JPH0918383A - Mobile object identification device - Google Patents

Abstract

PURPOSE: To reduce jamming and interference among lanes without arranging plural interrogators by peforming communication with the responders of mobile objects traveling the plural lanes. CONSTITUTION: An interrogation device is provided with an antenna part 5, the interrogator 2 and reflectors 51-53 provided corresponding to plural mobile object traveling lanes 11-13 for reflecting radio waves transmitted and received from the antenna part 5 and constituting communication areas Z1-Z3 on the traveling lanes 11-13. The antenna part 5 is provided with a directivity characteristic means for supplying directivity characteristics to the transmitted and received radio waves and an orientation deflecting means for deflecting the orientation. The radio waves transmitted from the interroqator 2 are deflected in the orientation deflecting means, the reflector 51 (52 and 53) corresponding to the pertinent traveling lane 11 (12 and 13) is selected and radio communication is performed with the responder 4A (4B) of the mobile object 3A (3B) present inside the communication area Z1 (Z2 and Z3) of the pertinent traveling lane 11 (12 and 13).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed to a device for performing wireless communication between an interrogator installed in a ground facility and a responder activated by the interrogator. The present invention relates to a mobile body identification device provided with a method of preventing interference between interrogators.

[0002]

2. Description of the Related Art FIG. 4 is a layout diagram of an interrogator and a responder according to the prior art. In FIG. 4, for example, the interrogators 21 to 25 attached to the above-ground structure of a gate such as the entrance and exit of a highway, and the interrogators 21 to 25 activated by the interrogators 21 to 25 are illustrated as vehicles 3A to 3D. Is a moving body 3A, (3B ~ 3
Responders 4A, (4B-4D) and interrogators 21, (22-2
By performing wireless communication with 5) and performing predetermined communication, for example, a toll clearing process for expressways is performed. In such a system, for example, when there are transponders 4A, 4X, ... Mounted on a plurality of mobile units 3A, 3X, ... Since the plurality of transponders 4A, 4X, ... Simultaneously respond using the same frequency band, a plurality of signals are input to the receiver of the interrogator 21, which causes a problem of interference.

As a method of preventing this interference problem, it is disclosed in Japanese Patent Application No. 6-271636 "Mobile Object Identification System": When an interrogator calls a plurality of responders for reading information. , The response method from each transponder is
Information is returned by changing the timing of starting the response according to the time determined by the random number table that is held in advance, or each responder responds by shifting the carrier frequency, or Japanese Patent Application No. 7-22470. Disclosed in "Response control method of wireless transponder": When the interrogator calls for reading information, it attaches the interrogator's own ID code and receives the response from the transponder normally When the communication is completed, the responder does not respond even if it receives a call to read the information again from the same interrogator, reducing the probability of a reply collision with another responder, and as a result, another untransmitted communication response. Methods such as increasing opportunities for communication of vessels have been proposed.

There is also a problem of interference between a plurality of interrogators arranged corresponding to driving lanes. Hereinafter, a communication method of a mobile body identification device that wirelessly exchanges information to identify a mobile body and an interference problem that occurs at that time will be described. In FIG. 4, it is assumed that the moving body identifying apparatus is configured with five lanes 11 to 15 on which the moving bodies 3A to 3D travel. In the illustrated example, five interrogators 21 to 25 are arranged across the traveling lanes 11 to 15 in a ground facility such as a gate 10 having a plurality of traveling lanes 11 to 15 such as a toll road. In addition, the transponders 4A to 4D are provided in the individual moving bodies 3A to 3D.

The procedure for establishing communication between the interrogators 21 to 25 and the responders 4A to 4D is as follows. First, the interrogators 21 to 25 provided in the lanes 11 to 15 on which the mobile units 3A to 3D travel are instructed by a response invitation signal. With transponder
Start up 4A-4D. Responders 4A to 4D provided in the individual mobile units 3A to 3D receive the response invitation signal and return the ID codes 4a to 4d held by themselves as ID transmission signals. Hereinafter, as a representative example, the interrogator 21 of the traveling lane 11 will be mainly described. The moving body 3A traveling on the traveling lane 11 is
The ID code 4a of the responder 4A of the mobile unit 3A is returned by the ID transmission signal, which is activated by the response invitation signal from the interrogator 21 provided in the.

The interrogator 21 installed in the ground facility receives the ID transmission signal of the moving body 3A traveling in the traveling lane 11,
When the ID code 4a of the responder 4A is recognized,
From 21 the ID code 4a of the responder 4A of the mobile unit 3A that is the communication partner
Is specified to exchange information messages between the interrogator 21 and the responder 4A. This interrogator 21-25 and responder 4A-4D
The simplest way to communicate with
The transmission direction from the responders 4A to 4D to the interrogators 21 to 25 at the same frequency f1 (hereinafter, this direction is referred to as an uplink) and the transmission direction from the interrogators 21 to 25 to the responders 4A to 4D (hereinafter, this Downlink direction), and there is a method to do in half-duplex communication that does not overlap the communication at the same time. For example, in the example of the lane 11 described above, the ID transmission signal and the information message data from the responder 4A correspond to the uplink transmission data SU1. Also, as the downlink transmission data SD1, a response invitation signal from the interrogator 21 and
ID code specified communication and information message data correspond to this.

The interference noise received by the interrogator 21 is partially omitted in the figure for the sake of simplicity, but interference noise signals N2 to N5 from other interrogators 22 to 25 arranged in the same gate 10 and There are interference noise signals R2 to R5 due to reflected waves from the vehicle bodies of the moving bodies 3B to 3D running on other lanes.
These interference noises are generated by the interrogators 21 to 25 and the responders 4A to
It can be reduced by the directional characteristics of the antenna given to 4D. Now, the interference noise signals N2 to N5 will be considered including the interference noise signals R2 to R5.

Generally, the transmission / reception between the interrogators 21 to 25 is not synchronized. Therefore, when a certain interrogator (for example, 21) is performing uplink communication, a neighboring interrogator 22 may perform downlink communication. Normally, the transmission power transmitted by the interrogator 22 in the downlink direction is much larger than the reception power received by the interrogator 21 in the uplink communication, so in the method of communicating at the same transmission / reception frequency f1, It is necessary to prevent the interference by separating the devices 21 to 25 that are adjacent to each other by a considerable distance.

When the interrogators are separated from each other in order to avoid these interference / interference problems, the range in which the interrogator can interrogate the responder (hereinafter referred to as the communication area) is limited. If this distance is too large, a gap is created in the communication area. Therefore, when the transponder passes through this gap, communication with the corresponding interrogator cannot be performed.

[0010]

As described above, in the mobile body identification device according to the prior art, (1) when the downlink frequency and the uplink frequency are the same, the interrogator communicating with the uplink is , A carrier for downlink transmission output from an interrogator adjacent to this interrogator, or a passive method (a transponder receives the carrier from the interrogator and modulates and returns this carrier) Is sent,
These transmission outputs become interference noise and interfere with uplink communication. In order to reduce this interference noise, it is sufficient to increase the distance between the interrogators, but this distance is determined by the width of the driving lane and is a fixed distance due to the system configuration.

(2) Further, even if the downlink frequency and the uplink frequency are different, if the frequency has only one pair of channels f0 and f1 and the interrogators are not synchronized, interference occurs. The distance to reduce noise is
Only the installation interval with the interrogator located one place apart from the interrogator can be set. (3) Therefore, it is possible to prepare a plurality of pairs of frequency channels.

The present invention has been made in view of the above points, and an object thereof is to solve the above-mentioned problems and to communicate with a transponder of a mobile body traveling in a plurality of traveling lanes.
It is an object of the present invention to provide a mobile body identification device which does not have a plurality of interrogators and which has a width equivalent to a traveling lane and has less interference and interference between lanes.

[0013]

In order to achieve the above object, in the present invention, an interrogator arranged on the ground facility and a responder arranged on the mobile body and activated by the interrogator are provided, In a mobile body identification device that identifies a mobile body by performing wireless communication between an interrogation device and a responder, the interrogation device includes an antenna unit, a transmission unit that transmits a signal for wirelessly interrogating the transponder, and a responder. An interrogator consisting of a receiver that receives information from the mobile phone and an arithmetic and control unit that controls each part, and an interrogator that is provided corresponding to a plurality of moving lanes and reflects radio waves transmitted and received from the antenna part. A reflection plate that forms a communication area on the traveling lane, and the antenna unit includes a directional characteristic unit that imparts a directional characteristic to the transmitted and received radio waves, and a directional direction deflection unit that deflects the directional direction. You .

The antenna section is an array antenna in which a plurality of radiating elements are arranged, and the excitation phase of each element is controlled to deflect the pointing direction. The antenna unit is an array antenna in which a plurality of radiating elements are arrayed, and the pointing direction is deflected by switching the feeding point to each element. The antenna unit is a parabolic antenna, and the direction of the antenna is deflected by rotating the direction of the antenna.

[0015]

With the above structure, the radio wave transmitted from the interrogator is given a sharp directivity characteristic to the radio wave by the directivity characteristic means of the antenna section, and the radio wave is deflected by the directivity direction deflecting means to correspond to the corresponding traveling lane. Select the reflectors to be used in sequence, reflect the radio waves with this reflector to form a communication area,
It communicates with the responder of the mobile unit in this communication area. In other words, most of the radio waves emitted from the antenna unit are concentrated on the selected reflector, and the radio waves do not reach the parts other than this reflector. There is no unwanted intrusion of radio waves other than the reply from the transponder.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram for explaining a moving object identifying apparatus according to the present invention, FIG. 2 is a principle diagram of phase scanning of an electronic scanning antenna, and FIG. 3 is a principle diagram of feed point switching scanning of an electronic scanning antenna. The same functional members corresponding to FIG. 4 are denoted by the same reference numerals. First, an example in which the response control method of the wireless transponder between the interrogator and the transponder according to the present invention is applied to an automatic toll collection system on a highway will be described as an embodiment with reference to FIG. In FIG. 1, an automatic toll collection system for a highway has an interrogator 2 and an antenna unit 5 installed in a roadside zone for collecting tolls, reflectors 51 to 53 installed in a gate 10, and is shown as a vehicle in the illustrated example. Responder to the moving body 3A, (3B…)
It is equipped with 4A, (4B ...). In this system, the amount paid by the user in advance is stored in the transponders 4A, (4B ...) and
When the mobile body 3A, (3B ...) equipped with 4A, (4B ...) passes through the communication area Z1, (Z2 ...) of the interrogator 2 installed in the roadside zone, the charge of the highway toll road is used. Depending on the responder 4A,
We assume a prepaid service that subtracts from (4B ...). For the sake of simplicity, the expressway has, for example, a flat-rate system for all lines, and the fare changes only depending on the vehicle type. The vehicle type information is stored in the transponders 4A, (4B ...).

The basic processing of this system is that the interrogator 2 knows the ID codes 4a, (4b ...) Of the responders 4A, (4B ...) And the vehicle type information, and after calculating the charge based on that, Transponder 4A, (4B ...)
Specify the ID code 4a, (4b…) of the request, and send the usage charge, and the responder 4A, (4B…) stores it in the memory of the responder 4A, (4B…) based on the sent data. The processing is performed by subtracting the usage fee from the stored prepaid amount. Although not shown in the drawing, a plurality of moving bodies 3A, (3X
…) Can exist at the same time.

In FIG. 1, the system which constitutes the moving body identifying apparatus includes an interrogating apparatus which is arranged in a roadside zone and a ground facility such as a gate 10 and a transponder which is arranged in each of the moving bodies 3A and 3B and activated by the interrogating apparatus. 4A, 4B, and by performing wireless communication between the interrogation device and the responders 4A, 4B, the interrogation device recognizes the mobile body, and, for example, in the usage fee settlement process as described above, Exchange necessary information.

Here, the interrogator transmits information from the antenna section 5 and the transmitting section 21 for transmitting a signal for wirelessly interrogating the responders 4A and 4B (not shown for simplification) and the responders 4A and 4B. Receiving unit 22 for receiving and arithmetic control unit for controlling each unit
An interrogator 2 consisting of 23 and a plurality of moving body traveling lanes 1
The communication area Z is provided on the traveling lanes 11, 12, and 13 by reflecting radio waves transmitted and received from the antenna unit 5 provided corresponding to 1, 12, and 13.
And reflectors 51, 52 and 53 that configure 1, Z2 and Z3. In addition, the antenna unit 5 is configured to include directivity characteristic means for imparting directivity characteristics to the transmitted and received radio waves, and directivity direction deflection means for deflecting the directivity direction.

In such a configuration, the radio wave transmitted from the interrogator 2 is deflected by the directional deflecting means, and the reflector 51 corresponding to the corresponding traveling lane, for example, the traveling lane 11, is selected (hereinafter, unless otherwise specified). (For example, the traveling lane 11 will be described as a representative.) Wireless communication is performed with the responder 4A of the mobile unit 3A in the communication area Z1 of the traveling lane 11. When an interrogation signal is transmitted from the interrogator 2 to the responder 4A of the mobile unit 3A, the responder 4A receives the transmitted interrogation signal, and, for example, the necessary information such as highway entrance information and passage information is required. Information (hereinafter referred to as data) is transmitted to the interrogator 2 via the above-mentioned reflector 51. The data transmitted from the responder 4A is input to, for example, a host computer on the interrogator 2 side, and required data processing and data management are performed.

In the configuration of the present invention, the interrogators 21 to 25 of the prior art moving body identifying apparatus shown in FIG. 4 are replaced with the reflectors 51 to 53 in the present invention, and one interrogator 2 in the illustrated example.
Is installed in the roadside band, and the radio waves to be transmitted and received are sequentially selected from the reflectors 51 to 53 by the antenna unit 5 having the directional characteristics and the directional deflection means described later, and the communication areas Z1 to Form Z3.

Now, when the interrogator 2 transmits a radio wave to the reflector 51, the reflector 51 reflects the radio wave toward the ground of the traveling lane 11. At this time, the reflection plate 51 is installed at an angle so as to reflect radio waves to the ground and secure an appropriate communication area Z1 necessary for communication. As a result, the radio wave reflected by the reflector 51 forms the communication area Z1 on the ground.

When the mobile unit 3A enters the communication area Z1, the transponder 4A mounted on the mobile unit 3A receives the radio wave (response interrogation signal) reflected by the reflector 51 from the interrogator 2 and responds. The ID code 4a owned by the container 4A itself is returned toward the reflection plate 51. The reflector 51 reflects the radio wave having the ID code 4a toward the antenna unit 5, and the interrogator 2 receives the ID code 4a transmitted from the responder 4A and identifies the responder 4A of the moving body 3A. To do.

Next, the interrogator 2 designates the identified ID code 4a and performs necessary communication with the responder 4A of the mobile unit 3A. That is, the radio wave having the ID code 4a identified and specified by the interrogator 2 is received by the transponder 4A from the antenna section 5 via the reflector 51, and the communication right between the interrogator 2 and the transponder 4A is established. However, even if another transponder 4X exists in this communication area Z1, this transponder 4X enters the silent state because it is not designated. The radio wave having the necessary reply data is returned from the transponder 4A with the established communication right to the reflecting plate 51, the reflection plate 51 reflects the radio wave having the reply data toward the antenna unit 5, and the interrogator 2 The reply data transmitted from the responder 4A is received, and the data is further transmitted to the host computer or the like. An information processing device such as a host computer communicates information such as a usage charge with the responder 4A via the interrogator 2 as necessary.

The above-described series of operations is the same for the reflectors 52 and 53. The interference problem between the lanes 11 to 13 is (1) by sharpening the directional characteristics of the antenna unit 5, (2) For example, when the interrogator 2 and the responder 4A are communicating in the lane 11, Since no communication is performed in the lanes 12 and 13, the interference between the lanes can be reduced.

2 and 3 show an example of an electronic scanning antenna which gives the antenna section 5 directivity and scanning characteristics. Scanning antennas using an array antenna in which a plurality of radiating elements are arranged are roughly classified into mechanical scanning antennas and electronic scanning antennas. Of these, focusing on the electronic scanning antenna, there are the following types from the operating principle. (1) Phase scanning (2) Frequency scanning (3) Feeding point switching scanning In the present invention, since the communication of a plurality of lanes with a carrier of a single frequency is considered, the phase scanning method will be described below with reference to FIG. 3, the feeding point switching scanning method will be described.

In FIG. 2, the antenna unit 5 includes an array antenna in which a plurality of radiating elements 5a to 5h are arranged, and phase shifters 6a to 6a.
It consists of 6h. The radiating elements 5a to 5h shift the excitation phases of the radiating elements 5a to 5h via the phase shifters 6a to 6h, and control the excitation phases to deflect the pointing direction. The directional deflecting means deflects at an angle determined by the distance d between the radiating elements 5a to 5h, the carrier frequency f, and the phase shift angle.

In FIG. 3, the antenna unit 5 is, in the illustrated example, an array antenna in which a plurality of radiating elements 5a to 5d are arranged, and a hybrid circuit having a distribution function and a phase delay characteristic.
It consists of 6m, 6n, 6p, 6q and -45 ° phaser. The radiating elements 5a to 5d are fed by the hybrid circuits 6p and 6q, and by switching the feeding points to the input terminals 1 to 4 of the hybrid circuits 6m and 6n, the excitation phases to the radiating elements 5a to 5d are shifted to direct the radiation. Deflection the direction.

Although not shown, the antenna unit 5 uses a parabolic antenna, and the direction of the parabolic antenna can be deflected by mechanically rotating the parabolic antenna.

[0030]

As described above, according to the configuration of the present invention, in the prior art, an interrogator is installed in each lane by installing a reflector instead of the interrogator arranged in each lane. It is possible to configure the system of the mobile body identification device at a lower cost than the method. Also, when communicating with a moving object in the communication area via a reflector in one lane, data communication by radio waves is not performed at all in the other lanes. It is possible to provide a mobile body identification device with less interference and interference.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a moving body identification device according to the present invention.

FIG. 2 Principle diagram of phase scanning of electronic scanning antenna

FIG. 3 is a principle diagram of scanning for switching a feeding point of an electronic scanning antenna.

FIG. 4 is a layout relationship diagram of an interrogator and a responder according to a conventional technique.

[Explanation of symbols]

 1 to 4 terminals 10 gates 11 to 15 lanes 2, 21 to 25 Interrogator 3A to 3D Mobile unit 4A to 4D Transponder 5 Antenna part 51 to 53 Reflector 5a to 5h Radiating element 6a to 6h, 6j, 6k Phaser 6m , 6n, 6p, 6q Hybrid circuit Z1 ~ Z3 Communication area N2 ~ N5 Interference noise R2 ~ R5 Interference noise SC carrier

Claims (4)

[Claims] 1. An interrogation device installed in a ground facility and an answering device activated by the interrogation device installed in a moving body, and moving by performing wireless communication between the interrogation device and the answering device. In the mobile identification device that identifies the body, the interrogation device includes an antenna unit, a transmission unit that transmits a signal to wirelessly call a transponder, a reception unit that receives information from the transponder, and a calculation that controls each unit. An interrogator including a control unit; and a reflector plate that is provided corresponding to a plurality of moving body traveling lanes, reflects a radio wave transmitted and received from the antenna unit, and forms a communication area on the traveling lane. The antenna unit includes directivity means for giving directivity characteristics to the transmitted and received radio waves, and directivity deflecting means for deflecting the directivity direction, and deflects the radio waves transmitted from the interrogator by the directivity deflecting means. Applicable Select the reflection plate corresponding to the traveling lane, a response unit and the wireless communication of the mobile body is within the contact area of the travel lane, the mobile identification device, characterized in that. 2. The moving body identifying apparatus according to claim 1, wherein the antenna unit is an array antenna in which a plurality of radiating elements are arranged, and the excitation phase of each element is controlled to deflect the pointing direction. Mobile identification device. 3. The moving body identifying apparatus according to claim 1, wherein the antenna section is an array antenna in which a plurality of radiating elements are arranged, and the pointing direction is deflected by switching a feeding point to each element. Mobile identification device. 4. The moving body identifying apparatus according to claim 1, wherein the antenna section is a parabolic antenna and the direction of the antenna is deflected by rotating the direction of the antenna.