measured, In a water level measuring device that includes one or more fixed stations installed in a location where wireless communication with the aforementioned free station is possible and whose height from the ground is known, The water level measurement method may include calculating the water level based on a first distance between the fixed station and the free station, obtained by wireless communication between the fixed station and the free station, and a second distance between the free stations, obtained by wireless communication between the free stations. [Eighth form] In the water level measurement method described in the seventh embodiment, it is preferable that the calculation of the water level includes using the height from the bottom of the water in the three-dimensional coordinates of each free station as a common value, and calculating the common value based on the first distance and the second distance. [Ninth form] The program is sent to the computer of a wireless communication terminal installed at a known height from the ground. The system may also perform a process to obtain a first distance by wirelessly communicating with multiple first wireless communication terminals floating on the water surface of the target water level to be measured. The program may cause the computer to perform a process of receiving the second distance between the plurality of first wireless communication terminals, which the plurality of first wireless communication terminals have obtained through wireless communication with each other. The program may cause the computer to perform a process to calculate the water level based on the first distance and the second distance. [Tenth form] In the program described in the ninth embodiment, the process for calculating the water level preferably includes using the height from the bottom of the water in the three-dimensional coordinates of each free station as a common value, and calculating the common value based on the first distance and the second distance. Furthermore, the seventh form described above can be expanded from the second to the third form, similar to the first form.

[0100] Furthermore, the disclosures in the above-mentioned patent documents are incorporated into this work by reference. Within the framework of the full disclosure of the present invention (including the claims), further modifications and adjustments to the embodiments or examples are possible based on the fundamental technical concept. Also, within the framework of the disclosure of the present invention, various combinations or selections of various disclosure elements (including each element of each claim, each element of each embodiment or example, each element of each drawing, etc.) are possible. In other words, the present invention naturally includes the full disclosure, including the claims, and various modifications and alterations that a person skilled in the art could make in accordance with the technical concept. In particular, with respect to the numerical ranges described in this work, any numerical value or sub-range included within that range should be interpreted as being specifically described, even if not otherwise stated. Furthermore, each disclosure item of the above-mentioned cited documents may, if necessary, be used in combination with the items described in this work as part of the disclosure of the present invention, in accordance with the spirit of the present invention, in part or in whole, and this is also considered to be included in the disclosure of this application. [Explanation of symbols]

[0101] 10 Water level measuring device 101, 102 fixed station 111, 211 Central Processing Unit 121, 221 Storage unit 131, 231 Data Communications Department 141, 241 Analysis Processing Unit 151 Server Communication Unit 201, 202, 203 Freedom Bureau 301 Server 401 tags 402 Anchor 701 Reservoir 9000 Computers 9010 CPU 9020 Communication Interface 9030 memory 9040 Auxiliary storage device

Claims

1. Multiple free stations floating on the water surface to be measured, It includes one or more fixed stations installed in a location where wireless communication with the aforementioned free station is possible, and whose height from the ground is known. A water level measuring device that calculates the water level based on a first distance between the fixed station and the free station, obtained by wireless communication between the fixed station and the free station, and a second distance between the free stations, obtained by wireless communication between the free stations.

2. The water level measuring device according to claim 1, wherein the fixed station is one station, the free stations are three stations, and the fixed station and the free stations are wireless terminal devices.

3. The water level measuring device according to claim 1, wherein the fixed stations are two stations, the free stations are two stations, and the fixed stations and the free stations are wireless terminal devices.

4. The water level measuring device according to claim 1, wherein the calculation of the water level includes using the height from the bottom of the water in the three-dimensional coordinates of each free station as a common value, and calculating the common value based on the first distance and the second distance.

5. It is installed at a known height from the ground, Multiple first wireless communication terminals floating on the water surface to be measured communicate wirelessly with each other to obtain a first distance. The plurality of first wireless communication terminals receive the second distance between the plurality of first wireless communication terminals, which has been obtained by the plurality of first wireless communication terminals performing wireless intercommunication. A wireless communication terminal that calculates the water level based on the first distance and the second distance.

6. The wireless communication terminal according to claim 5, wherein the calculation of the water level includes using the height of the three-dimensional coordinates of the plurality of first wireless communication terminals from the bottom of the water as a common value, and calculating the common value based on the first distance and the second distance.

7. Multiple free stations floating on the water surface to be measured, In a water level measuring device that includes one or more fixed stations installed in a location where wireless communication with the aforementioned free station is possible and whose height from the ground is known, A water level measurement method that calculates the water level based on a first distance between the fixed station and the free station, obtained by wireless communication between the fixed station and the free station, and a second distance between the free stations, obtained by wireless communication between the free stations.

8. The water level measurement method according to claim 7, wherein the calculation of the water level includes using the height from the bottom of the water in the three-dimensional coordinates of each free station as a common value, and calculating the common value based on the first distance and the second distance.

9. The computer of a wireless communication terminal installed at a known height from the ground, A process to obtain a first distance by performing wireless communication with multiple first wireless communication terminals floating on the water surface of the target to be measured, The process of receiving the second distance between the plurality of first wireless communication terminals, which the plurality of first wireless communication terminals have obtained through wireless mutual communication, A program that performs a process to calculate the water level based on the first distance and the second distance.

10. The program according to claim 9, wherein the process for calculating the water level includes using the height from the bottom of the water in the three-dimensional coordinates of each free station as a common value, and calculating the common value based on the first distance and the second distance.

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