JP2007168676A - Train detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To certainly detect a spectrum-diffusion-modulated train detection signal by a receiving part and to enhance transmission efficiency. <P>SOLUTION: A PN code generated in a receiver 2a is fed to a diffusion recovery part 14 according to an output of a matching filter 12 for generating an output signal at each one period of a diffusion code transmitted by a transmitter from a received signal wave, and the received wave is diffusion-modulated by using the same PN code as the transmitter 1a. Thereby, the train detection signal transmitted from the transmitter 1a is certainly detected by the receiver 2a and a time required for synchronous capturing is shortened to enhance transmission efficiency. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a train detection device that detects the presence or absence of a train using a spread spectrum communication system, and more particularly to improvement of stability and transmission efficiency of train detection.

  The track circuit in a railway divides the rail into a predetermined length to form an electric circuit, transmits a train detection signal from the boundary of the track circuit on the train entry side, and trains of a predetermined level at the boundary of the track circuit on the train entry side When the detection signal is received, it is determined that the train is not on the track circuit, the train enters the track circuit, the rail is short-circuited by the axle, and the train detection signal received is below a certain level. When it becomes, it is determined that the train is on the track circuit.

  When the train detection signal is transmitted to this track circuit, the harmonics of the operating current are extremely strong in the case of the AC electrification section. In order to detect a train without being affected by harmonic noise or the like of this operating current, a train detection device using a spread spectrum communication method is disclosed in Patent Document 1, Patent Document 2, Patent Document 3, and the like. ing. The train detection device using this spread spectrum communication system, the train detection signal from the transmission unit is spread spectrum modulated with a pseudo noise code (hereinafter referred to as PN code), spread to a wide frequency band and transmitted to the rail, the reception unit Receives a spectrum-spread signal sent to the rail, and spread-modulates the received signal using the same PN code as the transmitter. When spread modulation is performed using this PN code, the noise signal mixed in the received signal is spread in spectrum, and the train detection signals are collected in the original frequency band and returned to the original train detection signal generated in the transmitter. It is. By removing the noise component from the spread-modulated signal through a narrow bandpass filter, a transmitted train detection signal is obtained.

In order to obtain a train detection signal by performing spread modulation in this receiving unit, it is necessary to match the phase of the PN code to be spread modulated with the phase of the received PN code. A received signal spread-modulated using a PN code has a very small S / N ratio, and the synchronization timing cannot be extracted from the received signal by a normal method. Therefore, the PN code of the receiving unit is changed to the time series of the PN code of the received signal. The synchronization acquisition to convert the signal into a narrow-band signal in accordance with the above and the synchronization holding to operate so that the synchronization is not lost even after a lapse of time after the synchronization acquisition is completed.
Japanese Patent No. 3291607 JP-A-9-99836 JP 2004-276761 A

  In order to make the phase of the PN code subjected to spread modulation in the receiving unit coincide with the phase of the received PN code as described above, if the receiving unit is provided with synchronization acquisition means and synchronization holding means, the configuration of the receiving unit becomes very complicated. As a result, synchronization acquisition takes time. Further, in the case of a non-insulated track circuit, at the time of detecting a train in which the track circuit is short-circuited at the train axle, the reception level is lowered, so that synchronization detection by the received signal becomes unstable. In addition, there is a disadvantage that the train detection performance is deteriorated due to the malfunction due to the malfunction due to the interference with the train detection signal transmitted to the adjacent track circuit.

  An object of the present invention is to improve such a disadvantage and to obtain a train detection device capable of reliably detecting a train detection signal subjected to spread spectrum modulation at a transmission unit at a reception unit and increasing transmission efficiency. is there.

The train detection apparatus according to the present invention includes a transmitter connected to one boundary of each track circuit and a receiver connected to the other boundary, and the transmitter includes an information processing unit, a clock signal generation unit, and a diffusion unit. A code generation unit, a spread modulation unit, and a transmission unit; the information processing unit generates a train detection signal having a different frequency for each adjacent track circuit; and the clock signal generation unit is a clock signal having a preset frequency. The spread code generation unit generates different pseudo noise codes (hereinafter referred to as PN codes) in adjacent track circuits based on the clock signal generated by the clock signal generation unit, and the spread modulation unit transmits from the information processing unit. The train detection signal and the PN code generated by the spread code generator are multiplied to generate a spread modulated signal wave, and the transmitter sends out the spread modulated signal wave to the rail,
The receiver includes a receiver, a clock signal generator, a matched filter, a spread code generator, a spread demodulator, a bandpass filter, and a train detector, and the receiver receives a signal wave sent to a rail. The clock signal generator generates a clock signal having the same frequency as the clock signal generator of the transmitter, and the matched filter generates an output signal for each period of the PN code transmitted from the received wave by the transmitter, The spreading code generation unit generates the same PN code as the PN code generated by the transmitter connected to the same track circuit by the clock signal generated by the clock signal generation unit, and outputs the generated PN code to the matched filter In response to the signal, the signal is sent to the spread spectrum demodulator, and the spread spectrum demodulator performs spread modulation on the received wave received by the receiver using the PN code generated by the spread code generator. Has a passband in the frequency band of the train detection signal generated by the transmitter connected to the same track circuit, extracts the train detection signal from the signal wave spread by the spread demodulation unit, the train detection unit It is characterized by detecting whether or not a train is present on each track circuit based on a change in the level of the train detection signal extracted by the pass filter.

Another train detection device of the present invention includes a transmitter connected to one boundary of each track circuit and a receiver connected to the other boundary, and the transmitter includes an information processing unit and a clock signal generation unit. A spread code generator, a spread modulator, and a transmitter, the information processor generates a train detection signal having a different frequency for each adjacent track circuit, and the clock signal generator has a frequency set in advance. A clock signal is generated and sent to the spreading code generator and the receiver, and the spreading code generator is different in a pseudo-noise code (hereinafter referred to as a PN code) in an adjacent track circuit depending on the clock signal generated by the clock signal generator. The spread modulation unit multiplies the train detection signal sent from the information processing unit and the PN code generated by the spread code generation unit to generate a spread modulated signal wave, and the transmission unit performs spread modulation. Sending a signal wave to the rail,
The receiver includes a shift amount storage unit, a reception unit, a clock control unit, a spread code generation unit, a spread demodulation unit, a bandpass filter, and a train detection unit, and the shift amount storage unit includes a rail of each track circuit in advance. Of the PN code generated between the transmitter and the receiver depending on the difference between the length and the cable length between the transmitter and the receiver or the rail length of each track circuit and the connecting cable length between the transmitter and the receiver rail. The phase shift amount detected by measuring the phase shift is stored, the receiving unit receives the signal wave transmitted to the rail, and the clock control unit stores the clock signal transmitted from the transmitter in the shift amount storage unit. The spread code generator is shifted by the phase shift amount, and the same P as the PN code generated by the spread code generator of the transmitter connected to the same track circuit by the clock signal shifted by the clock controller The spread demodulating unit spread-modulates the received wave received by the receiver with the PN code generated by the spreading code generating unit, and the band-pass filter is generated by a transmitter connected to the same track circuit. It has a pass band of the frequency band of the detection signal, extracts the train detection signal from the signal wave spread by the spread demodulation unit, the train detection unit, each by the change in the level of the train detection signal extracted by the band pass filter, It is characterized by detecting whether or not a train is on the track circuit.

  The PN code used in the adjacent track circuit uses a preferred pair M-sequence code whose cross-correlation value is sufficiently smaller than the autocorrelation peak value.

  The present invention relates to a spreading demodulator according to the output of a matched filter that generates an output signal for each period of a spreading code transmitted from a transmitter to a PN code generated by a receiver. Since the received wave is spread and modulated using the same PN code as the transmitter, the train detection signal sent from the transmitter can be reliably detected by the receiver and the time required for synchronization acquisition is reduced. Thus, transmission efficiency can be increased.

  In addition, the phase shift amount detected by measuring the phase shift of the PN code caused by the transmission delay between the transmitter and the receiver is stored in advance in the receiver, and the clock signal generated in the transmitter is stored. Since the received signal wave using the same PN code as the transmitter is spread and modulated with the clock signal shifted by the phase shift amount, the train detection signal sent from the transmitter can be reliably detected by the receiver. Therefore, it is possible to increase transmission efficiency by eliminating the time required for synchronization acquisition.

  Further, since different PN codes are used in adjacent track circuits and train detection signals having different frequencies are used in adjacent track circuits, interference with signal waves sent to adjacent track circuits can be reduced.

  Furthermore, by using a preferred pair M-sequence code whose cross-correlation value is sufficiently smaller than the peak value of autocorrelation as a PN code used in the adjacent track circuit, a signal sent to the adjacent track circuit is used. Interference with waves can be further reduced.

  FIG. 1 is a layout diagram of the train detection apparatus of the present invention. As shown in the figure, the train detection apparatus has a transmitter 1 connected to the boundary on the train entry side of each track circuit 1T to 6T and a receiver 2 connected to the boundary on the train advance side.

  As shown in the block diagram of FIG. 2, the transmitter 1 includes an information processing unit 3, a clock signal generation unit 4, a spread code generation unit 5, a spread modulation unit 6, a band pass filter (BPF) 7, and a transmission unit 8. . The information processing unit 3 generates a train detection signal including each track circuit ID and sends the train detection signal to the spread modulation unit 6. The frequency of the train detection signal is at least 2 and different frequencies are used in adjacent track circuits. For example, as shown in FIG. 1, the frequency f1 is used in the track circuit 2T, the frequency f2 is used in the track circuit 3T, and the frequency f1 is used in the track circuit 4T. The clock signal generator 4 generates a clock signal having a preset frequency and sends it to the spreading code generator 5. The spread code generator 5 generates a predetermined wideband pseudo-noise code (hereinafter referred to as PN code) based on the clock signal sent from the clock signal generator 4, and sends the generated PN code to the spread modulator 6. The PN code generated by the spreading code generator 4 uses a preferred pair M-sequence code whose cross-correlation value is sufficiently smaller than the autocorrelation peak value. There are six types of preferred pair M-sequence codes at a period of 127, for example. Different PN codes are used in one group of track circuits. For example, in one group of track circuits 2T to 5T, the track circuit 2T uses PN1, the track circuit 3T uses PN2, the track circuit 4T uses PN3, and the track circuit 5T uses PN4. The spread modulation unit 6 multiplies the train detection signal sent from the information processing unit 3 by the PN code sent from the spread code generation unit 5, and spreads the signal to a frequency band far wider than the frequency band of the train detection signal. Generates a spread modulated signal wave. The BPF 7 removes unnecessary frequency components from the spread-modulated signal wave. The transmission unit 8 sends out the signal wave subjected to the spread modulation to the rail 9.

  The receiver 2 includes a receiver 10, a clock signal generator 11, a matched filter 12, a spread code generator 13, a spread demodulator 14, a narrow band pass filter (BPF) 15, and a train detector 16. The receiving unit 10 receives a signal wave transmitted from the transmitter 1 to the rail 9. The clock signal generator 11 generates a clock signal having the same frequency as that of the clock signal generator 4 of the transmitter 1 and sends it to the spread code generator 13. The matched filter 12 generates an output signal for each period of the spreading code transmitted from the transmitter 1 a from the received wave sent from the receiving unit 10 and sends the output signal to the spreading code generating unit 13. The spread code generator 13 generates the same PN code as the PN code generated in the spread code generator 5 of the transmitter 1 connected to the same track circuit by the clock signal generated in the clock signal generator 11 The transmitted PN code is sent to the spread demodulation unit 14 according to the output signal of the matched filter 12. The spread demodulator 14 performs spread spectrum modulation on the received wave received by the receiver 10 using the PN code sent from the spread code generator 13, spreads the noise signal mixed in the received wave over a wide frequency band, and generates a train detection signal. The signal waves collected in the frequency band are generated. The BPF 15 has a pass band in the frequency band of the train detection signal generated by the information processing unit 3 for each track circuit 2T to 5T, and is transmitted from the signal wave spread by the spread demodulation unit 14 to the track circuit adjacent to the noise component. The detected signal wave is removed, and a train detection signal is extracted and sent to the train detection unit 16. The train detection unit 16 detects whether or not the train 17 is present in each track circuit 2T to 5T based on a change in the level of the transmitted train detection signal.

  The operation when detecting whether or not the train 17 is on the track circuit 2T by the train detection apparatus configured as described above will be described with reference to the waveform diagram of FIG.

  The clock signal generator 4 of the transmitter 1a provided in the track circuit 2T generates a clock signal having a preset frequency and sends it to the spread code generator 5 as shown in FIG. As shown in FIG. 3B, the spread code generator 5 generates a PN code of PN1 determined in advance by the sent clock signal, and sends the generated PN code to the spread modulator 6. The spread modulation unit 6 multiplies the train detection signal of the frequency f1 sent from the information processing unit 3 and the PN code sent from the spread code generation unit 4 to obtain a frequency band far wider than the frequency band of the train detection signal. A signal wave that is spread and spread-modulated is generated and sent to the BPF 7. The BPF 7 removes unnecessary frequency components from the transmitted signal wave and sends the signal wave to the transmission unit 8. The transmission unit 8 sends the transmitted signal wave to the rail 9.

  The receiver 10 of the receiver 2a receives the signal wave transmitted from the transmitter 1a to the rail 9, and sends the received signal wave to the matched filter 12 and the spread demodulator 14. The received reception wave includes a noise signal when propagating through the rail 9 and also includes a signal wave transmitted from the transmitter 1b of the track circuit 3T to the rail 9. As shown in FIG. 3 (e), the matched filter 12 generates an output signal for each cycle of the spread code transmitted by the transmitter 1 a from the transmitted signal wave and sends it to the spread code generator 13. . On the other hand, the clock signal generator 11 generates a clock signal having the same frequency as that of the clock signal generator 4 of the transmitter 1a and sends it to the spread code generator 13, as shown in FIG. As shown in FIG. 3 (d), the spread code generator 13 uses the clock signal sent to the PN of the same PN1 as the PN code generated in the spread code generator 5 of the transmitter 1a connected to the track circuit 2T. A code is generated, and the generated PN code is sent to the spread demodulator 14 by the output signal of the matched filter 12 as shown in FIG. The spread demodulation unit 14 performs spread spectrum modulation on the reception wave received by the reception unit 10 using the PN code sent from the spread code generation unit 13 and spreads the noise signal mixed in the reception wave over a wide frequency band to generate a train detection signal. The signal waves collected in the frequency band are generated. The BPF 15 removes the noise component and the PN code transmitted to the track circuit 3T adjacent to the signal wave spread by the spread demodulation unit 14, extracts the train detection signal having the frequency f 1, and sends the train detection signal to the train detection unit 16. The train detection unit 16 determines that the train 17 is not on the track circuit 2T when the level of the transmitted train detection signal exceeds a preset threshold, and the threshold of the train detection signal is set in advance. When it becomes smaller, it is determined that the train 17 is on the track circuit 2T, and a train presence signal is output.

  Thus, the PN code generated by the receiver 2a is spread according to the output of the matched filter 12 that generates an output signal for each period of the spread code transmitted by the transmitter 1a from the received signal wave. Since it is sent to the demodulator 14 and the received wave is spread and modulated using the same PN code as the transmitter 1a, the train detection signal sent from the transmitter 1a can be reliably detected by the receiver 2a and synchronized. Transmission time can be increased by shortening the time required for acquisition.

  Further, since different PN codes are used in one group of track circuits and train detection signals having different frequencies are used in adjacent track circuits, interference with signal waves sent to adjacent track circuits can be reduced. . Furthermore, if a guard band is provided at the frequency of the train detection signal transmitted to the adjacent track circuit, interference with the adjacent track circuit can be prevented more reliably.

  In the above description, the case where the clock signal generators 4 and 11 that generate clock signals of the same frequency are provided in the transmitter 1 and the receiver 2 has been described. However, an external signal such as an AC signal from the same power source or a GPS time is described. A synchronization signal may be generated from the pulse.

  In the above description, the case where the clock signal generators 4 and 11 are provided in the transmitter 1a and the receiver 2a has been described. However, as shown in the block diagram of FIG. A clock signal may be sent to the receiver 2 via a cable. In this case, the receiver 2a includes a shift amount storage unit 18 and a clock signal control unit 19 in addition to the reception unit 10, the spread code generation unit 13, the spread demodulation unit 14, the BPF 15, and the train detection unit 16. When the installation location of the transmitter 1a and the receiver 2a is separated, the shift amount storage unit 18 corresponds to the difference between the rail length of the track circuit 2T and the cable length for sending the clock signal from the transmitter 1a to the receiver 2a. The phase shift amount detected by measuring the phase shift of the PN code generated between the transmitter 1a and the receiver 2a in advance due to the transmission delay is stored, and the transmitter 1a and the receiver 2a are installed at the same place. The phase of the PN code generated between the transmitter 1a and the receiver 2a with a transmission delay according to the difference between the rail length of the track circuit 2T and the connection cable length between the rail 1 of the transmitter 1a and the receiver 2a. The phase shift amount detected by measuring the deviation is stored. Since the rail length of each track circuit 2T to 5T, the cable length for sending a clock signal, or the connection cable length between the transmitter 1a and the rail 9 of the receiver 2a is known and does not vary, the transmission delay also varies for each track circuit 2T to 5T. This is because it becomes constant. The clock control unit 19 shifts the clock signal sent from the clock signal generation unit 4 of the receiver 1 a by the phase shift amount stored in the shift amount storage unit 18 and sends it to the spread code generation unit 13.

  When this train detection device detects whether or not the train 17 is present on the track circuit 2T, the clock signal generator 4 of the transmitter 1a has a clock with a preset frequency as shown in FIG. 5 (a). A signal is generated and sent to the spread code generator 5, and the spread code generator 5 generates a PN code of PN1 determined in advance by the sent clock signal, as shown in FIG. 5B. The spread modulation unit 6 spreads and modulates the train detection signal of the frequency f1 sent from the information processing unit 3 with the PN code sent from the spread code generation unit 4, and the spread modulated signal wave via the BPF 7 and the transmission unit 8. Send it to the rail 9.

  The receiving unit 10 of the receiver 2 a receives the signal wave transmitted from the transmitter 1 a to the rail 9, and sends the received received wave to the spread demodulation unit 14. On the other hand, as shown in FIG. 5C, the clock control unit 19 shifts the clock signal transmitted from the transmitter 1a by shifting the clock signal by the phase shift amount S (θ) stored in the shift amount storage unit 18. The signal is sent to the spread code generator 13. As shown in FIG. 5 (d), the spread code generator 13 generates a PN of the same PN1 as the PN code generated by the spread code generator 5 of the transmitter 1a connected to the track circuit 2T. A code is generated and sent to the spread demodulation section 14. The spread demodulator 14 performs spread spectrum modulation on the received wave received by the receiver 10 by the PN code sent from the spread code generator 13 to generate a signal wave that collects train detection signals in the original frequency band, and generates The PN code transmitted to the track circuit 3T adjacent to the noise component from the spread signal wave is removed by the BPF 15 to extract the train detection signal of the frequency f1 and send it to the train detection unit 16. The train detection unit 16 determines that the train 17 is not on the track circuit 2T when the level of the transmitted train detection signal exceeds a preset threshold, and the threshold of the train detection signal is set in advance. When it becomes smaller, it is determined that the train 17 is on the track circuit 2T, and a train presence signal is output.

  In this manner, the phase shift amount detected by measuring the phase shift of the PN code generated between the transmitter 1a and the receiver 2a due to the transmission delay in advance is stored in the receiver 2a, and the phase shift amount is shifted by this amount. Since the received signal wave using the same PN code as the transmitter 1a is spread and modulated with the clock signal, the train detection signal sent from the transmitter 1a can be reliably detected by the receiver 2a, and the synchronization acquisition is also possible. Transmission efficiency can be improved by eliminating the time required.

It is a layout view of the train detection device of the present invention. It is a block diagram which shows the structure of a train detection apparatus. It is a wave form diagram which shows the process of a train detection apparatus. It is a block diagram which shows the structure of another train detection apparatus. It is a wave form diagram which shows the process of another train detection apparatus.

Explanation of symbols

1; Transmitter, 2; Receiver, 3; Information processing unit, 4; Clock signal generation unit,
5; spread code generator, 6; spread modulation, 7; BPF, 8; transmitter, 9; rail,
10; receiver, 11; clock signal generator, 12; matched filter,
13; Spreading code generation unit, 14; Spreading demodulation unit, 15; BPF, 16; Train detection unit,
17; train, 18; shift amount storage unit, 19; clock control unit.

Claims (3)

Having a transmitter connected to one boundary of each track circuit and a receiver connected to the other boundary;
The transmitter includes an information processing unit, a clock signal generation unit, a spread code generation unit, a spread modulation unit, and a transmission unit,
The information processing unit generates a train detection signal having a different frequency for each adjacent track circuit, the clock signal generating unit generates a clock signal having a preset frequency, and the spreading code generating unit is a clock signal generating unit Different pseudo-noise codes (hereinafter referred to as PN codes) are generated in adjacent track circuits by the clock signal generated in step 1, and the spread modulation unit generates the train detection signal sent from the information processing unit and the PN generated by the spread code generation unit. A signal wave that is spread-modulated by multiplying by a code is generated, and the transmitter sends out the signal wave that is spread-modulated to the rail,
The receiver includes a receiver, a clock signal generator, a matched filter, a spread code generator, a spread demodulator, a bandpass filter, and a train detector, and the receiver receives a signal wave sent to a rail. The clock signal generator generates a clock signal having the same frequency as the clock signal generator of the transmitter, and the matched filter generates an output signal for each period of the PN code transmitted from the received wave by the transmitter, The spreading code generation unit generates the same PN code as the PN code generated by the transmitter connected to the same track circuit by the clock signal generated by the clock signal generation unit, and outputs the generated PN code to the matched filter In response to the signal, the signal is sent to the spread spectrum demodulator, and the spread spectrum demodulator performs spread modulation on the received wave received by the receiver using the PN code generated by the spread code generator. Has a passband in the frequency band of the train detection signal generated by the transmitter connected to the same track circuit, extracts the train detection signal from the signal wave spread by the spread demodulation unit, the train detection unit A train detection device that detects whether a train is present on each track circuit based on a change in the level of a train detection signal extracted by a path filter. Having a transmitter connected to one boundary of each track circuit and a receiver connected to the other boundary;
The transmitter includes an information processing unit, a clock signal generation unit, a spread code generation unit, a spread modulation unit, and a transmission unit,
The information processing unit generates a train detection signal having a different frequency for each adjacent track circuit, and the clock signal generation unit generates a clock signal having a preset frequency to the spreading code generation unit and the receiver. The spread code generation unit generates a different pseudo noise code (hereinafter referred to as PN code) in the adjacent track circuit based on the clock signal generated by the clock signal generation unit, and the spread modulation unit is sent from the information processing unit Multiply the train detection signal and the PN code generated by the spread code generator to generate a spread modulated signal wave, the transmitter sends out the spread modulated signal wave to the rail,
The receiver includes a shift amount storage unit, a reception unit, a clock control unit, a spread code generation unit, a spread demodulation unit, a bandpass filter, and a train detection unit, and the shift amount storage unit includes a rail of each track circuit in advance. Of the PN code generated between the transmitter and the receiver depending on the difference between the length and the cable length between the transmitter and the receiver or the rail length of each track circuit and the connecting cable length between the transmitter and the receiver rail. The phase shift amount detected by measuring the phase shift is stored, the receiving unit receives the signal wave transmitted to the rail, and the clock control unit stores the clock signal transmitted from the transmitter in the shift amount storage unit. The spread code generator is shifted by the phase shift amount, and the same P as the PN code generated by the spread code generator of the transmitter connected to the same track circuit by the clock signal shifted by the clock controller The spread demodulating unit spread-modulates the received wave received by the receiver with the PN code generated by the spreading code generating unit, and the band-pass filter is generated by a transmitter connected to the same track circuit. It has a pass band of the frequency band of the detection signal, extracts the train detection signal from the signal wave spread by the spread demodulation unit, the train detection unit, each by the change in the level of the train detection signal extracted by the band pass filter, A train detection device for detecting whether or not a train is on a track circuit.   3. The train detection device according to claim 1, wherein the PN code used in the adjacent track circuit is a preferred pair M-sequence code whose cross-correlation value is sufficiently small with respect to the autocorrelation peak value. 4.

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