JPH06236497A - Vehicle identifying device - Google Patents

Abstract

PURPOSE:To simultaneously and immediately obtain each vehicle information from all vehicles existing along a wide range even when they travel or stop, and to offer various kinds of service based on the vehicle information, regarding a vehicle identifying device useful for obtaining the vehicle information from the plural vehicles in a remote situation. CONSTITUTION:A range to be identified is divided into plural blocks Ai, Bj, Ck,... by using both a means which devices the range to be identified into plural zones Z1, Z2,... by shifting each beam angle only by a beam width by using plural antenna elements having the antenna pattern of the beam width which is not beyond the area of one vehicle, and a means which divides each zone into plural areas E1, E2,... in at every constant distance from an antenna 1 or by using a self-correlation characteristic obtained by demodulating a received signal by a code delayed by prescribed time for a PN code used for transmission. Then, the size of each block is set smaller than the size of one vehicle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle identification technique, and more particularly to a vehicle identification device useful for obtaining vehicle information from a plurality of vehicles in a state of being separated from each other.

[0002]

2. Description of the Related Art FIG. 13 schematically shows the structure of a conventional vehicle identification device as an example. The configuration shown in the figure shows the configuration of a device installed at a toll gate that accesses an expressway, and is shown in, for example, Japanese Patent Laid-Open No. 62-159526. In FIG. 13, reference numeral 21 denotes a terminal installed indoors, 22 denotes a charge indicator provided outdoors, and the charge indicator is arranged at a location easily visible to a driver of an incoming vehicle 25. , Is connected to the terminal 21.
Reference numeral 23 denotes an antenna provided at the outdoor gate portion, which is embedded in the approach path of the vehicle 25 and connected to the terminal device 21. Reference numeral 24 denotes a transponder installed in the lower part of the vehicle body of the vehicle 25.

Next, the operation will be described. When the vehicle 25 arrives at the gate of the toll gate to enter the highway, the radio wave is transmitted from the antenna 23. The in-vehicle transponder 24 that receives this radio wave adds vehicle information (vehicle type, serial number, size, weight, etc.) specific to the vehicle, which is pre-recorded inside the radio wave, to the received radio wave and transmits it to the antenna 23. . The signal received by the antenna 23 is demodulated by the radio wave used at the time of transmission in the terminal 21 to recognize the vehicle information. The terminal device 21 calculates the traveling charge of the vehicle 25 based on the vehicle information, and displays it on the charge display device 22. In this way, the collection of charges is made more efficient.

Further, not only the collection of tolls on the expressway, but also various applications such as crackdown of a vehicle whose vehicle inspection has expired and checking of entry and exit of the vehicle to the parking lot are possible depending on the content of the vehicle information.

[0005]

In the apparatus using the prior art, when obtaining vehicle information, it is necessary to guide the vehicle to a predetermined position or a narrow range, and the vehicle stops or runs at a low speed. Vehicle information was available only when It can be said that this is not a limitation due to the simple realization of the device, but is a phenomenon inevitably accompanying when the conventional communication method is used. That is, when a plurality of vehicles respond to one transmission signal, interference occurs and information cannot be correctly transmitted. Therefore, in order to reliably transmit the information, the above-mentioned installation situation is inevitably limited.

In order to deal with this, it is conceivable to give various variations to the in-vehicle transponder so as to identify and respond to the ground transmission signal to prevent interference. However, in this method, a large number of such transponders are required in terms of operation, so that a transponder having a complicated function is unsuitable in view of the constraint that the transponder must be small, lightweight and inexpensive.

As described above, in the conventional device, the vehicle information can be obtained only when the vehicle passes through the position of the determined narrow range. Therefore, the number of vehicles that can obtain the vehicle information is extremely limited. Therefore, there is a problem that the content of the service using the vehicle information is naturally limited. The present invention has been created in view of the problems in the related art, and makes it possible to simultaneously and instantaneously obtain each vehicle information for all vehicles existing over a wide range regardless of whether the vehicle is running or stopped. It is an object of the present invention to provide a vehicle identification device that can contribute to the provision of various services based on the vehicle information.

[0008]

In order to solve the above-mentioned problems, the present invention uses a plurality of antennas and a so-called spread spectrum technique that utilizes the autocorrelation characteristic in the process of signal processing to reduce a wide range into small blocks. The vehicle information is obtained by dividing each block. Therefore, according to the present invention, as shown in the principle diagram of FIG. 1, a vehicle which radiates a radio wave in a predetermined range to be identified and which has a transponder 4 responsive to the radio wave and which is present in the predetermined range Antenna 1 for receiving the reflected wave from 5,
A transceiver 2 coupled to the antenna for processing a received signal of the antenna to generate vehicle information specific to the vehicle;
A data processor 3 for appropriately calculating the vehicle information, and the antenna uses a plurality of antenna elements each having an antenna pattern having a beam width that does not exceed the area of one vehicle to beam each antenna beam angle. By shifting by the width, the predetermined range is divided into a plurality of zones Z ₁ ,
Z _2, Z _3, has a first dividing means for dividing the ......, the transceiver, obtained by demodulating the received signal by the pseudorandom code to delayed a predetermined time code used in the transmission By using the autocorrelation characteristics provided, each zone is divided into a plurality of areas E ₁ , E ₂ , E ₃ , ... The predetermined range is divided into a plurality of blocks Ai, Bj, C using two dividing means.
There is provided a vehicle identification device characterized in that the size of each block is set to be smaller than the size of one vehicle.

Regarding the spread spectrum technology, "SP
Since it is described in many documents such as "READ SPECTRUM SYSTEMS, by RCDIXON", detailed description thereof will be omitted. Hereinafter, only the element parts related to the present invention will be briefly described.

[0010]

With spread spectrum, when a transmission signal is modulated with a PN code represented by an M sequence or the like, the transmission signal is spread in the frequency domain in accordance with the modulation clock of this PN code, and the spread signal is the same. When the demodulation (correlation processing) is performed with the PN code of, the original signal is restored again. On the other hand, since nothing can be obtained when demodulating with a PN code different from the code used for transmission, this PN code serves as a kind of key. The reason why it works in this way is that this PN code has a peculiar autocorrelation characteristic, as shown as an example in FIG.

As shown in FIG. 2 (a), first, the PN code is divided into two, and then the phase P is delayed by the delay means 2a.
When an autocorrelation is obtained between the N code and the PN code that does not pass through the delay means (that is, the code directly input to the correlation means 2b), a pulsed correlation output signal is obtained as shown in FIG. . That is, when the phase difference between the two PN codes is 0, it peaks, and the phase difference linearly increases and decreases within 1 bit, and when the phase difference becomes 1 bit or more, no correlation output can be obtained.

That is, the original signal cannot be restored unless demodulation is performed using the same PN code as the spread PN code and within 1 bit. The correlation characteristics are all determined by the PN code, and the peak power of the correlation is 20 l with respect to the level when there is no correlation.
It is represented by og (code length). For example, when the code length is 255 bits, the power difference between the correlation and the non-correlation is about 48 dB.

Next, using a spread spectrum technique, a predetermined range to be identified for vehicle identification is divided into a plurality of zones Z ₁ , Z ₂ , Z ₃ ,.
The method of dividing into ... will be described. Zone division is performed with multiple antennas that have beam angles and beam widths corresponding to each zone, but usually, in the same frequency band, each antenna is electromagnetically coupled and zone division becomes impossible. Or, there arises a problem that a reflected signal is received by a plurality of antennas due to the influence of multipath.

In the present invention, the autocorrelation obtained by modulating the transmission signal of each antenna pattern with a different PN code and demodulating the reception signal with the same PN code as the code used for the corresponding transmission. Utilize characteristics.
This is a multiplexing technique based on spread spectrum technology.
Explaining with reference to FIG. 1B, a PN code used for a signal transmitted from an antenna forming a zone Z ₁ (referred to as A zone) is PN1, and a PN used for correlation of a received signal.
The code is also PN1. Further, the PN code used for the transmission signal from the antenna forming the zone Z ₂ (referred to as the B zone) is PN2, and the PN code used for the correlation processing of the reception signal is also PN2. Further, the PN code used for the transmission signal from the antenna forming the zone Z ₃ (referred to as the C zone) is PN3, and the PN code used for the correlation processing of the reception signal is also PN3.
Change the code.

Since the PN code is transmitted and received by the same device without using different types of codes for each antenna, the phase of one code is changed in view of the established period. It can be easily realized by using If there is a vehicle in the B zone,
Due to the antenna pattern characteristics, the signal transmitted from the B-zone antenna is retransmitted by the transponder of the vehicle, and the power received by the B-zone antenna is naturally the strongest, so that the zone can be specified. At this time, the signals transmitted from the antennas in the A zone and the C zone and received by the antennas in the B zone via the vehicle are subjected to correlation processing with different PN codes, and thus are greatly attenuated. This attenuation amount is 48 dB when the PN code is 255 bits. In other words, in addition to the antenna characteristics, the effect of multipath can be removed by this spread spectrum method, and the zones can be completely separated.

Next, each zone is divided into a plurality of areas E ₁ , E ₂ , E at a constant distance from the antenna by using a spread spectrum technique.
Explain how to divide into ₃ ,. As can be seen from the above description using FIG. 1 (b), the signal that the transmission signal hits the vehicle and is reflected by the vehicle (that is, the reception signal) is demodulated with the same PN code as the code used for transmission (that is, correlation processing). In this case, whether or not a correlation output is obtained depends not only on whether or not the same PN code is used, but also on whether or not to perform correlation processing with a PN code having a phase difference of 1 bit or less. To do.

That is, the PN code used for the transmission signal is
Since it is delayed by an amount corresponding to the round-trip propagation distance between the antenna and the vehicle, if the PN code subjected to correlation processing with the received signal is forcibly delayed by this amount, a correlation output can be obtained. It will be. As a method of forcibly delaying, for example, there is a method of delaying the bits of the PN code in clock units. If the clock of the PN code is 100M
Hz, 1 clock is 3m (= 300,000k)
m / 100 MHz), so the PN used for transmission
When the received signal is subjected to the correlation processing with the PN code obtained by delaying the code by one clock, the signal from the vehicle existing in the range of 0 to 3 m is reproduced. Similarly, when the received signal is subjected to the correlation processing by the PN code obtained by delaying the PN code used for transmission by 3 clocks, the signal from the vehicle existing in the range of 3 to 6 m is reproduced. In this way, if the clocks are sequentially set to 5 clocks, 7 clocks, and 9 clocks, the range becomes 6 to 9 m, 9 to 12 m, and 12 to 15 m, respectively, and the area is expanded far.

Thus, the PN code used for transmission is forcibly delayed by an amount corresponding to the round-trip propagation distance of the radio wave,
By performing correlation processing with the received signal, it is possible to specify the area within each zone. In this way, the predetermined range that is the target of vehicle identification is divided into a plurality of zones Z ₁ , Z ₂ , Z ₃ ,
By the first dividing means for dividing into ... and the second dividing means for dividing each zone into a plurality of areas E ₁ , E ₂ , E ₃ , ...
A plurality of blocks A ₁ , A ₂ , A ₃ , ..., B ₁ , B ₂ , from which vehicle information can be obtained respectively without interfering with the predetermined range.
B ₃ , ..., C ₁ , C ₂ , C ₃ ,.

3 to 5 show examples of block division. FIG. 3 shows an example of block division in the case where the traveling vehicle 5 equipped with the transponder 4 transmits vehicle information to the antenna 1 installed on the road shoulder.
In the figure, the vehicle information is divided into blocks D6 → E.
It is transmitted in the process of passing in the order of 5 → F4 → G4 → H4 → I4.

Further, FIG. 4 shows an example of block division for a plurality of traveling vehicles 5 when the antenna 1 is installed in the center of the road. Similarly, FIG. Predetermined area to be the target of) 10
3 shows an example of block division for a plurality of vehicles 5 existing in the above. It will be apparent to those skilled in the art that the example of block division is not limited to the examples of FIG. 3 to FIG. 5 and appropriate block division can be performed depending on the situation.

Details of other structural features and operations of the present invention will be described with reference to the embodiments described below with reference to the accompanying drawings.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle identification apparatus according to an embodiment of the present invention has the same schematic configuration as the principle configuration shown in FIG. In the figure, the antenna 1 and the transmitter / receiver 2 are integrated, and an optimum place such as the outdoors, that is, a large number of vehicles 5
It is installed at the optimum position to get vehicle information from. The antenna 1 is composed of a plurality of antenna elements (described later),
Transmitter / receiver 2 each having a large number of input / output ports
And transmits the transmission signal from the transceiver 2 to the outside as a radio wave, receives the reflection signal from the outside in response to the radio wave, and outputs it to the transceiver 2. Transceiver 2 is
The reception signal of the antenna 1 is processed to generate unique vehicle information for each vehicle 5 and output to the data processor 3. The data processor 3 constitutes equipment on the ground, acquires vehicle information, and performs arithmetic processing on this vehicle information.
It provides various services. On the other hand, the transponder 4 is mounted on a large number of vehicles 5 that are running or stopped, receives a signal from the antenna 1, adds vehicle information of the vehicle 5 to the received signal, and transmits the signal to the antenna 1 again. To do.

Next, a detailed internal structure of the simplified block division shown in FIG. 1B will be described. Of course, it is self-evident that by extending this basic configuration, practical operation can be approached. FIG. 6 shows a configuration example of the antenna 1. As shown in FIG.
It is composed of three antennas, a zone antenna 101, a B zone antenna 102, and a C zone antenna 103. Each antenna 101, 102 and 103
Respectively send the signals of the corresponding A zone, B zone and C zone and mainly receive the reflected signals in the A zone, B zone and C zone respectively. Each antenna looks like a planar array antenna lined up on one plane in appearance, but it is an independent linear antenna.
It is an array antenna. This linear array antenna may be constructed by using a waveguide, but it is preferable to manufacture it by using a microstrip line printed circuit board technology because it is complicated to assemble the three antennas on a plane. It is easier to do.

In this case, by controlling the radiation power of each radiating element EL and its phase as shown in the figure, an antenna pattern for radiating a sharp beam in an arbitrary direction can be obtained. The radiated power can be set by the size of the radiating element EL or the degree of coupling to the feeding, and the phase is the interval between the radiating elements in the case of a traveling wave type antenna, and the feeding means ( This can be set by changing the electrical length of the power feeding ports 111 to 113). The numerical basis for these is left to many technical books. By using a microstrip line to fabricate three antennas each having a special antenna pattern on one plane,
Three zones Z ₁ , Z ₂ , Z ₃ can be easily formed.

FIG. 7 shows an example of the configuration of the transceiver 2. First, a portion related to the zone Z ₁ (A zone) in FIG. 1B will be described. The PN1 code for the A zone such as the M sequence generated by the code generator 202 is output to the modulator 203 and the shift register 204. The oscillation signal from the oscillator 201 is input to the modulator 203, but is also input to the modulator 213 for the B zone and the modulator 223 for the C zone. This oscillating signal (that is, the carrier wave signal) is modulated by the above-mentioned PN1 code in the modulator 203 and spread as a signal through the circulator 205, and the antenna 1 for the A zone of the antenna 1 is transmitted.
Radio waves are radiated to the outside through 01. The reflected wave signal from the outside with respect to this radiated radio wave is passed through the A-zone antenna 101 of the antenna 1 again to the circulator 20.
5 and is input to the demodulator 206 as a high frequency signal. The demodulator 206 uses the carrier signal from the oscillator 201 to demodulate the high frequency signal to generate a baseband demodulated signal. This baseband demodulated signal is divided into three, and then input to correlators 207, 208 and 209, respectively. On the other hand, in the shift register 204, a code D ₁₁ , 3 obtained by delaying the same PN code (PN1 code) as the modulation code used for transmission by 1 bit, respectively.
The bit delayed code D ₁₃ and the 5-bit delayed code D ₁₅ are generated and sent to the correlators 207, 208 and 209, respectively. Each correlator 207, 208 and 2
In 09, the 1-bit delay code D ₁₁ , the 3-bit delay code D _13, and the 5-bit delay code D ₁₅ are respectively correlated with the baseband demodulated signal, and respective correlator outputs are output to the data determiners 210 and 211. And 212 respectively. Each of the data determiners 210 to 212 determines vehicle information after passing only the signal processing band, and
1 data, A2 data and A3 data are output. Here, each data of A1 to A3 is a block A.
1, the vehicle information from the vehicles existing in A2 and A3 is designated. The above is the configuration for the A zone.

The construction of the B zone is also the same as that of the A zone described above. However, in this case, the PN2 code is used in place of the PN1 code used for the A zone, and a transmission signal for the B zone is generated and vehicle information B1 data, B2 data, and B3 data for the B zone are output. Similarly, the configuration regarding the C zone is the same as that of the A zone and the B zone. In this case, PN3 code is used instead of PN1 code used for A zone and PN2 code used for B zone,
The C zone transmission signal is generated and the C zone vehicle information C1 data, C2 data and C3 data are output.

FIG. 8 shows an example of the configuration of the data processor 3. The illustrated data processor has nine data registers 3
01 to 309, a controller 310 and a memory 311. Vehicle information output A1 data, A2 data, A3 data for each block from the transceiver 2 described above,
B1 data, B2 data, B3 data, C1 data, C
The 2 data and the C3 data are temporarily stored in the data registers 301 to 309, respectively. These data are stored in the memory 311 in a organized form by the controller 310. On the other hand, the controller 310 can perform arithmetic processing on the data in the memory 311 according to an instruction from the outside and can output the data to the outside to provide information suitable for system operation.

FIG. 9 shows an example of the structure of the transponder 4. The transponder shown has antennas 401, B
It is composed of a PSK modulator 402, a ROM 403, a timing controller 404, a power supply circuit 405, and a resonator 406. The spread transmission signal from the ground antenna 1 (see FIG. 1) is received by the vehicle-mounted antenna 401, and
It is input to the SK modulator 402. This BPSK modulator 4
Reference numeral 02 denotes the received signal based on a binary signal from the ROM 403 which stores vehicle information peculiar to the vehicle in advance.
PSK modulation is performed, and the modulated signal is transmitted from the antenna 401 to the ground antenna 1. The resonator 406 and the power supply circuit 405 are composed of a strip line in the shape of a dipole and a diode for rectification, and rectify the spread transmission signal transmitted from the ground antenna 1,
Generates DC power output. This DC power output is ROM
It is used as a power source for 403 and timing controller 404. The timing controller 404 generates the timing for setting the address of the ROM 403 and periodically outputting the vehicle information.

Next, the operation of each section related to the transmission of vehicle information will be described. The vehicle information referred to here is
Vehicle-specific information represented by vehicle type, manufacturing number, size, weight, vehicle inspection date, owner, account, etc., and in this embodiment, corresponds to the ROM value written in the ROM 403 of the transponder 4. Further, it is assumed that the vehicle 5 is stopped at the block A3.

FIG. 10 shows signal waveforms of various parts illustrating vehicle information transmission when the vehicle is stopped. The oscillator 201 of the transceiver 2 installed on the ground oscillates a carrier wave, and the modulator 203 phase-modulates the carrier wave with the PN1 code generated by the code generator 202 to spread the spectrum. The spread transmission signal is transmitted from the A-zone antenna 101 of the antenna 1 to the outside. Block A
When the transponder 4 mounted on the vehicle 5 existing in No. 3 receives this signal, the transponder 4 outputs the received signal to the ROM of the ROM 403.
The value is phase-modulated by the BPSK modulator 402 and transmitted to the antenna 1 on the ground. At this time, the phase modulation in the transponder 4 is performed in a cycle several times as long as the cycle of the PN1 code so as to be separated from the PN1 code. The signal transmitted from the transponder 4 is received by the A zone antenna 101 of the antenna 1.

Next, the received signal is mixed with the carrier wave by the two demodulators 206 for transmission and reception, and becomes a baseband demodulated signal with the carrier wave canceled. This signal is divided into three, and the PN1 code used for transmission is delayed by the propagation time required for the radio wave to travel back and forth to the vehicle 5 (1
When the correlation processing by the phase demodulation is performed by the correlators 207 to 209 using the bit delay code D ₁₁ , the 3-bit delay code D ₁₃ and the 5-bit delay code D ₁₅ ), the PN1 code delayed by the distance of the block A3 is used. The vehicle information is reproduced only from the output of the correlator 209 that has been used.

In this way, the information of the transponder 4 mounted on the vehicle 5 existing in the block A3 can be transmitted as A3 data of the transceiver 2. The above description is about the transmission method when the vehicle 5 is stopped, but it can be similarly described when the vehicle is running. Figure 1
1 shows the signal waveforms of the respective parts illustrating the vehicle information transmission when the vehicle is traveling.

In this case, even if the above-mentioned PN1 code component disappears, due to the influence of the carrier wave, the Doppler frequency component corresponding to the relative speed with the vehicle is balanced-modulated to the baseband demodulated signal. When determining information from the signal of the balanced modulation wave, all vehicle information including the stopped vehicle can be transmitted by the following method. That is, when the received signal from the antenna 1 is divided into two by the transceiver 2 and mixed with the carrier having a 90 ° phase difference, a balanced modulation signal having a Doppler frequency having a 90 ° phase difference is obtained. By detecting the rising and falling edges of this signal and taking the logical sum (OR) of the two detection signals, it is possible to faithfully reproduce the rising and falling edges of the phase modulation for the vehicle information, and as a result, the vehicle information Will be obtained.

FIG. 12 illustrates the vehicle information transmission timing of the transponder 4. The phase modulation of the transponder 4 may be executed periodically instead of continuously and repeatedly taking into consideration the amount of vehicle information, the speed of the vehicle, and the like. For example, at a speed of 180 km / h, 1
If the vehicle information is transmitted every 20 ms for a period of 20 ms, the information can be transmitted at intervals of 5 m and while traveling a distance of 1 m. Naturally, if the speed is lower than this speed, the repetition of transmission will increase. Thus, even if the vehicle information is not continuously sent back from the transponder 4 to the device on the ground, by sending it back periodically and in bursts, a plurality of transponders may be mounted on the same vehicle, or a plurality of transponders may be sent to the same block. Even when the vehicles are gathering, it is possible to cope with this because the cycle of the burst occurs independently for each transponder.

As described above, in this embodiment, the vehicle 5
Whether the vehicle is running or stopped, it is possible to simultaneously and instantly obtain the vehicle information of all the vehicles existing in a preset predetermined range. Therefore, various services based on the vehicle information can be provided. As an example, toll calculation on toll roads is not limited to vehicles that pass through the gate, and each toll can be processed instantly and simultaneously for a large number of vehicles. It will be possible to realize significant labor savings and significantly reduce traffic congestion.

As another example, even for a vehicle stopped at a gas station, the vehicle information of each vehicle can be obtained without interference between the vehicles. Therefore, charge calculation and the like should be performed and processed for each vehicle. Is possible. As another example, when obliging a transponder to be installed in a vehicle, it is not only possible to crack down on violations such as speed over, signal disregard, and vehicle inspection from fixed base stations, but also from moving stations such as police cars. It becomes possible to crack down.

As still another example, not only checking of the entry and exit of vehicles in the parking lot but also where in the parking lot and which vehicle is parked can be grasped, so that the control in the parking lot can be efficiently performed. Becomes

[0038]

As described above, according to the present invention, by using a plurality of antennas and a spread spectrum technique utilizing autocorrelation characteristics in the process of signal processing, a wide range can be obtained regardless of whether the vehicle is running or stopped. It becomes possible to simultaneously and instantaneously obtain the vehicle information of each of all the vehicles existing over the period. This greatly contributes to the provision of many services using the vehicle information.

[Brief description of drawings]

FIG. 1 is a principle explanatory view of a vehicle identification device of the present invention.

FIG. 2 is an explanatory diagram of an autocorrelation characteristic of a PN code.

FIG. 3 is a diagram showing an example of block division.

FIG. 4 is a diagram showing another example of block division.

FIG. 5 is a diagram showing still another example of block division.

FIG. 6 is a diagram showing a configuration example of an antenna in FIG.

FIG. 7 is a diagram showing a configuration example of a transceiver in FIG.

FIG. 8 is a diagram showing a configuration example of a data processor in FIG.

FIG. 9 is a diagram showing a configuration example of a transponder in FIG.

FIG. 10 is an operation waveform diagram for explaining vehicle information transmission when the vehicle is stopped.

FIG. 11 is an operation waveform diagram for explaining vehicle information transmission when the vehicle is traveling.

FIG. 12 is an explanatory diagram of vehicle information transmission timing of a transponder.

FIG. 13 is a diagram schematically showing a configuration of a conventional vehicle identification device as an example.

[Explanation of symbols]

1 ... antenna 2 ... transceiver 3 ... data processor 4 ... transponder 5 ... vehicle Ai, Bj, Ck, ..., ... ( divided) block _{D 11, ..., D 21,} ..., D 31, ..., ... predetermined , The time-delayed PN codes E ₁ , E ₂ , E ₃ , ..., (Divided) areas PN1 to PN3 ... Pseudo-random code (PN) used for transmission
Code) Z ₁ , Z ₂ , Z ₃ , ..., ... (divided) zones

Claims (4)

[Claims] 1. An antenna for emitting a radio wave in a predetermined range to be identified, mounting a transponder (4) responsive to the radio wave, and receiving a reflected wave from a vehicle (5) existing in the predetermined range. (1) and a transceiver (2) which is coupled to the antenna and processes a received signal of the antenna to generate vehicle information specific to the vehicle
And a data processor (3) for appropriately calculating the vehicle information, each antenna using a plurality of antenna elements each having an antenna pattern having a beam width not exceeding the area of one vehicle. By shifting the beam angle by the beam width, the predetermined range is divided into a plurality of zones (Z ₁ , Z ₂ ,
Z ₃ , ...), and the transmitter / receiver obtains the received signal by demodulating the received signal with a code delayed by a predetermined time from the pseudo-random code used for transmission. By utilizing the correlation characteristics, each zone is divided into a plurality of areas (E ₁ , E ₂ , E ₃ , ...
...) and divides the predetermined range into a plurality of blocks (Ai, Bj, Ck, ...) Using the first and second dividing means, and divides each block into A vehicle identification device characterized in that the size is set to be smaller than the size of one vehicle. 2. The vehicle identification device according to claim 1, wherein the first dividing unit has a linear array antenna (101 to 103) formed in a planar shape. 3. The transmitter / receiver, when the vehicle is traveling, has a Doppler frequency component corresponding to a relative speed between the transceiver and the vehicle, which is balanced-modulated by 90 °.
2. The vehicle identification device according to claim 1, further comprising means for canceling the influence of the Doppler frequency by using two demodulated signals having a phase difference, thereby generating vehicle information specific to the vehicle. . 4. The transceiver has means for periodically executing a response from the transponder, whereby multiple transponders are mounted on the same vehicle or there are multiple vehicles in the same block. The vehicle identification device according to claim 1, wherein the vehicle identification device is adapted to handle such a case.