JPH0248799A - Buried vehicle detector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a vehicle sensor having a sensor section buried underground to detect a vehicle passing over the sensor section.

(Prior Art) FIG. 2 shows the installation configuration of this type of buried vehicle sensor. Reference numeral 1 denotes a sensor section of the buried vehicle sensor, which is buried under the road surface. , 2 is a signal processing unit, which is usually installed on the side of the road, determines whether the sensor unit detects or not detects a vehicle, and transmits the information to a host device. 63 is a vehicle running on the road surface.

FIG. 3 shows the configuration of a conventional sensor section, where 4 is a magnet meter that detects changes in geomagnetism, 5 is its detection circuit, 6 is a modulation circuit, 7 is a drive circuit for antenna 8, and 9
is the battery that supplies power to each circuit.

Next, the operation of the above conventional example will be explained. In FIG. 2, when the vehicle 3 passes over the sensor section 1, since the vehicle 3 is made of metal, the earth's magnetism near the sensor section 1 is affected and the magnetic flux changes. Therefore, the sensor section 1 in FIG.
An internal magnet meter 4 captures the change, and a detection circuit 5 detects and outputs the change. The modulation circuit 6 uses the level of the detection output as information to perform modulation, and transmits radio waves from the antenna 8 through the drive circuit 7. The transmitted radio wave is then received by the signal processing unit 2 shown in FIG. 2, and vehicle detection is determined based on the modulation information.

(Problem to be Solved by the Invention) However, the conventional buried geomagnetic vehicle sensor described above has a geomagnetic detection section (magnet meter, detection circuit, etc.) and a radio wave transmission section (antenna, drive circuit, modulation circuit, etc.) inside the sensor. ), and as a result, there was a problem in that there was a limit to miniaturization. Furthermore, since the sensor section is powered by a battery, there is a problem in that driving the two device sections described above shortens the service life.

The present invention is intended to solve these conventional problems, and aims to provide an excellent buried vehicle sensor that can realize miniaturization and a long life of the sensor section. be.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a receiving means for receiving radio waves transmitted by the sensor unit itself, a modulating means for performing modulation according to the intensity of the received radio waves, It consists of a transmitting means that transmits modulated radio waves, and a battery that supplies power to each means.

(Function) According to the above configuration, when a vehicle passes over the sensor section, radio waves are reflected from the vehicle and the reception level of the receiving means becomes high, and the modulated signal radio waves containing the information are transmitted to the signal processing section. receives the information and determines whether the vehicle has passed.

In this way, in the present invention, which does not employ a geomagnetic detection method as a means of vehicle sensing, the magnet meter and detection circuit can be omitted, and conversely, although a detection circuit for receiving radio waves is required, the receiving antenna Since it can be used in common with the transmitting antenna, there is no need to add a new antenna, and it is clear that the number of antennas that can be deleted is greater than the number of additions, which can promote miniaturization.

In addition, regarding battery life, detecting radio waves can technically save more power than detecting geomagnetism, making it possible to extend battery life.

(Embodiment) FIG. 1 shows the configuration of a sensor section of an embedded vehicle sensor according to an embodiment of the present invention. In FIG. 1, 8 is an antenna used for both transmission and reception, and IO is a detection circuit for detecting received radio waves. 6 is a modulation circuit that modulates the transmitted radio wave according to the level information received by the detection circuit 10;
is a drive circuit, and 9 is a battery. Note that the installation of the sensor section and signal processing section is the same as in the conventional case, as shown in FIG.

Next, the operation of the above embodiment will be explained. first.

The antenna 8 of the sensor section is used for both transmission and reception, and always transmits radio waves for communication to the signal processing section.

Next, the detection circuit 10 is set to detect only the radio waves in the frequency band of the radio waves it is transmitting among the radio waves received by the antenna 8, and the modulation circuit 6 is set to detect the radio waves detected by the detection circuit 10. Modulation corresponding to the level is applied to the transmitted radio waves. The signal is then transmitted from the antenna 8 through the drive circuit 7.

Therefore, when there is no vehicle directly above the sensor section, the radio waves transmitted from the sensor section are scattered in all directions and are rarely received by the sensor section, and the information that the reception level is low is modulated into the radio waves. Transmission continues If a vehicle approaches directly above the sensor unit, most of the radio waves sent upward by the sensor unit will be reflected by the vehicle body and will be reflected by the sensor unit again. Information that the reception level is high is modulated into radio waves and transmitted. Therefore, the roadside signal processing section 2 (see FIG. 2) can determine whether a vehicle is detected or not by receiving the radio waves from the sensor section and analyzing the modulation state thereof.

As described above, the above embodiment has the advantage that the circuit of the sensor section can be miniaturized because it does not have a dedicated device (geomagnetic measuring device) for vehicle detection unlike the conventional example. Furthermore, since the power consumed by the geomagnetic measuring device can be reduced, it also has the advantage of extending the life of the battery.

(Effects of the Invention) As is clear from the above embodiment, the present invention detects a vehicle by using the radio waves transmitted by the sensor unit, and uses the dedicated device for vehicle detection (geomagnetic measurement) shown in the conventional example. Device)
This has the advantage that the sensor part can be made smaller and the life of the battery can be extended.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a sensor section of a buried vehicle sensor according to an embodiment of the present invention, FIG. 2 is an installation configuration diagram of a buried vehicle sensor, and FIG. 3 is a diagram of a conventional buried geomagnetic vehicle. It is a block diagram of a sensor sensor part. 1...Sensor part of a buried vehicle detector. 2...Signal processing unit of buried vehicle sensor, 3...
Running vehicle, 6... Modulation circuit, 7... Drive circuit,
8...Antenna, 9...Battery, 10.
...Detection circuit. Patent applicant: Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] The sensor section includes a sensor section that is buried under a road surface on which a vehicle passes and detects the passage of a vehicle, and a signal processing section that is installed on the ground and receives radio waves transmitted from the sensor section and processes the signals. consists of a receiving means for receiving radio waves transmitted by itself, a modulating means for modulating the received radio waves according to the intensity of the received radio waves, a transmitting means for transmitting the modulated radio waves, and a battery for supplying power to each of the means, An embedded vehicle sensor characterized in that when a vehicle passes over the sensor section, radio waves are reflected from the vehicle and the reception level of the receiving means increases, thereby detecting the passage of the vehicle.