JP3021306B2 - Mobile object identification device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving object identification apparatus applied to a toll road toll collection system.

[0002]

2. Description of the Related Art Dedicated vehicles used for the purpose of road maintenance and the like on toll roads such as expressways are distinguished from ordinary vehicles and require no toll. In addition, in general vehicles, for persons with disabilities, discounts are taken as part of the welfare policy. At present, a certificate is issued in advance for a target general vehicle, and the above-mentioned discount treatment is performed by presenting the certificate to a collection member when passing through a tollgate.

[0003] Recently, however, automation of toll collection machines has been advanced. For this reason, in order to receive the above-mentioned treatment, it is necessary to press the call-to-collector button at the toll booth, and there is a demand for a simple treatment method for improving the service.

FIG. 6 is a diagram for explaining a conventional toll collection system using a contactless IC card. In the figure,
Reference numeral 1 denotes a center computer, which is connected to the ground station 2. This ground station 2 is installed on the side of the road near the tollgate. Similarly, the antenna 3 is installed adjacent to the side of the road, that is, the ground station 2. A non-contact IC card 5 is attached to the vehicle 4 traveling on the road, for example, inside a windshield. FIG. 7 shows the configuration of the non-contact IC card 5. As shown in FIG. 7, the non-contact IC card 5 basically includes a CPU 11, a memory 12, a communication controller 13, a modem 14, an antenna 15, a battery 16, It is constituted by.

In FIG. 6, when a running vehicle 4 enters a communication area (not shown) of the antenna 3, the center computer 1 performs wireless communication with the contactless IC card 5 through the ground station 2 and the antenna 3. As a result, information such as the vehicle-specific ID number and the remaining amount of the toll stored in the memory 12 in the non-contact IC card 5 shown in FIG.
It is read by U11 and sent to the ground station 2 via the communication controller 13, the modem 14, and the antennas 15 and 3. The ground station 2 communicates with the center computer 1 as necessary based on the above information, and performs processing such as calculation of toll charges and identification of unauthorized vehicles. Therefore, the vehicle 4 can pass through the toll booth without receiving or temporarily stopping the toll.

Therefore, if the classification such as "maintenance vehicle" and "vehicle for disabled person" is stored in the memory 12 inside the non-contact IC card 5 shown in FIG. The vehicle 4 is identified, and it is not necessary to press the above-described collection call button.

[0007]

In the non-contact IC card 5 shown in FIGS. 6 and 7, error detection / correction processing is performed by a dedicated communication controller 13 in order to improve communication reliability. And the CPU 11 manages the communication protocol. Since the CPU 11 and the communication controller 13 are expensive, there is a problem that the cost of the non-contact IC card 5 is relatively high. However, since the CPU 11 and the communication controller 13 are indispensable for executing the above-described processing, the non-contact
It is difficult to reduce the cost of the C card 5, and it is not expected to improve the service for vehicle identification.

Further, as shown in FIG. 7, a battery 16 is used in the non-contact IC card 5 to operate the CPU 11 and the communication controller 13. For this reason,
There has been a problem that the battery 16 needs to be replaced or that the communication reliability decreases with a decrease in the voltage generated in the battery 16.

[0009] The present invention has been made in view of the above-mentioned circumstances, and can reduce the cost and prevent a decrease in communication reliability due to a decrease in the power supply voltage of a battery in a non-contact IC card. An object of the present invention is to provide a mobile object identification device.

[0010]

According to the present invention, there is provided a surface acoustic wave device mounted on a vehicle, receiving a signal transmitted from the outside, and generating a predetermined delay time, and after receiving the delay time, providing a surface acoustic wave element to the outside. A non-contact card that transmits a signal equivalent to the received signal, an oscillating unit that is provided in a ground station that communicates with the non-contact card and outputs a carrier, and a carrier that is output by the oscillating unit. An output unit for transmitting a predetermined signal; a wireless communication unit for transmitting a signal from the output unit to the contactless card; and a signal for receiving a signal sent from the contactless card; Charge storage means for storing charge based on the received signal; comparison means for comparing a voltage stored in the charge storage means with a threshold voltage at a predetermined level; Is the signal based on the characterized by comprising determination means for determining whether the contactless card, and a reset means for discharging the charges accumulated in the charge storage means.

[0011]

The carrier wave from the oscillating means is generated as a predetermined signal by the output means and output to the wireless communication means.
The wireless communication means transmits the predetermined signal to a contactless card mounted on a vehicle. In the contactless card, the predetermined signal is delayed by a predetermined time and returned to the wireless communication unit. Next, the signal received by the wireless communication unit is input to the charge storage unit, and the charge is gradually stored. Next, the magnitude of the voltage stored in the charge storage means and the threshold voltage at a predetermined level are compared by the comparison means. As a result of this comparison, when the voltage stored in the charge storage means exceeds the threshold voltage, the determination means detects the presence of the non-contact card based on the signal output from the comparison means.

Accordingly, the contactless card is referred to as a "maintenance vehicle",
When mounted on a special vehicle such as a "disabled vehicle", the special vehicle can be distinguished from a general vehicle. As described above, the charge is stored in the charge storage means by the signal returned from the non-contact card, and as a result of comparison between the voltage value of the predetermined level and the voltage value stored in the charge storage means,
Since the presence of the contactless card is detected after the returned signal is stabilized, communication processing can be ensured and high communication reliability can be obtained.

[0013]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a ground station in a mobile unit identification apparatus according to one embodiment of the present invention.

The carrier output from the local oscillator 21 shown in FIG. 1 is amplified by the amplifier 22 and input to the PIN diode switch 23. The PIN diode switch 23 is turned on / off by a control signal output from the timing circuit 24, that is, a timing pulse. Further, the timing circuit 24 is connected to the CPU. The signal output from the PIN diode switch 23 is further amplified by the amplifier 26 and input to the PIN diode switch 27. The timing circuit 24 is also connected to the PIN diode switch 27 to perform on / off control. The signal output from the PIN diode switch 27 is
Is transmitted from the antenna 29 to the outside, that is, to a contactless card to be attached to the vehicle, which will be described in detail later.

The circulator 28 switches between transmission and reception, and is connected to a PIN diode switch 30. That is, the signal returned from the non-contact card is received by the antenna 29 and is transmitted through the circulator 28 to the PIN diode switch 3.
Input to 0. This PIN diode switch 30
Is connected to the timing circuit 24 via the logical inversion circuit 31.
It is connected to the. The logic inversion circuit 31 inverts the timing pulse output from the timing circuit 24, so that the PIN diode switch 30 and the PIN diode switch 30 are simultaneously turned on ("1").
Prevent from becoming. PIN diode switch 30
(The signal received by the antenna 29) is amplified by a low-noise amplifier 32 and an amplifier 33 to reduce noise, and then is detected by a detector 34, I
The signal is demodulated by the F amplifier 35. This IF amplifier 35
Are connected to a capacitor 37 via a buffer 36. That is, the demodulated signal from the IF amplifier 35 is
The electric charge is input to the capacitor 37 to accumulate the electric charge.
Further, a diode 38 is inserted between the power supply and the capacitor 37. A diode 39 is inserted between the capacitor 37 and the ground.

The capacitor 37 has a buffer 36
Is also input. That is, the buffer 36 includes a logical inversion circuit 40,
Capacitor 37 via PIN diode switch 41
Is also provided. An analog switch 42 is connected to the capacitor 37. The analog switch 42 is controlled by the timing circuit 24, and has the function of discharging the charge stored in the capacitor 37, that is, resetting the signal level determination value. The voltage value of the capacitor 37 is output to a comparison circuit, that is, a comparator 43. The comparator 43 is connected to a reference voltage generator 44 that outputs a threshold voltage of a certain level. That is, when the voltage value stored in the capacitor 37 exceeds the threshold voltage, the comparator 43 notifies the CPU 43 of the fact.
Inform Thus, the CPU detects the presence of the contactless card.

The local oscillator 21 is an oscillating means, PIN
Diode switches 23 and 27, timing circuit 24,
The CPU serves as an output unit for transmitting a predetermined signal, and the circulator 28 and the antenna 29 function as a wireless communication unit.
Further, the capacitor 37 is a charge storage means, the analog switch 42 is a reset means for discharging the charge stored in the charge storage means, and the comparator 43 and the reference voltage generator 44 are a threshold of a predetermined level with the voltage stored in the charge storage means. The comparing means for comparing with the value voltage and the CPU act as a determining means for determining the presence or absence of the non-contact card 61.

FIG. 2 is a block diagram of the timing circuit 24 shown in FIG. In the figure, reference numeral 51 denotes an oscillator that outputs a signal having a constant period. That is, a signal having a constant period output from the oscillator 51 is input to the AND circuit 53 via the inverter 52. Also, this AND circuit 5
A control signal sent from the CPU is input to 3. That is, in the timing circuit 24, the AND circuit 53
Thus, the control signal from the CPU is synchronized with the signal of a fixed period output from the oscillator 51. The control signal from the CPU synchronized in the AND circuit 53 is supplied to the outside of the timing circuit 24 through the flip-flop circuits 55 and 56, that is, the PIN diode switches 23, 27 and 3.
0 and 41 are transmitted as the timing pulses described above. The signal sent from the CPU is sent as a one-shot signal to the analog switch 42 through the monostable 54. That is, the CPU
The analog switch 42 is controlled through the monostable 54.

FIG. 3 is a block diagram of the contactless card according to the present invention. As shown in FIG.
An antenna 63 is connected to a SAW (Surface Acoustic Wave) device 62. The SAW device 62 receives the signal transmitted from the antenna 29 of the ground station shown in FIG. 1 via the antenna 63, delays the signal by a predetermined time, and returns the signal to the ground station again. The non-contact card 61 is mounted on a special vehicle such as a “maintenance vehicle” or a “disabled vehicle”.

Next, the operation of the above embodiment will be described.
First, a case will be described in which a vehicle on which the non-contact card 61 is mounted is present in the communication area of the antenna 29 shown in FIG.

In the ground station shown in FIG. 1, no signal is output from the CPU, and the carrier output from the local oscillator 21 is amplified by the amplifier 22 and input to the PIN diode switch 23. is there. In the above state, the control signal shown in FIG. 4A is turned on (“1”) from the CPU, and the timing circuit 24 is turned on.
Is output to While the control signal is on, the AND circuit 53 shown in FIG.
A pulse signal is output at the same time as the signal of a fixed period that has passed through 2 is on ("1"). This pulse signal passes through the flip-flop circuits 55 and 56 and is output to the PIN diode switches 23 and 27 as timing pulses shown in FIG. Also, the control signal is as shown in FIG.
Are input to the AND circuit 53 shown in FIG. From Monostable 54,
The one-shot signal shown in FIG. 4C is output to the analog switch 42. Thereby, the analog switch 42
Operates, and the electric charge accumulated in the capacitor 37 is discharged.

Next, the PIN diode switches 23 and 27 are turned on by the input of the timing pulse.
That is, the carrier amplified by the amplifier 22 has a PIN
By the amplifier 26 via the diode switch 23,
After another stage amplification, PIN diode switch 27
Pass through. At this time, the PIN diode switch 3
The timing circuit 24 is set to 0 by the logical inversion circuit 31.
The signal of the timing pulse output from the above is inverted and input. That is, the PIN diode switch 30 is off.

On the other hand, the carrier wave amplified by the amplifiers 22 and 26 passing through the PIN diode switch 27, that is, the modulated wave shown in FIG. 4D is transmitted from the antenna 29 via the circulator 28 to the contactless card 61 shown in FIG. Is transmitted as a transmission signal. This transmission signal is received by the antenna 63 of the contactless card 61 and
It is sent to the AW device 62. From the SAW device 62, after delaying the transmission signal by a certain time, FIG.
The received signal shown in (e) is returned to the ground station via the antenna 63.

The PIN diode switch 30 has a SAW
After the transmission signal delayed by the predetermined time by the operation of the device 62 is input to the antenna 29 as a reception signal, it is turned on by the CPU through the timing circuit 24 and the logic inversion circuit 31 (at this time, the PIN diode switch 27 is off). That is, the reception signal is a PIN
The signal passes through the diode switch 30, is amplified by the low noise amplifier 32 and the amplifier 33, and is output to the detector 34. The detector 34 performs a detection process from the received signal (modulated wave), and outputs a signal wave shown in FIG. The demodulated signal shown in FIG. 9G is output from the IF amplifier 35 to the capacitor 37 via the buffer 36.

At the same time, the demodulated signal is input to the capacitor 37 via the logic inverting circuit 40 and the PIN diode switch 41 as an inverted demodulated signal shown in FIG. That is, while the demodulated signal is being generated (the non-contact card 61 is returning the reception signal shown in FIG. 9E to the ground station), the capacitor 37 is gradually accumulating charge. . Also, the demodulated signal is not generated (the received signal is not returned to the ground station)
In the meantime, charges are accumulated in the capacitor 37 by the inverted demodulation signal. The voltage waveform at the capacitor 37 at this time is as shown in FIG.

At this time, the voltage stored in the capacitor 37 is output to the comparator 43. Further, a constant threshold voltage A shown in FIG. 2I generated by the reference voltage generator 44 is input to the comparator 43. That is, the comparator 43 compares the voltage output from the capacitor 37 with the threshold voltage A. As a result, when the voltage output from the capacitor 37 is equal to or higher than the threshold voltage A as shown in FIG. 4 (j), that is, when the voltage is stabilized, the comparator 43 outputs an ON signal, and the CPU reads the signal. . This allows
The CPU detects the presence of the contactless card 61.

Next, a case where the non-contact card 61 attached to the vehicle is not present in the communication area of the antenna 29 of the ground station will be described with reference to FIG. Also in this case, the waveforms shown in FIGS. 8A to 8D are output in the same manner as in the above-described process. But,
Since the contactless card 61 does not exist in the communication area of the antenna 29, the reception signal at the antenna 29 of the ground station is small and discontinuous as shown in FIG. It becomes noise. Accordingly, the signal wave output from the detector 34 is small and not continuous, as shown in FIG. As a result, the demodulated signal output from the IF amplifier 35 and the inverted demodulated signal obtained via the logic inversion circuit 40 and the PIN diode switch 41 also have low levels as shown in FIGS. , Will not be continuous. For this reason,
As shown in FIG. 7I, the capacitor 37 is discharged without accumulating electric charges, and does not reach the threshold value A. Therefore, as shown in FIG. The output signal of 43 remains off ("0"). Thereby, the CPU determines that the non-contact card 61 does not exist.

As described above, by detecting the presence or absence of the non-contact card 61, the passing vehicle is, for example, a "maintenance vehicle".
Whether the vehicle is a special vehicle such as a "disabled vehicle" or a general vehicle can be identified.

According to the present invention, as shown in the above embodiment,
A SAW device 62 is provided in the contactless card 61 to create a predetermined delay time, and the ground station manages a timing corresponding to the delay time to perform demodulation processing on a received signal. Further, after the voltage at the capacitor 37 exceeds the threshold value A shown in FIG. 4 (i), that is, after the demodulated signal output from the IF amplifier 35 is stabilized, the CPU recognizes the presence of the contactless card 61. ing.
Therefore, between the ground station and the contactless card 61,
Reliable communication processing becomes possible, and high communication reliability can be obtained. In addition, the device is resistant to external noise.

Further, since the non-contact card 61, including the SAW device 62 used therein, is entirely composed of passive components, a battery is not required and a semi-permanent operation is possible. Therefore, it is possible to prevent the complexity of the process associated with battery replacement and the reduction in communication reliability due to a decrease in power supply voltage.

Further, since the SAW device 62 can be manufactured in the same process as a semiconductor, it is possible to realize mass production and low cost. Therefore, the cost of the moving object identification device according to the present invention is reduced.

Further, when the timing of the signal output from the CPU is not pseudo-randomly transmitted but is pseudo-randomized and transmitted, the device is less likely to be affected by periodically generated noise and the like.

[0033]

As explained above, according to the present invention,
By determining the presence or absence of the non-contact card, it is possible to reliably identify whether the passing vehicle is a special vehicle or a general vehicle. In addition, the charge is stored in the charge storage means by a signal received after a predetermined delay time from the contactless card, and the magnitude of the threshold voltage of the predetermined level is compared with the voltage stored in the charge storage means. As a result, by detecting the presence of the contactless card after the received signal is stabilized, reliable communication processing can be performed, and high communication reliability can be obtained. Further, since an inexpensive surface acoustic wave element is used in the non-contact card, the cost of the device can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a ground station in a mobile object identification device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a timing circuit in the embodiment.

FIG. 3 is an exemplary view showing the inside of the non-contact card according to the embodiment.

FIG. 4 is an exemplary view for explaining waveforms of respective components in the ground station when a contactless card is present in a communication area of an antenna at a tollgate in the embodiment.

FIG. 5 is an exemplary view for explaining waveforms at respective components in the ground station when a contactless card does not exist in the communication area of the antenna at the tollgate in the embodiment.

FIG. 6 is a diagram showing a conventional toll collection system using a contactless IC card.

FIG. 7 is a configuration diagram of the conventional non-contact IC card.

[Explanation of symbols]

 21 Local oscillator 22, 26, 33 Amplifier 23, 27, 30, 41 PIN diode switch 24 Timing circuit 28 Circulator 29 Antenna 31, 40 Logic inversion circuit 32 Low noise amplifier 34 Detector 35 IF amplifier 36 Buffer 37 Capacitor 38, 39 Diode 42 Analog switch 43 Comparator 44 Reference voltage generator 51 Oscillator 52 Inverter 53 AND circuit 54 Monostable 55, 56 Flip-flop 61 Non-contact card 62 SAW device 63 Antenna

────────────────────────────────────────────────── (5) References JP-A-7-43458 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04B 5/00 G01S 13/78 G07B 15 / 00 G08G 1/017

Claims (1)

(57) [Claims] 1. A signal which is mounted on a vehicle, receives a signal sent from outside, and generates a predetermined delay time, and a signal equivalent to the reception signal to the outside after the delay time A contactless card that transmits a signal, an oscillating unit that is provided in a ground station that communicates with the contactless card and outputs a carrier wave, and an output unit that sends a predetermined signal based on the carrier wave output by the oscillating unit And transmitting a signal from the output means to the contactless card,
Wireless communication means for receiving a signal sent from the non-contact card; charge storage means for storing charge based on the signal received by the wireless communication means; Comparing means for comparing the threshold voltage of the non-contact card, a determining means for determining the presence or absence of the non-contact card based on a signal output from the comparing means, and a charge stored in the charge storing means. And a reset means for discharging the electric field.