JPH0242600A - Automatic detecting method in entrance/exit gate - Google Patents

Abstract

PURPOSE:To surely attain automatic detection by making lower the frequencies of the call signals of plural transmitting and receiving antennas as a vehicle progress farther from the gate, and setting output levels with making them variable to plural stages. CONSTITUTION:Transmitting and receiving antennas 3 and 4 are provided at some interval farther from the gate 2 of an entrance crossing barrier 1 of a parking area. Call signals respectively at frequencies f1 and f2 in the range of 1 to 10 MHz (however, f1>f2) and having two output levels are transmitted from the antennas 3 and 4 under the control of a transceiver 5. At such a time, assuming that No.1 vehicle 6 and No.2 vehicle 7 are stopped. By their transceivers 6A and 7A, different code signals are outputted in response to the said call signals. As a result, by the receiving identification code signal, whether or not the vehicle is that of a member or the front and rear of the vehicle can be generally and reliably detected.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is useful, for example, for automatic detection of vehicles parked in front of entrance/exit gates in parking lots, automatic detection of vehicles parked in front of entrance/exit gates in factories, etc. The present invention relates to an automatic detection method at an entrance/exit gate that performs detection.

(Prior Art) Conventionally, for example, when controlling entry and exit to a parking lot, the member's car is positioned in front of the gate of the parking lot by receiving an identification code signal (ID code signal) from a transceiver of the member's car in the parking lot. An automatic detection method to automatically detect when the car is parked is to place the transmitting and receiving antenna at the gate! A method of detecting the identification code signal coming back from the member's car by transmitting a medium wave call signal of around 100KHz, and a method of transmitting a microwave or millimeter wave call signal.
There was a method of detecting the return of an identification code signal from a member's car. In the case of the former frequency, the number 10
In the case of the latter frequency, the member's car at a distance of several meters can be detected. In the latter case, the antenna was given directivity to detect a limited area.

<Problem to be Solved by the Invention> However, in the former case, which uses a frequency of several 100 KHz, the reach of the call signal transmitted from the transmitting/receiving antenna of the gate is too short, and the distance of the call signal transmitted from the transmitting/receiving antenna of the gate is too short, making it difficult to detect the position of a car parked in front of the gate. There is a problem that detection may not be possible in some cases. On the other hand, the latter method using microwaves or millimeter waves is advantageous in that the call signal has a long reach and is directional, but has the problem that the transmitter/receiver is expensive.

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic detection method at an entrance/exit gate that is inexpensive, has a long range of call signals, and is reliable.

(Means for Solving the Problems) To explain in detail the present invention for achieving the above object, the present invention provides a transmitter/receiver attachment that transmits an identification code signal using a call signal, which is located in front of an entrance/exit gate. In an automatic detection method at an entrance/exit gate that automatically detects whether or not a person is present at the entrance/exit gate, a plurality of transmitting/receiving antennas are installed at a distance ahead of the entrance/exit gate, and the frequency from each transmitting/receiving antenna decreases as the distance from the gate increases. IMH
Call signals of different frequencies in the 2 to 10 MHz band are transmitted with output levels changed in multiple stages, and the identification code signal responded from the transmitter/receiver of the passing object in front of the gate is received by each of the transmitting/receiving antennas. The present invention is characterized in that, based on the identification code signals received by each of the transmitting and receiving antennas, a comprehensive determination is made as to whether or not a passing object in front of the gate has a predetermined transmitter/receiver.

(Function) In this way, in the case of a call signal with a frequency in the 1 MHz to 10 MHz band, although it has the advantage of having a detection distance of about 2 m to 5 m, it has no directivity, so as mentioned above, the transmitting and receiving antennas are separated by a distance. The call signals emitted from these transmitting/receiving antennas also change the frequency for each transmitting/receiving antenna, decreasing as the distance from the gate increases, and the output level of the call signals at these frequencies is changed in multiple steps. This makes it possible to detect the identification code signal from a predetermined transceiver from a comprehensive situation.

(Example) Hereinafter, an example in which the present invention is applied to automatic detection of a parked vehicle in front of an entrance/exit gate in a parking lot will be described in detail with reference to the drawings.

As shown in FIGS. 1 and 2, in this embodiment, there is a distance M beyond the gate 2 of the barrier 1 at the entrance to the parking lot (inside the parking lot).
First and second transmitting/receiving antennas 3.4 are installed separated by L. In this case, the first transmitting/receiving antenna 3 is provided at the gate 2. From the first transmitting/receiving antenna 3 near the gate 2, a first call signal of level E and level ■ (however, level I and level ■) with different levels at frequency f1 (however, fl is a frequency in the 1 MHz to lOMHz band) is transmitted. Transmission is controlled by the transceiver 5.

The second transmitting/receiving antenna 4, which is far from the gate 2, has a frequency fz lower than fl (however, f2 is f).

A second call signal of level (2) and level (2) (however, level (2) and level (3)) which are different in level (1 MHz to 10 MHz band frequency) and different from (1 MHz to 10 MHz band frequency) is transmitted under control from the transceiver 5. In this case, in front of the gate 2, the first car 6, which is a passenger car, and the second car 7, which is a bus, are parked with the first car 6 in front and the second car 7 in the back, as shown in the figure. do. These 1st car 6 and 2nd car 7
It is assumed that both members' cars are equipped with transceivers 6A and 7A that output different identification code signals in response to call signals.

In this case, each transmitter/receiver 6A, 7A of the No. 1 car 6 and No. 2 car 7 outputs in response to the first and second call signals of each level I and ■ from the first and second transmitting/receiving antennas 3.4. The identification code signal is received as shown in Table 1.

Table 1 Be able to identify cars.

Next, Table 2 shows the response when the first car 6 is a non-member who does not have a transmitter/receiver 6A and the second car 7 is a member in the state shown in FIG.
Shown below.

Here, the X mark indicates no response. ◎ mark cannot be detected due to both responses O mark can be detected shows.

In this case, the level of the second transmitting/receiving antenna 4
Based on the second call signal, the transmitter/receiver 5 can comprehensively determine and detect that the No. 1 car 6 is stopped in front of the gate 2.

In other words, when the frequency is changed as fl, fl, fl, f4 (where ft > fl > fl > f4), there is a relationship between the reach distance of the call signal and the reception level as shown in Figure 3. Yes, such frequency changes and
Due to changes in the output level and changes in the distance from the transmitting/receiving antenna to the vehicle, the automatic table 2 before and after. I can see that No. 2 car 7 is behind me.

That is, the present invention determines the corresponding vehicle based on the respective output levels of the first and second call signals transmitted from the first and second transmitting/receiving antennas 3.4 of the gate 201, and determines the identification code emitted from the vehicle. This is an attempt to detect the presence of a car based on traffic signals.

The distance ML between the first and second transmitting and receiving antennas 3.4 is adjusted depending on the surrounding situation. By increasing the installation positions of the transmitting and receiving antennas of the gate 2rpJ and by changing the output level many times, more reliable detection becomes possible. Furthermore, by using FM as a transmitter/receiver, strong radio waves suppress weak radio waves during input, allowing more effective detection.

In the above embodiment, a case has been described in which the entry of a vehicle is detected at the barrier at the entrance of the parking lot, but exit detection can also be performed in the same manner at the barrier at the exit of the parking lot. In this case, the frequencies are (fl+α), (f2+β)
It is preferable to prevent interference by differentiating the signals as follows, where α and β are minute values of several tens of kilohertz to several hundred kilohertz. Further, it is preferable to distinguish, for example, bit N is 1 on the exit side and bit N is 0 on the input side.

It goes without saying that the present invention can be applied not only to the above-mentioned parking lot entry/exit control, but also to automatic detection when controlling the entry/exit of people, working machines, and luggage to a specific location such as a factory.

(Effects of the Invention) As explained above, the automatic detection method at the entrance/exit gate according to the present invention uses a frequency in the 1 MHz to IOMH2 band that has no directivity but has a detection distance of about 2 m to 5 m, and detects the gate exit. Multiple transmitting and receiving antennas are installed at a distance from each other, and the frequency of the call signals emitted from these transmitting and receiving antennas decreases as the distance from the antenna increases, and the output level of each call signal is changed in multiple stages. By emitting a signal, a member's car or the like can be comprehensively detected from the identification code signal received as a result of changes in these conditions, so that reliable detection can be performed. Another advantage is that accurate detection can be performed even if a vehicle equipped with a transceiver that emits a specific identification code signal and a vehicle that is not equipped with a transmitter/receiver that emits a specific identification code signal arrive in front of the entrance/exit gate at the same time. Furthermore, according to the present invention, from 1 MHz to 10 MH
Since the Z-band frequency is used, there is an advantage that the system can be formed at a lower cost than when microwaves or millimeter waves are used.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the front and back of the gate showing the implementation status of the method of the present invention, Fig. 2 is a front view of the gate, and Fig. 3 shows the relationship between the reach distance of the call signal and the reception level with respect to changes in frequency. It is a line diagram. 1...Breaker, 2...Gate, 3...
...First transmitting and receiving antenna, 4... Second transmitting and receiving antenna, 5... Transmitting and receiving system, 6.
...Car 1, 6A...Transmitter/receiver, 7...
...Car 2, 7A...Transmitter/receiver. Patent applicant Showa R&D Co., Ltd. Figure 2 Figure 3 - One distance

Claims (1)

[Claims] In an automatic detection method at an entrance/exit gate that automatically detects whether or not a transmitter/receiver attached object that emits an identification code signal based on a call signal is present in front of the entrance/exit gate,
A plurality of transmitting/receiving antennas are installed at a distance ahead of the entrance/exit gate, and each transmitting/receiving antenna transmits a frequency of 1 MHz to 10 MHz, the frequency of which decreases as the distance from the gate increases.
transmitting call signals of different frequencies in the Hz band with output levels changed in multiple stages, and receiving the identification code signal responded from the transmitter/receiver of the passing object in front of the gate with each of the transmitting/receiving antennas; Automatic detection at an entrance/exit gate, characterized in that a comprehensive judgment is made as to whether or not an object passing in front of the gate has a predetermined transmitter/receiver based on the identification code signal received by each of the transmitting/receiving antennas. Method.