JPS61117929A - On-road equipment for radio communication between on-road equipments having vehicle detection radar function - Google Patents

Abstract

PURPOSE:To attain simplicity and miniaturization by using a plane type print antenna for circularly polarized wave for two-terminal drive for both transmission and reception in common while a circularly polarized wave is used for all radio propagation in three operations of an on-road equipment so as to use a carrier oscillator in common in the three operations. CONSTITUTION:Two terminals A, B of the TEM two-terminal drive plane type circularly polarized wave print antenna 31 are connected to a hybrid circuit 32 and two terminals C, D of the hybrid circuit 32 are terminals from which circularly polarized waves having opposite rotatory directions are driven. A circulator 33 using the antenna in common for transmission/reception is connected to the drive terminal C and a radar wave receiver 34 is connected to the terminal D. A carrier oscillator 37 and a transmission modulator 36 are connected to a transmission port of the circulator 33, and an output of the carrier oscillator 37 is transmitted by pulse modulation by a transmission modulator 36 or by no modulation depending on the radar system. Further, the transmission port circuit is used entirely in common for two-way information communication between on-vehicle equipment.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a road device for road-to-vehicle wireless communication that has a radar function to detect vehicles running on the road and performs wireless communication with other vehicles on the road. .

[Conventional technology]

BACKGROUND OF THE INVENTION With the recent progress of motorization and the development of an advanced information society, various traffic and transportation information systems and route guidance systems have appeared.

In these systems, the construction of a wireless communication system that can commonly provide imaging to the systems has become a major issue.

FIGS. 2 and 3 are diagrams schematically showing the form of transmission of information communication to a conventional moving vehicle.

Figure 2 (a) shows a wireless transmission form using the car telephone system for the purpose of connection to the general public telephone network and the MCA system targeting vehicles of one specific company.
Communication is carried out between a base station (not shown) having a wireless zone of approximately Km and a vehicle 2 traveling on a road 1. However, this wireless transmission form requires a very large number of wireless channels, and both the base station and the vehicle-mounted device require expensive equipment configurations in connection with channel switching. Furthermore, due to the size of the wireless zone, it is essentially difficult to extend this system to a traffic flow control system that requires close contact with the moving vehicle 2 and highly accurate communication.

No. 21 ((b) is an extremely small scene developed in a bus location control system or a comprehensive vehicle control system, and is a wireless transmission form, and includes a road surface loop 3 buried in the road 1 and an on-vehicle device coil installed in the vehicle 2. 4. In this case, due to the structure of the road surface loop coil 3, the carrier frequency is limited to 300 Hz or less, and there are significant restrictions on the transmission speed. It is completely impossible to transmit image information between the two.

The transmission form shown in Fig. 2(n) was originally developed as a vehicle number recognition system, and a carrier wave in the microwave band is sent from a roadside device S, and the carrier wave is received by an on-vehicle device 6 installed in a vehicle 2. modulated with the vehicle number code and sent back to the roadside device 5.
It performs so-called question-and-answer type communication, and has a great feature in that it can be realized by an extremely simple and low-cost vehicle-mounted device 6, but on the other hand, it is a one-way communication using only simple code information.

FIG. 3 is based on the transmission form of FIG. 2(C).

1 is a block diagram showing a conventional configuration of a road device and an on-vehicle device in a millimeter wave communication method used in a comprehensive vehicle control system that performs bidirectional communication between a base station and road vehicles in a time-sharing manner. FIG. In this comprehensive vehicle control system, different carrier waves are used for both links between the base station and the road vehicle, and both the road device and the vehicle-mounted device have the same circuit configuration each having a millimeter wave oscillator 11, and Magic-T12 and 1/4 The antenna 14 is used for both transmission and reception by the operation of the wavelength phase shifter 13, and is connected to an intermediate wave circuit by means of two mixer/modulators 15 and 16.

FIG. 4 is a diagram showing a schematic configuration of a conventional detection method for detecting a vehicle moving on a road. FIG. 2(a) shows an ultrasonic vehicle sensor, and a speaker 21 installed on the road 1.
It detects the passing of cars by sending out ultrasonic waves and measuring the reflection time.

In addition, the same figure (b) shows a loop coil 22 buried in the road 1.
It senses the change in the inductance of the coil when the vehicle 2, which is a metal body, passes over it.

In addition, a Doppler radar device that detects the speed or relative speed of a traveling vehicle has been developed. Figure 4 (C) shows a Doppler radar system for collision prevention that detects waves reflected from a stationary object or from a vehicle traveling in the oncoming lane. For the purpose of identifying the radiated waves of Kaisho 49-51884
(Japanese Unexamined Patent Publication No. 49-36294).

[Problem that the invention aims to solve]

However, even the above-mentioned conventional transmission forms have various drawbacks as mentioned above, and even in the roadside and in-vehicle devices shown in Figure 3, at the stage when road-to-vehicle communication has become widespread, the in-vehicle devices are less effective than the on-road devices. Considering that the number is much larger,
In particular, it is necessary to reduce the cost of in-vehicle equipment, and systems such as Magic-T12, which can be configured only with waveguide circuit systems, have drawbacks that are a major hindrance to reducing the cost and size of equipment. are doing.

Furthermore, the moving vehicle detection methods shown in FIGS. 4(a), 4(b), and 4(e) have the drawback that they essentially do not have an information communication function for the vehicle. In contrast, recently, focusing on the similarity of the transmission forms shown in Figures 2(b) and 4(b), loop coils buried in the road surface have been used for vehicle sensing and road-to-vehicle information communication. A common method has been proposed, for example, in IEICE Technical Report 5ANE, 83-46, but this method also has the disadvantages of the loop coil method as described in the explanation of Fig. 2(b) above. Therefore, it has the disadvantage that high-quality road-to-vehicle information communication cannot be expected.

The present invention has been made in view of the above points.

A simple configuration that realizes three operations: radar operation for vehicle detection to collect traffic flow information, information communication from on-road equipment to on-vehicle equipment, and from on-board equipment to on-road equipment, and a small and low-cost on-road equipment. The goal is to provide the following.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention provides an on-road system for road-to-vehicle wireless communication that performs three operations in a time-sharing manner: radar operation for vehicle detection, information communication operation from on-road device to on-vehicle device, and from on-vehicle device to on-road device. The machine is provided with a carrier wave oscillator and a transmission modulator that are commonly used for the three operations, and the transmission modulator is controlled to perform pulse modulation or no modulation during vehicle detection radar operation.

When communicating information from the on-road device to the on-vehicle device, the information signal is modulated, and when communicating from the on-board device to the on-road device, it is not modulated, and all radio wave propagation in the three operations is circularly polarized. A printed antenna for polarization is used as an antenna for both transmitting and receiving, and the rotation direction of the circularly polarized wave of the radar transmission wave for vehicle detection and the circularly polarized wave of the unmodulated carrier wave transmitted from the on-road device when transmitting information from the on-vehicle device to the road device are Receiving a transmission wave from an on-vehicle device that receives the unmodulated wave from the on-road device, modulates it with an information signal, and transmits it in the same turning direction as the circularly polarized wave of the unmodulated carrier wave. and a pulse radar type or Doppler radar type receiver that receives radar reflections in a direction opposite to the circularly polarized wave of the radar transmitted wave. The rotating direction of the circularly polarized wave is configured to be the same as or opposite to the rotating direction of the circularly polarized wave of the unmodulated carrier wave transmitted from the on-road device during information communication from the on-vehicle device to the on-road device.

[Effect]

By configuring the roadside unit as described above, the radio wave propagation in the three operations of the roadside unit is all circularly polarized, and the two-terminal drive planar printed antenna for circularly polarized waves is used for both transmission and reception. The direction of rotation of the polarized waves is optimally selected,
Since the carrier wave oscillator for three operations can be shared, it is possible to obtain a low-cost, multi-purpose road device with a simplified and compact configuration.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1(a) is a block diagram showing the configuration of a road device that is an embodiment of the present invention, and FIG. 1(b) is a block diagram showing the structure of an on-vehicle device applied to the road device. It is.

In FIG. 1(a), numeral 31 is a planar printed antenna for circularly polarized waves driven by two terminals of TEM, and two terminals A and B of the printed antenna for circularly polarized waves 31 are connected to a hybrid circuit 3.
2, and the two terminals C and D of the hybrid circuit 32
serve as terminals that drive circularly polarized waves whose rotation directions are opposite to each other. A circulator 33 is connected to the drive terminal C for making the antenna both transmitting and receiving. The radio waves of both road-vehicle links and the transmission waves of the vehicle detection radar are circularly polarized waves in the same turning direction using terminal C as the drive terminal, and the radar reflected waves in the opposite turning direction to the circularly polarized waves are received. A radar wave receiver 34 is connected to the terminal. Vehicle detection radar methods include the pulse method, which detects targets based on the round-trip time of radio waves, and the CW method, which measures the speed of targets by detecting changes in frequency due to the Doppler effect. Either method can be applied. Circulator 33
The transmission boat includes a carrier wave oscillation 1137 and a transmission modulator 36.
During radar operation, the output of the carrier wave oscillation 1137 is transmitted by the transmission modulator 36 without pulse modulation or without modulation, corresponding to the above-mentioned radar system. In addition, the circuit of the transmission boat is used in common for two-way information communication between road and vehicle, and when transmitting information from roadside equipment to onboard equipment, it is modulated with the information signal to the onboard equipment and transmitted. However, when communicating information from the on-vehicle device to the on-road device, it supplies an unmodulated carrier wave from the on-road device to the on-vehicle device, which is useful for simplifying the configuration of the on-vehicle device.Circulator 3
A receiving port 3 is connected to a receiving port 1I35 for receiving transmission waves from the vehicle-mounted device.

In FIG. 1(b), numeral 38 is a plane layer circularly polarized printed antenna driven by one terminal of TEM, and the terminal C' is the first one.
It is configured to drive circularly polarized waves in the same direction of rotation as terminal C in Figure (a). Reference numeral 39 is a circulator for making the on-vehicle device antenna 38 shared for transmitting and receiving, and a line switch @40 consisting of a high frequency diode switch circuit is connected to the receiving port of the circulator 39, and the line switch 40 is connected to the on-vehicle device antenna 38. A receiver 41 is connected. Furthermore, an on-vehicle transmitter modulator 4I42 is connected to the transmitter port of the circulator 39. When communicating information from the on-road device to the on-vehicle device, the line switching device 40 connects to the on-vehicle device receiver 41 to receive information signals from the on-road device, and when communicating information from the on-vehicle device to the on-road device, the information signals are transmitted from the on-road device. It is configured to receive an unmodulated carrier wave, connect it to an on-board equipment transmission modulator 42 via the line switch 40, modulate it with an information signal from the on-board equipment, and transmit it via a transmission port of a circulator 39.

FIG. 5(a) is a block diagram showing the configuration of a road device which is another embodiment of the present invention, and FIG. 5(b) is a diagram showing an embodiment of an on-vehicle device applied to the road device. .

In FIG. 5, (a), 51 is a planar circularly polarized printed antenna driven by TEM two terminals, and the two terminals A and B of the circularly polarized printed antenna 51 are connected to a hybrid circuit 52. The two terminals C and D of the hybrid circuit 52 are the same as the road machine shown in FIG. 1(a) in that they serve as terminals for driving circularly polarized waves with opposite directions of rotation. However, in the case of FIG. 5(a), circulators 53 and 54 are connected to two terminals C and D, respectively, and a receiver 55 and a radar wave receiver that receive communication information from an on-vehicle device are connected to respective receiving ports. 56 are connected. Further, a carrier wave oscillator 59 and a transmission modulator 58, which are commonly used in the three operating states of the road device, are connected to a circulator 53 of the drive terminal C example during radar operation and information communication from the on-vehicle device to the road device by a line switch 57. When transmitting information from the on-road device to the on-vehicle device, the circulator 5 is used as a drive terminal.
It is configured to be connected to four transmission ports, respectively.

As shown in FIG. 5(b), the in-vehicle device corresponding to the above road device has a hybrid circuit 61 connected to two terminals A' and B' of a planar circularly polarized wave printed antenna 60 driven by a TEM two-terminal.
and drive terminals C' and D' corresponding to terminals C and D in FIG. 5(a), a circulator 6 is connected to terminal C'.
2 is connected, and an on-vehicle device transmission modulator 64 is provided between the receiving port and the transmitting boat, so that the unmodulated carrier wave sent from the on-road device is modulated with the information signal of the on-vehicle device and transmitted. An on-vehicle device receiver 63 for receiving transmission signals from on-road devices is connected.

The on-road device shown in FIG. 1(a) above changes the turning direction of the circularly polarized wave of the transmission wave of the on-road device during information communication from the on-vehicle device to the on-vehicle device. The circular polarization direction of the unmodulated carrier wave from the on-vehicle device to the on-vehicle device and the circular polarization of the transmission wave from the on-vehicle device to the on-road device should be the same. On the other hand, the on-road device shown in FIG. 5(a) uses the rotating direction of the circularly polarized wave of the on-road device transmission wave during information communication from the on-road device to the vehicle-mounted device.

When information is communicated from the on-vehicle device to the on-road device, the circular polarization of an unmodulated carrier wave from the on-road device to the on-vehicle device and the circular polarization of the transmission wave from the on-vehicle device to the on-road device are made to be opposite to the circular polarization direction.

As the transmission modulation $36.42.58.64 used in the on-road equipment and in-vehicle equipment shown in Figs.
By using T, a modulator with high power gain can be constructed, and GaA can also be used in receivers 34, 35, 41, 42, 55°56.
Noise can be easily reduced by incorporating an sMES-FET preamplifier.

As explained above, one feature of the basic configuration of the roadside equipment shown in Figures 1(a) and 5(a) is that circularly polarized waves are used for vehicle radar operation and road-to-vehicle two-way information communication operation. The objective is to optimize the setting of each turning direction. In general, linear polarization is usually applied in wireless communications, and there are very few examples of circular polarization being applied outside of the field of satellite communications.
The reason for applying circular waves in the case of satellite communications is to avoid variations in the plane of polarization due to Faraday rotation caused by the attitude of the satellite and the action of the earth's magnetism when radio waves pass through the ionosphere. In this case, as another example of application of zero circularly polarized waves in which circular waves with different carrier numbers and opposite rotations are used in both links between the satellite station and the earth station, the travel shown in Fig. 4(c) is A Doppler radar system for detecting the relative speed of a vehicle has been proposed (Japanese Patent Application Laid-Open No. 49-36294). A special reflector 24 is installed for the purpose of identifying radar radiation waves from vehicles traveling in the oncoming lane, and the reflector 24 is constructed by combining two helical antennas whose turning directions are opposite to each other. are doing.

In contrast, in the case of this embodiment, the radar wave transmitting station is a fixed roadside device and the beam direction of the radar wave is relatively perpendicular to the road surface as shown in FIG. 2(c). , there is almost no problem with radiation waves from vehicles traveling in the oncoming lane, and since the purpose of the radar operation in this example is a traffic flow control system, there is no special need for collecting traffic flow information. The target is the reflected waves from the body of a normal vehicle that is not being operated.

What should be noted here is that the reflection of circularly polarized waves by a metal reflector has a property in which the direction of rotation is reversed, and a special reflector that reverses the direction of rotation and reflects the wave, such as the conventional example mentioned above, is It's unnecessary.

On the other hand, in the road-to-vehicle information communication of this embodiment, when information is communicated from the on-vehicle device to the on-road device, the unmodulated carrier wave transmitted from the on-road device is circularly polarized, and the information signal from the on-vehicle device to the road device is transmitted modulated by the circularly polarized carrier wave. It is configured so that the direction of rotation of the wave is the same as that of the circularly polarized wave. By setting the relationship between the rotation directions of the circularly polarized waves of both waves in this way, the unmodulated carrier wave transmitted from the road device is reflected by the vehicle body or the road surface, the direction of rotation is reversed, and it returns to the road device. Unnecessary reflected waves can be distinguished from waves transmitted from the in-vehicle device to the roadside device, contributing to improved communication quality.

Regarding information communication from on-road equipment to on-vehicle equipment.

Since the communication is performed in a time-sharing manner, any turning direction may be used in principle. The case where the turning direction is the same as that of the waves corresponds to the embodiment shown in FIG. 1. The case where the turning direction is opposite to that shown in FIG. 1 corresponds to the embodiment shown in FIG.

Furthermore, in the above-mentioned road device, the planar circularly polarized wave printed antenna 31.51 is effectively applied to reduce the size and cost of the device. In other words, conventional helical antennas as antennas for circularly polarized waves have problems in that the direction of rotation of the circularly polarized waves handled is fixed depending on the winding direction, and that there are problems with high frequencies. There are problems such as the need for a circularly polarized wave converter, which makes it difficult to downsize and reduce costs, and this has become a factor that precludes the application of circularly polarized waves in the field of road-to-vehicle wireless communication. On the other hand, the planar printed antenna used in the above-mentioned on-road equipment has a high-gain array configuration and expansion of the applicable frequency to the millimeter wave band, etc., mainly for application in the satellite communication field. Including, rapid progress has been made in recent years (K, R, Carver & J, V, Min
k; IEE Tfani, vol, AP-29
, NO, I PP2-241981), based on element structures such as microstrip type and slot type, it is easy to connect to the TEM circuit system, and mass production is possible using photo-etching technology. Cost reduction is also possible.

The following features of the basic configuration of the above-mentioned on-road unit are that all three operations of the on-road unit, namely radar operation for vehicle detection, information communication from the on-road unit to the on-board unit, and from the on-board unit to the on-road unit, are performed. In contrast, only one carrier wave oscillator 37.59 is used in common. Carrier wave oscillator 37.5
9, it is necessary to ensure a predetermined frequency stability even under the relatively severe temperature conditions under which the road-to-vehicle communication equipment is placed.

The cost of countermeasures for this accounts for a relatively large proportion of the equipment cost, and as shown in the above embodiment, using the carrier wave oscillator only on the roadside equipment simplifies and miniaturizes the on-vehicle equipment.
This is extremely effective in reducing costs.

Various traffic information systems, comprehensive vehicle control systems, etc. require a road-to-vehicle information communication function and a traffic flow information collection function. The embodiment is a road device that completely integrates both functions, and is extremely useful in traffic information systems, comprehensive vehicle control systems, and the like.

〔Effect of the invention〕

As explained above, according to the present invention, the radio wave propagation in the three operations of the roadside device is all circularly polarized waves, and the two-terminal drive planar printed antenna for circularly polarized waves is used for both transmission and reception, and circularly polarized waves are transmitted and received in the various operations. By optimally selecting the direction of rotation for each of the robots and configuring the carrier wave oscillator to be common for the three operations, an extremely simple and compact multipurpose road machine can be provided at low cost. can get.

[Brief explanation of drawings]

FIG. 1(a) is a block diagram showing the configuration of a roadside device for road-to-vehicle wireless communication having a vehicle detection function according to the present invention.
b) is a block diagram showing the configuration of an on-vehicle device corresponding to the on-road device; FIGS. 2(a), (b), (C) and 3.
4(a), (b), and (C) are schematic diagrams showing a conventional method of detecting moving vehicles, and FIG. 5(a) ) is a diagram showing the configuration of another road device according to the present invention, and FIG. 5(b) is a block diagram showing the configuration of an on-vehicle device corresponding to the road device. In the figure, 31.51...Circularly polarized wave printed antenna, 3
2.52...Hybrid circuit, 33,53°54
...Circulator, 34.56...Radar wave receiver, 35.55...Receiver, 36.58...Transmission modulation, 37,59...Carrier wave oscillator, 57...Line switching vessel.

Claims (1)

[Claims] In a roadside device that performs three operations in a time-sharing manner: radar operation for vehicle detection, information communication from the roadside device to the onboard device, and from the onboard device to the roadside device, a carrier wave oscillator and a transmission modulator commonly used for the three operations are used. and controlling the transmission modulator to control the pulse modulator when the vehicle detection radar is operating, so that the pulse modulation or no modulation is performed when the vehicle detection radar is operating;
When transmitting information from the on-road device to the on-vehicle device, the information signal is modulated, and during the information communication from the on-vehicle device to the on-road device, no modulation is performed, and all radio wave propagation in the three operations is circularly polarized. A circularly polarized printed antenna of the form is used for both transmission and reception, and the rotation direction of the circularly polarized wave of the radar transmission wave for vehicle detection and the unmodulated carrier wave transmitted from the on-road device when information is communicated from the on-vehicle device to the road device are used. A receiver that receives a transmission wave from an on-vehicle device that is transmitted in the same direction as the circularly polarized wave of the radar, and a pulse radar type or A Doppler radar type receiver is provided, and a non-modulated carrier wave transmitted from the on-road device during information communication from the on-vehicle device to the on-road device determines the turning direction of the circularly polarized wave of the transmitted wave during information communication from the on-road device to the on-vehicle device. 1. A road equipment for road-to-vehicle wireless communication having a vehicle detection radar function, characterized in that the turning direction of circularly polarized waves is the same as or opposite to the direction of rotation of the circularly polarized waves.