JP3308093B2 - Train detection 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 train detection device,
In particular, the present invention relates to a system in which an induction loop is laid along a traveling path to detect a train.

[0002]

2. Description of the Related Art Conventionally, an urban traffic type train running on rubber tires does not use a rail for a traveling path, so that it is not possible to employ train detection in which the rail is formed in a part of a track circuit, and an induction loop is used. Train detection is being carried out.

[0003] In this train detection apparatus of the induction loop type, an induction loop (hereinafter, referred to as a loop) including a loop coil having a predetermined length along a traveling path is laid, and a signal is transmitted from the vehicle (train) to the loop. It is configured to be sent.

[0004] Therefore, on the ground side, when a predetermined signal is received from the loop, it is possible to detect that the train is located on the guidance loop.

[0005] Further, in the conventional loop type train detection device, a signal wave suppression system is adopted in order to achieve fail-safe performance. In this method, a transmitter that constantly supplies a predetermined check signal consisting of a normal analog single frequency or AM modulated wave is provided at the beginning of the loop, and the check signal is always detected at the end of the loop. A receiver is provided. Then, when a train enters this loop and a signal from the vehicle is superimposed, the check signal is suppressed to become no signal, and train detection is performed by detecting this no signal.

However, the conventional loop-type train detection device has a problem that the S / N is poor. This is because a train line is laid near the loop and noise increases. If the S / N ratio is deteriorated, there is a problem that the train is detected only when the train approaches, before the train exists in the loop. For this reason, measures such as increasing the signal output to improve the S / N have been taken.
Increasing the signal output has resulted in a new problem of increased power consumption.

In order to solve the above-mentioned problems, the present applicant has applied a spread spectrum communication system disclosed in Japanese Patent Application Laid-Open No. 5-294241 to improve the S / N ratio of a train position. Equipment is provided. The train position detecting device according to the earlier proposal is configured to detect the PN code transmitted from the terrestrial transmitting unit and the on-vehicle transmitting unit by the terrestrial receiving unit, and to have excellent noise resistance. Can be.

[0008]

By the way, the train position detecting device according to the above-mentioned proposal can detect a train position with good noise resistance, but does not have a function of detecting the traveling direction of the train. It has been desired that the train direction detection can be performed with good noise resistance.

SUMMARY OF THE INVENTION The present invention has been made in order to meet the above-mentioned demand, and has as its object to apply a spread spectrum communication system to improve the S / N ratio capable of detecting the direction of a train as well. It is to provide a device.

[0010]

In order to achieve the above object, a train detecting apparatus according to the present invention comprises a spreading means for spreading a pair of predetermined transmission signals having a predetermined frequency difference with a predetermined PN code. Ground signal supply means for alternately supplying a pair of spread signals spread by the spread means to a start end of a loop laid along a train travel path with an interval of at least one chip of the PN code; The same transmission signal as the pair of predetermined transmission signals is spread using the same PN code as the PN code, and one of the spread signals is continuously transmitted from the position on the traveling direction side of the train to the loop. On-board signal supply means for continuously transmitting the other signal subjected to the diffusion processing to the loop from a position at a predetermined distance away from a position on the traveling direction side of the train from a position behind the train,
Receiving means for receiving a signal from the end of the loop, first demodulating means for demodulating a signal received by the receiving means with the same signal as one of the pair of predetermined transmission signals, and receiving by the receiving means A second demodulation means for demodulating the demodulated signal with the same signal as the other of the pair of predetermined transmission signals, and a PN code using the same PN code as the PN code from the signal demodulated by the first demodulation means. First P to extract sign
N code extracting means, and using the same PN code as the PN code from the signal demodulated by the second demodulating means,
A second PN code extracting means for extracting a code;
When the code extracting means extracts the PN code at a predetermined cycle or more, it is determined that the train has entered the loop, and when the second PN code extracting means extracts the PN code at the predetermined cycle or more, Determining means for determining that the train is about to enter the loop.

In addition, there is provided an inspection signal generating means for outputting a predetermined inspection signal based on the PN code extracted by the first PN code extraction means and the second PN code extraction means, The determination of the determination means is performed by using. Then, the frequency difference is (spread bandwidth) ÷ (number of chips of PN code × 2) × n (where n
≧ 1). Further, the above n =
1, 2, 3,...

[0012]

In the above configuration, signals obtained by spreading two transmission signals (carriers) having different frequencies with the same PN code are alternately and intermittently supplied from the loop start end. Also, a signal obtained by spreading the same signal as the two transmission signals with the same PN code as the PN code is continuously supplied from the vehicle (train).

The signals at the end of the loop received via the receiving means are processed by the first and second demodulating means, respectively, and the PN code is extracted by the first and second PN code extracting means, respectively. Then, the determination means determines whether the first P
When the N code extracting means extracts the PN code at a predetermined cycle or more, it is determined that the train has entered the loop, and when the second PN code extracting means extracts the PN code at the predetermined cycle or more, the train is It is determined that the user is about to advance from the loop.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a train detection device according to one embodiment, in which a loop P is formed by a loop-shaped coil having a length forming one block section, and is laid along a traveling path (not shown). ing.

A terrestrial transmission unit A is provided at the start end PS of the loop P, and a terrestrial reception unit B is provided at the end PR.

The terrestrial transmission unit b includes a carrier generator 1 for generating a transmission signal having a predetermined frequency (hereinafter, referred to as a carrier).
a and a predetermined second frequency having a predetermined frequency difference from the frequency of the first carrier (f1) transmitted from the carrier generator 1a.
A carrier generator 1b for generating a carrier (f2), and an intermittent signal for generating an intermittent signal that maintains an interval of one chip or more of a PN code (PN1) described later (three times the PN code (PN1) in this embodiment). A signal generator 2, a first carrier (f1) and a signal from the intermittent signal generator 2 are input, and a second carrier (f1) is input.
2) and a pair of AND circuits 3a and 3b for inputting signals from the intermittent signal generator 2, an OR circuit 4 for inputting the outputs of both AND circuits 3a and 3b, and a PN for generating a predetermined PN code (PN1). A code generator 5, a spreading circuit 6 for spreading the PN code (PN1) from the PN code generator 5, and an amplifier for amplifying the spread signal;
And a transmitter 7 for supplying to the start-end side PS.

The terrestrial receiving unit b receives the signal input from the terminal side PR of the loop P via the transformers T, T
Demodulators 11a and 11b that perform multiplication processing (demodulation processing) using signals from signal generators 10a and 10b that generate signals (f1 and f2) having the same frequency as the second carrier (f1 and f2) and demodulate the signals. The outputs of the demodulators 11a and 11b are input through low-pass filters 12a and 12b, respectively, and the same type of PN code (PN1) as the PN code (PN1) is input from a PN code generator 13 to provide a demodulator 11a. , 11b from the output of the PN code (PN
1), and a matched matched filter 14a, 14b for detecting (extracting)
flip-flop circuits 15a and 15b triggered by respective outputs of
a, 16b, detection circuits 17a, 17b, level determination circuits 18a, 18b,
a, an input of the OR circuit 19 and the flip-flop circuit 1 connected to the output side of the OR circuit 19
5c, a bandpass filter 16c, and a detection circuit 17c
, A level determination circuit 18c, and each level determination circuit 18
a, 18b, and 18c are respectively connected to an entrance detection relay (IN), an advance relay (OUT), and a check relay (CH).

[0018] The first on-vehicle transmitter c is a leading car a of the train a.
1, a carrier generator 20a for generating a carrier (f1) having the same frequency as the carrier generator 1a;
A PN code generator 21a for generating the same type of PN code (PN1) as the PN code generator 5;
A spreading circuit 22a for performing spreading processing with a code (PN1);
And a transmitter 23a for transmitting the signal to the loop P through the transmission line 23.

The second on-vehicle transmission unit d is a rear vehicle a of the train a.
2, a carrier generator 20b for generating a carrier (f2) having the same frequency as the carrier generator 1b;
A PN code generator 21b for generating the same type of PN code (PN1) as the PN code generator 5;
A spreading circuit 22b for performing spreading processing with a code (PN1);
2 and a transmitter 23b for transmitting the signal to the loop P through the loop 23.

Before describing the train detection operation of the apparatus of this embodiment, the difference between the frequencies of both carrier waves (f1, f2) and the extraction of the PN code will be described with reference to FIGS.

[0021] FIG. 2 (a), in FIG. 1, by using the first carrier (f1) demodulates the demodulation circuit 11a, furthermore, represents the PN code (PN1) when treated with a low-pass filter 12a . That is, the demodulation circuit 11a
Is expanded with the PN code (PN1) supplied from the starting end PS.
Scattered signal is input, and this input signal is
Indicates the state when demodulated using one carrier (f1)
ing.

[0022] In contrast, FIG. 2 (b), as shown in FIG. 1 smell
Te, the second carrier (f2) by using the demodulation processing by the demodulation circuit 11a, are tables the PN code that has been extracted by further treatment with a low-pass filter 12a. That is, the demodulation circuit 11
a is the PN code (PN1) supplied from the starting end PS.
The signal spread in is input, and this input signal is
Indicates the state when demodulated using two carriers (f2)
ing. The PN code shown here has the shape shown in FIG.
As is clear from FIG. 5, a waveform (PN1 ') amplitude-modulated by a sine wave of the difference | (f1)-(f2) | between the frequencies of the first carrier (f1) and the second carrier (f2). Become.

The PN code (PN) of the amplitude-modulated waveform
1 ′) is correlated by the correlation matched filter 14a .
As shown in FIG. 3, it can be seen that the frequency difference increases or decreases or fluctuates depending on the frequency difference.

As is apparent from FIG. 3, when there is no frequency difference, that is, when the first carrier (f1) in the transmitting and receiving sections A and B in the embodiment of FIG.
It can be seen that the maximum correlation value is obtained. Then, as the difference increases, the correlation value rapidly decreases.

Therefore, in the apparatus of the present invention, even if there is a leakage signal, if the frequency difference between the two carriers is greater than a predetermined value, the frequency difference between the two carriers can be detected without being affected by the other carrier. The difference is expressed as (spread bandwidth) ÷ (P
The number of chips of N code × 2) × n (where n ≧ 1).

Hereinafter, the train detection operation of the apparatus of this embodiment will be described with reference to the time charts of FIGS. In these figures, 〜 is a waveform of a portion indicated by 〜 in FIG.

First, a case where the train a does not exist on the loop P will be described with reference to FIG.

A signal spread with a PN code (PN1) is intermittently supplied from the terrestrial transmission unit A to the starting end PS of the loop P. Then, from the terminal side PR of the loop P, the signal is received by the terrestrial receiving unit b, and the demodulator 11
When demodulated by a and 11b, a signal containing a PN code (PN1) is extracted. When this extracted signal is processed by the correlation matched filters 14a and 14b, respectively, FIG.
A pulse signal is output every time the PN code (PN1) is detected, as shown in FIG.

Each flip-flop circuit 15a to 15c
Outputs a signal having a frequency corresponding to the pulse signal. Each band-pass filter 16a, 16b is a filter that does not pass the frequency, so that each relay (IN, OUT) keeps the OFF state, and gives an output without a train on a loop P to a monitoring panel (not shown). .
The band-pass filter 16c is a filter that allows the frequency to pass therethrough, thereby keeping the CH relay operating, checking that no train is present on the loop P, and that the loop is not broken.

When the leading vehicle a1 of the train a enters the loop P, the ground receiving unit B receives not only the signal from the ground transmitting unit A but also the signal from the first vehicle transmitting unit C. Is done.

That is, since a continuous spread signal spread by the spread circuit 22a is transmitted from the antenna A1, the correlation matched filter 14a outputs the first on-vehicle transmitter C in addition to the pulse shown in FIG. The pulse corresponding to the PN code (PN1) is also detected, as shown in FIG. The frequency at this time is four times that of FIG. 4 and eight times that of FIG. Therefore, the entry relay (IN) is turned on, and the checking relay (CH) is turned off. In such an operation state, an output indicating that the train a has entered the loop P is given to the monitoring panel.

When the train a is present in the loop P, the ground receiving unit b also receives signals from the first and second on-board transmitting units c and d in addition to the signal from the above-mentioned ground transmitting unit b. Received.

That is, since continuous spread signals spread by the spreading circuits 22a and 22b are transmitted from the antennas A1 and A2, the correlation matched filters 14a and 14b are transmitted.
At b, in addition to the pulse shown in FIG. 4, a pulse corresponding to the PN code (PN1) from the first and second on-vehicle transmitters c and d is also detected, as shown in FIG. The frequency at this time is 4 in FIG.
4 times that of FIG. Therefore, each relay (I
N, OUT) turns ON, and the check relay (CH) turns off.
It becomes F. In such an operation state, an output indicating that the train a exists in the loop P is given to the monitoring panel.

When the leading vehicle a1 of the train a advances from the loop P, the ground receiving unit B receives a signal from the second on-vehicle transmitting unit D in addition to the signal from the ground transmitting unit A.

That is, since a continuous spread signal spread by the spreading circuit 22b is transmitted from the antenna A2, the correlation matched filter 14b outputs a signal other than the pulse shown in FIG. A pulse corresponding to the PN code (PN1) is also detected, as shown in FIG. The frequency at this time is four times that of FIG. 4 and eight times that of FIG. Therefore, the advance relay (OUT) is turned on, and the check relay (CH) is turned off. In such an operation state, an output indicating that the train a is about to advance from the loop P is given to the monitoring panel.

As described above, the train detecting apparatus according to the present embodiment detects the PN code transmitted from the ground transmitting unit A, the first and second on-board transmitting units C and D by the ground receiving unit B. Not only train position detection, but also train direction detection can be performed in a state where the S / N is extremely good.

In the above-described embodiment, the checking relay (CH) is driven by the outputs of the two correlation matched filters 14a and 14b, and this is combined with the entry relay (IN) or the exit relay (OUT) to perform train detection. However, the control relay (CH) is used for detecting breakage of the loop, and the train is detected by the entry relay (IN) and the exit relay (OU).
T). However, this check relay (CH)
If the train detection is performed in combination with the entry relay (IN) or the entry relay (OUT), the reliability can be further improved.

[0038]

According to the present invention, the PN code transmitted from the terrestrial transmitter and the first and second on-vehicle transmitters is detected and detected by the terrestrial receiver. The direction of the train can be detected below. Further, when the train detection is performed under the control signal, the reliability can be improved. Further, when the frequency difference between the two carriers is equal to or more than a predetermined value, it is possible to prevent the mutual interference and perform the train detection.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a train detection device according to one embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining a PN code in an interference state.

FIG. 3 is a graph showing a correlation value of a PN code in an interference state.

FIG. 4 is a time chart when a train does not exist in a loop.

FIG. 5 is a time chart when the leading vehicle enters the loop.

FIG. 6 is a time chart when a train exists in a loop.

FIG. 7 is a time chart when the leading vehicle advances from the loop.

[Explanation of symbols]

 1a, 1b Transmission signal generator 3a, 3b AND circuit 4 OR circuit 5, 13, 21a, 21b PN code generator 6, 22a, 22b Spreading circuit 11a, 11b Demodulator 14a, 14b Correlation matched filter 15a-15c Flip-flop circuit 16a to 16c Band pass filter 17a to 17c Detection circuit 18a to 18c Level judgment circuit 19 OR circuit P Induction loop (loop) PS Start end side PR Termination side IN Entry detection relay OUT Entry detection relay CH Review relay A Ground transmission unit B Ground reception Part C First vehicle transmission part D Second vehicle transmission part

Claims (4)

(57) [Claims] 1. A spreading means for spreading a pair of predetermined transmission signals having a predetermined frequency difference with a predetermined PN code, and transmitting the pair of spread signals spread by the spreading means to the P signal.
Ground signal supply means for alternately supplying to the starting end side of an induction loop laid along the running path of the train while maintaining an interval of one chip or more of N codes, and transmitting the same transmission signal as the pair of predetermined transmission signals. Each spread processing is performed using the same PN code as the PN code, and one of the spread processed signals is continuously transmitted from the position on the traveling direction side of the train to the guidance loop, and the other of the spread processed other signals is transmitted. On-board signal supply means for continuously sending a signal to the guidance loop from a position a predetermined distance away from a position on the traveling direction side of the train, and reception means for receiving a signal from the terminal side of the guidance loop. A first demodulation unit that demodulates a signal received by the reception unit with the same signal as one of the pair of predetermined transmission signals, and a signal that is received by the reception unit and is the other of the pair of predetermined transmission signals. Same as A second demodulating means for demodulating the same PN code using the same PN code as the PN code from the signal demodulated by the first demodulating means.
PN code extracting means for extracting the PN code from the signal demodulated by the second demodulating means using the same PN code as the PN code.
When the PN code extracting means and the first PN code extracting means extract the PN code at a predetermined cycle or more, it is determined that the train has entered the guidance loop, and the second PN code extracting means determines that the train has entered at least a predetermined cycle. And a determination means for determining that the train is about to advance from the guidance loop when the PN code is extracted in (1). 2. An inspection signal generating unit that outputs a predetermined inspection signal based on the PN code extracted by the first PN code extraction unit and the second PN code extraction unit, and determines in the presence of the predetermined inspection signal. 2. The train detection device according to claim 1, wherein the means is determined. 3. The train detection apparatus according to claim 1, wherein the frequency difference is (spread bandwidth) ÷ (number of chips of PN code × 2) × n (where n ≧ 1). . 4. The method according to claim 1, wherein the frequency difference is (spread bandwidth) ÷ (number of chips of PN code × 2) × n (where n = 1, 2, 3,...). The train detection device as described.