KR102613787B1 - Flood Monitoring System Using IoT Instruments - Google Patents

Abstract

The present invention relates to a flooding monitoring system using IoT measuring devices. More specifically, it relates to a flood monitoring system using an IoT instrument that can cost-effectively secure time-series flood data using a low-cost absolute pressure sensor.
To this end, the present invention includes a solar module capable of controlling the direction of the solar panel and converting solar energy into electrical energy; A power supply unit capable of storing electrical energy generated by solar modules and supplying power when solar energy is not supplied; A pressure sensor that can sense water pressure in case of flooding; A microcontroller that receives signals from a pressure sensor, digitizes them, and transmits them to a communication module; A communication module including an antenna that can transmit signals received from a microcontroller to a remote integrated control server; It can transmit and receive signals wirelessly, calculates and stores the submersion depth using the water pressure information of the pressure sensor transmitted through the communication module, and includes an integrated control server that can update the device software wirelessly. We provide a flooding monitoring system using IoT measuring instruments.

Description

Flood Monitoring System Using IoT Instruments}

The present invention relates to a flooding monitoring system using IoT measuring devices. More specifically, it relates to a flood monitoring system using an IoT instrument that can cost-effectively secure time-series flood data using a low-cost absolute pressure sensor.

Generally, in order to prepare for floods, flooding, etc., water level measuring devices are installed to measure and measure the water level in reservoirs, reservoirs, lakes, rivers, or flood prone areas.

However, existing measurement systems are too large to be installed on roads or sidewalks, so they often interfere with traffic or are damaged by impacts from vehicles, etc., and measurement errors occur depending on the installation environment and have advantages and disadvantages depending on the measurement method. Because the form and configuration of the system varied at each site, it was difficult to mass-produce a device that only measures the depth of flooding. As a result, the system became more complex and the time and cost required for construction increased, making it impossible to secure sufficient measurement points, so there was no data to compare when a mismeasurement occurred. In addition, since expensive sensors and data loggers are used, precision is high, but the density of measurement points is low, so if mismeasurements continue to occur due to environmental influences, calibration is impossible and accuracy is low. During on-site construction, sensors, data loggers, and power sources must be connected by wires to cut and restore roads, which requires manpower, heavy equipment, and protection with auxiliary devices, further increasing costs.

In addition, the water cycle repeats rainfall-(infiltration-retention)-runoff-evaporation. In cities, the time and space required for this cycle are distorted by pavement materials such as asphalt or concrete, leading to an increase in the amount of rainwater that cannot infiltrate. Because rainwater generated in this way moves through pipes, the outflow speed and arrival time become faster, which can lead to urban flooding problems. In addition, climate change is causing record-breaking heavy rain and flooding damage not only in Korea but also throughout the world, so it is necessary to secure time to evacuate or prepare through not only prevention but also prediction. To achieve this, it is necessary to secure a large amount of measurement points and time series data. need.

In the case of flood depth, local governments collect information such as maximum flood depth, flood period, and flooded area through post-site surveys, but information on changes in flood depth over time is insufficient.

For this reason, we have continuously attempted to predict flooding through numerical analysis based on situational scenarios, but it has the disadvantage of being difficult to predict detailed areas and taking a long time, and due to the too large number of cases and insufficient past history data, it is difficult to predict flooding in a satisfactory manner. I'm not getting results.

In addition, the sensor method for measuring water depth is largely divided into a contact type that measures underwater and a non-contact type that measures distance on the water. The contact type is mainly a pressure method that measures the distance from the bottom to the water surface through water pressure, and the non-contact type is mainly a ToF (Time of Flight) method that calculates the distance from the measuring device to the water surface by measuring the time for radio waves to travel back and forth. achieves The ToF method is sometimes used in rainwater pipe manholes, but it has problems with radio waves being interrupted by vehicles and pedestrians and cannot be applied to rainwater drains where the measurement distance is short, so the pressure method is mainly applied.

Pressure sensors include absolute pressure sensors, differential pressure sensors, and relative pressure sensors. Conventionally, most sensors that measure water depth use the relative pressure method to correct atmospheric pressure. The relative pressure sensor is connected to a tube so that it can be exposed to atmospheric pressure. I am using it.

The tube used at this time must be less damaged and resistant to bending, but it is mainly made of polyurethane, and has the disadvantage of being relatively expensive and difficult to replace if damaged.

Therefore, there is a need to develop new water depth measuring devices that can secure measurement points at low cost.

Prior art literature: KR Registered Patent Publication No. 10-1204059 (announced on November 23, 2012)

The present invention was developed to solve the above problems. It operates at low power to reduce power consumption, does not require excavation and recovery work for wired connection, or auxiliary devices for system protection, and has an economically inexpensive absolute pressure. The purpose is to provide a flood monitoring system using an IoT instrument that uses sensors and has an atmospheric pressure correction unit that compensates to offset changes in atmospheric pressure for the accuracy of the absolute pressure sensor.

The flooding monitoring system using an IoT measuring device according to the present invention developed to achieve the above purpose includes a solar module capable of converting solar energy into electrical energy; A power supply unit capable of storing electrical energy generated by solar modules and supplying power when solar energy is not supplied; A pressure sensor that can sense water pressure in case of flooding; A microcontroller that receives signals from a pressure sensor, digitizes them, and transmits them to a communication module; A wireless communication module including an antenna that can transmit signals received from a microcontroller to a remote integrated control server via the Internet; It can calculate, process, and store flooding information using the water pressure information from the transmitted pressure sensor, and includes an integrated control server that can update software for processing the received data.

In addition, the integrated control server includes an atmospheric pressure correction unit that corrects the atmospheric pressure in the pressure sensor to measure water pressure excluding atmospheric pressure; Data store that can store raw data sensed from a pressure sensor; A data purification unit capable of purifying raw data sensed from the pressure sensor; A database unit capable of storing refined data; It further includes a visualization unit for monitoring data.

In addition, the integrated control server converts the collected data into water depth and stores it, and is equipped with a data conversion unit to solve the problem of inconsistent measurement intervals; The data conversion unit can receive an atmospheric pressure correction algorithm from the atmospheric pressure correction unit, and further includes converting the pressure into water depth with the atmospheric pressure correction algorithm and matching the measurement time on the hour every minute.

According to the present invention, since it is equipped with a solar panel, there is no need for separate power construction, and since it is equipped with a power supply unit, power can be maintained even in the absence of sunlight, and communication between a microcontroller and LPWAN (Low Power Wide Area Network) There is an effect of minimizing power consumption by using .

In addition, an absolute pressure sensor that is easy to install and economical can be used, and since it is equipped with an atmospheric pressure correction unit, it is effective in securing time series flood depth data by correcting the sensing value of the absolute pressure sensor.

1 is a flow chart showing the flow of information in a flood monitoring system using an IoT instrument according to a preferred embodiment of the present invention;
Figure 2 is a flow chart showing the flow of power generated from a solar module;
Figure 3 is a diagram showing measured values for atmospheric pressure correction;
Figure 4 is a diagram showing the atmospheric pressure correction algorithm;
Figure 5 is a diagram showing the configuration when configured as a cloud environment;
Figure 6 is a diagram showing information visualized through a user terminal;
Figure 7 is a diagram showing an example of field installation.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. First, when adding reference signs to components in each drawing, it should be noted that the same components are given the same reference numerals as much as possible even if they are shown in different drawings. Additionally, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description will be omitted. In addition, preferred embodiments of the present invention will be described below, but the technical idea of the present invention is not limited or restricted thereto, and of course, it can be modified and implemented in various ways by those skilled in the art.

Figure 1 is a flow chart showing the flow of information in a flood monitoring system using an IoT instrument according to a preferred embodiment of the present invention, Figure 2 is a flow chart showing the flow of power generated from a solar module, and Figure 3 is a flow chart showing atmospheric pressure correction. Figure 4 is a diagram showing the measured values for, Figure 4 is a diagram showing the atmospheric pressure correction algorithm, Figure 5 is a diagram showing the configuration when configured in a cloud environment, Figure 6 is a diagram showing information visualized through a user terminal, Figure 7 is a diagram showing the information visualized through a user terminal. This is a drawing showing an example of installation applied in the field.

Referring to FIGS. 1 and 2, the flooding monitoring system using an IoT measuring device according to a preferred embodiment of the present invention includes a solar module 100, a power supply unit 200, a pressure sensor 300, a microcontroller 400, and communication. It consists of a module 500, an integrated control server 600, and a user terminal 700.

Hereinafter, the components of a flooding monitoring system using an IoT measuring device according to a preferred embodiment of the present invention will be described in detail.

The solar module 100 can control the direction of the solar panel, convert solar energy into electrical energy, and store it in the power supply unit 200.

The power supply unit 200 can store the electric energy generated by the solar module 100, and can supply power using the stored electric energy even when solar energy is not supplied, so it can provide power even when solar energy is not supplied. This can be maintained, but the capacity of the battery provided in the power supply unit can be varied depending on the state of solar power in the installation location.

For example, devices installed in places with insufficient sunlight can increase the capacity of solar modules and batteries, while devices installed in places with sufficient sunlight can have relatively smaller capacities.

Additionally, the capacity of the solar module and battery can be adjusted depending on the purpose to increase the time the power is maintained.

The electrical energy generated by the solar module 100 can be stored in the power supply unit 200, and the electrical energy stored in the power supply unit 200 is transmitted to the pressure sensor 300, the microprocessor 400, and the pressure sensor 300 through a microcontroller. It is used as energy to operate the communication module 500.

The present invention has the advantage of being equipped with a solar module so that it can be used without power construction, operating at low power, and being able to be used for a long time without charging.

In addition, in the present invention, in order to reduce power consumption, the RTC (Real-Time Clock) chip, which measures accurate time so that power consumption is as low as possible, is not applied, and the time at which data is received from the server is used as the measurement time.

As a result, when using Wifi, data arrives about 5 seconds later than the set measurement interval, and when using LTE-M, data arrives about 38 seconds later. To minimize this time, you can keep communication connected, but in this case, there is a problem that the power consumption of the LTE-M module increases, so it is set to turn the power on and off before and after data transmission.

In addition, the measurement interval was set to 15 seconds so that data could be received more than once per minute, allowing data to be received every 53 to 54 seconds, including the transmission delay time.

In other words, measurements can be made at intervals of at least 1 minute, and the time interval can be adjusted by the user.

The pressure sensor 300 can sense water pressure, which is the pressure caused by rainwater, when flooded.

When using non-contact sensors including ultrasonic waves and radar, sensors for measuring flood depth may cause measurement errors due to vehicles, pedestrians, insects, etc., so it is better to use a pressure sensor that senses contact pressure rather than using a non-contact sensor. This reduces the probability of measurement errors and is advantageous for calibration through post-processing.

In addition, pressure sensors include absolute pressure sensors, differential pressure sensors, and relative pressure sensors. The absolute pressure sensor measures the pressure difference applied to the outside by setting the vacuum state to 0, and the differential pressure sensor measures the pressure values at two points. Additionally, a relative pressure sensor measures the difference from atmospheric pressure by exposing the pressure at one of two points to atmospheric pressure.

Conventional pressure sensors that measure water depth use the relative pressure sensor method and are used by connecting a tube so that they can be exposed to atmospheric pressure. In this case, the tube used must be less damaged and resistant to bending, but it is mainly made of polyurethane and has the problem of being relatively expensive and difficult to replace if damaged.

In the present invention, an absolute pressure sensor is used to solve the above problem, and an atmospheric pressure correction unit is provided in the integrated control server to compensate for changes in atmospheric pressure, so that the absolute pressure sensor can accurately measure the water level.

The microcontroller 400 includes a microprocessor 410, and the microcontroller 400 can receive a pressure signal from the pressure sensor 300, digitize it, convert it into a water depth value, and transmit it to a communication module.

The microprocessor 410 is a system semiconductor that controls various characteristics ranging from simple control to special functions, and has additional devices such as memory and input/output control interface circuits built in, so it can run a control program that performs a specific function through a computer. It has the advantage of being able to be transplanted at any time and perform various roles.

The microcontroller 400 transmits the pressure and temperature measured by the sensor as a digital signal to the microprocessor, and the microprocessor interprets the digital signal and converts it into pressure and temperature. Additionally, the data transmission interval, communication method (LTE, WiFi), communication port, IP address, device ID, etc. can be changed using a microprocessor.

For low power consumption, miniaturization, and cost reduction, direct data storage and processing is performed in the integrated control server 600, and the microcontroller 400 only performs the minimum function to enable the communication module 500 to transmit data to the integrated control server. Perform.

The communication module 500 can transmit signals received from the microcontroller 400 to a remote integrated control server 600 via the Internet.

MQTT (Message Queuing Telemetry Transport), which is generally used in IoT, adds a Fixed Header of 2 to 5 Bytes every time data is transmitted, increasing communication capacity. The Broker issues topics through Publisher and subscribes to Subscribers. It acts as a relay, but this method does not fit the present invention in which data is transmitted in one direction from Device → Socket Server → Socket Client → DB and has a problem with large data usage. In order to reduce data usage in the present invention, a communication module 500 is used. The communication protocol was TCP/IP. However, the communication protocol can be changed according to the development of IoT technology and changes in the environment.

The integrated control server 600 can transmit and receive signals wirelessly with the communication module 500, and calculates the depth of flooding after correcting atmospheric pressure using the water pressure information of the pressure sensor 300 transmitted through the communication module 500. It can be processed and stored, and includes an atmospheric pressure correction unit 610, a data store 620, a data purification unit 630, a data conversion unit 640, and a database unit 650.

In addition, the integrated control server 600 allows distribution and updates without an on-site visit, such as adjusting sensor sensitivity or improving performance through software, saving manpower and time.

In addition, the integrated control server 600 may be configured in a cloud environment, and in order to prevent the cloud computing environment from being exposed to the Internet, a VPN (Virtual Private Network) can be set up to allow access only to the system administrator. there is.

VPN is security at the network level, so only users who have access to the cloud computing environment can access it, and it protects the network by creating a virtual tunnel with users and encrypting data.

Access to the VPC (Virtual Private Cloud) inside the cloud can be restricted to specific IP addresses, completely blocking access from other locations. The VPC sets up a network inside the cloud computing environment, preventing direct connection to the Internet. This can play a role in strengthening security.

TCP/IP communication, which is the communication protocol for IoT flood depth measuring devices, has the disadvantage of being vulnerable to security. To solve this problem, NLB (Network Load Balancer) can be used to access the VPC.

NLB has fast latency, which is the time it takes to respond to a request, and can handle millions of requests per second, allowing it to connect to a large number of instruments.

No separate security is applied between IoT instruments and NLB, but after passing NLB, the cloud computing environment can be protected according to EC2 (Elastic Compute Cloud) security rules. Socket Server allows the Client program to receive data from IoT flood depth measuring instruments.

The Client program stores 10 pieces of raw data received through the server in the data storage unit and stores one record of the instrument ID, time the data was received, remaining battery capacity, temperature, and pressure in the database unit. The instrument ID used the IMEI (International Mobile Equipment Identity) of the LTE-M module.

In order to convert and store the collected data into water depth and solve the problem of inconsistent measurement intervals, a separate data conversion unit is provided. The data conversion unit can receive the atmospheric pressure correction algorithm from the atmospheric pressure correction unit, and the atmospheric pressure correction algorithm can be used to calculate the pressure. It converts to water depth and matches the measurement time every minute. For example, data measured between 00 minutes and 01 minutes is collected by the data conversion unit at 01 minutes, converted to 01 minute measurement data, and stored in the database unit.

The data conversion unit 640 replaces the calculations that the IoT flood depth meter must perform, and can be modified without going to the site where the meter is located, making maintenance easier.

The atmospheric pressure correction unit 610 corrects the atmospheric pressure in the pressure sensor to measure water pressure excluding atmospheric pressure.

More specifically, the absolute pressure sensor used in the present invention must correct atmospheric pressure that changes depending on location and time to convert the measured pressure into tens.

In the above equation (1), P _s refers to the pressure received by the sensor, P _w refers to water pressure, and P _atm refers to atmospheric pressure. Absolute pressure sensors measure based on a vacuum state, and in the absence of water pressure, P _s is equal to atmospheric pressure. And the change in water pressure ΔP _w measured at the two measurement points can be obtained as the difference between the change in measured pressure and the change in atmospheric pressure as shown in Equation (2).

If you classify the change in atmospheric pressure among the measured changes in pressure and treat it as 0, you can find out the change in water pressure. The change in water pressure can be calculated as the change in water depth using the above equation (3), which converts pressure (mbar) to millimeters of water column (mmH ₂ O).

An experiment was conducted to determine the degree of change in atmospheric pressure and derive a correction method in the atmospheric pressure correction unit of the present invention, and the atmospheric pressure measured by the pressure sensor is shown in FIG. 3.

Referring to Figure 3, the minimum value was 996.7mb, the maximum value was 1,004.2mb, and the average was 1,000.1mb. The difference between the maximum and minimum values, 4.1mb, becomes 41.82mm when converted to millimeters of water column (mmH ₂ O). Since atmospheric pressure changes depending on the location and weather to be measured, this value could be larger, so correction was deemed necessary.

Additionally, referring to Figure 3, it can be seen that although the change in measured pressure over a long period of time is large, the standard deviation for each measurement is small, with a maximum of 0.1. Therefore, in order to determine whether the change in measured pressure is the effect of atmospheric pressure or water pressure, you can check the standard deviation of the 10 raw data transmitted by the instrument.

In other words, when flooding occurs, the standard deviation of the pressure measured due to waves on the water surface will be greater than 0.1, which is the maximum value of the standard deviation due to changes in atmospheric pressure. Also, when testing accuracy by changing the water depth, the water depth may change in a situation where the instrument is in a power-saving state and is not measuring.

In this case, since the water level may fluctuate while the standard deviation is less than 0.1, it is set as if the water level has changed if the pressure change is more than 0.2 mbar. When set to 0.2 mbar, the measurement unit of the absolute pressure sensor used is 0.1 mbar, and the neighboring Since the change in atmospheric pressure at the time of measurement does not exceed 0.1 mbar, this is to ensure that the test can respond as sensitively as possible to changes in water level when testing without movement of the water surface. In other words, adjusting the threshold value of pressure change and standard deviation determines the sensitivity of the sensor, and this can be processed without an on-site visit.

Figure 4 is an atmospheric pressure correction algorithm that reflects the above contents. Referring to Figure 4, when 10 pieces of raw data (mbar) are received from a measuring instrument, the standard deviation (STD) is calculated, and the initial value is discarded for 9 pieces. Find the median value of the data and use it as the current measured pressure value (Median mbar: Mmb). Find the difference between the currently measured pressure value (Mmb) and the previous measured pressure value (Previous mbar: Pmb), and if the absolute value is greater than 0.2 mbar, recognize that the water depth has changed, and convert the pressure difference into a change in water depth according to the above formula (3) ( Convert to Water depth: ΔWD).

At this time, if the value obtained by subtracting the previous pressure from the current pressure is a positive number, ΔWD also becomes a positive number and the water depth increases. If it is negative, it becomes the opposite. The water depth change (ΔWD) is added to the previous water depth (Water Depth: WD) and updated to the current water depth (WD). Even if the difference between the current pressure (Mmb) and the previous pressure (Pmb) is less than or equal to 0.2 mbar, if the standard deviation is greater than 0.1, it is converted to ΔWD and the water depth is added. If it is small, ΔWD is set to 0 and the water depth is assumed to have not changed.

The user terminal 700 can transmit and receive information through communication with the integrated control server, and is equipped with a display unit, so referring to FIG. 6, the information received from the integrated control server can be visualized.

Each component of the flooding monitoring system using the IoT measuring device according to the present invention is modularized, so referring to FIG. 7, when installing the measuring instrument in the field, the solar module, power supply unit, microcontroller, and communication module are subject to flooding. It can be installed in a high place where water is not exposed, and in case of flooding, a pressure sensor that can sense water pressure is installed on the floor to sense water pressure.

Conventional flood monitoring systems and devices are integrated so that when flooded, communication devices and control devices are also flooded, causing a risk of failure or malfunction. However, according to the present invention, only the pressure sensor that senses water pressure is flooded. This problem was solved by being installed in a high place where other components would not be flooded.

In addition, when the pressure sensor breaks down due to vehicle and pedestrian traffic, the relative pressure sensor used conventionally had the disadvantage of being relatively expensive and not easy to replace. However, according to the present invention, the absolute pressure sensor is relatively inexpensive and easy to replace. This problem was solved using sensors.

The above description is merely an illustrative explanation of the technical idea of the present invention, and various modifications, changes, and substitutions can be made by those skilled in the art without departing from the essential characteristics of the present invention. will be. Accordingly, the embodiments disclosed in the present invention and the attached drawings are not intended to limit the technical idea of the present invention, but are for illustrative purposes, and the scope of the technical idea of the present invention is not limited by these embodiments and the attached drawings. . The scope of protection of the present invention should be interpreted in accordance with the claims below, and all technical ideas within the equivalent scope should be construed as being included in the scope of rights of the present invention.

100 - solar module 200 - power supply unit
300 - Pressure sensor 400 - Microcontroller
500 - Communication module 600 - Integrated control server
700 - User terminal

Claims (3)

A solar module that can adjust the direction of the solar panel and convert solar energy into electrical energy;
A power supply unit capable of storing electrical energy generated by solar modules and supplying power when solar energy is not supplied;
A pressure sensor that can sense water pressure in case of flooding;
A microcontroller that receives signals from a pressure sensor, digitizes them, and transmits them to a communication module;
A communication module including an antenna that can transmit signals received from a microcontroller to a remote integrated control server; and
An integrated control server that can process and store the calculation of the depth of flooding using the received sensing information from the pressure sensor, and can update software for adjusting and controlling the sensitivity of the pressure sensor.
Including,
Integrated control server
An atmospheric pressure correction unit that corrects the atmospheric pressure in the pressure sensor to measure water pressure excluding atmospheric pressure;
Data store that can store raw data sensed from a pressure sensor;
A data purification unit capable of purifying the raw data sensed from the pressure sensor;
A database unit capable of storing refined data;
Includes,
The integrated control server converts and stores the collected data into water depth and is equipped with a data conversion unit to solve the problem of inconsistent measurement intervals;
The data conversion unit can receive an atmospheric pressure correction algorithm from the atmospheric pressure correction unit, and converts the pressure into water depth with the atmospheric pressure correction algorithm and matches the measurement time on the hour every minute;
The pressure sensor is an absolute pressure sensor that can measure the pressure difference applied to the outside by setting the vacuum state to 0;
For low power consumption, miniaturization, and cost reduction, data storage and processing are performed in the integrated control server, and the microcontroller only performs the function of allowing the communication module to transmit data to the integrated control server;
Each component, including the solar module, power supply, pressure sensor, microcontroller, and communication module, is modularized, so when installed in the field, the solar module, power supply, microcontroller, and communication module are placed at a high level that will not be submerged. It can be installed in any location, and the pressure sensor can be installed on a floor that may be flooded to sense water pressure;
Including, a flooding monitoring system using an IoT instrument.

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