JPH0452893A - Counter for the number of entering/exiting persons - Google Patents

Abstract

PURPOSE:To count up the number of entering/exiting persons into/from a construction by allowing an entering person to carry a transmitter terminal, arranging guide line loop antennas in a closed space area, providing the transmitter terminal with a transmitting antenna driver and a modulator, and providing a central control unit (CCU) with a demodulator and a decoder. CONSTITUTION:The entering person is allowed to carry the transmitter 4 for generating an AC magnetic field of frequency less than minimum frequency f0, the guide line loop antennas 3 are arranged in respective areas in the closed space 1 and the CCU 6 monitors an induced voltage generated in each antenna 3. The driver 41 in the transmitter 4 drives an antenna 42 at the frequency (f) less than cut-off frequency f0 and generates an AC magnetic field H. The demodulator 61 in the CCU 6 demodulates the signal and the decoder 62 decodes an ID number, so that the existence of respective entering persons in respective areas can be detected.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an entry/exit counting device, and more specifically,
In closed spaces such as tunnels, tunnels, underground structures, and inside buildings, it is possible to divide the space into appropriate areas and detect and identify the presence of people entering each area. Relating to a counting device.

<Problems to be solved by conventional technology and inventions> Cables, etc. are laid in tunnels, underground tunnels, basements, or closed spaces inside buildings, where people can enter and exit as needed to carry out work. It can be understood as a closed space system in which

Work in a closed space is difficult to observe from the outside, and if someone entering the building is left behind, it could lead to a serious accident. For this reason, it is extremely important to constantly observe and understand how many people or persons are in a closed space. Additionally, if an abnormal situation such as a fire occurs in the vicinity of a person entering the premises, it is important to inform the outside and take some measures.

For this reason, corporate entities that manage closed spaces such as tunnels have established management centers to observe and understand the number of people entering the premises and their identification numbers (IDs) in each area of the closed space.

That is, conventionally, as shown in FIG.
is divided into appropriate areas, and infrared counters 21, 22.2B, etc. are installed at the boundaries of each area, and the number of people passing in front of them is counted. It controlled the number of people present.

This system is economically advantageous in that it uses a simple infrared counter, but human behavior is complex, and it requires multiple people to walk back and forth in front of a single counter many times. When they line up and cross the counter,
The number of people entering the tank in each area no longer matches the calculation.

In addition, counting errors occur even when the machine passes in front of the counter. If such an error occurs, the purpose of the system, which is to detect the presence or absence of someone entering the premises, will not be achieved.

Therefore, each person entering the campus is required to carry a wireless transmitting terminal, receiving antennas are installed in each area of the campus, and the location of the person entering the campus is estimated in the area corresponding to the receiving antenna that most strongly received the radio waves emitted by the wireless transmitting terminal. can also be considered.

However, with this method, radio waves are thought to be able to travel long distances with almost no attenuation inside tunnels, so the radio waves emitted from the wireless transmission terminal owned by the person entering the building are received by many receiving antennas, and It becomes difficult to determine.

It becomes even more difficult if radio waves or facing occur.

It may be possible to notify the current location via voice from a wireless transmitter terminal, but it would be costly to prepare a large number of voice wireless transmitters, and it would require complicated work for those entering the premises, making it almost impractical.

The present invention has been made in view of the above-mentioned problems, and its purpose is to determine which people are in the area within a closed space such as an underground structure or inside a building.
To provide an entrance/exit counting device that requires complicated work from those entering the premises and can accurately detect them.

Means and Effects for Solving the Problems> As shown in FIG.
A transmitter terminal 4 that generates an alternating current magnetic field (inductive field) at a frequency of less than A signal is guided from the terminal of the guide wire loop antenna 3 to a central control device 6, and the induced voltage generated in each guide wire loop antenna 3 is observed in the central control device 6.

The guide wire loop antenna 3 may be installed at a position depending on the shape of the closed space 1, etc., as long as it can receive an alternating current magnetic field. For example, it may be installed along the ceiling of a closed space 1 formed by a tunnel as shown in Figure 2(a), or it may be installed along both side walls as shown in Figure 2(b). good. It may be installed along the bottom surface of the closed space 1 as shown in FIG. 1C, or it may be installed along one side wall as shown in FIG. 1D.

In particular, a position close to the bottom surface as shown in FIG. 2(C) is preferable because even if a person holding the transmitter terminal falls down in the event of an accident, it can be reliably detected.

As shown in FIG. 3, the transmitter terminal 4 includes a driver 41 that generates an alternating current with a frequency f that is lower than the antenna cutoff frequency fO, and an antenna 42.
An alternating current magnetic field H is generated from the antenna 42 by driving the antenna 42 at a frequency f equal to or less than O. AC magnetic field H
is an induced field, and as shown in Figure 4, it has the characteristic that its intensity decreases rapidly with distance.

A modulator 43 that modulates the AC signal of the frequency f using modulation data including the identification number of the transmitter terminal is connected to the driver 41, and the central management device 6, together with the central management device main body 63, It includes a demodulator 61 that demodulates a voltage signal induced in the guide wire loop antenna, and a decoder 62 that decodes an identification number included in the demodulated signal.

Due to the above configuration, the magnetic field H generated from the transmitter terminal 4 is linked only to the guide wire loop antenna 3 installed in the area where the bather is located due to its locality, and the guide wire loop is A voltage is induced in the antenna 3. The central management device 6 can identify the guided wire loop antenna 3 in which the voltage is induced, and specify the area where the guided wire loop antenna 3 is installed as the area where the person entering the tank exists.

Furthermore, the alternating current signal of the frequency f is modulated by the modulation data including the identification number of the transmitter terminal, and the central management device 6 demodulates this signal to decipher the identification number included in the demodulated signal. I can do it,
It is possible to know whether the detected transmitter terminal 4 has been assigned an ID.

Therefore, if the correspondence between the persons entering the tank and the transmitter terminal 4 is known, it is possible to know whether the persons entering the tank are in each area within the closed space.

In addition, in the entry/exit person counting device of the present invention, the transmitter terminal is provided with a switch that is operated in the event of an abnormality, and when the switch is operated, the encoder changes the normal/abnormal display code in the modulated data to an abnormal state. It is preferable that there is further provided.

When managing the number of people entering the tank, it is important that when an abnormality occurs near the location of the person entering the tank, it is reported to the control center so that the center can understand and respond to the situation. If you insert a normal/abnormal indicator code,
When an abnormality occurs in the vicinity of the tank user's location, the tank user can send a message to that effect, allowing the management center or the like to take prompt action.

The modulator controls the frequency f according to the modulation data.
It is preferable that the alternating current signal is repeatedly modulated at a constant period, and the repetition period is different for each transmitter terminal.

This is because, in general, there may be multiple participants in one area, so if each participant sends data at the same time, the data will collide due to interference between signals, and the central control device 6 will not be able to read the data. Sometimes.

To solve this problem, if transmitter terminals with different modulation repetition periods are used, even if data accidentally collides at one point, it will be possible to separate and read the data at the next point.

The modulator controls the frequency f according to the modulation data.
The same is true even if the alternating current signal is repeatedly modulated at random cycles.

It is preferable that the modulated data includes an error detection code in order to clearly know when data cannot be read due to data collision or the like.

The central management device also includes a management table that stores the number of transmitter terminals detected for each area, and performs reception observation in the area according to the past number of transmitter terminals stored in the management table. Preferably, the time is determined.

Data is transmitted from a transmitter terminal at predetermined time intervals, so if data from one transmitter terminal is to be reliably acquired, reception must continue for a certain period of time. The more transmitter terminals there are, the longer the reception observation time will be. On the other hand, since it is not known how many transmitter terminals are included in one area, it is necessary to set a longer reception observation time for each area if you want to eliminate the possibility of missing detection of transmitter terminals.

However, this takes a lot of time to observe every transmitter terminal. Therefore, based on the prediction that the number of transmitter terminals in each area will not change rapidly in a short period of time, the number of transmitter terminals in each area is determined according to the past (preferably the immediately previous) data on the number of transmitter terminals in the area. By determining the reception observation time, the overall reception observation time can be reduced.

<Example> Embodiments will be described in detail below with reference to the accompanying drawings showing embodiments.

FIG. 5 is a schematic diagram illustrating an example of an incoming/outgoing person counting device, in which a plurality of areas are set in opposite directions, and each area has parallel guiding wire loop antennas 3a, 3b, 3C1... (hereinafter referred to as "3"). ) has been established. Those entering the campus should use their own transmitter terminals 4a, 4b, 4c, etc. (hereinafter referred to as "
4)). One end of the guide wire loop antenna 3 is connected to a switching circuit 7 through signal lines 5a, 5b, 5c, . The switching circuit 7 performs switching at appropriate time intervals and connects one of the signal lines 5 to the central management device 6.

The central management device 6 includes a demodulator 61 outside the central management device main body 63 that demodulates the voltage signal input manually through the signal line 5.
and a decoder 62 that decodes the identification number included in the demodulated signal.
Contains.

As shown in FIG. 12, the transmitter terminal 4 includes a driver 41 that generates an alternating current with a frequency f below the antenna cutoff frequency fo, an antenna 42, and a modulator 43 that modulates the alternating current signal with the frequency f. and a switch 44 that is operated by a person entering the premises when an abnormality occurs.

FIG. 6 is a sectional view of the tunnel, and the width of the tunnel is indicated by W. Cutoff wavelength λC when the path is viewed as a waveguide
can be approximated by λc -2W, so the cutoff frequency fc at which electromagnetic waves can propagate is f c-(/2 W
(c is the speed of light)...■. Transmitter terminal 4
As mentioned above, the transmission frequency f is selected to be below the antenna cutoff frequency fo, and furthermore, to eliminate the propagation of electromagnetic waves in the opposite direction, it is selected to be a frequency smaller than the cutoff frequency fc. (in this embodiment, fc<fo).

Figure 7 shows the frequency characteristics of the spatial noise level (equivalent noise figure) up to several tens of MHz, which is standard in CCIR
II? Figure 8 shows the frequency characteristics of the equivalent noise figure actually measured in the reverse direction, and the noise is very low in frequency. Therefore, in order to reduce the influence of urban noise, it is preferable to choose the frequency f to be as high as possible within a smaller range than fc.

Furthermore, in order to reduce the influence of noise, it is also important that the magnetic field is detected as efficiently as possible by the guide wire loop antennas 3a, 3b, 3c, . Figure 9 is a model for calculating reception efficiency, in which the spacing between the parallel guiding wire loop antennas 3 is 2D, the wire diameter is 2r, and the distance from the center of the parallel guiding wire loop antenna 3 to the transmitter terminal 4 is X. It is said that The coupling coefficient C [dB] between the guide wire loop antenna and the transmitter terminal is as follows, where ω is the angular frequency and A is a predetermined coefficient. From this equation, it can be seen that the coupling coefficient C increases in proportion to the square of the frequency, so from this point, the frequency f
It is preferable that fc be higher than fc within a smaller range.

Next, specific guidelines for selecting the frequency f will be explained.

Assume a tunnel with width W shown in Figure 6. The cutoff frequency is 2WW[m using the equation (2), and since radio waves no longer propagate below this frequency, the only electromagnetic waves that can exist are local induced fields. fc
The attenuation constant of the electromagnetic field in the length direction of the tunnel at the following frequency f is approximately a fdB/mJ − (1, Htl, 9 f fM) by adopting waveguide theory.
Iz] It is estimated that J Tekon Aku Ding Near Ding.
...■If the tunnel width W is -5m, fC-30MHz is obtained from the formula (■), or f=20MHz is selected with a slight margin. ■From the formula, the damping coefficient α−
4d B/m is obtained. According to this, since the attenuation is 40 dB if the distance is 10 m and 80 dB if the distance is 20 m, the locality of the magnetic field can be sufficiently achieved.

It is preferable that the ends of the parallel induction wire loop antenna 3 are connected through a resistor Ro having a value approximately equal to the characteristic impedance of the antenna (see FIG. 10 (a)).

For example, if the frequency f is 20 MHz, the wavelength will be 15 m. The length of the induction wire loop antenna is 100m.
In this case, the length of the loop antenna becomes sufficiently long compared to the wavelength. In such a case, if a conductive wire is used instead of the resistor Ro, the coupling degree C between the inductive wire loop antenna and the transmitter terminal will be such that the wave is 1/2 wavelength long, as shown in Figure 10(b). It becomes a standing wave shape. Therefore, when it comes to the position of the transmitter terminal 4 or the position of the trough of the standing wave, it is no longer coupled to the guide wire loop antenna.

Therefore, as shown in Fig. 10(a), the terminal end of the inductive wire loop antenna is connected to a resistor R approximately equal to its characteristic impedance.
If the antenna is connected at the same position, the degree of coupling C between the guide wire loop antenna and the transmitter terminal becomes almost uniform at both positions, and the transmitter terminal can be connected at any position.

This entry/exit person counting device has an identification number (hereinafter referred to as rlDJ) in the transmitter terminal 4, and is designed to not only detect the presence of persons entering the tank but also individually identify the persons entering the tank. There is.

Figure 11 shows the format of the magnetic field modulation signal generated from the transmitter terminal 4, which includes a preamble, a synchronization bit, a start bit, an ID bit indicating the affiliation and number of the person entering the tank, and a normal/abnormal display bit. , an error detection bit, and an end bit.

In the central management device 6, the AC voltage signal received through the signal line 5 is demodulated by a demodulator 61, and the ID bits contained therein are decoded by a decoder 62 to determine the affiliation of the person entering the tank and his/her individual status. This makes it easier to count and manage the number of people entering the tank.

Table 1 shows each area A, B, and
The number of Omizo players for each C,... and their ID (001,
002,003,...) is shown.

Table 1 In addition, when an abnormality occurs near the tank user's location, the person operating the switch 44 on the transmitter terminal 4 changes the contents of the normal/abnormal display bit from O to 1, for example. By doing so, abnormalities can be reported to the management center, which can then understand and respond to the situation.

To explain the modulation signal in more detail, the modulation signal is a first
As shown in FIG. 3, it is repeatedly transmitted at a period T. The transmission time of one modulated signal is To (constant). This period T is selected to be a different value Ta, Tb, Tc, . . . for each transmitter terminal 4 in order to avoid data collisions. It is preferable that Ta, Tb, Tc, . . . are not selected in a multiple relationship with each other, but are completely unrelated. This is because if there is a multiple relationship, if they collide by − degrees, they will collide again later.

Further, as shown in FIG. 14, the period T has different values TI, T2 . T3
．． You may also choose to take...

Even if you change the frequency of transmitting modulated data as described above, if there are multiple terminals in a certain area, the magnetic fields will be modulated at the same time, and the probability of signal collision due to interference between magnetic fields will be 0. I can't say that.

For this reason, it is necessary for the management device 6 to check the demodulated signal, adopt and register only correct data without errors. The error detection bit in FIG. 11 is a bit provided for this check.

The period during which the switching circuit 7 shown in FIG. 5 is connected to one signal line varies depending on how many transmitter terminals are to be detected in the observed area. For example, 7.511 for the modulated data transmission time TO force in FIG.
sec, the interval of occurrence Tl, T2T3. Assuming that ... follows a uniform random distribution with an average period of 1 sec, the actual number of transmitter terminals in one area and the time required to detect all of that number of transmitter terminals are calculated by simulation. This is Kula 7 in Figure 15. The conditions of the simulation are such that registration is performed immediately when a transmitter terminal is detected, and registration is deleted when the non-detection state continues twice.

From the results in FIG. 15, it can be seen that the number of transmitter terminals existing in one area is 5, 10, . As the time increases to '25.50, the time required to detect almost all the transmitter terminals increases to 5, 7.5, 11.20g+sec.

Therefore, assuming that the number of transmitter terminals that may exist simultaneously in one area is 50, the time required to observe one area is 201 seconds.

If the total number of areas in which the antenna is moving is 30 (that is, the number of guiding wire loop antennas is 30), it will take 20×3 (1-Eioomsec-10 minutes) to search all the areas. However, the observation time would be too long to be practical.

Therefore, it is necessary to minimize the period during which the switching circuit 7 shown in FIG. 5 is connected to one signal line. However, if the number of transmitter terminals is reduced strictly, there is a risk that if there are many transmitter terminals in one area, it will not be possible to detect all of them. Therefore, the next detection time may be determined according to the number of people in each area detected in the previous search (see Table 1). For example, according to Table 1 above, each area A, B
.

C9..., N has 1 person, 3 people, 0 people, etc., respectively.
・Assuming that one person is included, the number of people in each area will not change rapidly at the time of the next search, so the observation time will vary depending on the number of registrations in Table 1 (for example, the number of registrations or 0 people). In that case, take 1-2 people and choose n+1 or n+2.
All you have to do is allocate the time required to detect a person and conduct the observation.

<Effects of the Invention> As described above, according to the entry/exit counting device of the present invention, the alternating current magnetic field H generated from the transmitter terminal, due to its locality, can be applied to the guide wire loop installed in the area where the large number of people are located. It interlinks only with the antenna and induces voltage. The central management device can identify the guide wire loop antenna in which the voltage is induced, and specify the area where the guide wire loop antenna is installed as the area where the large grocer is present.

Furthermore, the AC magnetic field H generated from the transmitter terminal is
Since modulation is performed using modulation data that includes the identification number of the transmitter terminal, the central management device demodulates the voltage signal induced in the guide wire loop antenna and decodes the identification number included in the demodulated signal. This makes it possible to identify individuals individually.

Therefore, in a closed space such as an underground structure or inside a building, it is possible to accurately detect whether or not there is a major ditcher in which area, and if so, which major ditcher is present, without requiring the major ditcher to perform complicated work. can do.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an outline of the entry/exit counting device of the present invention, Fig. 2 is a diagram illustrating the shape of a guide wire loop antenna, Fig. 3 is a diagram showing an outline of a transmitter terminal, and Fig. 4 is a diagram showing an outline of a transmitter terminal. A graph showing the distance attenuation characteristics of the guided field output from the aircraft terminal, Fig. 5 is a diagram showing an example of the entry/exit counting device, Fig. 6 is a cross-sectional view of the tunnel, and Fig. 7 is the CCIR standard Graph showing the frequency characteristics of the spatial noise level (equivalent noise figure) up to several tens of MH2, Figure 8 is a graph showing the frequency characteristic of the equivalent noise figure actually measured in the opposite direction, Figure 9 is the transmitter A cross-sectional view showing the positional relationship between the terminal and the guiding wire loop antenna. Figure 10(a) is a perspective view showing the guiding wire loop antenna with the terminal ends connected with a resistor. Figure 10(b) is the guiding wire loop antenna with the terminal ends short-circuited. Fig. 11 is a diagram showing the signal format of the modulation signal that modulates the alternating current magnetic field generated from the transmitter terminal; Fig. 12 is a block diagram of the transmitter terminal; Fig. 13 is a perspective view showing the wire loop antenna;
Figure 14 is a time structure diagram of data transmitted from one transmitter terminal, Figure 15 is a diagram showing the relationship between the number of transmitter terminals in one area and detection time, and Figure 16 is a diagram showing the relationship between the number of transmitter terminals in one area and detection time. 1 is a diagram showing a conventional entry/exit counting device using an infrared counter. 1... Closed space, 3... Guide wire loop antenna,
4...Transmitter terminal, 6...Central management device, 4-core...Driver, 42...Transmission antenna, 43...Modulator, 44...Switch, 61...Demodulator, 62・・・
-Decoder, 63...Central management unit main body 4 -Transmitter terminal 42...Transmission antenna 41 -Driver 1 -Closed space 3a, 3b, 3c, 3d -Guiding wire loop antenna 4
a, 4b, 4c... Transmitter terminal fth (MHz) fth (MHz) 1 - Closed space 3 - Guide wire loop antenna 4 - Transmitter terminal Fig. 15 Detection time (SeC1 10, 11, synchronous STX ID, M2, false detection PAD4..., transmitter terminal, 12, 13, 14

Claims (1)

[Claims] 1. A person who enters a closed space such as an underground structure or inside a building is given a transmitter terminal, the closed space is divided into a plurality of areas, and each area is , a guide wire loop antenna is installed to detect the alternating current magnetic field generated from the transmitter terminal, and the voltage induced in one of the guide wire loop antennas is detected via the signal transmission line to detect the presence of a person entering the premises. The transmitter terminal includes a central management device that specifies an area, and the transmitter terminal has a transmitting antenna and a frequency f that is lower than the lowest frequency fo that can emit radio waves from the transmitting antenna.
a driver that drives the transmitting antenna with an AC signal of f, and a modulator that modulates the AC signal of frequency f with modulation data including an identification number of the transmitter terminal is connected to the driver; An entry/exit counting device, wherein the central management device includes a demodulator that demodulates a voltage signal induced in the guide wire loop antenna, and a decoder that decodes an identification number included in the demodulated signal. 2. The transmitter terminal is provided with a switch that is operated in the event of an abnormality, and by operating this switch, it is possible to further provide an encoder that changes the normal/abnormal display code in the modulated data to an abnormal display state. The entrance/exit counting device according to claim 1, characterized in that: 3. The modulator according to claim 1, wherein the modulator repeatedly modulates the alternating current signal of the frequency f at a constant cycle using the modulation data, and the cycle of this repetition is different for each transmitter terminal. entry/exit counting device. 4. The entrance/exit counting device according to claim 1, wherein the modulator repeatedly modulates the alternating current signal of the frequency f at a random cycle using the modulation data. 5. The entrance/exit counting device according to claim 1, wherein the modulated data includes an error detection code. 6. The central management device is equipped with a management table that stores the number of transmitter terminals detected for each area, and determines the reception observation time of the area according to the past data on the number of transmitter terminals stored in the management table. 2. The entry/exit counting device according to claim 1, wherein the incoming/outgoing person counting device determines.