JPH05312949A - Vehicle sensor - Google Patents

Abstract

PURPOSE:To establish a bilateral communication channel between a vehicle and a roadside unit economically by shifting the infrared ray projecting intervals for detecting a vehicle and for communication thereby using same carrier for detection of vehicle and for communication. CONSTITUTION:A roadside unit 100 is fixed to an arm stretching over a pavement in order to project infrared pulse ray onto the pavement and to receive infrared ray reflected on a vehicle and infrared pulses projected from a mobile unit 200. Infrared ray signal transmitted from the roadside unit 100 is received by a light receiving unit 210 in the mobile unit 200 and then passed through a receiving gate 213, subjected to data decision 214, and stored 216 to be used as a roadside data output. The data represents a passing point, for example. Output from the data decision circuit 214 is delayed through a delay timer circuit 217 and subjected to pulse amplification 232 and then outputted 234 as mobile unit information in the form of light. Two types of signal received by the roadside unit 100 are discriminated through a receiving gate circuit 113 and a decision circuit 114 based on the timings thereof. Light signal reflected on a vehicle is stored during an interval when the vehicle is being detected 115 whereas the information of mobile unit (ID and the like) is stored 116 during an interval when the vehicle is not detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has an infrared ray emitting / receiving unit installed on a road so that a vehicle can be sensed by infrared rays and can communicate with the vehicle by the same infrared ray used for vehicle sensing. The present invention relates to a vehicle sensor with a communication function.

[0002]

2. Description of the Related Art A vehicle sensor is installed on a road, projects a carrier wave such as an ultrasonic wave or an infrared ray onto a vehicle, and detects a reflected wave from the vehicle to detect the vehicle. In particular, a sensor using infrared rays emits intense infrared rays intermittently in pulses to detect the reflected waves. In this case, the device configuration is made so that the reflected infrared rays do not interfere with the projected infrared rays.

On the other hand, when the road and the vehicle try to communicate with each other, another frequency is used so as not to interfere with the above-mentioned vehicle detection signal.

[0004]

However, with such a structure, two devices must be provided, and there is a problem that economic efficiency is poor.

The present invention has been made in view of such circumstances, and has a bidirectional communication function capable of receiving information from a vehicle by using a signal used for vehicle detection for communication. Vehicle sensor.

[0006]

In order to solve such a problem, the present invention provides a light emitting / receiving unit for projecting and receiving a carrier signal installed on a road, and a reflected wave of the carrier signal projected by the light receiving / receiving unit. Is performed during the carrier signal projection period, and both vehicle detection and communication are performed by using the same carrier.

[0007]

[Function] An infrared signal is projected from a road infrared emitting / receiving unit installed on the road, and a signal reflected by the vehicle is received by the road infrared emitting / receiving unit during the infrared signal projection period, whereby the position of the vehicle is reduced. Detection is done. Further, during the period other than the infrared signal projection period, the signal projected from the vehicle infrared ray emitting / receiving unit is received by the road infrared ray emitting / receiving unit, so that communication between the vehicle and the road is performed.

[0008]

FIG. 1 is a block diagram showing an embodiment of the present invention. FIG. 2 shows an arm 1 projecting on the road to which a light emitting / receiving device 2 composed of a light emitting device and a light receiving device is attached, and an infrared pulsed light beam The reflected wave from the vehicle 3 and the infrared pulsed light from the vehicle-mounted device are simultaneously received. At this time, the roadside device 100 of FIG. 1 receives the infrared light while projecting the infrared light, so that the light emitting device 134 is provided so that transmission and reception interference does not occur.
The light receiver 110 is attached. The controller 5 attached to the support column 4 has a function of outputting a pulse to the light emitting device 134 and a function of discriminating a received pulse from the light receiving device 110, and has a structure capable of being connected to a communication line.

The vehicle-mounted device 200 mounted on the vehicle 3 receives a pulse from the light-emitting device 134 on the road to determine data by bidirectional communication, and at the same time, sends the on-vehicle device information to the light-receiver 110 on the road. Is equipped with.

The road device 100 shown in FIG. 1 is usually attached to an arm 1 projecting on the road, and an infrared pulsed beam, which is shown as a road light output in FIG. 3, is projected from a light emitter 134 toward a target lane. At this time, the infrared pulsed light beam is modulated by a signal containing a signal for transmitting information. In this case, one pulse has a value of about 5 ms, and the pulse interval has a value of about 15 ms.

When this signal is reflected by the vehicle, the signal from the road light receiver output shown in FIG.
The light is received by the light receiver 110. The infrared signal from the above-described roadside device 100 is received by the light receiver 210 of the vehicle-mounted device 200, and is supplied to the reception gate circuit 213 via the light reception amplifier 211 and the waveform shaping circuit 212.

The receiving gate circuit 213 is initially open,
It is ready to accept signals. Therefore, the signal that has passed through the reception gate circuit 213 is the data discrimination circuit 2
It is discriminated at 14, and stored at the memory circuit 216 and used as the road data output. This data is, for example, information about passage points or information such as road information.

The output of the data discriminating circuit 214 is also supplied to the delay timer circuit 217. Therefore, as shown in FIG. 4, the delay timer circuit 217 generates an output signal for a predetermined time during a predetermined time from the time when the output of the reception gate circuit becomes L level.

The output of the delay timer circuit 217 is supplied to the reference oscillating circuit 240, and the reference oscillating circuit 240 generates an output signal for a predetermined time after the output of the delay timer becomes L level. Also, the reference oscillator output is the reference timer circuit 2
The output signal is generated every time the delay timer output signal is supplied from 17, but the output signal is not generated when the delay timer output signal is not supplied twice in succession. The gate circuit 231 is opened by the output signal of the reference oscillation circuit 240, and the storage data of the storage circuit 230 in which the vehicle data input is stored is supplied to the pulse amplification circuit 232 via the gate circuit 231.

The signal output from the pulse amplification circuit 232 is supplied to the light emitter 234 via the light emission output circuit 233, and the infrared signal described as the on-vehicle light emitter output in FIG. 4 is output from the light emitter 234. Further, the output signal of the reference oscillation circuit 240 is supplied to the reception gate circuit 213, and the reception gate circuit 213 is configured to be closed while the gate circuit 231 is open so that transmission / reception interference does not occur. ing.

Note that the reception gate circuit 213 is always open initially as described above, but after receiving the signal from the roadside device 100, it opens at a predetermined time determined by the output signal of the reference oscillation circuit 240, and the others. I try to close it. When the signal from the roadside device cannot be received more than twice, for example, it returns to the initial state and is always open.

The information transmitted from the vehicle-mounted device 200 is, for example, an ID number of the vehicle, and the road-side device 100 side can identify which vehicle is traveling and where. The infrared signal transmitted from the vehicle-mounted device 200 is received by the light receiver 110 of the roadside device 100, and is supplied to the reception gate circuit 113 via the light receiving amplifier 111 and the waveform shaping circuit 112.

The reception gate circuit 113 is a reference oscillator circuit 14.
A signal from 0 is supplied, and the signal supplied from the waveform shaping circuit 113 is divided into a vehicle detection signal and a vehicle data signal and supplied to the determination circuit 114.

FIG. 3 is a waveform diagram for explaining the above-mentioned operation. First, a signal described as an output of a road light emitter is projected from the road device 100. This signal is reflected on the vehicle side and is output from the light receiver 110 of the roadside device as a hatched signal among the signals described as the roadside light receiver output. on the other hand,
The vehicle-mounted device that has received the signal transmitted from the roadside device 100 transmits the vehicle information to the roadside device 100 after a delay time determined by the delay timer circuit 214. This signal is also received by the light receiver 110, but in the signal marked as the road light reception output in FIG. 3, the unhatched part corresponds to the transmitted signal modulated by the information from the vehicle-mounted device 200. ..

These two types of signals are received gate circuit 113.
Therefore, the reception gate circuit 113 receives the signal reflected from the vehicle depending on the timing, or the vehicle-mounted device 200.
It is determined whether or not the signals are transmitted from, and each signal is distributed and output.

Similarly, the discrimination circuit 114 discriminates the distributed signals individually, and supplies the signal reflected from the vehicle to the vehicle detection circuit 115. That is, the hatched signal of the signals indicated as the road discrimination circuit output in FIG. 3 is supplied to the vehicle detection circuit 115. Then, a signal labeled as vehicle detection output in FIG. 3 is output, and vehicle detection is performed while the signal continues.

On the other hand, among the signals described as the road discriminator output in FIG. 3, the non-hatched signals are the memory circuit 11.
6 and outputs the signal marked as vehicle data output in FIG.

That is, the information transmission from the vehicle is performed during the period when the vehicle is not sensed.

When higher speed communication is required, as shown in FIG.
It outputs the signal labeled as the output of the on-road light emitter. This signal first transmits two pulses in a cycle of, for example, half of the pulse interval T, and uses this as a synchronization signal. After that, for example, a signal representing predetermined information is transmitted by a combination of pulses represented by whether or not there is a pulse at the timing of each cycle T. The number of bits is, for example, 3
It is considered that the pulse period T is about 100 μS for about 2 bits.

The reception gate circuit 113 opens the gate circuit for vehicle detection for a time slightly wider than the transmission pulse width,
I try not to be affected by noise. For communication, the gate is closed while the road light is projecting an infrared signal, and the gate is opened at other times.

The light emitting device 234 of the vehicle-mounted device 200 sends out an infrared signal about T / 4 after the infrared signal from the roadside device 100 ends. Also at this time T /
Two pulses having an interval of about 2 are used for synchronization, and the information is represented by the presence / absence of a pulse in a subsequent period of, for example, about 32 bits. Further, the vehicle-mounted reception gate closes the gate while the vehicle-mounted light emitting device 234 projects the infrared signal.

[0027]

As described above, according to the present invention, an information signal is placed on a vehicle detection signal, and whether the signal is for information communication or vehicle detection is discriminated according to the reception timing of the signal. Since communication and vehicle detection can be performed with a single light emitting and receiving device provided on the road, vehicle detection and communication can be performed at low cost. Further, since communication and vehicle detection can be performed with only one light emitting and receiving device provided on the road, there is no need to provide a sensor for each purpose on the road, which is preferable in terms of urban aesthetics. Furthermore, since communication and vehicle detection can be performed with a single light emitting and receiving device provided on the road, if installed in each lane, information can be transmitted for each lane,
When an accident occurs in the overtaking lane, it is possible to notify only the vehicle in the lane in advance.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a mounting state of the device.

FIG. 3 is a waveform diagram showing timings of a vehicle detection signal and a communication signal.

FIG. 4 is a waveform diagram showing the operation of the vehicle-mounted device.

[Fig. 5] Waveform diagram for high-speed communication

[Explanation of symbols]

 1 arm 2 light emitting and receiving device 3 vehicle 4 support 5 controller 100 roadside device 200 vehicle-mounted device

Claims (1)

[Claims] 1. A vehicle sensor for projecting a carrier signal modulated by a data signal to a vehicle, detecting the vehicle by the reflected wave thereof, and communicating between the vehicle and the road by the carrier signal. A light emitting / receiving unit for projecting and receiving light, a sensing unit for detecting a reflected wave of a carrier signal projected by the light emitting / receiving unit during a carrier signal projection period, and a predetermined period after the end of the carrier signal projection from the light emitting / receiving unit. A vehicle sensor comprising: a discrimination circuit for discriminating a carrier wave signal projected from a vehicle, and performing both vehicle detection and communication by using the same carrier wave.