JPH09304522A - Discrimination apparatus for moving body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a discrimination apparatus by which also information on a position in a direction at a right angle to the advance direction can be obtained by forming derivations in a direction at a right angle to the advance direction of two responders, whose subcarrier is different, respectively on the basis of a movement speed. SOLUTION: When a derivation in a direction at a right angle to the advance direction is to be found, a subcarrier for FSK modulation is set at 'f1' in a responder 51a, and a subcarrier for FSK modulation is set at 'f2' in a responder 51b. Consequently, demodulation circuits 9, 18 perform FSK demodulation operations respectively at the subcarriers 'f1', 'f2', and they discriminate the responders 51a, 51b. In addition, since the changeover time of an I/Q changeover signal is different between the two responders 51a, 51b, it is measured separately by a time measuring circuit 20. As a result, when derivations in a direction at a right angle to the advance direction of the two responders 51a, 51b whose subcarrier is different are found on the basis of a movement speed, it is possible to obtain information on a position in a direction at a right angle to the advance direction.

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 more particularly to a moving body identifying apparatus capable of detecting a position in a two-dimensional direction.

[0002]

2. Description of the Related Art A conventional mobile body identification device detects the presence or absence of the transponder by communicating with a transponder existing within the communicable area of the interrogator. However, this could not identify the location information.

FIG. 4 is an explanatory diagram showing an application example in which road position information is obtained by using a conventional moving body identifying apparatus. In FIG. 4, 1 is a truck which is a moving body, 50 is an interrogator mounted under the floor of the truck 1, and 51 is a transponder installed on the road.

Road position information is stored in advance in the responder 51. Truck 1 is moving on the road and responding device 51
Road data is obtained by reading the data from.

FIG. 5 is a block diagram showing an example of such a conventional moving body identifying apparatus. 5, 2 is an oscillator, 3 is a switch circuit, 4, 5 and 13 are antennas, 6 and 7 are mixers, 8 is a phase shifter, 9 is a demodulation circuit, 1
Reference numeral 0 is a comparison circuit, 11 is a time measurement circuit, 12 and 16 are control circuits, 14 is a detection circuit, 15 is a starting circuit, and 17 is a modulation circuit.

2-12 are interrogators 50, 13-1
7 is a transponder 51, and 6 to 8 are homodyne detection circuits 52.
2 to 4 are transmitting means 53, and 5 to 11 are receiving means 54.
Respectively.

In the interrogator 50, the output of the oscillator 2 is connected to the switch circuit 3 and one of the input terminals of the mixers 6 and 7, and the output of the switch circuit 3 is connected to the antenna 4.

The output of the antenna 5 is connected to the other input terminal of the mixer 6 and the phase shifter 8, and the output of the phase shifter 8 is connected to the other input terminal of the mixer 7. The outputs of the mixers 6 and 7 are connected to the demodulation circuit 9 and the comparison circuit 10, respectively.

The output of the demodulation circuit 9 is connected to the control circuit 12, and the control signal from the control circuit 12 is connected to the control terminal of the switch circuit 3.

Further, the output of the comparison circuit 11 is the demodulation circuit 9
And the time measurement circuit 11, and the output of the time measurement circuit 11 is connected to the control circuit 12.

On the other hand, in the responder 51, the antenna 13
Is connected to the detection circuit 14, and the output of the detection circuit 14 is connected to the starting circuit 15. The output of the starting circuit 15 is connected to the control circuit 16, and the output of the control circuit 16 is connected to the modulation circuit 17. Further, the output of the modulation circuit 17 is connected to the antenna 13.

The operation of the conventional example shown in FIG. 5 will be described. The interrogator 50 radiates the output signal of the oscillator 2 as an interrogation wave to the responder 51 via the switch circuit 3 and the antenna 4 without being modulated.

The responder 51 detects the interrogation wave by the antenna 13 and the detection circuit 14 and outputs it to the starting circuit 15.
The activation circuit 15 activates the control circuit 16 and the like when detecting the interrogation wave.

The control circuit 16 controls the subcarrier frequency based on the position information stored in advance in the modulator 17.
FSK (frequency shift keying) modulation is applied by f1 ".

Further, the FSK-modulated modulator 17
In the antenna 13, the unmodulated interrogation wave is subjected to BPSK (binary phase shift keying) modulation and reflected as an answer wave toward the interrogator 50.

This response wave is received by the antenna 5 and BPSK demodulated by the homodyne detection circuit 52, and FSK demodulated by the subcarrier frequency "f1" in the demodulator 9 and position information and the like are output to the control circuit 12.

Further, the operation of obtaining position information in the traveling direction will be described with reference to FIG. FIG. 6 is a timing chart for explaining the operation of the conventional example shown in FIG. 5, and (a) and (b) are “Ich signal” and “Q” which are output signals of the mixers 6 and 7.
ch signal ", (c) is the I / Q switching signal which is the output signal of the comparison circuit 10, and (d) is the output signal of the time measurement circuit 11.

As shown in FIGS. 6A and 6B, 90
The signal intensity of the “Ich signal” and the “Qch signal”, which are out of phase with each other, changes depending on the distance between the interrogator 50 and the responder 51.

Specifically, "Ich signal" and "Qch signal" are provided for each quarter wavelength of the carrier frequency of the interrogator 50.
The magnitude relationship of the signal strength of changes alternately. Therefore, the demodulation circuit 9 is based on the signal detected by the comparison circuit 10.
The Ich signal "or" Qch signal "is selected and demodulated.

That is, the channels are switched as shown in FIG. 6 (c). As can be seen from FIG. 6C, the switching interval becomes longer as the interrogator 50 gets closer to the responder 51, and the channel is hardly switched directly above the responder 51.

The time measuring circuit 11 sequentially measures the switching time of the I / Q switching signal, and the time "Tn-
1 ”,“ Tn ”,“ Tn + 1 ”, etc. are sequentially output to the control circuit 12.

The control circuit 12 obtains the time when it passed directly above the responder 51 based on the two sections in which the switching time is maximum.

For example, in FIG. 6 (d), "Tn" and "Tn +"
Interrogator 5 based on "1" and "Tm" and "Tm + 1"
The time "T" when 0 passes directly above the responder 51 is T = ((Tn + Tn + 1) / 2 + (Tm + Tm + 1) / 2) / 2 (3).

As a result, the interrogator 50 causes the interrogator 50 to respond based on the two sections in which the switching time of the I / Q switching signal is maximum.
The position information in the traveling direction can be accurately obtained by obtaining the time when the vehicle passes just above 1.

[0025]

However, in the conventional example as shown in FIG. 5, the position information of the transponder 51 regarding the traveling direction can be obtained, but the position information in the direction perpendicular to the traveling direction cannot be obtained. There was a problem that I said. Therefore, the problem to be solved by the present invention is to realize a moving body identification device that can also obtain position information in a direction perpendicular to the traveling direction.

[0026]

In order to achieve such a problem, according to the present invention, an interrogator and a transponder that modulates an interrogation wave from the interrogator based on data and reflects it as a response wave are provided. In the constructed mobile body identification device, two transponders having different subcarriers that transmit the position information of each installation point as a response wave when the interrogation wave is received, and a transmitting unit that communicates with these transponders. , The above 2
A homodyne detection circuit that detects the response waves of each of the two transponders, two demodulation circuits that demodulate each of the two transponders, and the signal strengths of the homodyne-detected two signals that are 90 degrees out of phase with each other. Two comparators for comparing each responder, two time measuring circuits for respectively measuring the switching time of the output signals of the two comparators, controlling the transmitting means, passing time at the responder installation point, and It is characterized by comprising an interrogator composed of a control circuit for obtaining position information in a direction orthogonal to the traveling direction.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of the moving body identifying apparatus according to the present invention.

In FIG. 1, reference numerals 2 to 12, 52 and 53 are the same as those in FIG. 5, 13a and 13b are antennas, 14a and 14b are detection circuits, 15a and 15b are start-up circuits, and 16a and 16b are control circuits. Circuit, 17a and 1
7b is a modulation circuit, 18 is a demodulation circuit, 19 is a comparison circuit, 2
0 is a time measuring circuit, and 100 is a moving speed signal.

2-12, 18, 19 and 20 are interrogators 50a, 13a-17a are transponders 51a, 13
b to 17b constitute a responder 51b, and 5 to 11, 18, 19 and 20 constitute a receiving means 54a.

Regarding the connection relationship, the responders 51a and 51b
Is the same as that of the responder 51 shown in FIG.

In the interrogator 50a, the output of the oscillator 2 is connected to the switch circuit 3 and one of the input terminals of the mixers 6 and 7, and the output of the switch circuit 3 is connected to the antenna 4.

The output of the antenna 5 is connected to the other input terminal of the mixer 6 and the phase shifter 8, and the output of the phase shifter 8 is connected to the other input terminal of the mixer 7. The outputs of the mixers 6 and 7 are connected to the demodulation circuits 9 and 18 and the comparison circuits 10 and 19, respectively.

The outputs of the demodulation circuits 9 and 18 are the control circuit 12
The control signal from the control circuit 12 is connected to the control terminal of the switch circuit 3. In addition, the moving speed signal 10
0 is input to the control circuit 12.

Further, the output of the comparison circuit 10 is the demodulation circuit 9
And the time measurement circuit 11, and the output of the time measurement circuit 11 is connected to the control circuit 12. In addition, the comparison circuit 19
Is connected to the demodulation circuit 18 and the time measuring circuit 20, and the output of the time measuring circuit 20 is connected to the control circuit 12.

The operation of the embodiment shown in FIG. 1 will be described with reference to FIGS. 2 and 3. However, the method of obtaining the position information in the traveling direction is similar to that of the conventional example shown in FIG.

As shown in FIG. 2, a truck 1 which is a moving body.
An interrogator 50a is installed under the floor of the vehicle, and two transponders 51a and 51b are installed on the road.

In the receiving means 54a, 9 to 11 take in the information from the responder 51a and 18 to 20 take in the information from the responder 51b, and the operation is basically the same. Therefore, for the sake of simplicity, the description will be made regarding the acquisition of information from the responder 51a.

As shown in FIG. 3, the deviation between the transponder 51a and the truck 1 which is a moving body in the direction perpendicular to the traveling direction is "Lx", and the moving speed of the truck 1 is "Vtruck". The switching time is "Tn-
1 ”and“ Tn ”, and the transit time of the transponder 51a is set to“ Ttran
s ″, L2 = (Tn-Ttrans) / Vtruck (4) L1 = (Tn-1-Ttrans) / Vtruck (5).

As described above, since the switching time changes every quarter wavelength of the carrier frequency of the interrogator 50, {(Lx ² + L2 ² ) ^1/2 + λ / 4} ² = L1 ² + Lx ² ( 6) is established.

From equation (6), the shift "L" in the direction perpendicular to the traveling direction of the responder 51a and the track 1 which is a moving body.
x ″ is Lx = [{2 / λ · (L1 ² −L2 ² − (λ / 4) ² } ^2- L2 ² ] ^1/2 (7).

However, as it is, it is not possible to know which of the "right" and the "left" the deviation "Lx" in the direction perpendicular to the traveling direction is.

Therefore, the shift "Ly" in the direction perpendicular to the traveling direction is obtained by using the second responder 51b as described above. In this case, the responder 51a sets the subcarrier for FSK modulation to "f1", and the responder 51b sets the subcarrier for FSK modulation to "f2".

Therefore, the demodulation circuits 9 and 18 discriminate the responders 51a and 51b by performing FSK demodulation on the subcarriers "f1" and "f2", respectively. Also, I
The time for switching the / Q switching signal is also two transponders 51a.
And 51b are different from each other, so that they are separately measured by the time measuring circuit 20 and used for the calculation such as the equation (7).

As a result, the shifts "Lx" and "Ly" in the direction perpendicular to the traveling direction of the two transponders 51a and 51b having different subcarriers are obtained based on the moving speed, and the positions in the direction orthogonal to the traveling direction are obtained. It becomes possible to obtain information.

In order to reduce the influence of noise or the like, a plurality of measuring times may be used instead of the measuring time of two points.

Further, it is possible to use only one antenna for the interrogator by switching the input / output of the switch circuit 3, the mixer 6 and the phase shifter 8 using a circulator.

[0047]

As is apparent from the above description,
The present invention has the following effects. By obtaining the shifts of the two transponders having different subcarriers in the direction perpendicular to the traveling direction based on the moving speed, it is possible to realize a moving body identification device that can also obtain position information in the direction orthogonal to the traveling direction.

[Brief description of drawings]

FIG. 1 is a configuration block diagram showing an embodiment of a moving body identifying apparatus according to the present invention.

FIG. 2 is an explanatory diagram showing an application example in which road position information is obtained by using the mobile body identification device according to the present invention.

FIG. 3 is an explanatory diagram showing the operation of the embodiment.

FIG. 4 is an explanatory diagram showing an application example in which road position information is obtained using a conventional mobile body identification device.

FIG. 5 is a configuration block diagram showing an example of a conventional mobile body identification device.

FIG. 6 is a timing diagram illustrating an operation of a conventional example.

[Explanation of symbols]

 1 Track 2 Oscillator 3 Switch Circuit 4, 5, 13, 13a, 13b Antenna 6, 7 Mixer 8 Phase Shifter 9, 18 Demodulation Circuit 10, 19 Comparison Circuit 11, 20 Time Measurement Circuit 12, 16, 16a, 16b Control Circuit 14, 14a, 14b Detection circuit 15, 15a, 15b Starting circuit 17, 17a, 17b Modulation circuit 50, 50a Interrogator 51, 51a, 51b Responder 52 Homodyne detection circuit 53 Transmitting means 54, 54a Receiving means 100 Moving speed signal

Claims (1)

[Claims] 1. A mobile body identification device comprising an interrogator and a transponder that modulates an interrogation wave from the interrogator based on data and reflects the interrogation wave as a response wave. Two transponders having different subcarriers for transmitting position information of a point as a response wave, transmission means for communicating with these transponders, and a homodyne detection circuit for detecting the respective response waves of the two transponders. , Two demodulator circuits for demodulating each of the two responders, two comparators for comparing the signal intensities of two signals that are homodyne-detected and 90 degrees out of phase with each other, and the two comparators. Two time measuring circuits for respectively measuring the switching time of the output signal of the comparator, the transmission means, and the position information in the direction perpendicular to the transit time and the traveling direction of the transponder installation point. Mobile identification device characterized by comprising a composed interrogator from the get control circuit.