KR20070089468A - A antenna structure for monitoring of manhole - Google Patents

Abstract

An antenna structure for monitoring a manhole is provided to miniaturize an antenna buried under the ground for monitoring the manhole by implementing the antenna as a 1/4 wavelength monopole patch antenna of a planer inverting F antenna type. In an antenna(13) for wireless communication between a plurality of collecting terminals(10) and a relay terminal, the plurality of collecting terminals(10) are connected with a sensor installed inside of a manhole to collect the detection information of the manhole from the sensor. The relay terminal collects and arranges the detection information of the manhole received from the collecting terminals(10). The antenna(13) is provided in a housing(100) of the collecting terminal(10). A circuit board(110) having a connector(120) at one surface is integrally formed with the antenna. The connector(120) of the circuit board(110) and the sensor are connected through a cable(130) passing through the housing(100).

Description

Antenna structure for manhole monitoring system.

1 is a block diagram of a radio system for manhole monitoring according to the present invention.

2 is a block diagram of a collecting terminal of a wireless system for manhole monitoring according to the present invention;

3 is a block diagram of a relay terminal of a wireless system for manhole monitoring according to the present invention;

4 is a block diagram of a server of the manhole monitoring wireless system according to the present invention.

5 is a cross-sectional conceptual view of a collecting terminal of a wireless system for manhole monitoring according to the present invention.

-Explanation of symbols for the main parts of the drawings-

2: open / close sensor 4: temperature sensor

6: water level sensor 8: power sensor

10: collecting terminal 13: collecting terminal antenna

20: repeater terminal 21: repeater antenna

30: server

100: collecting terminal housing

110: circuit board

120: connector 130: cable

140: waterproof cable

The present invention relates to an antenna of a manhole monitoring system, and more particularly, to grasp the position, state and history of the manhole using sensors installed inside the manhole, and to collect it for wireless transmission to the outside using a wireless communication module. The present invention relates to an antenna structure of a manhole monitoring system that has been improved in miniaturization and characteristics thereof of a terminal and a relay terminal.

In general, electric power facilities in urban areas are gradually becoming underground due to urban aesthetics, safety, and high-rise buildings, and their weight is increasing day by day.

However, research and development is underway in the joint districts where underground lines are installed along with other facilities, but manholes, etc., still have to rely on manpower because the environment is poor and access for identification or instantaneous access is not easy. Because.

In addition, the manhole is a characteristic that can not be immediately confirmed in case of emergency, such as intrusion or accident of outsiders.

Therefore, in order to overcome the difficulties of manhole management and to easily manage the manhole at a remote location, a manhole is installed to obtain necessary information inside the manhole, and the manhole can be delivered to a point of interest to the point of interest. It is essential to develop a system that allows the administrator to easily check the remote alarm system and the current detection information of the manhole.

In addition, it is essential to develop underground antennas that have excellent characteristics so that they can collect information inside the manhole and communicate with an external relay device or control server so as to remotely manage the state of the manhole at a remote location.

The present invention has been proposed by the above necessity,

First, an object of the present invention is to embed an antenna and a circuit board in a housing connected to a collecting terminal inside a manhole to facilitate maintenance such as battery replacement and program upgrade.

Secondly, it aims to realize the miniaturization of the antenna so that it can be buried underground on the road for manhole monitoring.

Third, an object of the present invention is to increase the current path by attaching a plurality of pins (FIN) to the bottom of the monopole patch antenna in the antenna.

Fourth, an object of the present invention is to enable shielding from the outside even when the antenna and the circuit board are embedded in the housing connected to the collecting terminal.

An antenna for wireless communication with a relay terminal for collecting and arranging sensing information of a plurality of manholes received from the collecting terminal, the antenna having a antenna inside a housing of the collecting terminal and having a connector mounted on one surface thereof. It is configured integrally with the antenna, the connector and the sensor of the circuit board is characterized in that connected by a cable penetrating, characterized in that connected by a cable passing through the housing.

Hereinafter, with reference to the accompanying drawings to describe the specific configuration and operation of the present invention.

1 is a block diagram of a manhole monitoring wireless system according to the present invention, [2] is a block diagram of a manhole monitoring collection terminal according to the present invention, [Figure 3] is a manhole monitoring according to the present invention 4 is a block diagram of a relay terminal, and FIG. 4 is a block diagram of a manhole monitoring server according to the present invention.

As shown in Fig. 1 to Fig. 4, the manhole monitoring wireless system according to the present invention (hereinafter referred to as "system" in the detailed description of the invention) is basically an opening and closing sensor (2), water level sensor (4), the collection terminal 10 including the temperature sensor 6 and the terminal unit, and the components such as the relay terminal 20 and the server 30 is provided.

Configurations other than those described above may also be added, but parts unnecessary for the description of the present invention will be omitted.

The above components will be described in more detail as follows.

The collection terminal 10 is

A terminal unit equipped with at least one sensor of the opening / closing sensor 2, the water level sensor 4, and the temperature sensor 6, and detecting an internal state of the manhole using the sensor;

And a wireless communication module 14 for collecting sensing information of the manhole detected by the sensor from the terminal unit and transmitting the collected sensing information to the relay terminal 20 using the antenna 13.

Here, the open / close sensor 2 detects whether the manhole is opened or closed, and is fixed to the manhole body by a lever-type limit switch, and the roller lever is installed in a form in which the manhole cover is pressed. When the manhole cover is opened, the lever returns to the position of the switch. It consists of the structure that the contact is operated.

In addition, the opening and closing oath (2) is made of a solid case of die casting to absorb external shocks, the built-in switch of the opening and closing sensor is composed of a two-stage double-stage basic switch, made of heat-resistant phenol (phenol) material.

The opening and closing sensor 2 configured as described above is a solid structure of oil, heat, and dustproof, and particularly has excellent mechanical strength.

In addition, the set position indicator is attached to prevent over-operation and long life of the lever.

And the water level sensor (4) is to detect the water level inside the manhole, it is made of an ottoman type level switch, installed in the lower part of the manhole when the flooded sensor stretched down to the buoyancy while the internal switch contact operates do.

The water level sensor 4 is preferably made of a synthetic resin, and is made of a structure resistant to corrosion.

In addition, the water level sensor 4 is a tact switch inside the float switch (tact) has a feature that is robust compared to the conventional mercury switch.

The temperature sensor 6 is for sensing a temperature inside the manhole, and in general, the temperature sensor uses a TGA130B, which is a diode thermister whose resistance value changes with temperature.

However, the temperature sensor 6 according to the present invention employs a model name STH10 of Swiss SENSIRION, which is a digital temperature sensor rather than a conventional analog method, in order to improve current consumption, straightness and precision.

Therefore, the temperature sensor 6 according to the present invention is precise and consumes very little power and can measure relative humidity.

And the collection terminal 10 includes a low power control unit 11 for collecting the state information generated in the sensor, and to control the sensors with a small current; And

The microcontroller 12 further wirelessly communicates the state information generated by the sensor from the low power controller 11 to the relay terminal 20 using the antenna 13 and the wireless communication module 14.

Due to the configuration as described above, the collection terminal 10 collects various types of sensing information generated in the manhole using the sensor, and immediately plays a role of wirelessly transmitting a small output to the relay terminal 20 to which the collecting terminal 10 belongs.

That is, the collection terminal 10 is input to the microcontroller 12 through the low power control unit 11 for controlling the sensing information generated by each sensor with a small current, the microcontroller 12 is the content In summary, the wireless communication module (RF module) 14 and the antenna 13 are transmitted to the relay terminal 20.

The battery 17 is built in the terminal unit of the collecting terminal 10 to supply power necessary for the sensor, and to supply the necessary power to each block of the collecting terminal 10.

Here, further comprising a power sensor (8) to determine whether the battery is discharged, the collection terminal 10 due to the discharge of the battery 17 by notifying the manager when the battery 17 of the collection terminal 10 is discharged ) Can prevent the inoperable state.

Here, the detection information of the manhole is a unique number of the manhole, the temperature value inside the manhole detected by the temperature sensor, the water level value inside the manhole detected by the water level sensor, and whether the manhole cover detected by the open / close sensor It includes.

When the collection terminal is described in more detail for the configuration of collecting the state of the sensor, the microcontroller 12 checks the enveloping and level sensor in a period of 1/1000 seconds once per second, power sensor once per minute Use to check the remaining battery capacity (preferably 2.7V or less will be sent immediately to the relay terminal).

In addition, it reads the temperature data once every 10 seconds from the temperature sensor, and transmits the operation status to the relay terminal as soon as the switchgear and the water level sensor operate.

In addition, if the temperature is more than 60 degrees, it is immediately transmitted to the relay terminal, and if more than 5 degrees change in 10 seconds to the relay terminal.

Finally, if there is no action within 24 hours, it automatically transmits its current status to the relay terminal.

Here, the collection terminal 10 is first equipped with sensors inside the manhole, and is equipped with a terminal unit including a battery for supplying power to the sensor, and all the circuit configuration connected to the sensor and the cable to control the sensor ( Antennas) have a configuration embedded in a housing in the collecting terminal 10 which is underground embedded around the manhole.

Therefore, the housing of the collecting terminal is made of acetal resin cover on the bottom plate of stainless steel, so it is durable without any damage to the compression load of 21 TON and does not penetrate moisture even if it is locked for 30 minutes at a depth of 1 meter. It is configured to protect the internal circuit even if the manhole is flooded in rainy season.

The microcontroller 12 preferably uses ATmega16, which is a low power CMOS 8-bit microcontroller 12 based on the AVR RISC structure.

Therefore, the ATmega16 can execute the instruction within one clock cycle and can achieve a processing speed of 1 MIPS / MHz, thereby optimizing power consumption.

In this case, the wireless communication module 14 for wireless communication between the collection terminal 10 and the relay terminal 20 is preferably designed using the model name CC1020 of CHIPCON Co., Ltd. and designed the basics of the wireless transmitting / receiving device, and the model name ATMEGA16 microcontroller of ATMEL Co., Ltd. To implement the control firmware.

In addition, the wireless communication module 14 preferably uses an unlicensed communication method using a frequency of the RF 424Mhz band.

The relay terminal 20 which communicates wirelessly using the collection terminal 10 and the wireless communication module 14 collects and organizes sensing information of a plurality of manholes received from the plurality of collection terminals 10, and collects and organizes them. It is installed with a certain area to transmit the detected information of the manhole to the server 30 wirelessly using the CDMA module.

The relay terminal 20 is preferably designed to manage 250 collection terminals per unit.

Referring to the components of the relay terminal 20 in more detail, the relay terminal

An antenna (13) for receiving state information of a sensor received in the form of a radio signal from the collection terminal (10);

A wireless communication module 14 and a microcontroller 12 for converting the radio wave signal of the event signal into data;

A CDMA module 31 connected to the microcontroller 12 through a connecting means and wirelessly communicating with a CDMA module 22 of a server using a CDMA antenna 26; And

It includes a power supply for supplying power to each of the components.

That is, the radio wave signal received through the antenna 21 of the relay terminal 20 becomes data in the wireless communication module (RF module) 22 and the microcontroller 1 (23-1).

The data is immediately transferred to the microcontroller 2 (23-2) and its contents are again connected to the server (30) via the CDMA public telecommunication network using a CDMA module (25) and an antenna (26) via connecting means, i.e., RS232. do.

The microcontroller 1 23-1 controls the wireless communication module 22 and the microcontroller 2 23-2 controls the CDMA module 25.

The reason for using the multi-CPU as described above is to increase the reliability of data transmission.

And all incoming data is processed as interrupt, so the order of processing is decided by priority.

However, in the case of the relay terminal 20, the priority of either of them may not be yielded, so each of them is processed by using a separate microcontroller and connected to each other in parallel handshake communication.

The CDMA module 25 uses the model name BSM-800 / 850 of BELLWAVE. The CDMA module 25 is connected by dialing using a CDMA public telecommunication network and transmits data using an AT command like a general module.

Here, the power supply unit for driving the relay terminal 20

A solar cell 27 for converting solar energy into electrical energy,

A power supply control unit 28 receiving electric energy from the solar cell 27 and charging the battery 29; And

It includes a battery 29 for supplying power to each block of the device by the power charged by the power control unit 28.

In the case of the solar cell 27, since the relay terminal 20 is installed on a telephone pole or a roof of a building which is not easily connected to a phase power source, self-generation is required.

Therefore, the power supply unit of the present invention preferably solved the power supply using an Amorphous solar cell.

The relay terminal 20 configured as described above may be operated without a collision between the collection terminal 10 communication and the server 30 communication by adopting a multiprocessor, and employing a solar cell, a CDMA module, and an antenna for an installation place. There is no limit.

Therefore, it is possible to secure excellent communication relay function because it is installed at the position of the most optimal radio wave transmission condition.

In addition, PIFA (Planer Inverting F Antenna) antenna is adopted to enhance the reliability of communication which is the life of the relay device.

Here, the relay terminal periodically reports its status and the status of the collecting terminal to the server. If communication is not made within 24 hours from the collecting terminal, the failure of the collecting terminal is reported to the server. Even if the detection information is not transmitted, it transmits its time information to the server once every 24 hours, thereby confirming that the relay terminal is normal.

In addition, the server receives time information from a server to be described later and performs a function of correcting its own time.

In addition, when receiving the collection command from the server reports the final communication with the collection terminal to the server.

In addition, the server 30 and the server 30 for wireless communication using the CDMA module 31 is

A CDMA module 31 for receiving sensing information of the manhole from the relay terminal using the CDMA antenna 31;

A storage unit storing sensing information of the manhole received from the CDMA module 31;

A map data storage unit 36 for storing map data for indicating a position of a manhole on the electronic map;

A central control unit 35 for controlling to display the detected information of the manhole by using an electronic map of the map data storage unit 36; And

Alarm means 34 for generating an alarm sound corresponding to the detection information of the manhole.

As shown in FIG. 5, the antenna of the collecting terminal for wireless communication between the collecting terminal and the relay terminal is

The antenna is provided in the housing of the collecting terminal,

The circuit board mounted on one side of the connector is integrated with the antenna,

The connector and the sensor of the circuit board are connected by a cable passing through the housing.

Therefore, the collection terminal 10 configured as described above is located inside the manhole, and the housing connected to the collection terminal and the cable and embedded in the ground around the manhole is embedded with a circuit board 110, so that the collection terminal 10 For the maintenance, such as replacement of the battery (17) mounted in the interior of the program upgrade and design a separate connection cable terminal box inside the manhole and all interfaces are possible.

The housing 100 is made of a stainless steel bottom plate 101 and the acetal resin cover 102, the outer circumference of the cable 130 penetrated through the stainless bottom plate 101 is shielded with the stainless steel bottom plate 101 In order to be surrounded by a waterproof cable (140).

The antenna 13 of the collection terminal 10 and the antenna 21 of the relay terminal 20 are basically the same configuration.

Here, the antenna 13 preferably uses a low-volume, low-profile microstrip patch antenna to wirelessly transmit information inside the manhole to an external collection device.

At this time, the low-wavelength patch antenna is very large at the low frequency of 425MHz, which is a wireless communication frequency band between the collecting terminal and the repeating terminal, so it is difficult to miniaturize the antenna because it is not practical.

Therefore, high dielectric constant is used for the miniaturization of the antenna, but the reduction in gain and radiation efficiency due to the dielectric loss occurs, so miniaturization through deformation of the patch structure is necessary.

Accordingly, the antenna 13 of the collecting terminal 10 of the present invention comprises a 1/4 wavelength monopole patch antenna of PIFA (Planer Inverting F Antenna) type in which the center of the patch of the half-wavelength microstrip patch antenna is grounded.

In this case, since the antenna of the relay terminal is always installed higher than the collecting terminal, a plurality of fins (FIN) are formed on the bottom of the monopole patch antenna in order to induce the downward frequency of the resonance frequency due to the visible resonance length increase by increasing the current path. Will be attached.

Looking at the performance test of the antenna as described above in more detail.

In order to determine the patch antenna width, the quarter-wave monopole patch antenna was tested as follows in order to determine the effect of the width.

Fixing the feed point and frequency and decreasing the width of the antenna little by little, the change of resonance frequency is less than 40mm, but increases rapidly when it is below. Therefore, the width of the patch is preferably 50mm.

And if you look at the spacing and quantity of the pins, the pin spacing should be more than 3/100 of the wavelength, so that the antenna current path does not intersect, it should be more than 22.5mm, but the experiment result was no problem up to 17.5mm.

In addition, the half wavelength did not saturate to 12. Therefore, a quarter-wave monopole patch consists of six pins.

And the distance between the antenna and the ground plane is 20.0mm in consideration of mechanical matters because the radiation resistance is lower and the closer the distance is larger.

Determining the feed point of the antenna, the feed point is closer to the ground point of the antenna, the lower the radiation resistance and inductive, the farther the resistance is high and capacitive.

Looking at the communication distance experiment for the antenna of the collecting terminal according to the present invention configured as described above are as follows.

Both the transmitter and receiver of the collection terminal used 10mW output and 424.7500MHz unlicensed output radio, and both of them were tested using a half-wavelength FIN-attached patch antenna.

(1) Visual distance test

It was confirmed that about 4,700 meters of communication were carried out without error from the Yangsu-ri railroad crossing in Gyeonggi-do and across the river to the Namyangju County General Cinema Center.

If more visibility was available, more than 5,000 meters would have been possible.

(2) Downtown Street Test

After testing with Epia Tech Co., Ltd. and surrounding area, it was possible to communicate about 400 meters.

Epia Tech Co., Ltd.'s 3 floors are low and the conditions are high due to the surrounding high-rise buildings and train stations.

In theory, the visible communication range of the wireless communication module of the present invention is 12 km, but in reality, about 5 km in the surrounding conditions.

Although the distance of downtown communication has been reduced considerably, it is only a problem in the test conditions. In fact, it is expected that more than 800 m will be secured if the repeater terminal is installed on the upper floor of 10 or more floors and the antenna is adjusted downward. However, propagation has many variables depending on the surrounding conditions and should be improved by continuous testing and research.

Therefore, the Planar Inverted F Antenna (PIFA) antenna proposed in the present invention is a small antenna and a reliable antenna that is less affected by the surroundings.

A general linear antenna does not act as an antenna at all if the ground plane or a metal plate is near, but this antenna is not affected by the ground plane, so it can maintain its performance even when it is buried in the ground and can be applied to steel plates, concrete walls, etc. .

The relay terminal 20 and the server 30 preferably communicate with each other using the CDMA modules 25 and 31 in the 848 MHz band.

Here, the configuration of the CDMA modules 25 and 31 of the server will be described in more detail. The CDMA module 31 includes an RF transmitter, an RF receiver, and a mode switch, and the RF transmitter is configured to receive data from a transceiver module. The RF receiver is a part that collects and transmits the acknowledgment about the signal wirelessly, and collects data from the transceiver module, processes the collected data, and transmits the data to the CDMA interface.

The mode switching unit is used to switch from a reception mode to a transmission mode and to switch from a transmission mode to a reception mode for RF transmission / reception.

 Due to the above configuration, the central control unit 35 expresses the detection information of the manhole received from the relay terminal using the display unit 37 such as a monitor, and generates an alarm sound using the alarm means 34. Will be.

Here, the display unit 37 may display the current location of the unique number of the manhole using the electronic map of the map data storage unit 36.

In this case, when the central control unit 35 emits an alarm sound using the alarm means 34, when receiving the detection information of the collection terminal 10 from the relay terminal 20, the manager detects the position and the detection according to the unique number of the manhole. It transmits and displays the information and generates an alarm sound.

In addition, the storage unit 33 stores the detected information on each received manhole and manages the history, and if the communication is interrupted within 24 hours from the relay terminal 20, the relay terminal 20 is recognized as faulty. Alerts the server administrator.

In addition, if the time data transmitted from the relay terminal 20 is more than 5 minutes, a time correction command is given to the relay terminal.

The operation of the manhole monitoring wireless system according to the present invention configured as described above will be described in more detail.

First, the open / close sensor 2, the temperature sensor 4, and the water level sensor 6 connected to the collecting terminal 10 are collected by the collecting terminal 10 detected by the lid opening / closing of the manhole, temperature and water level, and the power sensor 8. ) To collect the detection information including whether the battery (17) built in the discharge.

The sensing information is collected by the collecting terminal 10 and transmitted to the relay terminal 20 by the wireless communication module 14 and the antenna 15 of the collecting terminal 10.

Accordingly, the relay terminal 20 collects and organizes the sensing information of the manhole received from the collection terminal 10 and uses the CDMA module 25 and the CDMA antenna 26 to form the server 30 through the CDMA communication network. The sensing information of the manhole is transmitted.

The server receiving the manhole detection information from the relay terminal 20 using the CDMA module displays the detection information of the manhole in real time using a display means such as a monitor, so that the current state and the normal state of each manhole are displayed. You can tell the administrator in real time whether the operation.

Herein, the communication module for performing wireless communication between the relay terminal 20 and the server 30 may use the CDMA module and the CDMA antenna as well as all other means capable of wireless communication.

According to the present invention by the above configuration,

First, the present invention is provided with an antenna inside the housing connected to the collecting terminal and the cable, and a circuit board having a connector mounted on one surface is integrally formed with the antenna, and the connector and the collecting terminal of the circuit board pass through the housing. Will be connected.

Therefore, even though the antenna and circuit board are embedded in the collecting terminal, a separate connection cable terminal box is designed inside the manhole for maintenance such as battery replacement and program upgrade, and all interfaces are possible.

Second, the antenna is made of a quarter wavelength monopole patch antenna of PIFA (Planer Inverting F Antenna) type in which the center of the patch of the half-wavelength microstrip patch antenna is grounded.

Therefore, there is an effect that can be miniaturized underground antennas on the road for manhole monitoring.

Third, the antenna increases the current path by attaching a plurality of fins (FIN) to the bottom of the monopole patch antenna has the effect of inducing the resonance frequency downward due to the visible increase in the resonance length.

Fourth, the outer periphery of the cable penetrating the housing connected to the collecting terminal is surrounded by a waterproof cable, it is possible to shield the outside even when the housing of the collecting terminal is underground.

Claims (8)

A plurality of collection terminals connected to a sensor installed in the manhole and collecting sensing information of the manhole from the sensor; In the antenna for wireless communication with a relay terminal for collecting and organizing the sensing information of the plurality of manholes received from the collection terminal, An antenna is provided in the housing of the collecting terminal, The circuit board mounted on one side of the connector is integrated with the antenna, The antenna structure of the manhole monitoring system, characterized in that the connector and the sensor of the circuit board is connected by a cable passing through the housing. The method of claim 1, The antenna of the collection terminal and the relay terminal An antenna structure of a manhole monitoring system, comprising a quarter wavelength monopole patch antenna of PIFA (Planer Inverting F Antenna) type in which the center of the patch of the half-wavelength microstrip patch antenna is grounded. The method of claim 2, The antenna is An antenna structure of a manhole monitoring system, characterized by attaching a plurality of fins (FIN) to induce a decrease in the resonant frequency due to a visible increase in the resonance length by increasing the current path on the bottom of the monopole patch antenna. The method of claim 3, The antenna structure of the manhole monitoring system, characterized in that the width of the patch of the monopole patch antenna is about 50mm. The method of claim 4, wherein The distance between the pin and the pin of the monopole patch antenna is made in the range of 17.5mm-22.5mm, The antenna structure of the manhole monitoring system, characterized in that the number of the pin is six. The method according to any one of claims 3 to 4, The antenna structure of the manhole monitoring system, characterized in that the distance between the monopole patch antenna and the ground plane is about 20.0mm. The method of claim 1, The outer periphery of the cable penetrating the housing is surrounded by a waterproof cable for shielding the housing antenna structure of the manhole monitoring system. The method of claim 1, The housing of the collection terminal is a wireless system for manhole monitoring, characterized in that the cover of acetal resin on the bottom plate of stainless steel to have a rigid and waterproof function.

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