JP2004101239A - Obstacle detecting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an obstacle detecting apparatus for reliably detecting obstacles by appropriately updating a threshold and reducing erroneous detection. <P>SOLUTION: The obstacle detecting apparatus comprises a means 1 for radiating a transmission spectrum diffusion signal from a transmission LCX2 to a reception LCX3; a measurement distance setting means 4 for generating a control signal for setting delay time; a delay means 5 for generating delay time based on a control signal; a means 6 for generating a reference spectrum diffusion signal having phase timing according to delay time; a correlation means 7 for correlating the reference spectrum diffusion signal and the reception spectrum diffusion signal; and a means 8 for detecting obstacles based on the correlation output. The means 8 comprises: a threshold creation/storage means 81 for creating/storing the threshold based on unattendant time band information and an output level from the correlation means; and a comparison means 82 for detecting obstacles based on the comparison of the threshold level and the output level from the correlation means. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an obstacle detection device that detects the presence and position of an obstacle by using a leaky transmission line such as a leaky coaxial cable or a leaky waveguide using a spread spectrum technique.
[0002]
[Prior art]
In railways, it is necessary to detect obstacles on the railroads promptly and remove them immediately in order to prevent normal train operation and accidents. Further, in order to prevent a rear-end collision accident or a double accident on an expressway, it is necessary to detect a falling object from a truck or the like or an emergency stop vehicle and notify the following vehicle. Because of such a need, there is a device that uses a leaky transmission line such as a leaky coaxial cable or a leaky waveguide as a device for detecting an obstacle on a road or a track. In these leaky transmission lines, slots for leaking and radiating radio waves are arranged at appropriate intervals in the longitudinal direction of the conductor.Since leaky coaxial cables and leaky waveguides are in principle the same, Hereinafter, an apparatus using a leaky coaxial cable (hereinafter, referred to as LCX) will be described.
[0003]
Conventionally, as this kind of obstacle detection device, there has been one having a configuration shown in FIG. 4 (for example, see Patent Document 1). In FIG. 4, 2 is a transmission LCX (leakage transmission line) laid along the road, 3 is a reception LCX (leakage transmission line) laid on the opposite side of the road, and 9 is one end (near end) of the transmission LCX2. A signal generator (transmitter) 10 connected to generate a pulse-modulated signal is a receiver (receiver) connected to one end (near end) on the same side of the receiving LCX 3 to receive the signal.
[0004]
Reference numeral 101 denotes a low-pass filter (hereinafter, referred to as an LPF) included in the receiver 10 for extracting an envelope (hereinafter, referred to as an envelope) from the waveform of the received signal; 102, a storage device that stores an envelope of the signal waveform; Is an arithmetic unit that detects the position of an obstacle using the envelope stored in the storage device 102 and the envelope output from the LPF 101. A non-reflection terminator is connected to each of the far end of the transmission LCX2 and the far end of the reception LCX3.
[0005]
Next, the operation will be described. A pulse signal is generated from the signal generator 9 and input to the transmission LCX2. This pulse signal is sequentially radiated as radio waves from each slot arranged in the longitudinal direction of the transmission LCX2. This radio wave enters from each slot of the reception LCX 3 facing the transmission LCX 2, and the signal incident on the reception LCX 3 is received by the receiver 10. The envelope of the signal waveform received by the receiver 10 is extracted by the LPF 101.
[0006]
The envelope of the signal waveform when there is no obstacle is stored in the storage device 102 in advance as a reference waveform. Each time the envelope of the signal waveform is obtained, the arithmetic unit 103 obtains a difference waveform between the envelope of the signal waveform and the reference waveform. If there is an obstacle, the radio wave is blocked at that position, so that the reception intensity at that position decreases by a certain ratio regardless of the magnitude of the intensity. Therefore, the position of the obstacle appears in the differential waveform.
[0007]
[Patent Document 1]
JP-A-10-95338 (page 3, FIG. 1)
[0008]
[Problems to be solved by the invention]
The conventional obstacle detection device is configured as described above. However, since the received signal fluctuates greatly due to environmental changes such as seasonal and weather conditions and changes over time, the obstacle is reliably detected without erroneous detection. Therefore, it is necessary to appropriately update the envelope stored in the storage device 102 and appropriately update the threshold value for detection.
[0009]
In addition, in order to create an appropriate threshold, the threshold is calculated by a method such as calculating an average value by referring to data for a relatively long time in consideration of the fact that the received signal is constantly fluctuating. It is desirable to do. However, if a train passes or a worker enters while collecting data for creating a threshold, received data that fluctuates greatly due to the influence of the train, the accuracy of the threshold increases. There are problems such as a decrease in the number of false detections and a decrease in the probability of detecting obstacles.
[0010]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. By creating and storing a threshold value by selecting an unmanned time zone, it is possible to reduce an erroneous detection and reliably detect an obstacle. It is an object to provide an object detection device.
[0011]
[Means for Solving the Problems]
The obstacle detection device according to the present invention is connected to one end of a transmission-side leakage transmission line of a pair of leakage transmission lines laid so as to face each other in free space, and is connected to the reception-side leakage transmission line from the transmission-side leakage transmission line. Transmission spread spectrum signal generation means for emitting a transmission spread spectrum signal toward, measurement distance setting means for generating a control signal for setting a delay time corresponding to a distance to a measurement distance for detecting an obstacle, and the measurement Delay means for generating a delay time based on a control signal from the distance setting means, reference spread spectrum signal generation means for generating a reference spread spectrum signal having a phase timing corresponding to the delay time from the delay means, Correlation means for taking a correlation between a spread spectrum signal and a received spread spectrum signal received on the receiving side leaky transmission path, based on an output from the correlation means Detecting means for detecting an obstacle, wherein the detecting means selects a time zone in which the detection target range becomes unmanned based on unmanned time zone information in which the detection target range becomes unmanned, and an output level from the correlation means. Threshold creating / storing means for creating / storing a threshold based on the threshold value; and comparing a threshold level stored in the threshold creating / storing means with an output level from the correlating means. And comparing means for detecting obstacles.
[0012]
The detecting means further includes an unmanned time zone database storing means for preliminarily storing unmanned time zone information in which the detection target range becomes unmanned, and the threshold value creation / storage means includes an unmanned time zone database storing means. The threshold value is created / stored based on the unmanned time zone information stored in.
[0013]
Further, the detection means further includes unmanned time zone information input means for externally inputting unmanned time zone information in which the detection target range becomes unmanned, and the threshold value creation / storage means includes the unmanned time zone information input. A threshold value is created / stored based on unmanned time zone information externally input to the means.
[0014]
Further, the detection means detects an obstacle in parallel with the creation of the threshold by the threshold creation / storage means, and when an obstacle is detected, the threshold creation / storage means stores the threshold value in the threshold creation / storage means. It is characterized by further comprising an obstacle detecting means for generating a threshold for outputting an instruction to redo the generation.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1 FIG.
FIG. 1 is a configuration diagram illustrating an obstacle detection device according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 1 denotes a transmission spread spectrum signal generating means which is connected to one end of a transmission LCX 2 to be described later and generates a transmission spread spectrum signal radiated from the transmission LCX 2 to a reception LCX 3 to be described later. A transmission LCX (transmitting leaky transmission line) 3 is laid in free space so as to face the transmitting LCX3, and a receiving LCX (reception leaking transmission) that receives a transmission spread spectrum signal that has arrived by propagating in space. Road).
[0016]
4 is a measuring distance setting means for generating a control signal for setting a delay time corresponding to a distance to a measuring distance for detecting an obstacle, and 5 is a delay time based on a control signal from the measuring distance setting means 4. , A reference spread-spectrum signal generating means for generating a reference spread-spectrum signal having a phase timing corresponding to the delay time from the delay means 5, and 7 is a reference spread-spectrum signal and an input from the reception LCX. Correlation means 8 for taking a correlation is a detection means for detecting an obstacle from a change in the output level of the correlation means 7.
[0017]
The detecting means 8 generates and stores a threshold value from the output level of the correlating means 7 based on the unmanned time zone information in which the detection target range becomes unmanned, and the threshold generating / storing means 81, Comparing means 82 for comparing the threshold value stored in the means 81 with the output level of the correlating means 7 to detect the position of the obstacle; storing an unmanned time zone database for storing a database relating to a time zone in which the detection target range is unmanned; Means 83 are provided.
[0018]
Next, the operation will be described. The transmission spread spectrum signal generating means 1 generates a transmission spread spectrum signal having a fixed repetition period in order to detect an obstacle. The transmit spread spectrum signal is radiated by the transmit LCX2 towards the receive LCX3. The radiated transmission spread spectrum signal propagates in space and is received by the reception LCX3. On the other hand, the measurement distance setting means 4 controls the delay means 5 to generate a delay time corresponding to a distance to a place where an obstacle is detected (referred to as a measurement point). The reference spread spectrum signal generating means 6 generates a reference spread spectrum signal having a phase timing corresponding to the delay time generated by the delay means 5, and inputs the generated signal to the correlation means 7.
[0019]
The correlation unit 7 correlates the reference spread spectrum signal with the received spread spectrum signal input from the reception LCX 3 and outputs the received signal level at the measurement point to the detection unit 8. In the detection means 8, the threshold value creation / storage means 81 selects a time zone in which the monitoring range (detection target range) becomes unmanned based on information from the unmanned time zone data database storage means 83, and The output level is collected as threshold calculation data, and the threshold is calculated and stored by a method such as obtaining an average value. In the unmanned time zone database storage means 83, information on the time zone in which the monitoring range is unmanned is obtained from the outside in advance and stored. The comparing means 82 detects the obstacle by comparing the threshold value stored in the threshold value creation / storage means 81 with the output level of the correlation means 7. At this time, the distance set by the measurement distance setting means 4 is the distance to the obstacle.
[0020]
Therefore, according to the first embodiment, information on the time zone during which the monitoring range is unmanned is obtained from the outside in advance and stored in the unmanned time zone database storage means 83, and the information in the unmanned time zone database storage means 83 is stored. The threshold is created and stored based on the timing, and the timing is determined and executed. Therefore, the threshold is not affected by the train or the operator during the creation of the threshold, and a highly accurate threshold can be obtained. Obstacles can be detected in a small and reliable manner.
[0021]
Embodiment 2 FIG.
FIG. 2 is a configuration diagram illustrating an obstacle detection device according to Embodiment 2 of the present invention. 2, the same components as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. As a new code, reference numeral 84 denotes an unmanned time zone information input unit according to the second embodiment provided in place of the unmanned time zone database storage unit 83 according to the first embodiment. Unmanned time zone information is input from the outside so as to be able to respond to changes in the unmanned time zone due to an emergency or the like.
[0022]
In the first embodiment described above, information relating to a time zone during which the monitoring range is unmanned is obtained from the outside in advance and stored in the unmanned time zone database storage means 83, and the threshold creation / storage means 81 stores the unmanned time. Based on the information from the band data database storage unit 83, a time period during which the monitoring range is unmanned is selected, the output level of the correlation unit 7 is collected as threshold value calculation data, and an average value is calculated. Although the threshold is calculated and stored, an unmanned time zone information input unit 84 shown in FIG. 2 may be used instead of the unmanned time zone database storage unit 83.
[0023]
When the unmanned time zone information input means 84 is used, the threshold value creation / storage means 81 obtains the latest information on the time zone in which the monitoring range is unmanned from the outside in real time by the unmanned time zone information input means 84. , When to create / store the threshold. By doing so, there is no danger that the data regarding the unmanned time zone becomes old and unusable, and it is possible to cope with a case where the unmanned time zone changes due to an emergency or the like. Can be created / stored.
[0024]
Embodiment 3 FIG.
FIG. 3 is a configuration diagram illustrating an obstacle detection device according to Embodiment 3 of the present invention. 3, the same parts as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted. As a new code, reference numeral 85 denotes an obstacle detecting means at the time of creating a threshold, and the obstacle detecting means 85 at the time of creating a threshold detects an obstacle in parallel at the time of creating a threshold. I have.
[0025]
In the first embodiment described above, information relating to the time zone during which the monitoring range is unmanned is obtained from the outside in advance and stored in the unmanned time zone database storage means 83, and the threshold generation / storage means 81 stores the unmanned time. Based on the information from the band data database storage unit 83, a time period in which the monitoring range is unmanned is selected, the output level of the correlation unit 7 is collected as threshold value calculation data, and the threshold is determined by a method such as obtaining an average value. Although the value is calculated and stored, an obstacle detecting means 85 at the time of creating a threshold may be further provided.
[0026]
In the case where the threshold value creation obstacle detection means 85 is provided, the threshold creation time obstacle detection means 85 is used in conjunction with the threshold creation / storage means 81 creating the threshold. The creation-time obstacle detection means 85 detects an obstacle and checks whether an obstacle such as a train or a worker exists during the creation of the threshold. If an obstacle is detected during the creation of the threshold value, an instruction to re-create the threshold value is returned to the threshold value creation / storage means 81. In this case, the data regarding the unmanned time zone stored in the threshold value creation / storage means 81 becomes old and is shifted from the actual unmanned time zone, or the unmanned time zone is changed due to an emergency or the like. In the event that the threshold value is not satisfied, a highly accurate threshold value can always be created / stored without being affected by trains or workers.
[0027]
【The invention's effect】
As described above, according to the present invention, the timing to create / store the threshold value is determined based on the unmanned time zone information in which the detection target range is unmanned. There is an effect that a threshold value with high accuracy can be obtained without being affected, and an erroneous detection is reduced and an obstacle can be detected reliably.
[0028]
In addition, an unmanned time zone database storage unit is provided, and thresholds are created / stored based on unmanned time zone information stored in the unattended time zone database storage unit. Thus, there is an effect that a high-precision threshold value can be obtained without being affected by the above, and an obstacle detection device that can reliably detect an obstacle with few erroneous detections can be obtained.
[0029]
In addition, an unmanned time zone information input means is provided, and a threshold is created / stored based on unmanned time zone information input from outside to the unmanned time zone information input means, so that the detection target range becomes unmanned. Since the latest information on the time zone can always be obtained from the outside, and the threshold can be created / stored, the threshold is not affected by trains and workers during the creation of the threshold, and a more accurate threshold can be obtained. Thus, there is an effect that an obstacle detection device which can obtain a value and can detect an obstacle reliably with less erroneous detection can be obtained.
[0030]
Furthermore, a threshold creation obstacle detection means for detecting obstacles in parallel with the creation of the thresholds is provided, and when an obstacle is detected during the creation of the thresholds, an instruction is given to restart the creation of the thresholds. The threshold value is output to the threshold creation / storage means. Therefore, even if an unscheduled train passes or works on the track due to an unforeseen or emergency situation, the accuracy is not affected. There is an effect that a high threshold value can be obtained, and an obstacle detection device that can detect an obstacle reliably with less erroneous detection can be obtained.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of an obstacle detection device according to Embodiment 1 of the present invention.
FIG. 2 is a block diagram showing a configuration of an obstacle detection device according to Embodiment 2 of the present invention.
FIG. 3 is a block diagram showing a configuration of an obstacle detection device according to Embodiment 3 of the present invention.
FIG. 4 is a block diagram showing a configuration of an obstacle detection device according to a conventional example.
[Explanation of symbols]
1 transmission spread spectrum signal generation means, 2 transmission LCX, 3 reception LCX, 4 measurement distance setting means, 5 delay means, 6 reference spread spectrum signal generation means, 7 correlation means, 8 detection means, 81 threshold value creation / storage means , 82 comparison means, 83 unmanned time zone database storage means, 84 unmanned time zone information input means, 85 threshold value creation obstacle detection means.

Claims (4)

A transmission that is connected to one end of a transmission-side leakage transmission line of a pair of leakage transmission lines laid so as to face each other in free space and radiates a transmission spread spectrum signal from the transmission-side leakage transmission line toward the reception-side leakage transmission line. Spread spectrum signal generating means;
Measuring distance setting means for generating a control signal for setting a delay time corresponding to a distance to a measuring distance for detecting an obstacle,
Delay means for generating a delay time based on a control signal from the measurement distance setting means,
Reference spread spectrum signal generation means for generating a reference spread spectrum signal having a phase timing according to the delay time from the delay means,
Correlation means for taking a correlation between the reference spread spectrum signal and the received spread spectrum signal received on the receiving leaky transmission path,
Detecting means for detecting an obstacle based on the output from the correlation means,
The detection means selects a time zone in which the detection target range becomes unmanned based on unmanned time zone information in which the detection target range becomes unmanned, and creates / stores a threshold based on an output level from the correlation means. Threshold generation / storage means; and comparison means for detecting an obstacle based on a comparison between the threshold level stored in the threshold generation / storage means and an output level from the correlation means. Obstacle detection device characterized by the above-mentioned. The obstacle detection device according to claim 1,
The detection unit further includes an unmanned time zone database storage unit that stores in advance unmanned time zone information in which the detection target range becomes unmanned,
The obstacle detection device according to claim 1, wherein the threshold value creation / storage means creates / stores a threshold value based on unmanned time zone information stored in the unmanned time zone database storage means. The obstacle detection device according to claim 1,
The detection means further includes unmanned time zone information input means for externally inputting unmanned time zone information in which the detection target range becomes unmanned,
The obstacle detection device according to claim 1, wherein the threshold value creation / storage means creates / stores a threshold value based on unmanned time zone information externally input to the unmanned time zone information input means. The obstacle detection device according to any one of claims 1 to 3,
The detection means detects an obstacle in parallel with the creation of a threshold by the threshold creation / storage means, and when an obstacle is detected, the threshold creation / storage means causes the threshold creation / storage means to create a threshold. An obstacle detection apparatus further comprising a threshold generation obstacle detection means for outputting a redo instruction.

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