JPH0896186A - Moving body discriminating device and its moving body deciding method - Google Patents

Abstract

PURPOSE: To decide at which position a moving body is by radiating a carrier to the moving body, receiving a receiving wave sent from a responder attached to the moving body, and judging the reception level and estimating the distance to the moving body on the basis of the obtained result. CONSTITUTION: The carrier oscillated by an oscillator 203 is passed through an amplifier 205 and radiated from a transmitting antenna 201, the receiving wave from the responder is received by a receiving antenna 202, a detection part 206 obtains a detection output by a phase difference double detection system. The obtained detection output is selected by a level comparator 209 and a signal selection part 210 and held by a reception level holding part 214 while sent to a signal processing part 211, and the level of the signal is sent to the signal processing part 211, which once recognizing the received signal from the responder through the selector 210 sends reception level data as distance data in addition to the response signal when sending the level data from a data buffer 217 to an external equipment from an input/output port 213.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving body identifying apparatus and a communication method for exchanging information by detecting the presence / position of a moving body such as an automobile, and more particularly to a moving body identifying apparatus using a carrier wave. Regarding the communication method.

[0002]

2. Description of the Related Art Conventionally, a moving body identifying apparatus system for detecting a moving body, recognizing it, and exchanging data is disclosed in JP-A-4-15429 and JP-A-5-8615. Thus, for example, a moving body identifying device applied to an automatic billing system for an automobile has a schematic configuration as shown in FIG. 4 (a). Here, the ground antennas 2a and 2b are in charge of checking the respective traveling lanes 5a and 5b, and radiate radio waves from the respective transmitting antennas,
Communication areas 21a and 21b are set so as to communicate with vehicles (moving bodies) passing through the respective traveling lanes 5a and 5b. A ground system 4 for controlling these ground antennas 2a, 2b collects data from the ground antennas and carries out a fee charge for each vehicle, and installs next to each ground antenna for a vehicle that cannot be charged. Photographing is performed by the enforced cameras 3a and 3b.

In this automatic billing system, the driving lane 5
Signals are sent from the ground antennas 2a and 2b to a transponder mounted on a vehicle passing through a and 5b, and the balance information in the transponder is charged only for the toll fee,
The amount is reduced and the result is sent to the ground system 4 for processing. The terrestrial system 4 is a block diagram as shown in FIG. 5, and an internal process in which an antenna interface 41 for controlling a plurality of terrestrial antennas and a camera interface 42 for controlling each of the enforcement cameras integrally controls those interfaces. It consists of a device 43.

Here, it is assumed that the two-wheeled vehicle 6 to which the transponder 1 is attached is traveling along the edge of the traveling lane 5b. At this time, the transponder 1 is assumed to be passing through the area 21ab in which both the ground antennas 2a and 2b can communicate. The communication areas 21a and 21b overlap each other so that the areas are sufficiently covered and there is no omission of check. Therefore, the two-wheeled vehicle 6 has the ground antennas 2a and 2b.
Both can communicate.

In this case, the communication procedure is as shown in the timing chart of FIG. 4 (b), in which the transponder 1 responds to the call signal (P1) from the ground antennas 2a and 2b in response to the I signal.
D is issued (P2), authentication (P3), authentication response (P4) and billing (P5) are made, and the response to the billing is that the billing is completed. At that time, as shown in the timing chart, since the two ground antennas 2a and 2b are in time-division communication, the ground antenna 2a that is communicating first is connected to the ground antenna 2a that is communicating first so as not to be charged twice. On the other hand, after the billing completion notice (P6a) is transmitted, the billing completion notice (P6b) is responded to the ground antenna 2b on the subsequent communication side. Then, the result is confirmed by the ground control device 4, and a series of billing communication is completed.

[0006]

However, if the internal balance of the transponder 1 is insufficient, the transponder 1 responds with a result of insufficient charge or incomplete charge when responding to the charge (P5). . As a result, the signal (P
6a ') is returned to the ground antenna 2a, and thus the ground control device 4 instructs the enforcement camera 3a to capture an image of the traveling vehicle in order to record the incomplete charging in the communication. This shooting is performed once for each incomplete charging.

However, in reality, a motorcycle has a traveling lane 5
There is no vehicle in the traveling lane 5a within the field of view angle 31a which is originally in charge of the enforcement camera 3a, and there is no vehicle for which charging has not been completed. At present, in order to prevent the problem, the taking lenses of the force cameras 3a and 3b are made wide-angle so that a sufficient range can be captured. Therefore, the photographed image is considerably small on the film or on the data, and there is a problem that individual determination of the vehicle is difficult.

Furthermore, the number of vehicles running is not limited to one, and it is difficult to read and specify which vehicle is not charged from the photographed data. In particular, as described above, when a vehicle for which billing has not been completed is running in the adjacent driving lane and there is a vehicle that is running directly in the intended driving lane immediately afterward, it can be distinguished from the vehicle based on the captured data. The difficulty is a big problem for an automatic billing system. In the end, it is not easy to identify the position of the target moving body in the conventional system.

Further, in an example (FIG. 6) in which the moving body identifying apparatus is applied to a maze guiding system, a rectangular maze block 7 is used.
Interrogators 2c, 2d, 2e and indicators 8c, 8d, 8e are installed in c, 7d, 7e, respectively, and the interrogator is controlled by the center host 4d. Then, a person holding the transponder 1d is passing through the maze. As shown in FIG. 7, the center host 4d includes an antenna interface 41d that controls a plurality of interrogators, an indicator interface 42d that controls a plurality of indicators, and a display processing device 43d that indicates a guiding direction. Device 43
d is almost always composed of a microcomputer.

In this maze guiding system, the center host 4d guides a person to the exit with an indicator. At this time, an indicator corresponding to the block where the person is present is selected and an instruction is given. However, even in this system, the communication areas of the interrogator antennas overlap as shown in Fig. 6, so it is not possible to determine which block a person is in, and it is not possible to guide the person, or it is possible to guide the person by mistake. There was a problem such as doing. This is also a problem because the position of the detection target cannot be specified.

Even if the moving body is identified as in the above two examples, it is difficult to identify the target moving body due to the presence of the plurality of moving bodies, or conversely, the identification of the moving body is performed. There was a problem that the detector could not detect the position by double detecting.

Therefore, in view of the above problems, an object of the present invention is to determine the position of a moving body by obtaining data indicating the distance from the interrogator to the responder. It is an object of the present invention to provide a mobile body identification device and a determination method thereof.

[0013]

In order to solve the above problems, the structure of the present invention radiates a carrier wave to a mobile unit and receives a received wave sent from a responder attached to the mobile unit. Then, in the mobile body identification device that takes out the detection signal in the detection unit, detects the presence of the mobile unit in the signal processing unit and exchanges information, the reception level which is calculated and holds the reception level of the detected detection signal. Determination means for determining the magnitude of the reception level based on the data retained by the reception level retaining means, and moving to the signal processing section based on the result obtained by the determination means. And a distance estimation means for estimating the distance of the body.

According to the structure of the related invention, the detection section detects a signal by phase difference double detection using an unmodulated wave of the carrier wave having a phase difference of 90 °, and one of the detected two detected signals is detected. The one having a higher level is selected and sent to the signal processing unit, and the reception level holding unit adds and holds the two detected signals, and outputs the signal to the signal processing unit. Alternatively, the detection signal of the higher level is peak-held for a predetermined time and then output to the signal processing unit.

In another configuration of the present invention, the reception level holding means retains data as a digital value by an A / D converter, and the judging means and the distance estimating means are constituted by a digital circuit by a microcomputer. It is characterized by

According to the configuration of the invention as a method for determining a moving body embodying the present invention, a carrier wave is radiated toward the moving body, a received wave sent from a responder attached to the moving body is received, and detection is performed. In the mobile body identification method of the mobile body identification device in which a detection signal is taken out by the unit, and the presence of the mobile body is detected by the signal processing unit to exchange information, in the detection unit, the received wave is detected by phase difference double detection. However, the reception level of the detected signal is calculated and held, and when the detected signal is processed by the signal processing unit, the magnitude of the calculated reception level is also incorporated in the data. is there.

[0017]

Since the signal strength emitted from the moving body becomes weaker in proportion to the fourth power of the distance, the distance from the receiving antenna can be estimated by measuring the signal strength. The signals from the two moving bodies are compared, and it is determined that the stronger one is closer. In addition, even when two moving antennas are used to detect a single moving body, it is assumed that the moving body is close to the receiving antenna with the stronger signal strength. The carrier wave whose phase is shifted by 90 ° is also used, the received wave is detected based on the two carrier waves by phase difference double detection, and both outputs are added to obtain the signal level of the received wave.

The phase difference double detection in the claims means
It is a term defined here, and is not a word that is generally used, but merely expresses a conventionally known detection method configured by the detection units shown in FIGS. 1 and 3 in one word.

[0019]

According to the configuration of the moving body identifying apparatus and the moving body judging method of the present invention, the positional relationship of which antenna is closest to the moving body is determined, and various measures can be taken based on it. The configuration according to claim 2 has an effect that it can be determined that the fluctuation does not occur depending on the detection level. Further, in the configuration of claim 4, there is an effect that the signal processing is executed promptly. For example, in the automatic billing system, a vehicle for which billing has not been completed can be specified, and in the maze guidance system, guidance for a person is appropriately instructed.

[0020]

EXAMPLES The present invention will be described below based on specific examples. FIG. 1 is a circuit block configuration diagram of a ground antenna 20 to which the present invention is applied. The carrier wave oscillated from the oscillator 203 is formed into a modulated wave by the modulator 204, and the modulated wave is generated by the amplifier 205.
It is radiated from the transmitting antenna 201 via the. The case where data is sent from the terrestrial antenna side on a carrier wave is called a downlink signal S1, and the case where an unmodulated carrier wave is sent for reflection from a transponder is called an uplink unmodulated wave signal S2 for distinction. . At the same time that the carrier wave is sent from the transmitting antenna, the carrier wave is also input to the detection unit 206 to serve as a reference at the time of detection.

The reception wave (uplink signal S3) from the responder 1 is received by the reception antenna 202, and the detection unit 206 obtains a detection output by the phase difference double detection method. The obtained detection output is selected by the level comparator 209 and the signal selection unit 210 and sent to the signal processing unit 211, and at the same time, is maintained by the reception level holding unit 214 and the magnitude of the signal is determined by the signal processing unit 2.
It is transmitted to 11. Here, the signal processing unit 211 is a CPU
It is composed of The signal processing unit 211 performs necessary signal processing, and the necessary processing result is output from the input / output port 213 via the input / output interface 212.

A transponder 1 attached to a moving body is a circuit block diagram as shown in FIG. 2, and the configuration of FIG. 2 is similar to the conventional configuration. That is, the receiving antenna 101 that receives the carrier waves (S1, S2) from the transmitting antenna 201 of the ground antenna 20, the detection unit 103 connected to the receiving antenna 101,
The signal level from the detector 103 is used as an input level determiner 10
5, the power supply control circuit 106 is energized to wake up the circuit of the responder in the sleep state, and the amplifier 107 and the signal processing unit 108 perform processing in order to respond based on the obtained signal, Data is sent to the modulator 104, and the transmission antenna 102 modulates and reflects the uplink non-modulation wave signal received from the ground antenna.

The uplink signal S3 reflected from the transponder 1 is the uplink non-modulated wave signal S2 transmitted.
Since it is not always in phase with, it is not possible to perform heterodyne detection, and conventionally, the reference carrier (unmodulated wave signal for uplink) and its phase
The phase-difference double detection is used to detect each signal with the signal shifted by 90 °. Since the signals detected on both sides are weak on either side, the two signals are compared by the level comparator 209, and the signal on the stronger side is selected by the selector 21.
Select with 0.

Here, in order to determine the level of the signal level from the moving body, the above two detection signals are obtained by the reception level holding unit 214. First, the added signal is obtained by the adder 215. This is because, regardless of the phase of the received signal, it will be included in any of the reference signals that are shifted by 90 °, so the sum of the two detected signals is proportional to the magnitude of the original received signal. This is to have. Therefore, since the two detection signals are added to obtain the magnitude, it can be detected as an amount related only to the magnitude of the distance irrespective of the phase difference of the received wave from the transponder 1 of the mobile body.

The added signal is stored in the buffer 217 as level data digitized by the A / D converter 216 so that the data can be easily processed to obtain the magnitude. When the signal processing circuit 211 recognizes the received signal from the responder 1 from the selector 210, the level data of the response signal is taken out from the data buffer 217, and when this response signal is transmitted to the external device from the input / output port 213. In addition to the response signal, the reception level data is transmitted as distance data. In this way, the distance data is obtained. By referring to the distance data from the ground antenna 20, the ground system determines from which ground antenna the signal is the strongest, and therefore the moving body (responder 1) is approaching the ground antenna. Then, if necessary, the specified responder 1 is processed.

(Second Embodiment) Next, the operation when the ground antenna according to the present invention is applied to an automatic billing system will be described.
Also in FIG. 4, when the answering device 1 of the vehicle gives a result that the billing has been normally performed, the same operation as in the conventional case is performed. However, when the result is returned from the transponder 1 after the charge is not completed, the response signal is sent to the ground system 4 through the ground antenna 2a or 2b together with the distance data from the received antenna. The ground system 4 determines which antenna the mobile unit is closest to based on the data from the plurality of ground antennas.

In the example of FIG. 4 (a), the ground system 4 includes
Since the ground antennas 2a and 2b are connected, the distance from each antenna to the vehicle having the transponder can be known together with the received response signal, and the result that the ground antenna 2b is closer by comparing those distances is obtained. As a result, the responder 1 can determine that the vehicle is traveling in the lane 5b, and the vehicle for which charging has not been completed can be captured by the enforcement camera 3b.
At that time, it is possible to limit the viewing angle range of the Enforcement camera to one lane, so other vehicles do not appear together and it is easy to identify the unpaid vehicles,
Has the advantage of being able to respond quickly.

(Third Embodiment) The same applies when the interrogator according to the present invention is applied to a maze guiding system. In the example of FIG. 6, when the interrogators 2d and 2e receive information from the responder 1d, The received signal is sent to the center host 4d together with the distance data, and the distance data is compared,
You can see in which block 7d or 7e the person with the transponder is. Since it is close to the interrogator 2d in FIG. 6 (a),
As a result, an appropriate direction can be guided to the person by the indicator 8d.

(Fourth Embodiment) Further, as another configuration,
In the configuration of the ground antenna 20 ′ shown in FIG. 8, a selector 215 ′ is used instead of the adder 215 shown in FIG. 1, and a peak hold circuit 21 is used instead of the data buffer 217.
7'is provided (however, the position of the peak hold is between the selector 215 'and the A / D converter 216). In such a configuration, the selector 215 ′ outputs the two signals having the higher detection levels and outputs the peak hold circuit 21.
In 7 ', the maximum value is held for a certain period. Then, the level is sent to the signal processing circuit 211 as digital data by the A / D converter 216.

In this configuration, by using the selector 215 ', when the level signal output of the detection amplifier 208 is non-linear, the magnitude of the output obtained by adding the two levels and the distance distance may not be correlated. It can be prevented by using the selector 215 '. However, when the level signal output is linear, the error is smaller when the adder is used. In addition, the advantage of using the peak hold circuit is that the control circuit is required in the case of the data buffer, but in this case it can be configured with the CR time constant of the analog circuit and about the diode, so the overall circuit configuration is simplified. To be

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a ground antenna to which the present invention is applied.

FIG. 2 is a block configuration diagram of a transponder (vehicle-mounted device).

FIG. 3 is a block diagram of a conventional ground antenna.

FIG. 4 is a schematic configuration diagram of a vehicle automatic charging system.

5 is a block configuration diagram of a ground system of the automatic charging system shown in FIG.

FIG. 6 is a schematic configuration diagram of a maze guiding system of a third embodiment.

7 is a block configuration diagram of a center host of the maze guiding system of FIG.

FIG. 8 is a block configuration diagram of a ground antenna according to a fourth embodiment.

[Explanation of symbols]

 1 Transponder (vehicle-mounted device) 2, 2a, 2b, 20, 20 'Ground antenna 4 Ground system 4d Center host 206 Detection unit (phase difference double detection) 214 Reception level holding unit

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Claims (4)

[Claims] 1. A carrier wave is radiated toward a mobile body, and a received wave sent from a responder attached to the mobile body is received,
In a mobile body identification device in which a detection unit extracts a detection signal, and a signal processing unit detects the presence of the mobile body and exchanges information, a reception level holding unit that calculates and holds a reception level of the detected detection signal. The signal processing unit, the determination unit for determining the magnitude of the reception level based on the data held by the reception level holding unit, and the moving body based on the result obtained by the determination unit. A moving object identifying apparatus, comprising: a distance estimating means for estimating a distance. 2. The detector has a phase of 90 ° with respect to the carrier wave.
A signal is detected by phase difference double detection using different unmodulated waves, and one of the detected two detected signals having the higher level is selected and sent to the signal processing unit. By means, the two detected signals detected are added and then held,
The method according to claim 1, wherein either the signal is output to the signal processing unit, or the detected signal with the higher level is peak-held for a predetermined time and then output to the signal processing unit. Mobile object identification device. 3. The reception level holding means holds data as a digital value by an A / D converter, and the judging means and the distance estimating means are constituted by a digital circuit by a microcomputer. Item 2. The moving body identification device according to item 2. 4. A carrier wave is radiated toward a mobile body, and a received wave sent from a responder attached to the mobile body is received,
In the mobile body identification method of the mobile body identification device that takes out the detection signal in the detection unit, detects the presence of the mobile unit in the signal processing unit and exchanges information, in the detection unit, the received wave by phase difference double detection Detect,
A mobile object identification device, characterized in that the reception level of the detection signal is calculated and held, and when the detection signal is processed by a signal processing unit, the magnitude of the reception level calculated is also taken into the data. Mobile object determination method.